register interest

Professor Adrianus Dondorp

Research Area: Global Health
Scientific Themes: Tropical Medicine & Global Health
Keywords: Severe malaria, Antimalarial drug resistance, Critical care in resource-poor settings and Malaria elimination
Web Links:
Difference in parasite clearance rates after oral artesunate in patients with uncomplicated falciparum malaria in Northwestern Thailand (Wang Pha) compared to Western Cambodia (Pailin)
(N Engl J Med. 2009 Jul 30;361(5):455-67)

Difference in parasite clearance rates after oral artesunate in patients with uncomplicated ...

Survival curves of (mainly adult) patients with severe malaria treated with intravenous quinine versus artesunate (SEAQUAMAT trial; n=1461; Lancet 2005 Aug;366(9487):717-25).

Survival curves of (mainly adult) patients with severe malaria treated with intravenous quinine ...

Relation between the calculated total body Plasmodium falciparum biomass and severity of disease. Parasite biomass was derived from the plasma PfHRP2 concentration, a protein released in discrete amounts at the moment of schizont rupture (PLoS Med 2005 Aug;2(8):e204)

Relation between the calculated total body Plasmodium falciparum biomass and severity of disease. ...

Since November 2000, I work at the Mahidol-Oxford Tropical Medicine Research Unit in Bangkok, Thailand, where I am currently the Deputy Director and Head of Malaria Research.

Our research unit studies a diversity of aspects of infectious (and other) diseases that are causing significant morbidity and mortality in the tropics. For this purpose we have a large network of clinical sites in both Africa and Asia, including Thailand, Bangladesh, India, Cambodia, Mozambique and elsewhere.

My main research interests include the pathophysiology and treatment of severe malaria, antimalarial drug resistance and improvement of intensive care practice in developing countries. We showed in a large multinational trial in SE Asia in 1461 mainly adult patients that parenteral artesunate is superior to quinine in preventing death; an even larger trial comparing the same drugs in African children with severe malaria is under way. Studies on the microcirculation in patients with severe malaria have revealed the likely contribution of red cell rigidity to the impairment of microcirculatory flow. We were the first to apply a new method to visualise obstruction of the microcirculation in vivo in patients with severe malaria. We also developed a method to calculate the sequestered parasite biomass from plasma PfHRP2, a protein released by the parasite and showed that yet to be identified organic acids other than lactate are an important contributor to the metabolic acidosis in severe malaria and have strong prognostic significance. Our team was the first to perform a comparative trial which unambiguously showed resistance of P. falciparum to artemisinins in Western Cambodia and in collaboration with other international groups are now working on further characterization of this resistance phenotype and identify molecular determinants of artemisinin resistance. We are also involved in finding new treatments for these patients and in the containment efforts against this serious threat to global malaria control.

In addition to this focus on malaria, we are coordinating a dedicated effort to improve intensive care medicine in developing countries in Asia, through teaching as well as the systematic implementation of cost-effective interventions and their assessment. My vision is that true collaborations with enthousiastic and like minded doctors and researchers from all countries where we are active help to identify important research questions, improves the quality of research, and builds capacity as an inherent side effect. Our unit has unique expertise and possibilities to conduct research from bench to bedside, and is in the centre of an extensive network enabling to conduct large multinational trials when definite answers are sought for important research questions aimed at improving treatment and reducing morbidity and mortality of malaria and other diseases.

Name Department Institution Country
Dr Mallika Imwong Tropical Medicine Oxford University, Bangkok Thailand
Dr Kesinee Chotivanich Tropical Medicine Oxford University, Bangkok Thailand
Professor Leann Tilley University of Melbourne Australia
Dr Zbynek Bozdech Biological Sciences Nanyang Technological University Singapore
Professor Dominic Kwiatkowski Wellcome Trust Centre for Human Genetics Oxford University, Henry Wellcome Building of Genomic Medicine United Kingdom
Professor Sanjib Mohanty Ispat General Hospital India
Professor M Abul Faiz FRCP Medicine Sir Salimullah Medical College Bangladesh
Professor Frank Smithuis Tropical Medicine Oxford University, Yangon Myanmar
Pascal Ringwald Malaria World Health Organization, Geneva Switzerland
Dr Lorenz Von Seidlein Tropical Medicine Oxford University, Bangkok Thailand
Professor Kasturi Haldar Notre Dame University United States
Dr Direk Limmathurotsakul Tropical Medicine Oxford University, Bangkok Thailand
Professor Chris V Plowe University of Maryland United States
WWARN K13 Genotype-Phenotype Study Group. 2019. Association of mutations in the Plasmodium falciparum Kelch13 gene (Pf3D7_1343700) with parasite clearance rates after artemisinin-based treatments-a WWARN individual patient data meta-analysis. BMC Med, 17 (1), pp. 1. | Show Abstract | Read more

BACKGROUND: Plasmodium falciparum infections with slow parasite clearance following artemisinin-based therapies are widespread in the Greater Mekong Subregion. A molecular marker of the slow clearance phenotype has been identified: single genetic changes within the propeller region of the Kelch13 protein (pfk13; Pf3D7_1343700). Global searches have identified almost 200 different non-synonymous mutant pfk13 genotypes. Most mutations occur at low prevalence and have uncertain functional significance. To characterize the impact of different pfk13 mutations on parasite clearance, we conducted an individual patient data meta-analysis of the associations between parasite clearance half-life (PC1/2) and pfk13 genotype based on a large set of individual patient records from Asia and Africa. METHODS: A systematic literature review following the PRISMA protocol was conducted to identify studies published between 2000 and 2017 which included frequent parasite counts and pfk13 genotyping. Four databases (Ovid Medline, PubMed, Ovid Embase, and Web of Science Core Collection) were searched. Eighteen studies (15 from Asia, 2 from Africa, and one multicenter study with sites on both continents) met inclusion criteria and were shared. Associations between the log transformed PC1/2 values and pfk13 genotype were assessed using multivariable regression models with random effects for study site. RESULTS: Both the pfk13 genotypes and the PC1/2 were available from 3250 (95%) patients (n = 3012 from Asia (93%), n = 238 from Africa (7%)). Among Asian isolates, all pfk13 propeller region mutant alleles observed in five or more specific isolates were associated with a 1.5- to 2.7-fold longer geometric mean PC1/2 compared to the PC1/2 of wild type isolates (all p ≤ 0.002). In addition, mutant allele E252Q located in the P. falciparum region of pfk13 was associated with 1.5-fold (95%CI 1.4-1.6) longer PC1/2. None of the isolates from four countries in Africa showed a significant difference between the PC1/2 of parasites with or without pfk13 propeller region mutations. Previously, the association of six pfk13 propeller mutant alleles with delayed parasite clearance had been confirmed. This analysis demonstrates that 15 additional pfk13 alleles are associated strongly with the slow-clearing phenotype in Southeast Asia. CONCLUSION: Pooled analysis associated 20 pfk13 propeller region mutant alleles with the slow clearance phenotype, including 15 mutations not confirmed previously.

Singhaboot Y, Keayarsa S, Piaraksa N, Phumratanaprapin W, Kunawut P, Dondorp A, Chotivanich K. 2019. Temperature Dependence of Plasmodium falciparum Erythrocytic Stage Development. Am J Trop Med Hyg, 100 (5), pp. 1191-1195. | Show Abstract | Read more

Plasmodium falciparum infection causes febrile illness and severe disease with multiple organ failure and death when treatment is delayed. Antipyretic treatment is standard, and inducing hypothermia has been proposed to protect the brain in cerebral malaria. Here, we investigated the temperature dependence of asexual-stage parasite development and parasite multiplication in vitro. Plasmodium falciparum laboratory strain TM267 was incubated for 2 hours (short exposure) or 48 hours (continuous exposure) at different temperatures (32°C, 34°C, 35°C, 38°C, 39°C, and 40°C). The starting parasite developmental stage (ring, trophozoite, or schizont) varied between experiments. The parasite multiplication rate (PMR) was reduced under both hyper- and hypothermic conditions; after continuous exposure, the mean PMR ± SD was 9.1 ± 1.2 at 37°C compared with 2.4 ± 1.8 at 32°C, 2.3 ± 0.4 at 34°C, and 0.4 ± 0.1 at 40°C (P < 0.01). Changes in PMR were not significant after 2-hour exposure at temperatures ranging from 32°C to 40°C. Morphological changes in parasite cytoplasm and nucleus could be observed after long exposure to low or high temperature. After 48-hour incubation, rosette formation (≥ 2 uninfected red blood cells bound to infected red blood cells) was decreased at 34°C or 39°C compared with that at 37°C. In conclusion, both hyper- and hypothermia reduce PMR and delay erythrocytic stage development of P. falciparum, subsequently reducing rosette formation.

Parker DM, Tun STT, White LJ, Kajeechiwa L, Thwin MM, Landier J, Chaumeau V, Corbel V, Dondorp AM, von Seidlein L et al. 2019. Potential herd protection against Plasmodium falciparum infections conferred by mass antimalarial drug administrations. Elife, 8 | Show Abstract | Read more

The global malaria burden has decreased over the last decade and many nations are attempting elimination. Asymptomatic malaria infections are not normally diagnosed or treated, posing a major hurdle for elimination efforts. One solution to this problem is mass drug administration (MDA), with success depending on adequate population participation. Here, we present a detailed spatial and temporal analysis of malaria episodes and asymptomatic infections in four villages undergoing MDA in Myanmar. In this study, individuals from neighborhoods with low MDA adherence had 2.85 times the odds of having a malaria episode post-MDA in comparison to those from high adherence neighborhoods, regardless of individual participation, suggesting a herd effect. High mosquito biting rates, living in a house with someone else with malaria, or having an asymptomatic malaria infection were also predictors of clinical episodes. Spatial clustering of non-adherence to MDA, even in villages with high overall participation, may frustrate elimination efforts.

Beane A, Wagstaff D, Abayadeera A, Wijeyaratne M, Ranasinghe G, Mirando S, Dondorp AM, Walker D, Haniffa R. 2019. A learning health systems approach to improving the quality of care for patients in South Asia. Glob Health Action, 12 (1), pp. 1587893. | Show Abstract | Read more

Poor quality of care is a leading cause of excess morbidity and mortality in low- and middle- income countries (LMICs). Improving the quality of healthcare is complex, and requires an interdisciplinary team equipped with the skills to design, implement and analyse setting-relevant improvement interventions. Such capacity is limited in many LMICs. However, training for healthcare workers in quality improvement (QI) methodology without buy-in from multidisciplinary stakeholders and without identifying setting-specific priorities is unlikely to be successful. The Care Quality Improvement Network (CQIN) was established between Network for Improving Critical care Systems and Training (NICST) and University College London Centre for Perioperative Medicine, with the aim of building capacity for research and QI. A two-day international workshop, in collaboration with the College of Surgeons of Sri Lanka, was conducted to address the above deficits. Innovatively, the CQIN adopts a learning health systems (LHS) approach to improving care by leveraging information captured through the NICST electronic multi-centre acute and critical care surveillance platform. Fifty-two delegates from across the CQIN representing clinical, civic and academic healthcare stakeholders from six countries attended the workshop. Mapping of care processes enabled identification of barriers and drivers to the delivery of care and facilitated the selection of feasible QI methods and matrices. Six projects, reflecting key priorities for improving the delivery of acute care in Asia, were collaboratively developed: improving assessment of postoperative pain; optimising sedation in critical care; refining referral of deteriorating patients; reducing surgical site infection after caesarean section; reducing surgical site infection after elective general surgery; and improving provision of timely electrocardiogram recording for patients presenting with signs of acute myocardial infarction. Future project implementation and evaluation will be supported with resources and expertise from the CQIN partners. This LHS approach to building capacity for QI may be of interest to others seeing to improve care in LMICs.

Duanguppama J, Mathema VB, Tripura R, Day NPJ, Maxay M, Nguon C, von Seidlein L, Dhorda M, Peto TJ, Nosten F et al. 2019. Polymorphisms in Pvkelch12 and gene amplification of Pvplasmepsin4 in Plasmodium vivax from Thailand, Lao PDR and Cambodia. Malar J, 18 (1), pp. 114. | Show Abstract | Read more

BACKGROUND: Mutations in Pfkelch13 and Pfplasmepsin2/3 gene amplification are well-established markers for artemisinin and piperaquine resistance in Plasmodium falciparum, a widespread problem in the Greater Mekong Subregion (GMS). The Plasmodium vivax parasite population has experienced varying drug pressure dependent on local drug policies. We investigated the correlation between drug pressure from artemisinins and piperaquine and mutations in the P. vivax orthologous genes Pvkelch12 and Pvplasmepsin4 (Pvpm4), as candidate resistance markers. METHODS: Blood samples from 734 P. vivax patients were obtained from Thailand (n = 399), Lao PDR (n = 296) and Cambodia (n = 39) between 2007 and 2017. Pvkelch12 and Pvpm4 was amplified and sequenced to assess gene mutations. To assess PvPM4 gene amplification, a Taqman® Real-Time PCR method was developed and validated. Selection of non-synonymous mutations was assessed by its ratio with synonymous mutations (Ka/Ks ratios). Mutation rates were compared to the estimated local drug pressure. RESULTS: Polymorphisms in Pvkelch12 were rare. Pvkelch12 mutations V552I, K151Q and M124I were observed in 1.0% (7/734) of P. vivax samples. V552I was the most common mutation with a frequency of 0.7% (5/734), most of which (4/5) observed in Ubon Ratchathani, Thailand. Polymorphisms in Pvpm4 were more common, with a frequency of 40.3% (123/305) in 305 samples from Thailand, Lao PDR and Cambodia, but this was not related to the estimated piperaquine drug pressure in these areas (Pearson's χ2 test, p = 0.50). Pvpm4 mutation V165I was most frequent in Tak, Thailand (40.2%, 43/107) followed by Pailin, Cambodia (43.5%, 37/85), Champasak, Lao PDR (40.4%, 23/57) and Ubon Ratchathani, Thailand (35.7%, 20/56). Pvpm4 amplification was not observed in 141 samples from Thailand and Cambodia. For both Pvkelch12 and Pvpm4, in all areas and at all time points, the Ka/Ks values were < 1, suggesting no purifying selection. CONCLUSIONS: A novel real-time PCR-based method to assess P. vivax Pvpm4 gene amplification was developed. Drug pressure with artemisinins and piperaquine in the GMS was not clearly related to signatures of selection for mutations in the P. vivax orthologous resistance genes Pvkelch12 and Pvpm4 in areas under investigation. Current resistance of P. vivax to these drugs is unlikely and additional observations including analysis of associated clinical data from these regions could further clarify current findings.

Kingston HW, Ghose A, Rungpradubvong V, Herdman MT, Plewes K, Ishioka H, Leopold SJ, Maude RJ, Intharabut B, Mohanty S et al. 2019. Does reduced oxygen delivery cause lactic acidosis in falciparum malaria? An observational study. Malar J, 18 (1), pp. 97. | Show Abstract | Read more

BACKGROUND: Lactic acidosis with an elevated lactate-pyruvate ratio suggesting anoxia is a common feature of severe falciparum malaria. High lactate levels are associated with parasitized erythrocyte sequestration in the microcirculation. To assess if there is an additional contribution to hyperlactataemia from relatively inadequate total oxygen delivery, oxygen consumption and delivery were investigated in patients with malaria. METHODS: Adult Bangladeshi and Indian patients with uncomplicated (N = 50) or severe (N = 46) falciparum malaria or suspected bacterial sepsis (N = 27) and healthy participants as controls (N = 26) were recruited at Chittagong Medical College Hospital, Chittagong, Bangladesh and Ispat General Hospital, Rourkela, India. Oxygen delivery (DO2I) was estimated from pulse oximetry, echocardiographic estimates of cardiac index and haematocrit. Oxygen consumption (VO2I) was estimated by expired gas collection. RESULTS: VO2I was elevated in uncomplicated median (IQR) 185.1 ml/min/m2 (135-215.9) and severe malaria 192 ml/min/m2 (140.7-227.9) relative to healthy persons 107.9 ml/min/m2 (69.9-138.1) (both p < 0.001). Median DO2I was similar in uncomplicated 515 ml/min/m2 (432-612) and severe 487 ml/min/m2 (382-601) malaria and healthy persons 503 ml/min/m2 (447-517) (p = 0.27 and 0.89, respectively). The VO2/DO2 ratio was, therefore, increased by similar amounts in both uncomplicated 0.35 (0.28-0.44) and severe malaria 0.38 (0.29-0.48) relative to healthy participants 0.23 (0.17-0.28) (both p < 0.001). VO2I, DO2I and VO2/DO2 did not correlate with plasma lactate concentrations in severe malaria. CONCLUSIONS: Reduced total oxygen delivery is not a major contributor to lactic acidosis in severe falciparum malaria.

Pell CL, Adhikari B, Myo Thwin M, Kajeechiwa L, Nosten S, Nosten FH, Sahan KM, Smithuis FM, Nguyen T-N, Hien TT et al. 2019. Community engagement, social context and coverage of mass anti-malarial administration: Comparative findings from multi-site research in the Greater Mekong sub-Region. PLoS One, 14 (3), pp. e0214280. | Show Abstract | Read more

BACKGROUND: Between 2013 and 2017, targeted malaria elimination (TME), a package of interventions that includes mass drug administration (MDA)-was piloted in communities with reservoirs of asymptomatic P. falciparum across the Greater Mekong sub-Region (GMS). Coverage in target communities is a key determinant of the effectiveness of MDA. Drawing on mixed methods research conducted alongside TME pilot studies, this article examines the impact of the community engagement, local social context and study design on MDA coverage. METHODS AND FINDINGS: Qualitative and quantitative data were collected using questionnaire-based surveys, semi-structured and in-depth interviews, focus group discussions, informal conversations, and observations of study activities. Over 1500 respondents were interviewed in Myanmar, Vietnam, Cambodia and Laos. Interview topics included attitudes to malaria and experiences of MDA. Overall coverage of mass anti-malarial administration was high, particularly participation in at least a single round (85%). Familiarity with and concern about malaria prompted participation in MDA; as did awareness of MDA and familiarity with the aim of eliminating malaria. Fear of adverse events and blood draws discouraged people. Hence, community engagement activities sought to address these concerns but their impact was mediated by the trust relationships that study staff could engender in communities. In contexts of weak healthcare infrastructure and (cash) poverty, communities valued the study's ancillary care and the financial compensation. However, coverage did not necessarily decrease in the absence of cash compensation. Community dynamics, affected by politics, village conformity, and household decision-making also affected coverage. CONCLUSIONS: The experimental nature of TME presented particular challenges to achieving high coverage. Nonetheless, the findings reflect those from studies of MDA under implementation conditions and offer useful guidance for potential regional roll-out of MDA: it is key to understand target communities and provide appropriate information in tailored ways, using community engagement that engenders trust.

Plewes K, Leopold SJ, Kingston HWF, Dondorp AM. 2019. Malaria: What's New in the Management of Malaria? Infect Dis Clin North Am, 33 (1), pp. 39-60. | Show Abstract | Read more

The global burden of malaria remains high, with 216 million cases causing 445,000 deaths in 2016 despite first-line treatment with artemisinin-based combination therapy. Decreasing transmission in Africa shifts the risk for severe malaria to older age groups as premunition wanes. Prompt diagnosis and treatment with intravenous artesunate in addition to appropriate supportive management are critical to reduce deaths from severe malaria. Effective individual management is challenging in settings with limited resources for higher-level care. Adjunctive therapies targeting the underlying pathophysiological pathways have the potential to reduce mortality. Resistance to artemisinin derivatives and their partner drugs threaten malaria management and control.

von Seidlein L, Peto TJ, Landier J, Nguyen T-N, Tripura R, Phommasone K, Pongvongsa T, Lwin KM, Keereecharoen L, Kajeechiwa L et al. 2019. The impact of targeted malaria elimination with mass drug administrations on falciparum malaria in Southeast Asia: A cluster randomised trial. PLoS Med, 16 (2), pp. e1002745. | Show Abstract | Read more

BACKGROUND: The emergence and spread of multidrug-resistant Plasmodium falciparum in the Greater Mekong Subregion (GMS) threatens global malaria elimination efforts. Mass drug administration (MDA), the presumptive antimalarial treatment of an entire population to clear the subclinical parasite reservoir, is a strategy to accelerate malaria elimination. We report a cluster randomised trial to assess the effectiveness of dihydroartemisinin-piperaquine (DP) MDA in reducing falciparum malaria incidence and prevalence in 16 remote village populations in Myanmar, Vietnam, Cambodia, and the Lao People's Democratic Republic, where artemisinin resistance is prevalent. METHODS AND FINDINGS: After establishing vector control and community-based case management and following intensive community engagement, we used restricted randomisation within village pairs to select 8 villages to receive early DP MDA and 8 villages as controls for 12 months, after which the control villages received deferred DP MDA. The MDA comprised 3 monthly rounds of 3 daily doses of DP and, except in Cambodia, a single low dose of primaquine. We conducted exhaustive cross-sectional surveys of the entire population of each village at quarterly intervals using ultrasensitive quantitative PCR to detect Plasmodium infections. The study was conducted between May 2013 and July 2017. The investigators randomised 16 villages that had a total of 8,445 residents at the start of the study. Of these 8,445 residents, 4,135 (49%) residents living in 8 villages, plus an additional 288 newcomers to the villages, were randomised to receive early MDA; 3,790 out of the 4,423 (86%) participated in at least 1 MDA round, and 2,520 out of the 4,423 (57%) participated in all 3 rounds. The primary outcome, P. falciparum prevalence by month 3 (M3), fell by 92% (from 5.1% [171/3,340] to 0.4% [12/2,828]) in early MDA villages and by 29% (from 7.2% [246/3,405] to 5.1% [155/3,057]) in control villages. Over the following 9 months, the P. falciparum prevalence increased to 3.3% (96/2,881) in early MDA villages and to 6.1% (128/2,101) in control villages (adjusted incidence rate ratio 0.41 [95% CI 0.20 to 0.84]; p = 0.015). Individual protection was proportional to the number of completed MDA rounds. Of 221 participants with subclinical P. falciparum infections who participated in MDA and could be followed up, 207 (94%) cleared their infections, including 9 of 10 with artemisinin- and piperaquine-resistant infections. The DP MDAs were well tolerated; 6 severe adverse events were detected during the follow-up period, but none was attributable to the intervention. CONCLUSIONS: Added to community-based basic malaria control measures, 3 monthly rounds of DP MDA reduced the incidence and prevalence of falciparum malaria over a 1-year period in areas affected by artemisinin resistance. P. falciparum infections returned during the follow-up period as the remaining infections spread and malaria was reintroduced from surrounding areas. Limitations of this study include a relatively small sample of villages, heterogeneity between villages, and mobility of villagers that may have limited the impact of the intervention. These results suggest that, if used as part of a comprehensive, well-organised, and well-resourced elimination programme, DP MDA can be a useful additional tool to accelerate malaria elimination. TRIAL REGISTRATION: NCT01872702.

Watson JA, Leopold SJ, Simpson JA, Day NP, Dondorp AM, White NJ. 2019. Collider bias and the apparent protective effect of glucose-6-phosphate dehydrogenase deficiency on cerebral malaria. Elife, 8 | Show Abstract | Read more

Case fatality rates in severe falciparum malaria depend on the pattern and degree of vital organ dysfunction. Recent large-scale case-control analyses of pooled severe malaria data reported that glucose-6-phosphate dehydrogenase deficiency (G6PDd) was protective against cerebral malaria but increased the risk of severe malarial anaemia. A novel formulation of the balancing selection hypothesis was proposed as an explanation for these findings, whereby the selective advantage is driven by the competing risks of death from cerebral malaria and death from severe malarial anaemia. We re-analysed these claims using causal diagrams and showed that they are subject to collider bias. A simulation based sensitivity analysis, varying the strength of the known effect of G6PDd on anaemia, showed that this bias is sufficient to explain all of the observed association. Future genetic epidemiology studies in severe malaria would benefit from the use of causal reasoning.

Intharabut B, Kingston HW, Srinamon K, Ashley EA, Imwong M, Dhorda M, Woodrow C, Stepniewska K, Silamut K, Day NPJ et al. 2019. Artemisinin Resistance and Stage Dependency of Parasite Clearance in Falciparum Malaria. J Infect Dis, 219 (9), pp. 1483-1489. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance in falciparum malaria is associated with kelch13 propeller mutations, reduced ring stage parasite killing, and, consequently, slow parasite clearance. We assessed how parasite age affects parasite clearance in artemisinin resistance. METHODS: Developmental stages of Plasmodium falciparum parasites on blood films performed at hospital admission and their kelch13 genotypes were assessed for 816 patients enrolled in a multinational clinical trial of artemisinin combination therapy. RESULTS: Early changes in parasitemia level (ie, 0-6 hours after admission) were determined mainly by modal stage of asexual parasite development, whereas the subsequent log-linear decline was determined mainly by kelch13 propeller mutations. Older circulating parasites on admission were associated with more-rapid parasite clearance, particularly in kelch13 mutant infections. The geometric mean parasite clearance half-life decreased by 11.6% (95% CI 3.4%-19.1%) in kelch13 wild-type infections and by 30% (95% CI 17.8%-40.4%) in kelch13 mutant infections as the mean age of circulating parasites rose from 3 to 21 hours. CONCLUSION: Following the start of antimalarial treatment, ongoing parasite sequestration and schizogony both affect initial changes in parasitemia. The greater dependency of parasite clearance half-life on parasite age in artemisinin resistant infections is consistent with ring stage resistance and consequent parasite clearance by sequestration. The stage of parasite development should be incorporated in individual assessments of artemisinin resistance.

Beane A, De Silva AP, Athapattu PL, Jayasinghe S, Abayadeera AU, Wijerathne M, Udayanga I, Rathnayake S, Dondorp AM, Haniffa R. 2019. Addressing the information deficit in global health: lessons from a digital acute care platform in Sri Lanka. BMJ Glob Health, 4 (1), pp. e001134. | Show Abstract | Read more

Lack of investment in low-income and middle-income countries (LMICs) in systems capturing continuous information regarding care of the acutely unwell patient is hindering global efforts to address inequalities, both at facility and national level. Furthermore, this of lack of data is disempowering frontline staff and those seeking to support them, from progressing setting-relevant research and quality improvement. In contrast to high-income country (HIC) settings, where electronic surveillance has boosted the capability of governments, clinicians and researchers to engage in service-wide healthcare evaluation, healthcare information in resource-limited settings remains almost exclusively paper based. In this practice paper, we describe the efforts of a collaboration of clinicians, administrators, researchers and healthcare informaticians working in South Asia, in addressing the inequality in access to patient information in acute care. Harnessing a clinician-led collaborative approach to design and evaluation, we have implemented a national acute care information platform in Sri Lanka that is tailored to priorities of frontline staff. Iterative adaptation has ensured the platform has the flexibility to integrate with legacy paper systems, support junior team members in advocating for acutely unwell patients and has made information captured accessible to diverse stakeholders to improve service delivery. The same platform is now empowering clinicians to participate in international research and drive forwards improvements in care. During this journey, we have also gained insights on how to overcome well-described barriers to implementation of digital information tools in LMIC. We anticipate that this north-south collaborative approach to addressing the challenges of health system implementation in acute care may provide learning and inspiration to other partnerships seeking to engage in similar work.

Leopold SJ, Ghose A, Allman EL, Kingston HWF, Hossain A, Dutta AK, Plewes K, Chotivanich K, Day NPJ, Tarning J et al. 2019. Identifying the Components of Acidosis in Patients With Severe Plasmodium falciparum Malaria Using Metabolomics. J Infect Dis, 219 (11), pp. 1766-1776. | Show Abstract | Read more

BACKGROUND: Acidosis in severe Plasmodium falciparum malaria is associated with high mortality, yet the pathogenesis remains incompletely understood. The aim of this study was to determine the nature and source of metabolic acids contributing to acidosis in patients with severe falciparum malaria. METHODS: A prospective observational study was conducted to characterize circulating acids in adults with P. falciparum malaria (n = 107) and healthy controls (n = 45) from Bangladesh using high-resolution liquid chromatography-mass spectrometry metabolomics. Additional in vitro P. falciparum culture studies were performed to determine if parasites release the acids detected in plasma from patients with severe malaria acidosis. RESULTS: We identified previously unmeasured plasma acids strongly associated with acidosis in severe malaria. Metabolomic analysis of P. falciparum parasites in vitro showed no evidence that these acids are released by the parasite during its life cycle. Instead, 10 of the plasma acids could be mapped to a gut microbial origin. Patients with malaria had low L-citrulline levels, a plasma marker indicating reduced gut barrier integrity. Longitudinal data showed the clearance of these newly identified acids was delayed in fatal cases. CONCLUSIONS: These data suggest that a compromise in intestinal barrier function may contribute significantly to the pathogenesis of life-threatening acidosis in severe falciparum malaria. CLINICAL TRIALS REGISTRATION: NCT02451904.

Zhu L, Tripathi J, Rocamora FM, Miotto O, van der Pluijm R, Voss TS, Mok S, Kwiatkowski DP, Nosten F, Day NPJ et al. 2018. The origins of malaria artemisinin resistance defined by a genetic and transcriptomic background. Nat Commun, 9 (1), pp. 5158. | Show Abstract | Read more

The predisposition of parasites acquiring artemisinin resistance still remains unclear beyond the mutations in Pfk13 gene and modulation of the unfolded protein response pathway. To explore the chain of casualty underlying artemisinin resistance, we reanalyze 773 P. falciparum isolates from TRACI-study integrating TWAS, GWAS, and eQTL analyses. We find the majority of P. falciparum parasites are transcriptomically converged within each geographic site with two broader physiological profiles across the Greater Mekong Subregion (GMS). We report 8720 SNP-expression linkages in the eastern GMS parasites and 4537 in the western. The minimal overlap between them suggests differential gene regulatory networks facilitating parasite adaptations to their unique host environments. Finally, we identify two genetic and physiological backgrounds associating with artemisinin resistance in the GMS, together with a farnesyltransferase protein and a thioredoxin-like protein which may act as vital intermediators linking the Pfk13 C580Y mutation to the prolonged parasite clearance time.

Chaumeau V, Kajeechiwa L, Fustec B, Landier J, Naw Nyo S, Nay Hsel S, Phatharakokordbun P, Kittiphanakun P, Nosten S, Thwin MM et al. 2019. Contribution of Asymptomatic Plasmodium Infections to the Transmission of Malaria in Kayin State, Myanmar. J Infect Dis, 219 (9), pp. 1499-1509. | Show Abstract | Read more

BACKGROUND: The objective of mass antimalarial drug administration (MDA) is to eliminate malaria rapidly by eliminating the asymptomatic malaria parasite reservoirs and interrupting transmission. In the Greater Mekong Subregion, where artemisinin-resistant Plasmodium falciparum is now widespread, MDA has been proposed as an elimination accelerator, but the contribution of asymptomatic infections to malaria transmission has been questioned. The impact of MDA on entomological indices has not been characterized previously. METHODS: MDA was conducted in 4 villages in Kayin State (Myanmar). Malaria mosquito vectors were captured 3 months before, during, and 3 months after MDA, and their Plasmodium infections were detected by polymerase chain reaction (PCR) analysis. The relationship between the entomological inoculation rate, the malaria prevalence in humans determined by ultrasensitive PCR, and MDA was characterized by generalized estimating equation regression. RESULTS: Asymptomatic P. falciparum and Plasmodium vivax infections were cleared by MDA. The P. vivax entomological inoculation rate was reduced by 12.5-fold (95% confidence interval [CI], 1.6-100-fold), but the reservoir of asymptomatic P. vivax infections was reconstituted within 3 months, presumably because of relapses. This was coincident with a 5.3-fold (95% CI, 4.8-6.0-fold) increase in the vector infection rate. CONCLUSION: Asymptomatic infections are a major source of malaria transmission in Southeast Asia.

Puaprasert K, Chu C, Saralamba N, Day NPJ, Nosten F, White NJ, Dondorp AM, Imwong M. 2018. Real time PCR detection of common CYP2D6 genetic variants and its application in a Karen population study. Malar J, 17 (1), pp. 427. | Show Abstract | Read more

BACKGROUND: Plasmodium vivax malaria is characterized by relapses arising from the hypnozoite stages in the liver. The only currently registered drug for radical treatment to prevent relapse is primaquine. Primaquine, a prodrug, requires metabolism through the liver cytochrome CYP2D6 isoenzyme to its active metabolite. Mutations in the CYP2D6 gene may thus affect primaquine efficacy. A SNPs genotyping technique was developed to characterize the CYP2D6 genetic variants and tested this in the patients with Plasmodium vivax infection collected in a Karen population on the Thailand-Myanmar border, where P. vivax malaria is endemic. METHODS: Direct sequencing of PCR-reamplified products (DSP) was used to uncover exonic CYP2D6 sequence variations. Subsequently, an allele-specific oligonucleotide probe real-time SNPs genotyping (ASO) assay was developed for rapid detection of the four clinically relevant CYP2D6 variants occurring in this population. These two in-house developed assays were used to genotype CYP2D6 mutations in blood samples obtained from 70 Karen adults. RESULTS: Results showed a high degree of concordance between the DSP and ASO methods. Six CYP2D6 point mutations were identified within the Karen population: C100T, C1039T, G1661C, G1846A, C2850T and G4180C, at frequencies of 0.43, 0.43, 0.76, 0.02, 0.32 and 0.76, respectively. The CYP2D6*2, *4, *5, *10 and *36 allelic frequencies were 0.33, 0.02, 0.03, 0.40 and 0.01, respectively. Alleles conferring an intermediate CYP2D6 metabolizer phenotype comprised 46% of the total number of alleles. CONCLUSION: The newly developed ASO assay is a reliable and rapid tool for large-scale CYP2D6 genotyping. The high frequency of the CYP2D6*10 allele in the Karen population warrants further assessment of its association with the radical curative efficacy of primaquine.

Pongvongsa T, Phommasone K, Adhikari B, Henriques G, Chotivanich K, Hanboonkunupakarn B, Mukaka M, Peerawaranun P, von Seidlein L, Day NPJ et al. 2018. The dynamic of asymptomatic Plasmodium falciparum infections following mass drug administrations with dihydroarteminisin-piperaquine plus a single low dose of primaquine in Savannakhet Province, Laos. Malar J, 17 (1), pp. 405. | Show Abstract | Read more

BACKGROUND: The increase in multidrug resistant Plasmodium falciparum infections threatens the malaria elimination goals in countries within the Greater Mekong Sub-region. A multi-pronged approach assuring access to basic malaria control measures, including insecticide-treated bed nets and early diagnosis and treatment was followed by mass drug administrations (MDA) in southern Savannakhet Province, Laos. The main objective of this study was to evaluate the effectiveness and safety of mass drug administrations as well as their effects on the dynamic of asymptomatic P. falciparum infections in 4 malaria endemic villages. METHODS: Two villages were randomized to early MDA consisting of 3 rounds of a 3-day course of dihydroartemisinin-piperaquine with a single low dose of primaquine. In the other 2 villages MDA was deferred by 1 year. A total of 1036 residents were enrolled in early MDA villages and 883 in control villages (deferred-MDA). Tri-monthly parasitaemia surveys using uPCR were conducted for a year in the 4 villages. RESULTS: Eighty-four percent (872/1036) of the residents participated in the MDAs, of whom 90% (781/872) completed 3 rounds of MDA (9 doses). In intervention villages, the prevalence of asymptomatic P. falciparum infections decreased by 85% after MDA from 4.8% (95% CI 3.4-6.4) at baseline (month 0 or M0) to 0.7% (95% CI 0.3-1.6) at month 12. In control villages there was a decrease of 33% in P. falciparum prevalence between M0: 17.5% (95% CI 15.9-20.3) and M12: 11.6% (95% CI 9.3-14.2). In bivariate and multivariate analyses P. falciparum infections were significantly reduced with early MDA (adjusted incidence rate ratios (AIRR): 0.08, CI 0.01-0.091) and completion of 3 MDA rounds (AIRR: 0.06; CI 0.01-0.66). A quarter of participants (226/872) reported adverse events of which 99% were mild. CONCLUSION: The study found a significant reduction in P. falciparum prevalence and incidence following MDA. MDA was safe, well tolerated, feasible, and achieved high population coverage and adherence. MDAs must be integrated in multi-pronged approaches such as vector control and preventive measures with a focus on specific risk groups such as mobile, migrant population and forest goers for a sustained period to eliminate the remaining parasite reservoirs. Trial registration Identifier: NCT01872702.

McLean ARD, Wai HP, Thu AM, Khant ZS, Indrasuta C, Ashley EA, Kyaw TT, Day NPJ, Dondorp A, White NJ, Smithuis FM. 2018. Malaria elimination in remote communities requires integration of malaria control activities into general health care: an observational study and interrupted time series analysis in Myanmar. BMC Med, 16 (1), pp. 183. | Show Abstract | Read more

BACKGROUND: Community health workers (CHWs) can provide diagnosis and treatment of malaria in remote rural areas and are therefore key to the elimination of malaria. However, as incidence declines, uptake of their services could be compromised if they only treat malaria. METHODS: We conducted a retrospective analysis of 571,286 malaria rapid diagnostic tests conducted between 2011 and 2016 by 1335 CHWs supported by Medical Action Myanmar. We assessed rates of decline in Plasmodium falciparum and Plasmodium vivax incidence and rapid diagnostic test (RDT) positivity rates using negative binomial mixed effects models. We investigated whether broadening the CHW remit to provide a basic health care (BHC) package was associated with a change in malaria blood examination rates. RESULTS: Communities with CHWs providing malaria diagnosis and treatment experienced declines in P. falciparum and P. vivax malaria incidence of 70% (95% CI 66-73%) and 64% (59-68%) respectively each year of operation. RDT positivity rates declined similarly with declines of 70% (95% CI 66-73%) for P. falciparum and 65% (95% CI 61-69%) for P. vivax with each year of CHW operation. In four cohorts studied, adding a BHC package was associated with an immediate and sustained increase in blood examination rates (step-change rate ratios 2.3 (95% CI 2.0-2.6), 5.4 (95% CI 4.0-7.3), 1.7 (95% CI 1.4-2.1), and 1.1 (95% CI CONCLUSIONS: CHWs have overseen dramatic declines in P. falciparum and P. vivax malaria in rural Myanmar. Expanding their remit to general health care has sustained community uptake of malaria services. In similar settings, expanding health services offered by CHWs beyond malaria testing and treatment can improve rural health care while ensuring continued progress towards the elimination of malaria.

Imwong M, Madmanee W, Suwannasin K, Kunasol C, Peto TJ, Tripura R, von Seidlein L, Nguon C, Davoeung C, Day NPJ et al. 2019. Asymptomatic Natural Human Infections With the Simian Malaria Parasites Plasmodium cynomolgi and Plasmodium knowlesi. J Infect Dis, 219 (5), pp. 695-702. | Show Abstract | Read more

BACKGROUND: In Southeast Asia, Plasmodium knowlesi, a parasite of long-tailed macaques (Macaca fascicularis), is an important cause of human malaria. Plasmodium cynomolgi also commonly infects these monkeys, but only one naturally acquired symptomatic human case has been reported previously. METHODS: Malariometric studies involving 5422 subjects (aged 6 months to 65 years) were conducted in 23 villages in Pailin and Battambang, western Cambodia. Parasite detection and genotyping was conducted on blood samples, using high-volume quantitative PCR (uPCR). RESULTS: Asymptomatic malaria parasite infections were detected in 1361 of 14732 samples (9.2%). Asymptomatic infections with nonhuman primate malaria parasites were found in 21 individuals living close to forested areas; P. cynomolgi was found in 11, P. knowlesi was found in 8, and P. vivax and P. cynomolgi were both found in 2. Only 2 subjects were female, and 14 were men aged 20-40 years. Geometric mean parasite densities were 3604 parasites/mL in P. cynomolgi infections and 52488 parasites/mL in P. knowlesi infections. All P. cynomolgi isolates had wild-type dihydrofolate reductase genes, in contrast to the very high prevalence of mutations in the human malaria parasites. Asymptomatic reappearance of P. cynomolgi occurred in 2 subjects 3 months after the first infection. CONCLUSIONS: Asymptomatic naturally acquired P. cynomolgi and P. knowlesi infections can both occur in humans. CLINICAL TRIALS REGISTRATION: NCT01872702.

Ye W, Chew M, Hou J, Lai F, Leopold SJ, Loo HL, Ghose A, Dutta AK, Chen Q, Ooi EE et al. 2018. Microvesicles from malaria-infected red blood cells activate natural killer cells via MDA5 pathway. PLoS Pathog, 14 (10), pp. e1007298. | Show Abstract | Read more

Natural killer (NK) cells provide the first line of defense against malaria parasite infection. However, the molecular mechanisms through which NK cells are activated by parasites are largely unknown, so is the molecular basis underlying the variation in NK cell responses to malaria infection in the human population. Here, we compared transcriptional profiles of responding and non-responding NK cells following exposure to Plasmodium-infected red blood cells (iRBCs) and identified MDA5, a RIG-I-like receptor involved in sensing cytosolic RNAs, to be differentially expressed. Knockout of MDA5 in responding human NK cells by CRISPR/cas9 abolished NK cell activation, IFN-γ secretion, lysis of iRBCs. Similarly, inhibition of TBK1/IKKε, an effector molecule downstream of MDA5, also inhibited activation of responding NK cells. Conversely, activation of MDA5 by liposome-packaged poly I:C restored non-responding NK cells to lyse iRBCs. We further show that microvesicles containing large parasite RNAs from iRBCs activated NK cells by fusing with NK cells. These findings suggest that NK cells are activated through the MDA5 pathway by parasite RNAs that are delivered to the cytoplasm of NK cells by microvesicles from iRBCs. The difference in MDA5 expression between responding and non-responding NK cells following exposure to iRBCs likely contributes to the variation in NK cell responses to malaria infection in the human population.

Kam RK-T, Chan MH-M, Wong H-T, Ghose A, Dondorp AM, Plewes K, Tarning J. 2018. Quantitation of paracetamol by liquid chromatography-mass spectrometry in human plasma in support of clinical trial. Future Sci OA, 4 (8), pp. FSO331. | Show Abstract | Read more

Aim: Paracetamol is a well-tolerated antipyretic widely used in severe malaria management. The study aimed to develop and validate a rapid LC-MS/MS assay to quantify paracetamol in plasma from patients with severe malaria. Materials & methods: Plasma sample was precipitated by organic solvent containing isotope-labeled paracetamol internal standard. Supernatant was isolated, diluted with water, followed by LC-MS/MS analysis. Results: Plasma samples were extracted and assayed in less than 5.5 min. The assay response was linear (0.125-50 mg/l) with total intra- and interassay imprecision of <1.4%, which were considerably lower than most published reports. Conclusion: We developed, validated and applied a rapid and small volume LC-MS/MS assay with high precision and accuracy for plasma paracetamol quantitation in 989 samples from 62 patients with severe malaria. The simple and high-throughput quality could facilitate assay automation for future clinical studies.

Blacksell SD, Kingston HWF, Tanganuchitcharnchai A, Phanichkrivalkosil M, Hossain M, Hossain A, Ghose A, Leopold SJ, Dondorp AM, Day NPJ, Paris DH. 2018. Diagnostic Accuracy of the InBios Scrub Typhus Detect™ ELISA for the Detection of IgM Antibodies in Chittagong, Bangladesh. Trop Med Infect Dis, 3 (3), pp. 95-95. | Show Abstract | Read more

Here we estimated the accuracy of the InBios Scrub Typhus Detect™ immunoglobulin M (IgM) ELISA to determine the optimal optical density (OD) cut-off values for the diagnosis of scrub typhus. Patients with undifferentiated febrile illness from Chittagong, Bangladesh, provided samples for reference testing using (i) qPCR using the Orientia spp. 47-kDa htra gene, (ii) IFA ≥1:3200 on admission, (iii) immunofluorescence assay (IFA) ≥1:3200 on admission or 4-fold rise to ≥3200, and (iv) combination of PCR and IFA positivity. For sero-epidemiological purposes (ELISA vs. IFA ≥1:3200 on admission or 4-fold rise to ≥3200), the OD cut-off for admission samples was ≥1.25, resulting in a sensitivity (Sn) of 91.5 (95% confidence interval (95% CI: 96.8⁻82.5) and a specificity (Sp) of 92.4 (95% CI: 95.0⁻89.0), while for convalescent samples the OD cut-off was ≥1.50 with Sn of 66.0 (95% CI: 78.5⁻51.7) and Sp of 96.0 (95% CI: 98.3⁻92.3). Comparisons against comparator reference tests (ELISA vs. all tests including PCR) indicated the most appropriate cut-off OD to be within the range of 0.75⁻1.25. For admission samples, the best Sn/Sp compromise was at 1.25 OD (Sn 91.5%, Sp 92.4%) and for convalescent samples at 0.75 OD (Sn 69.8%, Sp 89.5%). A relatively high (stringent) diagnostic cut-off value provides increased diagnostic accuracy with high sensitivity and specificity in the majority of cases, while lowering the cut-off runs the risk of false positivity. This study underlines the need for regional assessment of new diagnostic tests according to the level of endemicity of the disease given the high levels of residual or cross-reacting antibodies in the general population.

Haniffa R, Beane A, Dondorp AM. 2018. Is the Tail Wagging the Dog in Sepsis? Crit Care Med, 46 (8), pp. e818. | Read more

Njim T, Dondorp A, Mukaka M, Ohuma EO. 2018. Identifying risk factors for the development of sepsis during adult severe malaria. Malar J, 17 (1), pp. 278. | Show Abstract | Read more

BACKGROUND: Severe falciparum malaria can be compounded by bacterial sepsis, necessitating antibiotics in addition to anti-malarial treatment. The objective of this analysis was to develop a prognostic model to identify patients admitted with severe malaria at higher risk of developing bacterial sepsis. METHODS: A retrospective data analysis using trial data from the South East Asian Quinine Artesunate Malaria Trial. Variables correlating with development of clinically defined sepsis were identified by univariable analysis, and subsequently included into a multivariable logistic regression model. Internal validation was performed by bootstrapping. Discrimination and goodness-of-fit were assessed using the area under the curve (AUC) and a calibration plot, respectively. RESULTS: Of the 1187 adults with severe malaria, 86 (7.3%) developed clinical sepsis during admission. Predictors for developing sepsis were: female sex, high blood urea nitrogen, high plasma anion gap, respiratory distress, shock on admission, high parasitaemia, coma and jaundice. The AUC of the model was 0.789, signifying modest differentiation for identifying patients developing sepsis. The model was well-calibrated (Hosmer-Lemeshow Chi squared = 1.02). The 25th percentile of the distribution of risk scores among those who developed sepsis could identify a high-risk group with a sensitivity and specificity of 70.0 and 69.4%, respectively. CONCLUSIONS: The proposed model identifies patients with severe malaria at risk of developing clinical sepsis, potentially benefiting from antibiotic treatment in addition to anti-malarials. The model will need further evaluation with more strictly defined bacterial sepsis as outcome measure.

Saralamba N, Mayxay M, Newton PN, Smithuis F, Nosten F, Archasuksan L, Pukrittayakamee S, White NJ, Day NPJ, Dondorp AM, Imwong M. 2018. Genetic polymorphisms in the circumsporozoite protein of Plasmodium malariae show a geographical bias. Malar J, 17 (1), pp. 269. | Show Abstract | Read more

BACKGROUND: Plasmodium malariae is characterized by its long asymptomatic persistence in the human host. The epidemiology of P. malariae is incompletely understood and is hampered by the limited knowledge of genetic polymorphisms. Previous reports from Africa have shown heterogeneity within the P. malariae circumsporozoite protein (pmcsp) gene. However, comparative studies from Asian countries are lacking. Here, the genetic polymorphisms in pmcsp of Asian isolates have been characterized. METHODS: Blood samples from 89 symptomatic P. malariae-infected patients were collected, from Thailand (n = 43), Myanmar (n = 40), Lao PDR (n = 5), and Bangladesh (n = 1). pmcsp was amplified using semi-nested PCR before sequencing. The resulting 89 pmcsp sequences were analysed together with 58 previously published pmcsp sequences representing African countries using BioEdit, MEGA6, and DnaSP. RESULTS: Polymorphisms identified in pmcsp were grouped into 3 populations: Thailand, Myanmar, and Kenya. The nucleotide diversity and the ratio of nonsynonymous to synonymous substitutions (dN/dS) in Thailand and Myanmar were higher compared with that in Kenya. Phylogenetic analysis showed clustering of pmcsp sequences according to the origin of isolates (Asia vs. Africa). High genetic differentiation (Fst = 0.404) was observed between P. malariae isolates from Asian and African countries. Sequence analysis of pmcsp showed the presence of tetrapeptide repeat units of NAAG, NDAG, and NAPG in the central repeat region of the gene. Plasmodium malariae isolates from Asian countries carried fewer copies of NAAG compared with that from African countries. The NAPG repeat was only observed in Asian isolates. Additional analysis of 2 T-cell epitopes, Th2R and Th3R, showed limited heterogeneity in P. malariae populations. CONCLUSIONS: This study provides valuable information on the genetic polymorphisms in pmcsp isolates from Asia and advances our understanding of P. malariae population in Asia and Africa. Polymorphisms in the central repeat region of pmcsp showed association with the geographical origin of P. malariae isolates and can be potentially used as a marker for genetic epidemiology of P. malariae population.

Tun KM, Jeeyapant A, Myint AH, Kyaw ZT, Dhorda M, Mukaka M, Cheah PY, Imwong M, Hlaing T, Kyaw TH et al. 2018. Effectiveness and safety of 3 and 5 day courses of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in an area of emerging artemisinin resistance in Myanmar. Malar J, 17 (1), pp. 258. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance in Plasmodium falciparum has emerged and spread in Southeast Asia. In areas where resistance is established longer courses of artemisinin-based combination therapy have improved cure rates. METHODS: The standard 3-day course of artemether-lumefantrine (AL) was compared with an extended 5-day regimen for the treatment of uncomplicated falciparum malaria in Kayin state in South-East Myanmar, an area of emerging artemisinin resistance. Late parasite clearance dynamics were described by microscopy and quantitative ultra-sensitive PCR. Patients were followed up for 42 days. RESULTS: Of 154 patients recruited (105 adults and 49 children < 14 years) 78 were randomized to 3 days and 76 to 5 days AL. Mutations in the P. falciparum kelch13 propeller gene (k13) were found in 46% (70/152) of infections, with F446I the most prevalent propeller mutation (29%; 20/70). Both regimens were well-tolerated. Parasite clearance profiles were biphasic with a slower submicroscopic phase which was similar in k13 wild-type and mutant infections. The cure rates were 100% (70/70) and 97% (68/70) in the 3- and 5-day arms respectively. Genotyping of the two recurrences was unsuccessful. CONCLUSION: Despite a high prevalence of k13 mutations, the current first-line treatment, AL, was still highly effective in this area of South-East Myanmar. The extended 5 day regimen was very well tolerated, and would be an option to prolong the useful therapeutic life of AL. Trial registration NCT02020330. Registered 24 December 2013,

Henriques G, Phommasone K, Tripura R, Peto TJ, Raut S, Snethlage C, Sambo I, Sanann N, Nguon C, Adhikari B et al. 2018. Comparison of glucose-6 phosphate dehydrogenase status by fluorescent spot test and rapid diagnostic test in Lao PDR and Cambodia. Malar J, 17 (1), pp. 243. | Show Abstract | Read more

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy worldwide. Primaquine is the only licensed drug that effectively removes Plasmodium vivax hypnozoites from the human host and prevents relapse. While well tolerated by most recipients, primaquine can cause haemolysis in G6PD deficient individuals and is, therefore, underused. Rapid diagnostic tests (RDTs) could permit ascertainment of G6PD status outside of laboratory settings and hence safe treatment in remote areas. The performance of the fluorescent spot test (Trinity, Ireland; FST) and a G6PD RDT (Carestart, USA) against spectrophotometry were assessed. METHODS: Participants were enrolled during cross-sectional surveys in Laos and by purposive sampling in Cambodia. FST and RDT were performed during village surveys and 3 mL of venous blood was collected for subsequent G6PD measurement by spectrophotometry. RESULTS: A total of 757 participants were enrolled in Laos and 505 in Cambodia. FST and RDT performed best at 30% cut-off activity and performed significantly better in Laos than in Cambodia. When defining intermediate results as G6PD deficient, the FST had a sensitivity of 100% (95%CI 90-100) and specificity of 90% (95%CI 87.7-92.2) in Laos and sensitivity of 98% (94.1-99.6) and specificity of 71% (95%CI 66-76) in Cambodia (p < 0.001). The RDT had sensitivity and specificity of 100% (95%CI 90-100) and 99% (95%CI 97-99) in Laos and sensitivity and specificity of 91% (86-96) and 93% (90-95) in Cambodia (p < 0.001). The RDT performed significantly better (all p < 0.05) than the FST when intermediate FST results were defined as G6PD deficient. CONCLUSION: The interpretation of RDT results requires some training but is a good alternative to the FST. Trial registration; NCT01872702; 06/27/2013;

Peto TJ, Tripura R, Sanann N, Adhikari B, Callery J, Droogleever M, Heng C, Cheah PY, Davoeung C, Nguon C et al. 2018. The feasibility and acceptability of mass drug administration for malaria in Cambodia: a mixed-methods study. Trans R Soc Trop Med Hyg, 112 (6), pp. 264-271. | Show Abstract | Read more

Background: Mass drug administrations (MDAs) are part of the World Health Organization's Plasmodium falciparum elimination strategy for the Greater Mekong Subregion (GMS). In Cambodia, a 2015-2017 clinical trial evaluated the effectiveness of MDA. This article explores factors that influence the feasibility and acceptability of MDA, including seasonal timing, financial incentives and the delivery model. Methods: Quantitative data were collected through structured questionnaires from the heads of 163 households. Qualitative data were collected through 25 semi-structured interviews and 5 focus group discussions with villagers and local health staff. Calendars of village activities were created and meteorological and malaria treatment records were collected. Results: MDA delivered house-to-house or at a central point, with or without compensation, were equally acceptable and did not affect coverage. People who knew about the rationale for the MDA, asymptomatic infections and transmission were more likely to participate. In western Cambodia, MDA delivered house-to-house by volunteers at the end of the dry season may be most practicable but requires the subsequent treatment of in-migrants to prevent reintroduction of infections. Conclusions: For MDA targeted at individual villages or village clusters it is important to understand local preferences for community mobilisation, delivery and timing, as several models of MDA are feasible.

Barber BE, Grigg MJ, Piera KA, William T, Cooper DJ, Plewes K, Dondorp AM, Yeo TW, Anstey NM. 2018. Intravascular haemolysis in severe Plasmodium knowlesi malaria: association with endothelial activation, microvascular dysfunction, and acute kidney injury. Emerg Microbes Infect, 7 (1), pp. 106. | Show Abstract | Read more

Plasmodium knowlesi occurs throughout Southeast Asia, and is the most common cause of human malaria in Malaysia. Severe disease in humans is characterised by high parasite biomass, reduced red blood cell deformability, endothelial activation and microvascular dysfunction. However, the roles of intravascular haemolysis and nitric oxide (NO)-dependent endothelial dysfunction, important features of severe falciparum malaria, have not been evaluated, nor their role in acute kidney injury (AKI). In hospitalised Malaysian adults with severe (n = 48) and non-severe (n = 154) knowlesi malaria, and in healthy controls (n = 50), we measured cell-free haemoglobin (CFHb) and assessed associations with the endothelial Weibel-Palade body (WPB) constituents, angiopoietin-2 and osteoprotegerin, endothelial and microvascular function, and other markers of disease severity. CFHb was increased in knowlesi malaria in proportion to disease severity, and to a greater extent than previously reported in severe falciparum malaria patients from the same study cohort. In knowlesi malaria, CFHb was associated with parasitaemia, and independently associated with angiopoietin-2 and osteoprotegerin. As with angiopoietin-2, osteoprotegerin was increased in proportion to disease severity, and independently associated with severity markers including creatinine, lactate, interleukin-6, endothelial cell adhesion molecules ICAM-1 and E-selectin, and impaired microvascular reactivity. Osteoprotegerin was also independently associated with NO-dependent endothelial dysfunction. AKI was found in 88% of those with severe knowlesi malaria. Angiopoietin-2 and osteoprotegerin were both independent risk factors for acute kidney injury. Our findings suggest that haemolysis-mediated endothelial activation and release of WPB constituents is likely a key contributor to end-organ dysfunction, including AKI, in severe knowlesi malaria.

Rudd KE, Seymour CW, Aluisio AR, Augustin ME, Bagenda DS, Beane A, Byiringiro JC, Chang C-CH, Colas LN, Day NPJ et al. 2018. Association of the Quick Sequential (Sepsis-Related) Organ Failure Assessment (qSOFA) Score With Excess Hospital Mortality in Adults With Suspected Infection in Low- and Middle-Income Countries. JAMA, 319 (21), pp. 2202-2211. | Show Abstract | Read more

Importance: The quick Sequential (Sepsis-Related) Organ Failure Assessment (qSOFA) score has not been well-evaluated in low- and middle-income countries (LMICs). Objective: To assess the association of qSOFA with excess hospital death among patients with suspected infection in LMICs and to compare qSOFA with the systemic inflammatory response syndrome (SIRS) criteria. Design, Settings, and Participants: Retrospective secondary analysis of 8 cohort studies and 1 randomized clinical trial from 2003 to 2017. This study included 6569 hospitalized adults with suspected infection in emergency departments, inpatient wards, and intensive care units of 17 hospitals in 10 LMICs across sub-Saharan Africa, Asia, and the Americas. Exposures: Low (0), moderate (1), or high (≥2) qSOFA score (range, 0 [best] to 3 [worst]) or SIRS criteria (range, 0 [best] to 4 [worst]) within 24 hours of presentation to study hospital. Main Outcomes and Measures: Predictive validity (measured as incremental hospital mortality beyond that predicted by baseline risk factors, as a marker of sepsis or analogous severe infectious course) of the qSOFA score (primary) and SIRS criteria (secondary). Results: The cohorts were diverse in enrollment criteria, demographics (median ages, 29-54 years; males range, 36%-76%), HIV prevalence (range, 2%-43%), cause of infection, and hospital mortality (range, 1%-39%). Among 6218 patients with nonmissing outcome status in the combined cohort, 643 (10%) died. Compared with a low or moderate score, a high qSOFA score was associated with increased risk of death overall (19% vs 6%; difference, 13% [95% CI, 11%-14%]; odds ratio, 3.6 [95% CI, 3.0-4.2]) and across cohorts (P < .05 for 8 of 9 cohorts). Compared with a low qSOFA score, a moderate qSOFA score was also associated with increased risk of death overall (8% vs 3%; difference, 5% [95% CI, 4%-6%]; odds ratio, 2.8 [95% CI, 2.0-3.9]), but not in every cohort (P < .05 in 2 of 7 cohorts). High, vs low or moderate, SIRS criteria were associated with a smaller increase in risk of death overall (13% vs 8%; difference, 5% [95% CI, 3%-6%]; odds ratio, 1.7 [95% CI, 1.4-2.0]) and across cohorts (P < .05 for 4 of 9 cohorts). qSOFA discrimination (area under the receiver operating characteristic curve [AUROC], 0.70 [95% CI, 0.68-0.72]) was superior to that of both the baseline model (AUROC, 0.56 [95% CI, 0.53-0.58; P < .001) and SIRS (AUROC, 0.59 [95% CI, 0.57-0.62]; P < .001). Conclusions and Relevance: When assessed among hospitalized adults with suspected infection in 9 LMIC cohorts, the qSOFA score identified infected patients at risk of death beyond that explained by baseline factors. However, the predictive validity varied among cohorts and settings, and further research is needed to better understand potential generalizability.

Aguas R, Maude RJ, Gomes MGM, White LJ, White NJ, Dondorp AM. 2018. Infectivity of Chronic Malaria Infections and Its Consequences for Control and Elimination. Clin Infect Dis, 67 (2), pp. 295-302. | Show Abstract | Read more

Assessing the importance of targeting the chronic Plasmodium falciparum malaria reservoir is pivotal as the world moves toward malaria eradication. Through the lens of a mathematical model, we show how, for a given malaria prevalence, the relative infectivity of chronic individuals determines what intervention tools are predicted be the most effective. Crucially, in a large part of the parameter space where elimination is theoretically possible, it can be achieved solely through improved case management. However, there are a significant number of settings where malaria elimination requires not only good vector control but also a mass drug administration campaign. Quantifying the relative infectiousness of chronic malaria across a range of epidemiological settings would provide essential information for the design of effective malaria elimination strategies. Given the difficulties obtaining this information, we also provide a set of epidemiological metrics that can be used to guide policy in the absence of such data.

Algera AG, Pisani L, Bergmans DCJ, den Boer S, de Borgie CAJ, Bosch FH, Bruin K, Cherpanath TG, Determann RM, Dondorp AM et al. 2018. RELAx - REstricted versus Liberal positive end-expiratory pressure in patients without ARDS: protocol for a randomized controlled trial. Trials, 19 (1), pp. 272. | Show Abstract | Read more

BACKGROUND: Evidence for benefit of high positive end-expiratory pressure (PEEP) is largely lacking for invasively ventilated, critically ill patients with uninjured lungs. We hypothesize that ventilation with low PEEP is noninferior to ventilation with high PEEP with regard to the number of ventilator-free days and being alive at day 28 in this population.  METHODS/DESIGN: The "REstricted versus Liberal positive end-expiratory pressure in patients without ARDS" trial (RELAx) is a national, multicenter, randomized controlled, noninferiority trial in adult intensive care unit (ICU) patients with uninjured lungs who are expected not to be extubated within 24 h. RELAx will run in 13 ICUs in the Netherlands to enroll 980 patients under invasive ventilation. In all patients, low tidal volumes are used. Patients assigned to ventilation with low PEEP will receive the lowest possible PEEP between 0 and 5 cm H2O, while patients assigned to ventilation with high PEEP will receive PEEP of 8 cm H2O. The primary endpoint is the number of ventilator-free days and being alive at day 28, a composite endpoint for liberation from the ventilator and mortality until day 28, with a noninferiority margin for a difference between groups of 0.5 days. Secondary endpoints are length of stay (LOS), mortality, and occurrence of pulmonary complications, including severe hypoxemia, major atelectasis, need for rescue therapies, pneumonia, pneumothorax, and development of acute respiratory distress syndrome (ARDS). Hemodynamic support and sedation needs will be collected and compared. DISCUSSION: RELAx will be the first sufficiently sized randomized controlled trial in invasively ventilated, critically ill patients with uninjured lungs using a clinically relevant and objective endpoint to determine whether invasive, low-tidal-volume ventilation with low PEEP is noninferior to ventilation with high PEEP. TRIAL REGISTRATION: , ID: NCT03167580 . Registered on 23 May 2017.

de Jong HK, Parry CM, van der Vaart TW, Kager LM, van den Ende SJ, Maude RR, Wijedoru L, Ghose A, Hassan MU, Hossain MA et al. 2018. Activation of coagulation and endothelium with concurrent impairment of anticoagulant mechanisms in patients with typhoid fever. J Infect, 77 (1), pp. 60-67. | Show Abstract | Read more

OBJECTIVES: Typhoid fever caused by Salmonella Typhi remains a major burden worldwide. Gastrointestinal bleeding can be seen in up to 10 percent of patients and may be fatal. The coagulopathy, which may be the driver of this severe complication in patients with typhoid fever, however is ill defined. The aim of this study was to evaluate the activation of coagulation, anticoagulation, and fibrinolysis in patients with acute typhoid fever. METHODS: Parameters of coagulation and fibrinolysis were measured in 28 hospitalized patients with culture-confirmed or PCR-confirmed typhoid fever and compared to 38 age- and sex-matched healthy volunteers. RESULTS: Patients demonstrated activation of the coagulation system, as reflected by elevated in vitro thrombin generation and high plasma levels of fibrinogen, D-dimer and prothrombin fragment F1 + 2 in concert with consumption of coagulation factors resulting in a prolonged prothrombin-time and activated-partial-thromboplastin-time. Concurrently, the anticoagulant proteins, protein C and antithrombin, were significantly lower in comparison to healthy controls. Patients also demonstrated evidence of activation and inhibition of fibrinolysis and a marked activation of endothelial cells. The extent of coagulation activation was associated with the course of the disease, repeated testing during convalescence showed a return toward normal values. CONCLUSIONS: Activation of coagulation is an important clinical feature of typhoid fever and is associated with severity of disease.

Bopp S, Magistrado P, Wong W, Schaffner SF, Mukherjee A, Lim P, Dhorda M, Amaratunga C, Woodrow CJ, Ashley EA et al. 2018. Plasmepsin II-III copy number accounts for bimodal piperaquine resistance among Cambodian Plasmodium falciparum. Nat Commun, 9 (1), pp. 1769. | Show Abstract | Read more

Multidrug resistant Plasmodium falciparum in Southeast Asia endangers regional malaria elimination and threatens to spread to other malaria endemic areas. Understanding mechanisms of piperaquine (PPQ) resistance is crucial for tracking its emergence and spread, and to develop effective strategies for overcoming it. Here we analyze a mechanism of PPQ resistance in Cambodian parasites. Isolates exhibit a bimodal dose-response curve when exposed to PPQ, with the area under the curve quantifying their survival in vitro. Increased copy number for plasmepsin II and plasmepsin III appears to explain enhanced survival when exposed to PPQ in most, but not all cases. A panel of isogenic subclones reinforces the importance of plasmepsin II-III copy number to enhanced PPQ survival. We conjecture that factors producing increased parasite survival under PPQ exposure in vitro may drive clinical PPQ failures in the field.

Mazzinari G, Ball L, Serpa Neto A, Errando CL, Dondorp AM, Bos LD, Gama de Abreu M, Pelosi P, Schultz MJ. 2018. The fragility of statistically significant findings in randomised controlled anaesthesiology trials: systematic review of the medical literature. Br J Anaesth, 120 (5), pp. 935-941. | Show Abstract | Read more

The fragility index (FI), the number of events the statistical significance a result depends on, and the number of patients lost to follow-up are important parameters for interpreting randomised clinical trial results. We evaluated these two parameters in randomised controlled trials in anaesthesiology. For this, we performed a systematic search of the medical literature, seeking articles reporting on anaesthesiology trials with a statistically significant difference in the primary outcome and published in the top five general medicine journals, or the top 15 anaesthesiology journals. We restricted the analysis to trials reporting clinically important primary outcome measures. The search identified 139 articles, 35 published in general medicine journals and 104 in anaesthesiology journals. The median (inter-quartile range) sample size was 150 (70-300) patients. The FI was 4 (2-17) and 3 (2-7), and the number of patients lost to follow-up was 0 (0-18) and 0 (0-6) patients in trials published in general medicine and anaesthesiology journals, respectively. The number of patients lost to follow-up exceeded the FI in 41 and 27% in trials in general medicine journals and anaesthesiology journals, respectively. The FI positively correlated with sample size and number of primary outcome events, and negatively correlated with the reported P-values. The results of this systematic review suggest that statistically significant differences in randomised controlled anaesthesiology trials are regularly fragile, implying that the primary outcome status of patients lost to follow-up could possibly have changed the reported effect.



European Pubmed Central

Landier J, Parker DM, Thu AM, Lwin KM, Delmas G, Nosten FH, Malaria Elimination Task Force Group. 2018. Effect of generalised access to early diagnosis and treatment and targeted mass drug administration on Plasmodium falciparum malaria in Eastern Myanmar: an observational study of a regional elimination programme. Lancet, 391 (10133), pp. 1916-1926. | Show Abstract | Read more

BACKGROUND: Potentially untreatable Plasmodium falciparum malaria threatens the Greater Mekong subregion. A previous series of pilot projects in Myanmar, Laos, Cambodia, and Vietnam suggested that mass drug administration was safe, and when added to provision of early diagnosis and treatment, could reduce the reservoir of P falciparum and interrupts transmission. We examined the effects of a scaled-up programme of this strategy in four townships of eastern Myanmar on the incidence of P falciparum malaria. METHODS: The programme was implemented in the four townships of Myawaddy, Kawkareik, Hlaingbwe, and Hpapun in Kayin state, Myanmar. Increased access to early diagnosis and treatment of malaria was provided to all villages through community-based malaria posts equipped with rapid diagnostic tests, and treatment with artemether-lumefantrine plus single low-dose primaquine. Villages were identified as malarial hotspots (operationally defined as >40% malaria, of which 20% was P falciparum) with surveys using ultrasensitive quantitative PCR either randomly or targeted at villages where the incidence of clinical cases of P falciparum malaria remained high (ie, >100 cases per 1000 individuals per year) despite a functioning malaria post. During each survey, a 2 mL sample of venous blood was obtained from randomly selected adults. Hotspots received targeted mass drug administration with dihydroartemisinin-piperaquine plus single-dose primaquine once per month for 3 consecutive months in addition to the malaria posts. The main outcome was the change in village incidence of clinical P falciparum malaria, quantified using a multivariate, generalised, additive multilevel model. Malaria prevalence was measured in the hotspots 12 months after mass drug administration. FINDINGS: Between May 1, 2014, and April 30, 2017, 1222 malarial posts were opened, providing early diagnosis and treatment to an estimated 365 000 individuals. Incidence of P falciparum malaria decreased by 60 to 98% in the four townships. 272 prevalence surveys were undertaken and 69 hotspot villages were identified. By April 2017, 50 hotspots were treated with mass drug administration. Hotspot villages had a three times higher incidence of P falciparum at malarial posts than neighbouring villages (adjusted incidence rate ratio [IRR] 2·7, 95% CI 1·8-4·4). Early diagnosis and treatment was associated with a significant decrease in P falciparum incidence in hotspots (IRR 0·82, 95% CI 0·76-0·88 per quarter) and in other villages (0·75, 0·73-0·78 per quarter). Mass drug administration was associated with a five-times decrease in P falciparum incidence within hotspot villages (IRR 0·19, 95% CI 0·13-0·26). By April, 2017, 965 villages (79%) of 1222 corresponding to 104 village tracts were free from P falciparum malaria for at least 6 months. The prevalence of wild-type genotype for K13 molecular markers of artemisinin resistance was stable over the three years (39%; 249/631). INTERPRETATION: Providing early diagnosis and effective treatment substantially decreased village-level incidence of artemisinin-resistant P falciparum malaria in hard-to-reach, politically sensitive regions of eastern Myanmar. Targeted mass drug administration significantly reduced malaria incidence in hotspots. If these activities could proceed in all contiguous endemic areas in addition to standard control programmes already implemented, there is a possibility of subnational elimination of P falciparum. FUNDING: The Bill & Melinda Gates Foundation, the Regional Artemisinin Initiative (Global Fund against AIDS, Tuberculosis and Malaria), and the Wellcome Trust.

Pisani L, Algera AG, Serpa Neto A, Ahsan A, Beane A, Chittawatanarat K, Faiz A, Haniffa R, Hashemian R, Hashmi M et al. 2018. PRactice of VENTilation in Middle-Income Countries (PRoVENT-iMIC): rationale and protocol for a prospective international multicentre observational study in intensive care units in Asia. BMJ Open, 8 (4), pp. e020841. | Show Abstract | Read more

INTRODUCTION: Current evidence on epidemiology and outcomes of invasively mechanically ventilated intensive care unit (ICU) patients is predominantly gathered in resource-rich settings. Patient casemix and patterns of critical illnesses, and probably also ventilation practices are likely to be different in resource-limited settings. We aim to investigate the epidemiological characteristics, ventilation practices and clinical outcomes of patients receiving mechanical ventilation in ICUs in Asia. METHODS AND ANALYSIS: PRoVENT-iMIC (study of PRactice of VENTilation in Middle-Income Countries) is an international multicentre observational study to be undertaken in approximately 60 ICUs in 11 Asian countries. Consecutive patients aged 18 years or older who are receiving invasive ventilation in participating ICUs during a predefined 28-day period are to be enrolled, with a daily follow-up of 7 days. The primary outcome is ventilatory management (including tidal volume expressed as mL/kg predicted body weight and positive end-expiratory pressure expressed as cm H2O) during the first 3 days of mechanical ventilation-compared between patients at no risk for acute respiratory distress syndrome (ARDS), patients at risk for ARDS and in patients with ARDS (in case the diagnosis of ARDS can be made on admission). Secondary outcomes include occurrence of pulmonary complications and all-cause ICU mortality. ETHICS AND DISSEMINATION: PRoVENT-iMIC will be the first international study that prospectively assesses ventilation practices, outcomes and epidemiology of invasively ventilated patients in ICUs in Asia. The results of this large study, to be disseminated through conference presentations and publications in international peer-reviewed journals, are of ultimate importance when designing trials of invasive ventilation in resource-limited ICUs. Access to source data will be made available through national or international anonymised datasets on request and after agreement of the PRoVENT-iMIC steering committee. TRIAL REGISTRATION NUMBER: NCT03188770; Pre-results.

Beane A, De Silva AP, De Silva N, Sujeewa JA, Rathnayake RMD, Sigera PC, Athapattu PL, Mahipala PG, Rashan A, Munasinghe SB et al. 2018. Evaluation of the feasibility and performance of early warning scores to identify patients at risk of adverse outcomes in a low-middle income country setting. BMJ Open, 8 (4), pp. e019387. | Show Abstract | Read more

OBJECTIVE: This study describes the availability of core parameters for Early Warning Scores (EWS), evaluates the ability of selected EWS to identify patients at risk of death or other adverse outcome and describes the burden of triggering that front-line staff would experience if implemented. DESIGN: Longitudinal observational cohort study. SETTING: District General Hospital Monaragala. PARTICIPANTS: All adult (age >17 years) admitted patients. MAIN OUTCOME MEASURES: Existing physiological parameters, adverse outcomes and survival status at hospital discharge were extracted daily from existing paper records for all patients over an 8-month period. STATISTICAL ANALYSIS: Discrimination for selected aggregate weighted track and trigger systems (AWTTS) was assessed by the area under the receiver operating characteristic (AUROC) curve.Performance of EWS are further evaluated at time points during admission and across diagnostic groups. The burden of trigger to correctly identify patients who died was evaluated using positive predictive value (PPV). RESULTS: Of the 16 386 patients included, 502 (3.06%) had one or more adverse outcomes (cardiac arrests, unplanned intensive care unit admissions and transfers). Availability of physiological parameters on admission ranged from 90.97% (95% CI 90.52% to 91.40%) for heart rate to 23.94% (95% CI 23.29% to 24.60%) for oxygen saturation. Ability to discriminate death on admission was less than 0.81 (AUROC) for all selected EWS. Performance of the best performing of the EWS varied depending on admission diagnosis, and was diminished at 24 hours prior to event. PPV was low (10.44%). CONCLUSION: There is limited observation reporting in this setting. Indiscriminate application of EWS to all patients admitted to wards in this setting may result in an unnecessary burden of monitoring and may detract from clinician care of sicker patients. Physiological parameters in combination with diagnosis may have a place when applied on admission to help identify patients for whom increased vital sign monitoring may not be beneficial. Further research is required to understand the priorities and cues that influence monitoring of ward patients. TRIAL REGISTRATION NUMBER: NCT02523456.

Cooper DJ, Plewes K, Grigg MJ, Rajahram GS, Piera KA, William T, Chatfield MD, Yeo TW, Dondorp AM, Anstey NM, Barber BE. 2018. The effect of regularly dosed paracetamol versus no paracetamol on renal function in Plasmodium knowlesi malaria (PACKNOW): study protocol for a randomised controlled trial. Trials, 19 (1), pp. 250. | Show Abstract | Read more

BACKGROUND: Plasmodium knowlesi is the most common cause of human malaria in Malaysia. Acute kidney injury (AKI) is a frequent complication. AKI of any cause can have long-term consequences, including increased risk of chronic kidney disease, adverse cardiovascular events and increased mortality. Additional management strategies are therefore needed to reduce the frequency and severity of AKI in malaria. In falciparum malaria, cell-free haemoglobin (CFHb)-mediated oxidative damage contributes to AKI. The inexpensive and widely available drug paracetamol inhibits CFHb-induced lipid peroxidation via reduction of ferryl haem to the less toxic Fe3+ state, and has been shown to reduce oxidative damage and improve renal function in patients with sepsis complicated by haemolysis as well as in falciparum malaria. This study aims to assess the ability of regularly dosed paracetamol to reduce the incidence and severity of AKI in knowlesi malaria by attenuating haemolysis-induced oxidative damage. METHODS: PACKNOW is a two-arm, open-label randomised controlled trial of adjunctive paracetamol versus no paracetamol in patients aged ≥ 5 years with knowlesi malaria, conducted over a 2-year period at four hospital sites in Sabah, Malaysia. The primary endpoint of change in creatinine from enrolment to 72 h will be evaluated by analysis of covariance (ANCOVA) using enrolment creatinine as a covariate. Secondary endpoints include longitudinal changes in markers of oxidative stress (plasma F2-isoprostanes and isofurans) and markers of endothelial activation/Weibel-Palade body release (angiopoietin-2, von Willebrand Factor, P-selectin, osteoprotegerin) over 72 h, as well as blood and urine biomarkers of AKI. This study will be powered to detect a difference between the two treatment arms in a clinically relevant population including adults and children with knowlesi malaria of any severity. DISCUSSION: Paracetamol is widely available and has an excellent safety profile; if a renoprotective effect is demonstrated, this trial will support the administration of regularly dosed paracetamol to all patients with knowlesi malaria. The secondary outcomes in this study will provide further insights into the pathophysiology of haemolysis-induced oxidative damage and acute kidney injury in knowlesi malaria and other haemolytic diseases. TRIAL REGISTRATION:, NCT03056391 . Registered on 12 October 2016.

Haniffa R, Silva APD, Beane A, Sigera PC, Athapattu PL, Rathnayake S, Jayasinghe KSA, Keizer NFD, Dondorp AM. 2018. To: The Epimed Monitor ICU Database®: a cloud-based national registry for adult intensive care unit patients in Brazil. Rev Bras Ter Intensiva, 30 (2), pp. 251-252. | Read more

Vercesi V, Pisani L, van Tongeren PSI, Lagrand WK, Leopold SJ, Huson MMA, Henwood PC, Walden A, Smit M, Riviello ED et al. 2018. External confirmation and exploration of the Kigali modification for diagnosing moderate or severe ARDS. Intensive Care Med, 44 (4), pp. 523-524. | Read more

Kingston HW, Hossain M, Leopold S, Anantatat T, Tanganuchitcharnchai A, Sinha I, Plewes K, Maude RJ, Chowdhury MAH, Paul S et al. 2018. Rickettsial Illnesses as Important Causes of Febrile Illness in Chittagong, Bangladesh. Emerg Infect Dis, 24 (4), pp. 638-645. | Show Abstract | Read more

We conducted a yearlong prospective study of febrile patients admitted to a tertiary referral hospital in Chittagong, Bangladesh, to assess the proportion of patients with rickettsial illnesses and identify the causative pathogens, strain genotypes, and associated seasonality patterns. We diagnosed scrub typhus in 16.8% (70/416) and murine typhus in 5.8% (24/416) of patients; 2 patients had infections attributable to undifferentiated Rickettsia spp. and 2 had DNA sequence-confirmed R. felis infection. Orientia tsutsugamushi genotypes included Karp, Gilliam, Kato, and TA763-like strains, with a prominence of Karp-like strains. Scrub typhus admissions peaked in a biphasic pattern before and after the rainy season, whereas murine typhus more frequently occurred before the rainy season. Death occurred in 4% (18/416) of cases; case-fatality rates were 4% each for scrub typhus (3/70) and murine typhus (1/28). Overall, 23.1% (96/416) of patients had evidence of treatable rickettsial illnesses, providing important evidence toward optimizing empirical treatment strategies.

Sriboonvorakul N, Ghose A, Hassan MMU, Hossain MA, Faiz MA, Pukrittayakamee S, Chotivanich K, Sukthana Y, Leopold SJ, Plewes K et al. 2018. Acidosis and acute kidney injury in severe malaria. Malar J, 17 (1), pp. 128. | Show Abstract | Read more

BACKGROUND: In severe falciparum malaria metabolic acidosis and acute kidney injury (AKI) are independent predictors of a fatal outcome in all age groups. The relationship between plasma acids, urine acids and renal function was investigated in adult patients with acute falciparum malaria. METHODS: Plasma and urinary acids which previously showed increased concentrations in proportion to disease severity in patients with severe falciparum malaria were quantified. Patients with uncomplicated malaria, sepsis and healthy volunteers served as comparator groups. Multiple regression and multivariate analysis were used to assess the relationship between organic acid concentrations and clinical syndromes, in particular AKI. RESULTS: Patients with severe malaria (n = 90), uncomplicated malaria (n = 94), non-malaria sepsis (n = 19), and healthy volunteers (n = 61) were included. Univariate analysis showed that both plasma and creatinine-adjusted urine concentrations of p-hydroxyphenyllactic acid (pHPLA) were higher in severe malaria patients with AKI (p < 0.001). Multiple regression analysis, including plasma or creatinine-adjusted urinary acids, and PfHRP2 as parasite biomass marker as independent variables, showed that pHPLA was independently associated with plasma creatinine (β = 0.827) and urine creatinine (β = 0.226). Principal component analysis, including four plasma acids and seven urinary acids separated a group of patients with AKI, which was mainly driven by pHPLA concentrations. CONCLUSIONS: Both plasma and urine concentrations of pHPLA closely correlate with AKI in patients with severe falciparum malaria. Further studies will need to assess the potential nephrotoxic properties of pHPLA.

Pieris L, Sigera PC, De Silva AP, Munasinghe S, Rashan A, Athapattu PL, Jayasinghe KSA, Samarasinghe K, Beane A, Dondorp AM, Haniffa R. 2018. Experiences of ICU survivors in a low middle income country- a multicenter study. BMC Anesthesiol, 18 (1), pp. 30. | Show Abstract | Read more

BACKGROUND: Stressful patient experiences during the intensive care unit (ICU) stay is associated with reduced satisfaction in High Income Countries (HICs) but has not been explored in Lower and Middle Income Countries (LMICs). This study describes the recalled experiences, stress and satisfaction as perceived by survivors of ICUs in a LMIC. METHODS: This follow-up study was carried out in 32 state ICUs in Sri Lanka between July and December 2015.ICU survivors' experiences, stress factors encountered and level of satisfaction were collected 30 days after ICU discharge by a telephone questionnaire adapted from Granja and Wright. RESULTS: Of 1665 eligible ICU survivors, 23.3% died after ICU discharge, 49.1% were uncontactable and 438 (26.3%) patients were included in the study. Whilst 78.1% (n = 349) of patients remembered their admission to the hospital, only 42.3% (n = 189) could recall their admission to the ICU. The most frequently reported stressful experiences were: being bedridden (34.2%), pain (34.0%), general discomfort (31.7%), daily needle punctures (32.9%), family worries (33.6%), fear of dying and uncertainty in the future (25.8%). The majority of patients (376, 84.12%) found the atmosphere of the ICU to be friendly and calm. Overall, the patients found the level of health care received in the ICU to be "very satisfactory" (93.8%, n = 411) with none of the survivors stating they were either "dissatisfied" or "very dissatisfied". CONCLUSION: In common with HIC, survivors were very satisfied with their ICU care. In contrast to HIC settings, specific ICU experiences were frequently not recalled, but those remembered were reported as relatively stress-free. Stressful experiences, in common with HIC, were most frequently related to uncertainty about the future, dependency, family, and economic concerns.

Keene CM, Dondorp A, Crawley J, Ohuma EO, Mukaka M. 2018. A Competing-Risk Approach for Modeling Length of Stay in Severe Malaria Patients in South-East Asia and the Implications for Planning of Hospital Services. Clin Infect Dis, 67 (7), pp. 1053-1062. | Show Abstract | Read more

Background: Management of severe malaria with limited resources requires comprehensive planning. Expected length of stay (LOS) and the factors influencing it are useful in the planning and optimisation of service delivery. Methods: A secondary, competing-risk approach to survival analysis was performed for 1217 adult severe malaria patients from the South-East Asia Quinine Artesunate Malaria Trial. Results: Twenty percent of patients died; 95.4% within 7 days compared to 70.3% of those who were discharged. Median time to discharge was 6 days. Compared to quinine, artesunate increased discharge incidence (subdistribution-Hazard ratio, 1.24; [95% confidence interval 1.09-1.40]; P = .001) and decreased incidence of death (0.60; [0.46-0.80]; P < .001). Low Glasgow coma scale (discharge, 1.08 [1.06-1.11], P < .001; death, 0.85 [0.82-0.89], P < .001), high blood urea-nitrogen (discharge, 0.99 [0.99-0.995], P < .001; death, 1.00 [1.00-1.01], P = .012), acidotic base-excess (discharge, 1.05 [1.03-1.06], P < .001; death, 0.90 [0.88-0.93], P < .001), and development of shock (discharge, 0.25 [0.13-0.47], P < .001; death, 2.14 [1.46-3.12], P < .001), or coma (discharge, 0.46 [0.32-0.65], P < .001; death, 2.30 [1.58-3.36], P < .001) decreased cumulative incidence of discharge and increased incidence of death. Conventional Kaplan-Meier survival analysis overestimated cumulative incidence compared to competing-risk model. Conclusions: Clinical factors on admission and during hospitalisation influence LOS in severe malaria, presenting targets to improve health and service efficiency. Artesunate has the potential to increase LOS, which should be accounted for when planning services. In-hospital death is a competing risk for discharge; an important consideration in LOS models to reduce overestimation of risk and misrepresentation of associations.

Rocamora F, Zhu L, Liong KY, Dondorp A, Miotto O, Mok S, Bozdech Z. 2018. Oxidative stress and protein damage responses mediate artemisinin resistance in malaria parasites. PLoS Pathog, 14 (3), pp. e1006930. | Show Abstract | Read more

Due to their remarkable parasitocidal activity, artemisinins represent the key components of first-line therapies against Plasmodium falciparum malaria. However, the decline in efficacy of artemisinin-based drugs jeopardizes global efforts to control and ultimately eradicate the disease. To better understand the resistance phenotype, artemisinin-resistant parasite lines were derived from two clones of the 3D7 strain of P. falciparum using a selection regimen that mimics how parasites interact with the drug within patients. This long term in vitro selection induced profound stage-specific resistance to artemisinin and its relative compounds. Chemosensitivity and transcriptional profiling of artemisinin-resistant parasites indicate that enhanced adaptive responses against oxidative stress and protein damage are associated with decreased artemisinin susceptibility. This corroborates our previous findings implicating these cellular functions in artemisinin resistance in natural infections. Genomic characterization of the two derived parasite lines revealed a spectrum of sequence and copy number polymorphisms that could play a role in regulating artemisinin response, but did not include mutations in pfk13, the main marker of artemisinin resistance in Southeast Asia. Taken together, here we present a functional in vitro model of artemisinin resistance that is underlined by a new set of genetic polymorphisms as potential genetic markers.

Plewes K, Kingston HWF, Ghose A, Wattanakul T, Hassan MMU, Haider MS, Dutta PK, Islam MA, Alam S, Jahangir SM et al. 2018. Acetaminophen as a Renoprotective Adjunctive Treatment in Patients With Severe and Moderately Severe Falciparum Malaria: A Randomized, Controlled, Open-Label Trial. Clin Infect Dis, 67 (7), pp. 991-999. | Show Abstract | Read more

Background: Acute kidney injury independently predicts mortality in falciparum malaria. It is unknown whether acetaminophen's capacity to inhibit plasma hemoglobin-mediated oxidation is renoprotective in severe malaria. Methods: This phase 2, open-label, randomized controlled trial conducted at two hospitals in Bangladesh assessed effects on renal function, safety, pharmacokinetic (PK) properties and pharmacodynamic (PD) effects of acetaminophen. Febrile patients (>12 years) with severe falciparum malaria were randomly assigned to receive acetaminophen (1 g 6-hourly for 72 hours) or no acetaminophen, in addition to intravenous artesunate. Primary outcome was the proportional change in creatinine after 72 hours stratified by median plasma hemoglobin. Results: Between 2012 and 2014, 62 patients were randomly assigned to receive acetaminophen (n = 31) or no acetaminophen (n = 31). Median (interquartile range) reduction in creatinine after 72 hours was 23% (37% to 18%) in patients assigned to acetaminophen, versus 14% (29% to 0%) in patients assigned to no acetaminophen (P = .043). This difference in reduction was 37% (48% to 22%) versus 14% (30% to -71%) in patients with hemoglobin ≥45000 ng/mL (P = .010). The proportion with progressing kidney injury was higher among controls (subdistribution hazard ratio, 3.0; 95% confidence interval, 1.1 to 8.5; P = .034). PK-PD analyses showed that higher exposure to acetaminophen increased the probability of creatinine improvement. No patient fulfilled Hy's law for hepatotoxicity. Conclusions: In this proof-of-principle study, acetaminophen showed renoprotection without evidence of safety concerns in patients with severe falciparum malaria, particularly in those with prominent intravascular hemolysis. Clinical Trials Registration: NCT01641289.

Dembele L, Gupta DK, Lim MY-X, Ang X, Selva JJ, Chotivanich K, Nguon C, Dondorp AM, Bonamy GMC, Diagana TT, Bifani P. 2018. Imidazolopiperazines Kill both Rings and Dormant Rings in Wild-Type and K13 Artemisinin-Resistant Plasmodium falciparum In Vitro. Antimicrob Agents Chemother, 62 (5), | Show Abstract | Read more

Artemisinin (ART) resistance has spread through Southeast Asia, posing a serious threat to the control and elimination of malaria. ART resistance has been associated with mutations in the Plasmodium falciparum kelch-13 (Pfk13) propeller domain. Phenotypically, ART resistance is defined as delayed parasite clearance in patients due to the reduced susceptibility of early ring-stage parasites to the active metabolite of ART dihydroartemisinin (DHA). Early rings can enter a state of quiescence upon DHA exposure and resume growth in its absence. These quiescent rings are referred to as dormant rings or DHA-pretreated rings (here called dormant rings). The imidazolopiperazines (IPZ) are a novel class of antimalarial drugs that have demonstrated efficacy in early clinical trials. Here, we characterized the stage of action of the IPZ GNF179 and evaluated its activity against rings and dormant rings in wild-type and ART-resistant parasites. Unlike DHA, GNF179 does not induce dormancy. We show that GNF179 is more rapidly cidal against schizonts than against ring and trophozoite stages. However, with 12 h of exposure, the compound effectively kills rings and dormant rings of both susceptible and ART-resistant parasites within 72 h. We further demonstrate that in combination with ART, GNF179 effectively prevents recrudescence of dormant rings, including those bearing pfk13 propeller mutations.



European Pubmed Central

Tripura R, Peto TJ, Chea N, Chan D, Mukaka M, Sirithiranont P, Dhorda M, Promnarate C, Imwong M, von Seidlein L et al. 2018. A Controlled Trial of Mass Drug Administration to Interrupt Transmission of Multidrug-Resistant Falciparum Malaria in Cambodian Villages. Clin Infect Dis, 67 (6), pp. 817-826. | Show Abstract | Read more

Background: The increase in multidrug-resistant Plasmodium falciparum in Southeast Asia suggests a need for acceleration of malaria elimination. We evaluated the effectiveness and safety of mass drug administration (MDA) to interrupt malaria transmission. Methods: Four malaria-endemic villages in western Cambodia were randomized to 3 rounds of MDA (a 3-day course of dihydroartemisinin with piperaquine-phosphate), administered either early in or at the end of the study period. Comprehensive malaria treatment records were collected during 2014-2017. Subclinical parasite prevalence was estimated by ultrasensitive quantitative polymerase chain reaction quarterly over 12 months. Results: MDA coverage with at least 1 complete round was 88% (1999/2268), ≥2 rounds 73% (1645/2268), and all 3 rounds 58% (1310/2268). Plasmodium falciparum incidence in intervention and control villages was similar over the 12 months prior to the study: 39 per 1000 person-years (PY) vs 45 per 1000 PY (P = .50). The primary outcome, P. falciparum incidence in the 12 months after MDA, was lower in intervention villages (1.5/1000 PY vs 37.1/1000 PY; incidence rate ratio, 24.5 [95% confidence interval], 3.4-177; P = .002). Following MDA in 2016, there were no clinical falciparum malaria cases over 12 months (0/2044 PY) in all 4 villages. Plasmodium vivax prevalence decreased markedly in intervention villages following MDA but returned to approximately half the baseline prevalence by 12 months. No severe adverse events were attributed to treatment. Conclusions: Mass drug administrations achieved high coverage, were safe, and associated with the absence of clinical P. falciparum cases for at least 1 year. Clinical Trials Registration: NCT01872702.

Haniffa R, Beane A, Baker T, Riviello ED, Schell CO, Dondorp AM. 2018. Development and internal validation of the Simplified Mortality Score for the Intensive Care Unit (SMS-ICU). Acta Anaesthesiol Scand, 62 (3), pp. 407-408. | Read more

Vercesi V, Pisani L, van Tongeren PSI, Lagrand WK, Leopold SJ, Huson MMA, Henwood PC, Walden A, Smit M, Riviello ED et al. 2018. Correction to: External confirmation and exploration of the Kigali modification for diagnosing moderate or severe ARDS. Intensive Care Med, 44 (3), pp. 403-404. | Show Abstract | Read more

In Table 1 of this article, the numerical data were correct but the graphic part was imprecise.

Haniffa R, Beane A, Dondorp AM. 2018. Decision-making in the detection and management of patients with sepsis in resource-limited settings: the importance of clinical examination. Crit Care, 22 (1), pp. 53. | Read more

Beane A, Athapattu PL, Dondorp AM, Haniffa R. 2018. Commentary: Challenges and Priorities for Pediatric Critical Care Clinician-Researchers in Low- and Middle-Income Countries. Front Pediatr, 6 pp. 38. | Read more

Nguyen T-N, von Seidlein L, Nguyen T-V, Truong P-N, Hung SD, Pham H-T, Nguyen T-U, Le TD, Dao VH, Mukaka M et al. 2018. The persistence and oscillations of submicroscopic Plasmodium falciparum and Plasmodium vivax infections over time in Vietnam: an open cohort study. Lancet Infect Dis, 18 (5), pp. 565-572. | Show Abstract | Read more

BACKGROUND: A substantial proportion of Plasmodium species infections are asymptomatic with densities too low to be detectable with standard diagnostic techniques. The importance of such asymptomatic plasmodium infections in malaria transmission is probably related to their duration and density. To explore the duration of asymptomatic plasmodium infections and changes in parasite densities over time, a cohort of participants who were infected with Plasmodium parasites was observed over a 2-year follow-up period. METHODS: In this open cohort study, inhabitants of four villages in Vietnam were invited to participate in baseline and subsequent 3-monthly surveys up to 24 months, which included the collection of venous blood samples. Samples were batch-screened using ultra-sensitive (u)PCR (lower limit of detection of 22 parasites per mL). Participants found to be infected by uPCR during any of these surveys were invited to join a prospective cohort and provide monthly blood samples. We estimated the persistence of Plasmodium falciparum and Plasmodium vivax infections and changes in parasite densities over a study period of 24 months. FINDINGS: Between Dec 1, 2013, and Jan 8, 2016, 356 villagers participated in between one and 22 surveys. These study participants underwent 4248 uPCR evaluations (11·9 tests per participant). 1874 (32%) of 4248 uPCR tests indicated a plasmodium infection; 679 (36%) of 1874 tests were P falciparum monoinfections, 507 (27%) were P vivax monoinfections, 463 (25%) were co-infections with P falciparum and P vivax, and 225 (12%) were indeterminate species of Plasmodium. The median duration of P falciparum infection was 2 months (IQR 1-3); after accounting for censoring, participants had a 20% chance of having parasitaemia for 4 months or longer. The median duration of P vivax infection was 6 months (3-9), and participants had a 59% chance of having parasitaemia for 4 months or longer. The parasite densities of persistent infections oscillated; following ultralow-density infections, high-density infections developed frequently. INTERPRETATION: Persistent largely asymptomatic P vivax and P falciparum infections are common in this area of low seasonal malaria transmission. Infections with low-density parasitaemias can develop into much higher density infections at a later time, which are likely to sustain malaria endemicity. FUNDING: The Wellcome Trust, Bill & Melinda Gates Foundation.

Barber BE, Russell B, Grigg MJ, Zhang R, William T, Amir A, Lau YL, Chatfield MD, Dondorp AM, Anstey NM, Yeo TW. 2018. Reduced red blood cell deformability in Plasmodium knowlesi malaria. Blood Adv, 2 (4), pp. 433-443. | Show Abstract | Read more

The simian parasite Plasmodium knowlesi can cause severe and fatal human malaria. However, little is known about the pathogenesis of this disease. In falciparum malaria, reduced red blood cell deformability (RBC-D) contributes to microvascular obstruction and impaired organ perfusion. In P knowlesi infection, impaired microcirculatory flow has been observed in Macaca mulatta (rhesus macaques), unnatural hosts who develop severe and fatal disease. However, RBC-D has not been measured in human infection or in the natural host M fascicularis (long-tailed macaques). Using ektacytometry, we measured RBC-D in adults with severe and non-severe knowlesi and falciparum malaria and in healthy controls. In addition, we used micropipette aspiration to determine the relative stiffness of infected RBCs (iRBCs) and uninfected RBCs (uRBCs) in P knowlesi-infected humans and M fascicularis Ektacytometry demonstrated that RBC-D overall was reduced in human knowlesi malaria in proportion to disease severity, and in severe knowlesi malaria, it was comparable to that of severe falciparum malaria. RBC-D correlated inversely with parasitemia and lactate in knowlesi malaria and HRP2 in falciparum malaria, and it correlated with hemoglobin nadir in knowlesi malaria. Micropipette aspiration confirmed that in humans, P knowlesi infection increased stiffness of both iRBCs and uRBCs, with the latter mostly the result of echinocytosis. In contrast, in the natural host M fascicularis, echinocyte formation was not observed, and the RBC-D of uRBCs was unaffected. In unnatural primate hosts of P knowlesi, including humans, reduced deformability of iRBCs and uRBCs may represent a key pathogenic mechanism leading to microvascular accumulation, impaired organ perfusion, and anemia.

Peto TJ, Debackere M, Etienne W, Vernaeve L, Tripura R, Falq G, Davoeung C, Nguon C, Rekol H, von Seidlein L et al. 2018. Community participation during two mass anti-malarial administrations in Cambodia: lessons from a joint workshop. Malar J, 17 (1), pp. 53. | Show Abstract | Read more

Two mass drug administrations (MDA) against falciparum malaria were conducted in 2015-16, one as operational research in northern Cambodia, and the other as a clinical trial in western Cambodia. During an April 2017 workshop in Phnom Penh the field teams from Médecins Sans Frontières and the Mahidol-Oxford Tropical Medicine Research Unit discussed lessons for future MDAs.

Haniffa R, Isaam I, De Silva AP, Dondorp AM, De Keizer NF. 2018. Performance of critical care prognostic scoring systems in low and middle-income countries: a systematic review. Crit Care, 22 (1), pp. 18. | Show Abstract | Read more

BACKGROUND: Prognostic models-used in critical care medicine for mortality predictions, for benchmarking and for illness stratification in clinical trials-have been validated predominantly in high-income countries. These results may not be reproducible in low or middle-income countries (LMICs), not only because of different case-mix characteristics but also because of missing predictor variables. The study objective was to systematically review literature on the use of critical care prognostic models in LMICs and assess their ability to discriminate between survivors and non-survivors at hospital discharge of those admitted to intensive care units (ICUs), their calibration, their accuracy, and the manner in which missing values were handled. METHODS: The PubMed database was searched in March 2017 to identify research articles reporting the use and performance of prognostic models in the evaluation of mortality in ICUs in LMICs. Studies carried out in ICUs in high-income countries or paediatric ICUs and studies that evaluated disease-specific scoring systems, were limited to a specific disease or single prognostic factor, were published only as abstracts, editorials, letters and systematic and narrative reviews or were not in English were excluded. RESULTS: Of the 2233 studies retrieved, 473 were searched and 50 articles reporting 119 models were included. Five articles described the development and evaluation of new models, whereas 114 articles externally validated Acute Physiology and Chronic Health Evaluation, the Simplified Acute Physiology Score and Mortality Probability Models or versions thereof. Missing values were only described in 34% of studies; exclusion and or imputation by normal values were used. Discrimination, calibration and accuracy were reported in 94.0%, 72.4% and 25% respectively. Good discrimination and calibration were reported in 88.9% and 58.3% respectively. However, only 10 evaluations that reported excellent discrimination also reported good calibration. Generalisability of the findings was limited by variability of inclusion and exclusion criteria, unavailability of post-ICU outcomes and missing value handling. CONCLUSIONS: Robust interpretations regarding the applicability of prognostic models are currently hampered by poor adherence to reporting guidelines, especially when reporting missing value handling. Performance of mortality risk prediction models in LMIC ICUs is at best moderate, especially with limitations in calibration. This necessitates continued efforts to develop and validate LMIC models with readily available prognostic variables, perhaps aided by medical registries.

Srisutham S, Saralamba N, Sriprawat K, Mayxay M, Smithuis F, Nosten F, Pukrittayakamee S, Day NPJ, Dondorp AM, Imwong M. 2018. Genetic diversity of three surface protein genes in Plasmodium malariae from three Asian countries. Malar J, 17 (1), pp. 24. | Show Abstract | Read more

BACKGROUND: Genetic diversity of the three important antigenic proteins, namely thrombospondin-related anonymous protein (TRAP), apical membrane antigen 1 (AMA1), and 6-cysteine protein (P48/45), all of which are found in various developmental stages of Plasmodium parasites is crucial for targeted vaccine development. While studies related to the genetic diversity of these proteins are available for Plasmodium falciparum and Plasmodium vivax, barely enough information exists regarding Plasmodium malariae. The present study aims to demonstrate the genetic variations existing among these three genes in P. malariae by analysing their diversity at nucleotide and protein levels. METHODS: Three surface protein genes were isolated from 45 samples collected in Thailand (N = 33), Myanmar (N = 8), and Lao PDR (N = 4), using conventional polymerase chain reaction (PCR) assay. Then, the PCR products were sequenced and analysed using BioEdit, MEGA6, and DnaSP programs. RESULTS: The average pairwise nucleotide diversities (π) of P. malariae trap, ama1, and p48/45 were 0.00169, 0.00413, and 0.00029, respectively. The haplotype diversities (Hd) of P. malariae trap, ama1, and p48/45 were 0.919, 0.946, and 0.130, respectively. Most of the nucleotide substitutions were non-synonymous, which indicated that the genetic variations of these genes were maintained by positive diversifying selection, thus, suggesting their role as a potential target of protective immune response. Amino acid substitutions of P. malariae TRAP, AMA1, and P48/45 could be categorized to 17, 20, and 2 unique amino-acid variants, respectively. For further vaccine development, carboxyl terminal of P48/45 would be a good candidate according to conserved amino acid at low genetic diversity (π = 0.2-0.3). CONCLUSIONS: High mutational diversity was observed in P. malariae trap and ama1 as compared to p48/45 in P. malariae samples isolated from Thailand, Myanmar, and Lao PDR. Taken together, these results suggest that P48/45 might be a good vaccine candidate against P. malariae infection because of its sufficiently low genetic diversity and highly conserved amino acids especially on the carboxyl end.

Tunpattu S, Newey V, Sigera C, De Silva P, Goonarathna A, Aluthge I, Thambavita P, Perera R, Meegahawatte A, Isaam I et al. 2018. A short, structured skills training course for critical care physiotherapists in a lower-middle income country. Physiother Theory Pract, 34 (9), pp. 714-722. | Show Abstract | Read more

OBJECTIVES: The aim of this article is to describe the delivery and acceptability of a short, structured training course for critical care physiotherapy and its effects on the knowledge and skills of the participants in Sri Lanka, a lower-middle income country. METHODS: The two-day program combining short didactic sessions with small group workshops and skills stations was developed and delivered by local facilitators in partnership with an overseas specialist physiotherapist trainer. The impact was assessed using pre/post-course self-assessment, pre/post-course multiple-choice-question (MCQ) papers, and an end-of-course feedback questionnaire. RESULTS: Fifty-six physiotherapists (26% of critical care physiotherapists in Sri Lanka) participated. Overall confidence in common critical care physiotherapy skills improved from 11.6% to 59.2% in pre/post-training self-assessments, respectively. Post-course MCQ scores (mean score = 63.2) and percentage of passes (87.5%) were higher than pre-course scores (mean score = 36.6; percentage of passes = 12.5%). Overall feedback was very positive as 75% of the participants were highly satisfied with the course's contribution to improved critical care knowledge. CONCLUSIONS: This short, structured, critical care focused physiotherapy training has potential benefit to participating physiotherapists. Further, it provides an evidence that collaborative program can be planned and conducted successfully in a resource poor setting. This sustainable short course model may be adaptable to other resource-limited settings.

Adhikari B, Phommasone K, Kommarasy P, Soundala X, Souvanthong P, Pongvongsa T, Henriques G, Newton PN, White NJ, Day NPJ et al. 2018. Why do people participate in mass anti-malarial administration? Findings from a qualitative study in Nong District, Savannakhet Province, Lao PDR (Laos). Malar J, 17 (1), pp. 15. | Show Abstract | Read more

BACKGROUND: As a part of targeted malaria elimination (TME) in the Greater Mekong Sub-region (GMS), mass drug administration (MDA) with anti-malarials was conducted in four villages in Nong District, Savannakhet Province, Lao PDR (Laos). A high proportion of the target population participated in the MDA, with over 87% agreeing to take the anti-malarial. Drawing on qualitative data collected alongside the MDA, this article explores the factors that led to this high population coverage. METHODS: Qualitative data collection methods included observations, which were recorded in field notes, focus group discussions (FGDs), and semi-structured interviews (SSIs). Data were collected on local context, MDA-related knowledge, attitudes and perceptions. FGDs and SSIs were audio-recorded, transcribed and translated to English. All transcriptions and field notes underwent qualitative content analysis using QSR NVivo. RESULTS: Respondents recognized malaria as a health concern and described the need for a malaria control program. The risk of malaria including asymptomatic infection was explained in terms of participants' work in forest and fields, and poor hygiene. During the MDA rounds, there was an improvement in knowledge on the concept of asymptomatic malaria, the rationale of MDA and the blood test. In all four villages, poverty affected access to healthcare and the provision of free care by TME was highly appreciated. TME was jointly undertaken by research staff and local volunteers. Authorities were involved in all TME activities. Lao Theung communities were cohesive and community members tended to follow each other's behaviour closely including participation in MDA. Factors such as understanding the concept and rationale of the study, free health care, collaboration with the village volunteers, support from authorities and cohesive communities contributed in building trust and high population coverage in MDA. CONCLUSION: Future malaria control programmes can become successful in achieving the high coverage in MDAs drawing from the success of TME in Laos. A high population coverage in TME was a combination of various factors that included the community engagement to promote the concept and rationale of MDA for asymptomatic malaria in addition to their baseline understanding of malaria as a health concern, provision of free primary health care, partnering of the research with local volunteers and authorities, building social relationship with community members and the cohesive nature of the communities boosted the trust and participation in MDA.

Samanamalee S, Sigera PC, De Silva AP, Thilakasiri K, Rashan A, Wadanambi S, Jayasinghe KSA, Dondorp AM, Haniffa R. 2018. Traumatic brain injury (TBI) outcomes in an LMIC tertiary care centre and performance of trauma scores. BMC Anesthesiol, 18 (1), pp. 4. | Show Abstract | Read more

BACKGROUND: This study evaluates post-ICU outcomes of patients admitted with moderate and severe Traumatic Brain Injury (TBI) in a tertiary neurocritical care unit in an low middle income country and the performance of trauma scores: A Severity Characterization of Trauma, Trauma and Injury Severity Score, Injury Severity Score and Revised Trauma Score in this setting. METHODS: Adult patients directly admitted to the neurosurgical intensive care units of the National Hospital of Sri Lanka between 21st July 2014 and 1st October 2014 with moderate or severe TBI were recruited. A telephone administered questionnaire based on the Glasgow Outcome Scale Extended (GOSE) was used to assess functional outcome of patients at 3 and 6 months after injury. The economic impact of the injury was assessed before injury, and at 3 and 6 months after injury. RESULTS: One hundred and one patients were included in the study. Survival at ICU discharge, 3 and 6 months after injury was 68.3%, 49.5% and 45.5% respectively. Of the survivors at 3 months after injury, 43 (86%) were living at home. Only 19 (38%) patients had a good recovery (as defined by GOSE 7 and 8). Three months and six months after injury, respectively 25 (50%) and 14 (30.4%) patients had become "economically dependent". Selected trauma scores had poor discriminatory ability in predicting mortality. CONCLUSIONS: This observational study of patients sustaining moderate or severe TBI in Sri Lanka (a LMIC) reveals only 46% of patients were alive at 6 months after ICU discharge and only 20% overall attained a good (GOSE 7 or 8) recovery. The social and economic consequences of TBI were long lasting in this setting. Injury Severity Score, Revised Trauma Score, A Severity Characterization of Trauma and Trauma and Injury Severity Score, all performed poorly in predicting mortality in this setting and illustrate the need for setting adapted tools.

Schultz MJ, Bos LD, Dondorp AM. 2018. How to improve quality of research in intensive care medicine. Ann Transl Med, 6 (2), pp. 35. | Show Abstract | Read more

This paper discusses several approaches to improve quality of research in intensive care medicine. The baseline standard of care is important in randomized controlled trials. If standard of care is low, trialists could consider improving this before starting the trial. Implementation studies and efficacy trials should not be mixed up. Trialists could further try to increase prognostic as well as predictive enrichment, e.g., through biological phenotyping. Robustness of statistical findings can increase by enrolling sufficiently high numbers of patients and minimizing loss to follow-up.

Leopold SJ, Ghose A, Plewes KA, Mazumder S, Pisani L, Kingston HWF, Paul S, Barua A, Sattar MA, Huson MAM et al. 2018. Point-of-care lung ultrasound for the detection of pulmonary manifestations of malaria and sepsis: An observational study. PLoS One, 13 (12), pp. e0204832. | Show Abstract | Read more

INTRODUCTION: Patients with severe malaria or sepsis are at risk of developing life-threatening acute respiratory distress syndrome (ARDS). The objective of this study was to evaluate point-of-care lung ultrasound as a novel tool to determine the prevalence and early signs of ARDS in a resource-limited setting among patients with severe malaria or sepsis. MATERIALS AND METHODS: Serial point-of-care lung ultrasound studies were performed on four consecutive days in a planned sub study of an observational cohort of patients with malaria or sepsis in Bangladesh. We quantified aeration patterns across 12 lung regions. ARDS was defined according to the Kigali Modification of the Berlin Definition. RESULTS: Of 102 patients enrolled, 71 had sepsis and 31 had malaria. Normal lung ultrasound findings were observed in 44 patients on enrolment and associated with 7% case fatality. ARDS was detected in 10 patients on enrolment and associated with 90% case fatality. All patients with ARDS had sepsis, 4 had underlying pneumonia. Two patients developing ARDS during hospitalisation already had reduced aeration patterns on enrolment. The SpO2/FiO2 ratio combined with the number of regions with reduced aeration was a strong prognosticator for mortality in patients with sepsis (AUROC 91.5% (95% Confidence Interval: 84.6%-98.4%)). CONCLUSIONS: This study demonstrates the potential usefulness of point-of-care lung ultrasound to detect lung abnormalities in patients with malaria or sepsis in a resource-constrained hospital setting. LUS was highly feasible and allowed to accurately identify patients at risk of death in a resource limited setting.

Adhikari B, Phommasone K, Pongvongsa T, Soundala X, Koummarasy P, Henriques G, Peto TJ, Seidlein LV, White NJ, Day NPJ et al. 2018. Perceptions of asymptomatic malaria infection and their implications for malaria control and elimination in Laos. PLoS One, 13 (12), pp. e0208912. | Show Abstract | Read more

BACKGROUND: In the Greater Mekong Sub-region (GMS), malaria elimination efforts are targeting the asymptomatic parasite reservoirs. Understanding community perceptions about asymptomatic malaria infections and interventions that target this reservoir is critical to the design of community engagement. This article examines knowledge, attitudes, perceptions and practices related to asymptomatic malaria infections and mass drug administration (MDA) in malaria-endemic villages in southern Savannakhet Province, Laos. METHODS: A questionnaire consisting of questions on socio-demographic characteristics, knowledge, attitudes, perceptions and practices on malaria and MDA was administered to each household head or representative (n = 281) in four villages. These topics were also further discussed in 12 single-gender focus group discussions (FGDs). The FGDs were conducted in all four villages and consisted of eight to 10 participants. RESULTS: A minority (14.2%; 40/281) of respondents agreed that a seemingly healthy person could have malaria parasite in his or her blood. Half (52%; 146/281) disagreed and one third (33.8%, 95/281) were unsure. Respondents who responded that "MDA aims to cure everyone" [AOR = 4.6; CI: 1.6-13.1], "MDA is to make our community malaria free" [AOR = 3.3; CI: 1.3-8.1] and "I will take part in future MDA" [AOR = 9.9; CI: 1.2-78.8] were more likely to accept the idea of asymptomatic malaria. During FGDs, respondents recalled signs and symptoms of malaria (fever, chills and headache), and described malaria as a major health problem. Symptomatic and asymptomatic malaria infections were associated with their work in the forest and living conditions. Measures described to eliminate malaria included using mosquito nets, wearing long-sleeved clothes and taking medicine when symptomatic. Most respondents were unaware of MDA as a tool to eliminate malaria. CONCLUSIONS: Awareness of asymptomatic malaria infections, and MDA as a tool to eliminate malaria, was low. With the need to target asymptomatic malaria carriers for elimination efforts in the GMS, as well as informing target groups about asymptomatic infection, accompanying community engagement must build trust in interventions through the active collaboration of government stakeholders, key local persons and community members. This entails training and devolving responsibilities to the community members to implement and sustain the control and elimination efforts.

Hashmi M, Beane A, Taqi A, Memon MI, Athapattu P, Khan Z, Dondorp AM, Haniffa R. 2018. Pakistan Registry of Intensive CarE (PRICE): Expanding a lower middle-income, clinician-designed critical care registry in South Asia Journal of the Intensive Care Society, | Show Abstract | Read more

© The Intensive Care Society 2018. Introduction: In resource-limited settings – with inequalities in access to and outcomes for trauma, surgical and critical care – intensive care registries are uncommon. Aim: The Pakistan Society of Critical Care Medicine, Intensive Care Society (UK) and the Network for Improving Critical Care Systems and Training (NICST) aim to implement a clinician-led real-time national intensive care registry in Pakistan: the Pakistan Registry of Intensive CarE (PRICE). Method: This was adapted from a successful clinician co-designed national registry in Sri Lanka; ICU information has been linked to real-time dashboards, providing clinicians and administrators individual patient and service delivery activity respectively. Output: Commenced in August 2017, five ICU’s (three administrative regions – 104 beds) were recruited and have reported over 1100 critical care admissions to PRICE. Impact and future: PRICE is being rolled out nationally in Pakistan and will provide continuous granular healthcare information necessary to empower clinicians to drive setting-specific priorities for service improvement and research.

Kingston HW, Ghose A, Plewes K, Ishioka H, Leopold SJ, Maude RJ, Paul S, Intharabut B, Silamut K, Woodrow C et al. 2017. Disease Severity and Effective Parasite Multiplication Rate in Falciparum Malaria. Open Forum Infect Dis, 4 (4), pp. ofx169. | Show Abstract | Read more

Patients presenting with severe falciparum malaria in a Bangladeshi tertiary hospital had higher total parasite burden, estimated by parasitemia and plasma PfHRP2, than uncomplicated malaria patients despite shorter fever duration. This suggests that higher parasite multiplication rates (PMR) contribute to causing the higher biomass found in severe disease. Compared with patients without a history of previous malaria, patients with previous malaria carried a lower parasite biomass with similar fever duration at presentation, suggesting that host immunity reduces the PMR.

Haniffa R, Pubudu De Silva A, de Azevedo L, Baranage D, Rashan A, Baelani I, Schultz MJ, Dondorp AM, Dünser MW. 2018. Improving ICU services in resource-limited settings: Perceptions of ICU workers from low-middle-, and high-income countries. J Crit Care, 44 pp. 352-356. | Show Abstract | Read more

PURPOSE: To evaluate perceptions of intensive care unit (ICU) workers from low-and-middle income countries (LMICs) and high income countries (HICs). MATERIALS AND METHODS: A cross sectional design. Data collected from doctors using an anonymous online, questionnaire. RESULTS: Hundred seventy-five from LMICs and 43 from HICs participated. Barriers in LMICs were lack of formal training (Likert score median 3 [inter quartile range 3]), lack of nurses (3[3]) and low wages (3[4]). Strategies for LMICs improvement were formal training of ICU staff (4[3]), an increase in number of ICU nurses (4[2]), collection of outcome data (3[4]), as well as maintenance of available equipment [3(3)]. The most useful role of HIC ICU staff was training of LMIC staff (4[2]). Donation of equipment [2(4)], drugs [2(4)], and supplies (2[4]) perceived to be of limited usefulness. The most striking difference between HIC and LMIC staff was the perception on the lack of physician leadership as an obstacle to ICU functioning (4[3] vs. 0[2], p<0.005). CONCLUSION: LMICs ICU workers perceived lack of training, lack of nurses, and low wages as major barriers to functioning. Training, increase of nurse workforce, and collection of outcome data were proposed as useful strategies to improve LMIC ICU services.

Beane A, De Silva AP, Munasinghe S, De Silva N, Arachchige SJ, Athapattu P, Sigera PC, Miskin MF, Liyanagama PM, Rathnayake RMD et al. 2017. Comparison of quick sequential organ failure assessment and modified systemic inflammatory response syndrome criteria in a lower middle income setting Journal of Acute Medicine, 7 (4), pp. 141-148. | Show Abstract | Read more

Introduction: Quick Sequential Organ Failure Assessment (qSOFA) is potentially feasible tool to identify risk of deteriorating in the context of infection for to use in resource limited settings. Purpose: To compare the discriminative ability of qSOFA and a simplified systemic inflammatory response syndrome (SIRS) score to detect deterioration in patients admitted with infection. Methods: Observational study conducted at District General Hospital Monaragala, Sri Lanka, utilising bedside available observations extracted from healthcare records. Discrimination was evaluated using area under the receiver operating curve (AUROC). 15,577 consecutive adult ( ≥ 18 years) admissions were considered. Patients classified as having infection per ICD-10 diagnostic coding were included. Results: Both scores were evaluated for their ability to discriminate patients at risk of death or a composite adverse outcome (death, cardiac arrest, intensive care unit [ICU], admission or critical care transfer). 1844 admissions (11.8%) were due to infections with 20 deaths (1.1%), 29 ICU admissions (1.6%), 30 cardiac arrests and 9 clinical transfers to a tertiary hospital (0.5%). Sixty-seven (3.6%) patients experienced at least one event. Complete datasets were available for qSOFA in 1238 (67.14%) and for simplified SIRS (mSIRS) in 1628 (88.29%) admissions. Mean (SD) qSOFA score and mSIRS score at admission were 0.58 (0.69) and 0.66 (0.79) respectively. Both demonstrated poor discrimination for predicting adverse outcome AUROC = 0.625; 95% CI, 0.56-0.69 and AUROC = 0.615; 95% CI, 0.55- 0.69 respectively) with no significant difference (p value = 0.74). Similarly, both systems had poor discrimination for predicting deaths (AUROC = 0.685; 95% CI, 0.55-0.82 and AUROC = 0.629; 95% CI, 0.50-0.76 respectively) with no statistically significant difference (p value = 0.31). Conclusions: qSOFA at admission had poor discrimination and was not superior to the bedside observations featured in SIRS. Availability of observations, especially for mentation, is poor in these settings and requires strategies to improve reporting.

Plewes K, Turner GDH, Dondorp AM. 2018. Pathophysiology, clinical presentation, and treatment of coma and acute kidney injury complicating falciparum malaria. Curr Opin Infect Dis, 31 (1), pp. 69-77. | Show Abstract | Read more

PURPOSE OF REVIEW: Cerebral impairment and acute kidney injury (AKI) are independent predictors of mortality in both adults and children with severe falciparum malaria. In this review, we present recent advances in understanding the pathophysiology, clinical features, and management of these complications of severe malaria, and discuss future areas of research. RECENT FINDINGS: Cerebral malaria and AKI are serious and well recognized complications of severe malaria. Common pathophysiological pathways include impaired microcirculation, due to sequestration of parasitized erythrocytes, systemic inflammatory responses, and endothelial activation. Recent MRI studies show significant brain swelling in both adults and children with evidence of posterior reversible encephalopathy syndrome-like syndrome although targeted interventions including mannitol and dexamethasone are not beneficial. Recent work shows association of cell-free hemoglobin oxidation stress involved in the pathophysiology of AKI in both adults and children. Paracetamol protected renal function likely by inhibiting cell-free-mediated oxidative stress. It is unclear if heme-mediated endothelial activation or oxidative stress is involved in cerebral malaria. SUMMARY: The direct causes of cerebral and kidney dysfunction remain incompletely understood. Optimal treatment involves prompt diagnosis and effective antimalarial treatment with artesunate. Renal replacement therapy reduces mortality in AKI but delayed diagnosis is an issue.

Leitgeb AM, Charunwatthana P, Rueangveerayut R, Uthaisin C, Silamut K, Chotivanich K, Sila P, Moll K, Lee SJ, Lindgren M et al. 2017. Inhibition of merozoite invasion and transient de-sequestration by sevuparin in humans with Plasmodium falciparum malaria. PLoS One, 12 (12), pp. e0188754. | Show Abstract | Read more

SEVERE MALARIA: Even with the best available treatment, the mortality from severe Plasmodium falciparum malaria remains high. Typical features at death are high parasite loads and obstructed micro- vasculature. Infected erythrocytes (IE) containing mature parasites bind to the host receptor heparan sulfate, which is also an important receptor for merozoite invasion. To block merozoite invasion has not previously been proposed as an adjunctive therapeutic approach but it may preclude the early expansion of an infection that else leads to exacerbated sequestration and death. SEVUPARIN IN PHASE I STUDY: The drug sevuparin was developed from heparin because heparan sulfate and heparin are nearly identical, so the rationale was that sevuparin would act as a decoy receptor during malaria infection. A phase I study was performed in healthy male volunteers and sevuparin was found safe and well tolerated. SEVUPARIN IN PHASE I/II CLINICAL STUDY: A phase I/II clinical study was performed in which sevuparin was administered via short intravenous infusions to malaria patients with uncomplicated malaria who were also receiving atovaquone/proguanil treatment. This was a Phase I/II, randomized, open label, active control, parallel assignment study. Sevuparin was safe and well tolerated in the malaria patients. The mean relative numbers of ring-stage IEs decreased after a single sevuparin infusion and mature parasite IEs appeared transiently in the circulation. The effects observed on numbers of merozoites and throphozoites in the circulation, were detected already one hour after the first sevuparin injection. Here we report the development of a candidate drug named sevuparin that both blocks merozoite invasion and transiently de-sequesters IE in humans with P. falciparum malaria. TRIAL REGISTRATION: NCT01442168.

Beane A, Ambepitiyawaduge PDS, Thilakasiri K, Stephens T, Padeniya A, Athapattu P, Mahipala PG, Sigera PC, Dondorp AM, Haniffa R. 2017. Practices and Perspectives in Cardiopulmonary Resuscitation Attempts and the Use of Do Not Attempt Resuscitation Orders: A Cross-sectional Survey in Sri Lanka. Indian J Crit Care Med, 21 (12), pp. 865-868. | Show Abstract | Read more

Objective: The objective of this study is to describe the characteristics of in-hospital cardiopulmonary resuscitation (CPR) attempts, the perspectives of junior doctors involved in those attempts and the use of do not attempt resuscitation (DNAR) orders. Methods: A cross-sectional telephone survey aimed at intern doctors working in all medical/surgical wards in government hospitals. Interns were interviewed based on the above objective. Results: A total of 42 CPR attempts from 82 hospitals (338 wards) were reported, 3 of which were excluded as the participating doctor was unavailable for interview. 16 (4.7%) wards had at least 1 patient with an informal DNAR order. 42 deaths were reported. 8 deaths occurred without a known resuscitation attempt, of which 6 occurred on wards with an informal DNAR order in place. 39 resuscitations were attempted. Survival at 24 h was 2 (5.1%). In 5 (13%) attempts, CPR was the only intervention reported. On 25 (64%) occasions, doctors were "not at all" or "only a little bit surprised" by the arrest. Conclusions: CPR attempts before death in hospitals across Sri Lanka is prevalent. DNAR use remains uncommon.

malERA Refresh Consultative Panel on Insecticide and Drug Resistance. 2017. malERA: An updated research agenda for insecticide and drug resistance in malaria elimination and eradication. PLoS Med, 14 (11), pp. e1002450. | Show Abstract | Read more

Resistance to first-line treatments for Plasmodium falciparum malaria and the insecticides used for Anopheles vector control are threatening malaria elimination efforts. Suboptimal responses to drugs and insecticides are both spreading geographically and emerging independently and are being seen at increasing intensities. Whilst resistance is unavoidable, its effects can be mitigated through resistance management practices, such as exposing the parasite or vector to more than one selective agent. Resistance contributed to the failure of the 20th century Global Malaria Eradication Programme, and yet the global response to this issue continues to be slow and poorly coordinated-too often, too little, too late. The Malaria Eradication Research Agenda (malERA) Refresh process convened a panel on resistance of both insecticides and antimalarial drugs. This paper outlines developments in the field over the past 5 years, highlights gaps in knowledge, and proposes a research agenda focused on managing resistance. A deeper understanding of the complex biological processes involved and how resistance is selected is needed, together with evidence of its public health impact. Resistance management will require improved use of entomological and parasitological data in decision making, and optimisation of the useful life of new and existing products through careful implementation, combination, and evaluation. A proactive, collaborative approach is needed from basic science and the development of new tools to programme and policy interventions that will ensure that the armamentarium of drugs and insecticides is sufficient to deal with the challenges of malaria control and its elimination.

Tun STT, von Seidlein L, Pongvongsa T, Mayxay M, Saralamba S, Kyaw SS, Chanthavilay P, Celhay O, Nguyen TD, Tran TN-A et al. 2017. Towards malaria elimination in Savannakhet, Lao PDR: mathematical modelling driven strategy design. Malar J, 16 (1), pp. 483. | Show Abstract | Read more

BACKGROUND: The number of Plasmodium falciparum malaria cases around the world has decreased substantially over the last 15 years, but with the spread of resistance against anti-malarial drugs and insecticides, this decline may not continue. There is an urgent need to consider alternative, accelerated strategies to eliminate malaria in countries like Lao PDR, where there are a few remaining endemic areas. A deterministic compartmental modelling tool was used to develop an integrated strategy for P. falciparum elimination in the Savannakhet province of Lao PDR. The model was designed to include key aspects of malaria transmission and integrated control measures, along with a user-friendly interface. RESULTS: Universal coverage was the foundation of the integrated strategy, which took the form of the deployment of community health workers who provided universal access to early diagnosis, treatment and long-lasting insecticidal nets. Acceleration was included as the deployment of three monthly rounds of mass drug administration targeted towards high prevalence villages, with the addition of three monthly doses of the RTS,S vaccine delivered en masse to the same high prevalence sub-population. A booster dose of vaccine was added 1 year later. The surveillance-as-intervention component of the package involved the screening and treatment of individuals entering the simulated population. CONCLUSIONS: In this modelling approach, the sequential introduction of a series of five available interventions in an integrated strategy was predicted to be sufficient to stop malaria transmission within a 3-year period. These interventions comprised universal access to early diagnosis and adequate treatment, improved access to long-lasting insecticidal nets, three monthly rounds of mass drug administration together with RTS,S vaccination followed by a booster dose of vaccine, and screening and treatment of imported cases.

Parker DM, Tripura R, Peto TJ, Maude RJ, Nguon C, Chalk J, Sirithiranont P, Imwong M, von Seidlein L, White NJ, Dondorp AM. 2017. A multi-level spatial analysis of clinical malaria and subclinical Plasmodium infections in Pailin Province, Cambodia. Heliyon, 3 (11), pp. e00447. | Show Abstract | Read more

Background: The malaria burden is decreasing throughout the Greater Mekong Subregion, however transmission persists in some areas. Human movement, subclinical infections and complicated transmission patterns contribute to the persistence of malaria. This research describes the micro-geographical epidemiology of both clinical malaria and subclinical Plasmodium infections in three villages in Western Cambodia. Methods: Three villages in Western Cambodia were selected for the study based on high reported Plasmodium falciparum incidence. A census was conducted at the beginning of the study, including demographic information and travel history. The total population was 1766. Cross-sectional surveys were conducted every three months from June 2013 to June 2014. Plasmodium infections were detected using an ultra-sensitive, high-volume, quantitative polymerase chain reaction (uPCR) technique. Clinical episodes were recorded by village health workers. The geographic coordinates (latitude and longitude) were collected for all houses and all participants were linked to their respective houses using a demographic surveillance system. Written informed consent was obtained from all participants. Results: Most clinical episodes and subclinical infections occurred within a single study village. Clinical Plasmodium vivax episodes clustered spatially in each village but only lasted for a month. In one study village subclinical infections clustered in geographic proximity to clusters of clinical episodes. The largest risk factor for clinical P. falciparum episodes was living in a house where another clinical P. falciparum episode occurred (model adjusted odds ratio (AOR): 6.9; CI: 2.3-19. 8). Subclinical infections of both P. vivax and P. falciparum were associated with clinical episodes of the same species (AOR: 5.8; CI: 1.5-19.7 for P. falciparum and AOR: 14.6; CI: 8.6-25.2 for P. vivax) and self-reported overnight visits to forested areas (AOR = 3.8; CI: 1.8-7. 7 for P. falciparum and AOR = 2.9; CI: 1.7-4.8 for P. vivax). Discussion: Spatial clustering within the villages was transient, making the prediction of spatial clusters difficult. Interventions that are dependent on predicting spatial clusters (such as reactive case detection) would only have detected a small proportion of cases unless the entire village was screened within a limited time frame and with a highly sensitive diagnostic test. Subclinical infections may be acquired outside of the village (particularly in forested areas) and may play an important role in transmission.

Son DH, Thuy-Nhien N, von Seidlein L, Le Phuc-Nhi T, Phu NT, Tuyen NTK, Tran NH, Van Dung N, Van Quan B, Day NPJ et al. 2017. The prevalence, incidence and prevention of Plasmodium falciparum infections in forest rangers in Bu Gia Map National Park, Binh Phuoc province, Vietnam: a pilot study. Malar J, 16 (1), pp. 444. | Show Abstract | Read more

BACKGROUND: Prophylaxis for high-risk populations, such as forest workers, could be one component for malaria elimination in the Greater Mekong Sub-region. A study was conducted to assess the malaria incidence in forest rangers and the feasibility of malaria prophylaxis for rangers sleeping in forest camps. METHODS: Forest rangers deployed in the Bu Gia Map National Park, Vietnam were invited to participate in the study. Plasmodium infections were cleared using presumptive treatment, irrespective of malaria status, with a 3-day course dihydroartemisinin/piperaquine (DP) and a 14-day course of primaquine. Before returning to the forest, study participants were randomly allocated to a 3-day course of DP or placebo. Fifteen days after returning from their forest deployment the participants were tested for Plasmodium infections using uPCR. RESULTS: Prior to treatment, 30 of 150 study participants (20%) were found to be infected with Plasmodium. Seventeen days (median) after enrolment the rangers were randomized to DP or placebo 2 days before returning to forest camps where they stayed between 2 and 20 days (median 9.5 days). One ranger in the DP-prophylaxis arm and one in the placebo arm were found to be infected with Plasmodium falciparum 15 days (median) after returning from the forest. The evaluable P. falciparum isolates had molecular markers indicating resistance to artemisinins (K13-C580Y) and piperaquine (plasmepsin), but none had multiple copies of pfmdr1 associated with mefloquine resistance. CONCLUSION: Anti-malarial prophylaxis in forest rangers is feasible. The findings of the study highlight the threat of multidrug-resistant malaria. Trial registration NCT02788864.

De Silva AP, Baranage DDS, Padeniya A, Sigera PC, De Alwis S, Abayadeera AU, Mahipala PG, Jayasinghe KS, Dondorp AM, Haniffa R. 2017. Critical Care Junior Doctors' Profile in a Lower Middle-income Country: A National Cross-sectional Survey. Indian J Crit Care Med, 21 (11), pp. 733-739. | Show Abstract | Read more

Background and Aims: Retention of junior doctors in specialties such as critical care is difficult, especially in resource-limited settings. This study describes the profile of junior doctors in adult state intensive care units in Sri Lanka, a lower middle-income country. Materials and Methods: This was a national cross-sectional survey using an anonymous self-administered electronic questionnaire. Results: Five hundred and thirty-nine doctors in 93 Intensive Care Units (ICUs) were contacted, generating 207 responses. Just under half of the respondents (93, 47%) work exclusively in ICUs. Most junior doctors (150, 75.8%) had no previous exposure to anesthesia and 134 (67.7%) had no previous ICU experience while 116 (60.7%) ICU doctors wished to specialize in critical care. However, only a few (12, 6.3%) doctors had completed a critical care diploma course. There was a statistically significant difference (P < 0.05) between the self-assessed confidence of anesthetic background junior doctors and non-anesthetists. The overall median competency for doctors improves with the length of ICU experience and is statistically significant (P < 0.05). ICU postings were less happy and more stressful compared to the last non-ICU posting (P < 0.05 for both). The vast majority, i.e., 173 (88.2%) of doctors felt the care provided for patients in their ICUs was good, very good, or excellent while 71 doctors (36.2%) would be happy to recommend the ICU where they work to a relative with the highest possible score of 10. Conclusion: Measures to improve training opportunities for these doctors and strategies to improve their retention in ICUs need to be addressed.

Misango D, Pattnaik R, Baker T, Dünser MW, Dondorp AM, Schultz MJ, Global Intensive Care Working Group, of the European Society of Intensive Care Medicine (ESICM) and the Mahidol Oxford Tropical Medicine Research Unit (MORU) in Bangkok, Thailand. 2017. Haemodynamic assessment and support in sepsis and septic shock in resource-limited settings. Trans R Soc Trop Med Hyg, 111 (11), pp. 483-489. | Show Abstract | Read more

Background: Recommendations for haemodynamic assessment and support in sepsis and septic shock in resource-limited settings are largely lacking. Methods: A task force of six international experts in critical care medicine, all of them members of the Global Intensive Care Working Group of the European Society of Intensive Care Medicine and with extensive bedside experience in resource-limited intensive care units, reviewed the literature and provided recommendations regarding haemodynamic assessment and support, keeping aspects of efficacy and effectiveness, availability and feasibility and affordability and safety in mind. Results: We suggest using capillary refill time, skin mottling scores and skin temperature gradients; suggest a passive leg raise test to guide fluid resuscitation; recommend crystalloid solutions as the initial fluid of choice; recommend initial fluid resuscitation with 30 ml/kg in the first 3 h, but with extreme caution in settings where there is a lack of mechanical ventilation; recommend against an early start of vasopressors; suggest starting a vasopressor in patients with persistent hypotension after initial fluid resuscitation with at least 30 ml/kg, but earlier when there is lack of vasopressors and mechanical ventilation; recommend using norepinephrine (noradrenaline) as a first-line vasopressor; suggest starting an inotrope with persistence of plasma lactate >2 mmol/L or persistence of skin mottling or prolonged capillary refill time when plasma lactate cannot be measured, and only after initial fluid resuscitation; suggest the use of dobutamine as a first-line inotrope; recommend administering vasopressors through a central venous line and suggest administering vasopressors and inotropes via a central venous line using a syringe or infusion pump when available. Conclusion: Recommendations for haemodynamic assessment and support in sepsis and septic shock in resource-limited settings have been developed by a task force of six international experts in critical care medicine with extensive practical experience in resource-limited settings.

van der Meer AJ, Zeerleder S, Blok DC, Kager LM, Lede IO, Rahman W, Afroz R, Ghose A, Visser CE, Zahed ASM et al. 2017. Neutrophil extracellular traps in patients with pulmonary tuberculosis. Respir Res, 18 (1), pp. 181. | Show Abstract | Read more

Tuberculosis is a devastating infectious disease causing many deaths worldwide. Recent investigations have implicated neutrophil extracellular traps (NETs) in the host response to tuberculosis. The aim of the current study was to obtain evidence for NETs release in the circulation during human tuberculosis. For this we measured the plasma concentrations of nucleosomes in conjunction with neutrophil elastase, in 64 patients with active pulmonary tuberculosis and 32 healthy controls. Patients with active tuberculosis had elevated plasma levels of nucleosomes and elastase when compared with local healthy blood donors. Furthermore nucleosome and elastase levels showed a positive correlation. These findings provide the first evidence for the release of NETs in the circulation of patients with active pulmonary tuberculosis.

Pisani L, Roozeman J-P, Simonis FD, Giangregorio A, van der Hoeven SM, Schouten LR, Horn J, Neto AS, Festic E, Dondorp AM et al. 2017. Risk stratification using SpO2/FiO2 and PEEP at initial ARDS diagnosis and after 24 h in patients with moderate or severe ARDS. Ann Intensive Care, 7 (1), pp. 108. | Show Abstract | Read more

BACKGROUND: We assessed the potential of risk stratification of ARDS patients using SpO2/FiO2 and positive end-expiratory pressure (PEEP) at ARDS onset and after 24 h. METHODS: We used data from a prospective observational study in patients admitted to a mixed medical-surgical intensive care unit of a university hospital in the Netherlands. Risk stratification was by cutoffs for SpO2/FiO2 and PEEP. The primary outcome was in-hospital mortality. Patients with moderate or severe ARDS with a length of stay of > 24 h were included in this study. Patients were assigned to four predefined risk groups: group I (SpO2/FiO2 ≥ 190 and PEEP < 10 cm H2O), group II (SpO2/FiO2 ≥ 190 and PEEP ≥ 10 cm), group III (SpO2/FiO2 < 190 and PEEP < 10 cm H2O) and group IV (SpO2/FiO2 < 190 and PEEP ≥ 10 cm H2O). RESULTS: The analysis included 456 patients. SpO2/FiO2 and PaO2/FiO2 had a strong relationship (P < 0.001, R 2 = 0.676) that could be described in a linear regression equation (SpO2/FiO2 = 42.6 + 1.0 * PaO2/FiO2). Risk stratification at initial ARDS diagnosis resulted in groups that had no differences in in-hospital mortality. Risk stratification at 24 h resulted in groups with increasing mortality rates. The association between group assignment at 24 h and outcome was confounded by several factors, including APACHE IV scores, arterial pH and plasma lactate levels, and vasopressor therapy. CONCLUSIONS: In this cohort of patients with moderate or severe ARDS, SpO2/FiO2 and PaO2/FiO2 have a strong linear relationship. In contrast to risk stratification at initial ARDS diagnosis, risk stratification using SpO2/FiO2 and PEEP after 24 h resulted in groups with worsening outcomes. Risk stratification using SpO2/FiO2 and PEEP could be practical, especially in resource-limited settings.

Adhikari B, Phommasone K, Pongvongsa T, Kommarasy P, Soundala X, Henriques G, White NJ, Day NPJ, Dondorp AM, von Seidlein L et al. 2017. Factors associated with population coverage of targeted malaria elimination (TME) in southern Savannakhet Province, Lao PDR. Malar J, 16 (1), pp. 424. | Show Abstract | Read more

BACKGROUND: Targeted malaria elimination (TME) in Lao PDR (Laos) included three rounds of mass drug administrations (MDA) against malaria followed by quarterly blood surveys in two villages in Nong District at Savannakhet Province. The success of MDA largely depends upon the efficacy of the anti-malarial drug regimen, local malaria epidemiology and the population coverage. In order to explore the reasons for participation in TME, a quantitative survey was conducted after the completion of the three rounds of MDA. METHODS: The survey was conducted in two villages with a total of 158 households in July and August 2016. Among the 973 villagers eligible for participation in the MDA, 158 (16.2%) adults (> 18 years) were selected, one each from every household for the interviews using a quantitative questionnaire. RESULTS: 150/158 (94.9%) respondents participated at least in one activity (taking medicine or testing their blood) of TME. 141/150 (94.0%) respondents took part in the MDA and tested their blood in all three rounds. 17/158 (10.7%) were partial or non-participants in three rounds of MDA. Characteristics of respondents which were independently associated with completion of three rounds of MDA included: attending TME meetings [AOR = 12.0 (95% CI 1.1-20.5) (p = 0.03)], knowing that malaria can be diagnosed through blood tests [AOR = 5.6 (95% CI 1.0-32.3) (p = 0.05)], all members from household participated [AOR = 4.2 (95% CI 1.3-14.0) (p = 0.02)], liking all aspects of TME [AOR = 17.2 (95% CI 1.6-177.9) (p = 0.02)] and the perception that TME was important [AOR = 14.9 (95% CI 1.3-171.2) (p = 0.03)]. CONCLUSION: Complete participation in TME was significantly associated with participation in community engagement activities, knowledge that the blood tests were for malaria diagnosis, family members' participation at TME and perceptions that TME was worthwhile. A responsive approach to community engagement that includes formative research and the involvement of community members may increase the uptake of the intervention.

Vellinga NAR, Boerma EC, Koopmans M, Donati A, Dubin A, Shapiro NI, Pearse RM, van der Voort PHJ, Dondorp AM, Bafi T et al. 2017. Mildly elevated lactate levels are associated with microcirculatory flow abnormalities and increased mortality: a microSOAP post hoc analysis. Crit Care, 21 (1), pp. 255. | Show Abstract | Read more

BACKGROUND: Mildly elevated lactate levels (i.e., 1-2 mmol/L) are increasingly recognized as a prognostic finding in critically ill patients. One of several possible underlying mechanisms, microcirculatory dysfunction, can be assessed at the bedside using sublingual direct in vivo microscopy. We aimed to evaluate the association between relative hyperlactatemia, microcirculatory flow, and outcome. METHODS: This study was a predefined subanalysis of a multicenter international point prevalence study on microcirculatory flow abnormalities, the Microcirculatory Shock Occurrence in Acutely ill Patients (microSOAP). Microcirculatory flow abnormalities were assessed with sidestream dark-field imaging. Abnormal microcirculatory flow was defined as a microvascular flow index (MFI) < 2.6. MFI is a semiquantitative score ranging from 0 (no flow) to 3 (continuous flow). Associations between microcirculatory flow abnormalities, single-spot lactate measurements, and outcome were analyzed. RESULTS: In 338 of 501 patients, lactate levels were available. For this substudy, all 257 patients with lactate levels ≤ 2 mmol/L (median [IQR] 1.04 [0.80-1.40] mmol/L) were included. Crude ICU mortality increased with each lactate quartile. In a multivariable analysis, a lactate level > 1.5 mmol/L was independently associated with a MFI < 2.6 (OR 2.5, 95% CI 1.1-5.7, P = 0.027). CONCLUSIONS: In a heterogeneous ICU population, a single-spot mildly elevated lactate level (even within the reference range) was independently associated with increased mortality and microvascular flow abnormalities. In vivo microscopy of the microcirculation may be helpful in discriminating between flow- and non-flow-related causes of mildly elevated lactate levels. TRIAL REGISTRATION:, NCT01179243 . Registered on August 3, 2010.

Haniffa R, Mukaka M, Munasinghe SB, De Silva AP, Jayasinghe KSA, Beane A, de Keizer N, Dondorp AM. 2017. Simplified prognostic model for critically ill patients in resource limited settings in South Asia. Crit Care, 21 (1), pp. 250. | Show Abstract | Read more

BACKGROUND: Current critical care prognostic models are predominantly developed in high-income countries (HICs) and may not be feasible in intensive care units (ICUs) in lower- and middle-income countries (LMICs). Existing prognostic models cannot be applied without validation in LMICs as the different disease profiles, resource availability, and heterogeneity of the population may limit the transferability of such scores. A major shortcoming in using such models in LMICs is the unavailability of required measurements. This study proposes a simplified critical care prognostic model for use at the time of ICU admission. METHODS: This was a prospective study of 3855 patients admitted to 21 ICUs from Bangladesh, India, Nepal, and Sri Lanka who were aged 16 years and over and followed to ICU discharge. Variables captured included patient age, admission characteristics, clinical assessments, laboratory investigations, and treatment measures. Multivariate logistic regression was used to develop three models for ICU mortality prediction: model 1 with clinical, laboratory, and treatment variables; model 2 with clinical and laboratory variables; and model 3, a purely clinical model. Internal validation based on bootstrapping (1000 samples) was used to calculate discrimination (area under the receiver operating characteristic curve (AUC)) and calibration (Hosmer-Lemeshow C-Statistic; higher values indicate poorer calibration). Comparison was made with the Acute Physiology and Chronic Health Evaluation (APACHE) II and Simplified Acute Physiology Score (SAPS) II models. RESULTS: Model 1 recorded the respiratory rate, systolic blood pressure, Glasgow Coma Scale (GCS), blood urea, haemoglobin, mechanical ventilation, and vasopressor use on ICU admission. Model 2, named TropICS (Tropical Intensive Care Score), included emergency surgery, respiratory rate, systolic blood pressure, GCS, blood urea, and haemoglobin. Model 3 included respiratory rate, emergency surgery, and GCS. AUC was 0.818 (95% confidence interval (CI) 0.800-0.835) for model 1, 0.767 (0.741-0.792) for TropICS, and 0.725 (0.688-0.762) for model 3. The Hosmer-Lemeshow C-Statistic p values were less than 0.05 for models 1 and 3 and 0.18 for TropICS. In comparison, when APACHE II and SAPS II were applied to the same dataset, AUC was 0.707 (0.688-0.726) and 0.714 (0.695-0.732) and the C-Statistic was 124.84 (p < 0.001) and 1692.14 (p < 0.001), respectively. CONCLUSION: This paper proposes TropICS as the first multinational critical care prognostic model developed in a non-HIC setting.

Imwong M, Hien TT, Thuy-Nhien NT, Dondorp AM, White NJ. 2017. Spread of a single multidrug resistant malaria parasite lineage (PfPailin) to Vietnam. Lancet Infect Dis, 17 (10), pp. 1022-1023. | Read more

Lohy Das J, Dondorp AM, Nosten F, Phyo AP, Hanpithakpong W, Ringwald P, Lim P, White NJ, Karlsson MO, Bergstrand M, Tarning J. 2017. Population Pharmacokinetic and Pharmacodynamic Modeling of Artemisinin Resistance in Southeast Asia. AAPS J, 19 (6), pp. 1842-1854. | Show Abstract | Read more

Orally administered artemisinin-based combination therapy is the first-line treatment against uncomplicated P. falciparum malaria worldwide. However, the increasing prevalence of artemisinin resistance is threatening efforts to treat and eliminate malaria in Southeast Asia. This study aimed to characterize the exposure-response relationship of artesunate in patients with artemisinin sensitive and resistant malaria infections. Patients were recruited in Pailin, Cambodia (n = 39), and Wang Pha, Thailand (n = 40), and received either 2 mg/kg/day of artesunate mono-therapy for 7 consecutive days or 4 mg/kg/day of artesunate monotherapy for 3 consecutive days followed by mefloquine 15 and 10 mg/kg for 2 consecutive days. Plasma concentrations of artesunate and its active metabolite, dihydroartemisinin, and microscopy-based parasite densities were measured and evaluated using nonlinear mixed-effects modeling. All treatments were well tolerated with minor and transient adverse reactions. Patients in Cambodia had substantially slower parasite clearance compared to patients in Thailand. The pharmacokinetic properties of artesunate and dihydroartemisinin were well described by transit-compartment absorption followed by one-compartment disposition models. Parasite density was a significant covariate, and higher parasite densities were associated with increased absorption. Dihydroartemisinin-dependent parasite killing was described by a delayed sigmoidal Emax model, and a mixture function was implemented to differentiate between sensitive and resistant infections. This predicted that 84% and 16% of infections in Cambodia and Thailand, respectively, were artemisinin resistant. The final model was used to develop a simple diagnostic nomogram to identify patients with artemisinin-resistant infections. The nomogram showed > 80% specificity and sensitivity, and outperformed the current practice of day 3 positivity testing.

Landier J, Kajeechiwa L, Thwin MM, Parker DM, Chaumeau V, Wiladphaingern J, Imwong M, Miotto O, Patumrat K, Duanguppama J et al. 2017. Safety and effectiveness of mass drug administration to accelerate elimination of artemisinin-resistant falciparum malaria: A pilot trial in four villages of Eastern Myanmar. Wellcome Open Res, 2 pp. 81. | Show Abstract | Read more

Background: Artemisinin and partner drug-resistant falciparum malaria is expanding over the Greater Mekong Sub-region (GMS). Eliminating falciparum malaria in the GMS while drugs still retain enough efficacy could prevent global spread of antimalarial resistance. Eliminating malaria rapidly requires targeting the reservoir of asymptomatic parasite carriers. This pilot trial aimed to evaluate the acceptability, safety, feasibility and effectiveness of mass-drug administration (MDA) in reducing malaria in four villages in Eastern Myanmar. Methods: Villages with ≥30% malaria prevalence were selected. Long-lasting insecticidal bednets (LLINs) and access to malaria early diagnosis and treatment (EDT) were provided. Two villages received MDA immediately and two were followed for nine months pre-MDA. MDA consisted of a 3-day supervised course of  dihydroartemisinin-piperaquine and single low-dose primaquine administered monthly for three months. Adverse events (AE) were monitored by interviews and consultations. Malaria prevalence was assessed by ultrasensitive PCR quarterly for 24 months. Symptomatic malaria incidence,entomological indices, and antimalarial resistance markers were monitored. Results: MDA was well tolerated. There were no serious AE and mild to moderate AE were reported in 5.6%(212/3931) interviews. In the smaller villages, participation to three MDA courses was 61% and 57%, compared to 28% and 29% in the larger villages. Baseline prevalence was higher in intervention than in control villages (18.7% (95%CI=16.1-21.6) versus 6.8%(5.2-8.7), p<0.0001) whereas three months after starting MDA, prevalence was lower in intervention villages (0.4%(0.04-1.3) versus 2.7%(1.7-4.1), p=0.0014). After nine months the difference was no longer significant (2.0%(1.0-3.5) versus 0.9%(0.04-1.8), p=0.10). M0-M9 symptomatic falciparum incidence was similar between intervention and control. Before/after MDA comparisons showed that asymptomatic P. falciparum carriage and anopheline vector positivity decreased significantly whereas prevalence of the artemisinin-resistance molecular marker remained stable. Conclusions: This MDA was safe and feasible, and, could accelerate elimination of P. falciparum in addition to EDT and LLINs when community participation was sufficient.

Shrestha GS, Kwizera A, Lundeg G, Baelani JI, Azevedo LCP, Pattnaik R, Haniffa R, Gavrilovic S, Mai NTH, Kissoon N et al. 2017. International Surviving Sepsis Campaign guidelines 2016: the perspective from low-income and middle-income countries. Lancet Infect Dis, 17 (9), pp. 893-895. | Read more

Fanello C, Onyamboko M, Lee SJ, Woodrow C, Setaphan S, Chotivanich K, Buffet P, Jauréguiberry S, Rockett K, Stepniewska K et al. 2017. Post-treatment haemolysis in African children with hyperparasitaemic falciparum malaria; a randomized comparison of artesunate and quinine. BMC Infect Dis, 17 (1), pp. 575. | Show Abstract | Read more

BACKGROUND: Parenteral artesunate is the treatment of choice for severe malaria. Recently, haemolytic anaemia occurring 1 to 3 weeks after artesunate treatment of falciparum malaria has been reported in returning travellers in temperate countries. METHODS: To assess these potential safety concerns in African children, in whom most deaths from malaria occur, an open-labelled, randomized controlled trial was conducted in Kinshasa, Democratic Republic of Congo. 217 children aged between 6 months and 14 years with acute uncomplicated falciparum malaria and parasite densities over 100,000/μL were randomly allocated to intravenous artesunate or quinine, hospitalized for 3 days and then followed for 42 days. RESULTS: The immediate reduction in haemoglobin was less with artesunate than with quinine: median (IQR) fall at 72 h 1.4 g/dL (0.90-1.95) vs. 1.7 g/dL (1.10-2.40) (p = 0.009). This was explained by greater pitting then recirculation of once infected erythrocytes. Only 5% of patients (in both groups) had a ≥ 10% reduction in haemoglobin after day 7 (p = 0.1). One artesunate treated patient with suspected concomitant sepsis had a protracted clinical course and required a blood transfusion on day 14. CONCLUSIONS: Clinically significant delayed haemolysis following parenteral artesunate is uncommon in African children hospitalised with acute falciparum malaria and high parasitaemias. TRIAL REGISTRATION: ; Identifier: NCT02092766 (18/03/2014).

Tran Vu Thieu N, Trinh Van T, Tran Tuan A, Klemm EJ, Nguyen Ngoc Minh C, Voong Vinh P, Pham Thanh D, Ho Ngoc Dan T, Pham Duc T, Langat P et al. 2017. An evaluation of purified Salmonella Typhi protein antigens for the serological diagnosis of acute typhoid fever. J Infect, 75 (2), pp. 104-114. | Show Abstract | Read more

OBJECTIVES: The diagnosis of typhoid fever is a challenge. Aiming to develop a typhoid diagnostic we measured antibody responses against Salmonella Typhi (S. Typhi) protein antigens and the Vi polysaccharide in a cohort of Bangladeshi febrile patients. METHODS: IgM against 12 purified antigens and the Vi polysaccharide was measured by ELISA in plasma from patients with confirmed typhoid fever (n = 32), other confirmed infections (n = 17), and healthy controls (n = 40). ELISAs with the most specific antigens were performed on plasma from 243 patients with undiagnosed febrile disease. RESULTS: IgM against the S. Typhi protein antigens correlated with each other (rho > 0.8), but not against Vi (rho < 0.6). Typhoid patients exhibited higher IgM against 11/12 protein antigens and Vi than healthy controls and those with other infections. Vi, PilL, and CdtB exhibited the greatest sensitivity and specificity. Specificity and sensitivity was improved when Vi was combined with a protein antigen, generating sensitivities and specificities of 0.80 and >0.85, respectively. Applying a dynamic cut-off to patients with undiagnosed febrile disease suggested that 34-58% had an IgM response indicative of typhoid. CONCLUSIONS: We evaluated the diagnostic potential of several S. Typhi antigens; our assays give good sensitivity and specificity, but require further assessment in differing patient populations.

de Jong HK, Garcia-Laorden MI, Hoogendijk AJ, Parry CM, Maude RR, Dondorp AM, Faiz MA, van der Poll T, Wiersinga WJ. 2017. Expression of intra- and extracellular granzymes in patients with typhoid fever. PLoS Negl Trop Dis, 11 (7), pp. e0005823. | Show Abstract | Read more

BACKGROUND: Typhoid fever, caused by the intracellular pathogen Salmonella (S.) enterica serovar Typhi, remains a major cause of morbidity and mortality worldwide. Granzymes are serine proteases promoting cytotoxic lymphocytes mediated eradication of intracellular pathogens via the induction of cell death and which can also play a role in inflammation. We aimed to characterize the expression of extracellular and intracellular granzymes in patients with typhoid fever and whether the extracellular levels of granzyme correlated with IFN-γ release. METHODS AND PRINCIPAL FINDINGS: We analyzed soluble protein levels of extracellular granzyme A and B in healthy volunteers and patients with confirmed S. Typhi infection on admission and day of discharge, and investigated whether this correlated with interferon (IFN)-γ release, a cytokine significantly expressed in typhoid fever. The intracellular expression of granzyme A, B and K in subsets of lymphocytic cells was determined using flow cytometry. Patients demonstrated a marked increase of extracellular granzyme A and B in acute phase plasma and a correlation of both granzymes with IFN-γ release. In patients, lower plasma levels of granzyme B, but not granzyme A, were found at day of discharge compared to admission, indicating an association of granzyme B with stage of disease. Peripheral blood mononuclear cells of typhoid fever patients had a higher percentage of lymphocytic cells expressing intracellular granzyme A and granzyme B, but not granzyme K, compared to controls. CONCLUSION: The marked increase observed in extra- and intracellular levels of granzyme expression in patients with typhoid fever, and the correlation with stage of disease, suggests a role for granzymes in the host response to this disease.

Haniffa R, Pubudu De Silva A, Weerathunga P, Mukaka M, Athapattu P, Munasinghe S, Mahesh B, Mahipala P, De Silva T, Abayadeera A et al. 2017. Applicability of the APACHE II model to a lower middle income country. J Crit Care, 42 pp. 178-183. | Show Abstract | Read more

PURPOSE: To determine the utility of APACHE II in a low-and middle-income (LMIC) setting and the implications of missing data. MATERIALS AND METHODS: Patients meeting APACHE II inclusion criteria admitted to 18 ICUs in Sri Lanka over three consecutive months had data necessary for the calculation of APACHE II, probabilities prospectively extracted from case notes. APACHE II physiology score (APS), probabilities, Standardised (ICU) Mortality Ratio (SMR), discrimination (AUROC), and calibration (C-statistic) were calculated, both by imputing missing measurements with normal values and by Multiple Imputation using Chained Equations (MICE). RESULTS: From a total of 995 patients admitted during the study period, 736 had APACHE II probabilities calculated. Data availability for APS calculation ranged from 70.6% to 88.4% for bedside observations and 18.7% to 63.4% for invasive measurements. SMR (95% CI) was 1.27 (1.17, 1.40) and 0.46 (0.44, 0.49), AUROC (95% CI) was 0.70 (0.65, 0.76) and 0.74 (0.68, 0.80), and C-statistic was 68.8 and 156.6 for normal value imputation and MICE, respectively. CONCLUSIONS: An incomplete dataset confounds interpretation of prognostic model performance in LMICs, wherein imputation using normal values is not a suitable strategy. Improving data availability, researching imputation methods and developing setting-adapted and simpler prognostic models are warranted.

Ndour PA, Larréché S, Mouri O, Argy N, Gay F, Roussel C, Jauréguiberry S, Perillaud C, Langui D, Biligui S et al. 2017. Measuring the Plasmodium falciparum HRP2 protein in blood from artesunate-treated malaria patients predicts post-artesunate delayed hemolysis. Sci Transl Med, 9 (397), pp. eaaf9377-eaaf9377. | Show Abstract | Read more

Artesunate, the recommended drug for severe malaria, rapidly clears the malaria parasite from infected patients but frequently induces anemia-called post-artesunate delayed hemolysis (PADH)-for which a simple predictive test is urgently needed. The underlying event in PADH is the expulsion of artesunate-exposed parasites from their host erythrocytes by pitting. We show that the histidine-rich protein 2 (HRP2) of the malaria parasite Plasmodium falciparum persists in the circulation of artesunate-treated malaria patients in Bangladesh and in French travelers who became infected with malaria in Africa. HRP2 persisted in whole blood (not plasma) of artesunate-treated patients with malaria at higher levels compared to quinine-treated patients. Using an optimized membrane permeabilization method, HRP2 was observed by immunofluorescence, Western blotting, and electron microscopy to persist in once-infected red blood cells from artesunate-treated malaria patients. HRP2 was deposited at the membrane of once-infected red blood cells in a pattern similar to that for ring erythrocyte surface antigen (RESA), a parasite invasion marker. On the basis of these observations, we developed a semiquantitative titration method using a widely available HRP2-based rapid diagnostic dipstick test. Positivity on this test using a 1:500 dilution of whole blood from artesunate-treated patients with malaria collected shortly after parasite clearance predicted subsequent PADH with 89% sensitivity and 73% specificity. These results suggest that adapting an existing HRP2-based rapid diagnostic dipstick test may enable prediction of PADH several days before it occurs in artesunate-treated patients with malaria.

Mohanty S, Benjamin LA, Majhi M, Panda P, Kampondeni S, Sahu PK, Mohanty A, Mahanta KC, Pattnaik R, Mohanty RR et al. 2017. Magnetic Resonance Imaging of Cerebral Malaria Patients Reveals Distinct Pathogenetic Processes in Different Parts of the Brain. mSphere, 2 (3), | Show Abstract | Read more

The mechanisms underlying the rapidly reversible brain swelling described in patients with cerebral malaria (CM) are unknown. Using a 1.5-Tesla (T) magnetic resonance imaging (MRI) scanner, we undertook an observational study in Rourkela, India, of 11 Indian patients hospitalized with CM and increased brain volume. Among the 11 cases, there were 5 adults and 6 children. All patients had reduced consciousness and various degrees of cortical swelling at baseline. The latter was predominately posterior in distribution. The findings on diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps were consistent with vasogenic edema in all cases. Reversibility after 48 to 72 h was observed in >90% of cases. DWI/ADC mismatch suggested the additional presence of cytotoxic edema in the basal nuclei of 5 patients; all of these had perfusion parameters consistent with vascular engorgement and not with ischemic infarcts. Our results suggest that an impairment of the blood-brain barrier is responsible for the brain swelling in CM. In 5 cases, vasogenic edema occurred in conjunction with changes in the basal nuclei consistent with venous congestion, likely to be caused by the sequestration of Plasmodium falciparum-infected erythrocytes. While both mechanisms have been individually postulated to play an important role in the development of CM, this is the first demonstration of their concurrent involvement in different parts of the brain. The clinical and radiological characteristics observed in the majority of our patients are consistent with posterior reversible encephalopathy syndrome (PRES), and we show for the first time a high frequency of PRES in the context of CM. IMPORTANCE The pathophysiology and molecular mechanisms underlying cerebral malaria (CM) are still poorly understood. Recent neuroimaging studies demonstrated that brain swelling is a common feature in CM and a major contributor to death in pediatric patients. Consequently, determining the precise mechanisms responsible for this swelling could open new adjunct therapeutic avenues in CM patients. Using an MRI scanner with a higher resolution than the ones used in previous reports, we identified two distinct origins of brain swelling in both adult and pediatric patients from India, occurring in distinct parts of the brain. Our results support the hypothesis that both endothelial dysfunction and microvascular obstruction by Plasmodium falciparum-infected erythrocytes make independent contributions to the pathogenesis of CM, providing opportunities for novel therapeutic interventions.

De Silva AP, Sujeewa JA, De Silva N, Rathnayake RMD, Vithanage L, Sigera PC, Munasinghe S, Beane A, Stephens T, Athapattu PL et al. 2017. A Retrospective Study of Physiological Observation-reporting Practices and the Recognition, Response, and Outcomes Following Cardiopulmonary Arrest in a Low-to-middle-income Country. Indian J Crit Care Med, 21 (6), pp. 343-345. | Show Abstract | Read more

BACKGROUND AND AIMS: In Sri Lanka, as in most low-to-middle-income countries (LMICs), early warning systems (EWSs) are not in use. Understanding observation-reporting practices and response to deterioration is a necessary step in evaluating the feasibility of EWS implementation in a LMIC setting. This study describes the practices of observation reporting and the recognition and response to presumed cardiopulmonary arrest in a LMIC. PATIENTS AND METHODS: This retrospective study was carried out at District General Hospital Monaragala, Sri Lanka. One hundred and fifty adult patients who had cardiac arrests and were reported to a nurse responder were included in the study. RESULTS: Availability of six parameters (excluding mentation) was significantly higher at admission (P < 0.05) than at 24 and 48 h prior to cardiac arrest. Patients had a 49.3% immediate return of spontaneous circulation (ROSC) and 35.3% survival to hospital discharge. Nearly 48.6% of patients who had ROSC did not receive postarrest intensive care. Intubation was performed in 46 (62.2%) patients who went on to have ROSC compared with 28 (36.8%) with no ROSC (P < 0.05). Defibrillation, performed in eight (10.8%) patients who had ROSC and eight (10.5%) in whom did not, was statistically insignificant (P = 0.995). CONCLUSIONS: Observations commonly used to detect deterioration are poorly reported, and reporting practices would need to be improved prior to EWS implementation. These findings reinforce the need for training in acute care and resuscitation skills for health-care teams in LMIC settings as part of a program of improving recognition and response to acute deterioration.

Tun STT, Lubell Y, Dondorp AM, Fieldman T, Tun KM, Celhay O, Chan XH, Saralamba S, White LJ. 2017. Identifying artemisinin resistance from parasite clearance half-life data with a simple Shiny web application. PLoS One, 12 (5), pp. e0177840. | Show Abstract | Read more

The emergence of artemisinin-resistant Plasmodium falciparum malaria is a major threat to malaria elimination. New tools for supporting the surveillance of artemisinin resistance are critical for current and future malaria control and elimination strategies. We have developed an open-access, user-friendly, web-based tool to analyse parasite clearance half-life data of P. falciparum infected patients after treatment with artemisinin derivatives, so that resistance to artemisinin can be identified. The tool can be accessed at

Pell C, Tripura R, Nguon C, Cheah P, Davoeung C, Heng C, Dara L, Sareth M, Dondorp A, von Seidlein L, Peto TJ. 2017. Mass anti-malarial administration in western Cambodia: a qualitative study of factors affecting coverage. Malar J, 16 (1), pp. 206. | Show Abstract | Read more

BACKGROUND: Mass anti-malarial administration has been proposed as a key component of the Plasmodium falciparum malaria elimination strategy in the Greater Mekong sub-Region. Its effectiveness depends on high levels of coverage in the target population. This article explores the factors that influenced mass anti-malarial administration coverage within a clinical trial in Battambang Province, western Cambodia. METHODS: Qualitative data were collected through semi-structured interviews and focus group discussions with villagers, in-depth interviews with study staff, trial drop-outs and refusers, and observations in the communities. Interviews were audio-recorded, transcribed and translated from Khmer to English for qualitative content analysis using QSR NVivo. RESULTS: Malaria was an important health concern and villagers reported a demand for malaria treatment. This was in spite of a fall in incidence over the previous decade and a lack of familiarity with asymptomatic malaria. Participants generally understood the overall study aim and were familiar with study activities. Comprehension of the study rationale was however limited. After the first mass anti-malarial administration, seasonal health complaints that participants attributed to the anti-malarial as "side effects" contributed to a decrease of coverage in round two. Staff therefore adapted the community engagement approach, bringing to prominence local leaders in village meetings. This contributed to a subsequent increase in coverage. CONCLUSION: Future mass anti-malarial administration must consider seasonal disease patterns and the importance of local leaders taking prominent roles in community engagement. Further research is needed to investigate coverage in scenarios that more closely resemble implementation i.e. without participation incentives, blood sampling and free healthcare.

De Silva AP, Harischandra PL, Beane A, Rathnayaka S, Pimburage R, Wijesiriwardana W, Gamage D, Jayasinghe D, Sigera C, Gunasekara A et al. 2017. A data platform to improve rabies prevention, Sri Lanka. Bull World Health Organ, 95 (9), pp. 646-651. | Show Abstract | Read more

PROBLEM: In Sri Lanka, rabies prevention initiatives are hindered by fragmented and delayed information-sharing that limits clinicians' ability to follow patients and impedes public health surveillance. APPROACH: In a project led by the health ministry, we adapted existing technologies to create an electronic platform for rabies surveillance. Information is entered by trained clinical staff, and both aggregate and individual patient data are visualized in real time. An automated short message system (SMS) alerts patients for vaccination follow-up appointments and informs public health inspectors about incidents of animal bites. LOCAL SETTING: The platform was rolled out in June 2016 in four districts of Sri Lanka, linking six rabies clinics, three laboratories and the public health inspectorate. RELEVANT CHANGES: Over a 9-month period, 12 121 animal bites were reported to clinics and entered in the registry. Via secure portals, clinicians and public health teams accessed live information on treatment and outcomes of patients started on post-exposure prophylaxis (9507) or receiving deferred treatment (2614). Laboratories rapidly communicated the results of rabies virus tests on dead mammals (328/907 positive). In two pilot districts SMS reminders were sent to 1376 (71.2%) of 1933 patients whose contact details were available. Daily SMS reports alerted 17 public health inspectors to bite incidents in their area for investigation. LESSONS LEARNT: Existing technologies in low-resource countries can be harnessed to improve public health surveillance. Investment is needed in platform development and training and support for front-line staff. Greater public engagement is needed to improve completeness of surveillance and treatment.

Mukherjee A, Bopp S, Magistrado P, Wong W, Daniels R, Demas A, Schaffner S, Amaratunga C, Lim P, Dhorda M et al. 2017. Artemisinin resistance without pfkelch13 mutations in Plasmodium falciparum isolates from Cambodia. Malar J, 16 (1), pp. 195. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance is associated with delayed parasite clearance half-life in vivo and correlates with ring-stage survival under dihydroartemisinin in vitro. Both phenotypes are associated with mutations in the PF3D7_1343700 pfkelch13 gene. Recent spread of artemisinin resistance and emerging piperaquine resistance in Southeast Asia show that artemisinin combination therapy, such as dihydroartemisinin-piperaquine, are losing clinical effectiveness, prompting investigation of drug resistance mechanisms and development of strategies to surmount emerging anti-malarial resistance. METHODS: Sixty-eight parasites isolates with in vivo clearance data were obtained from two Tracking Resistance to Artemisinin Collaboration study sites in Cambodia, culture-adapted, and genotyped for pfkelch13 and other mutations including pfmdr1 copy number; and the RSA0-3h survival rates and response to antimalarial drugs in vitro were measured for 36 of these isolates. RESULTS: Among these 36 parasites one isolate demonstrated increased ring-stage survival for a PfKelch13 mutation (D584V, RSA0-3h = 8%), previously associated with slow clearance but not yet tested in vitro. Several parasites exhibited increased ring-stage survival, yet lack pfkelch13 mutations, and one isolate showed evidence for piperaquine resistance. CONCLUSIONS: This study of 68 culture-adapted Plasmodium falciparum clinical isolates from Cambodia with known clearance values, associated the D584V PfKelch13 mutation with increased ring-stage survival and identified parasites that lack pfkelch13 mutations yet exhibit increased ring-stage survival. These data suggest mutations other than those found in pfkelch13 may be involved in conferring artemisinin resistance in P. falciparum. Piperaquine resistance was also detected among the same Cambodian samples, consistent with reports of emerging piperaquine resistance in the field. These culture-adapted parasites permit further investigation of mechanisms of both artemisinin and piperaquine resistance and development of strategies to prevent or overcome anti-malarial resistance.

Beane A, Padeniya A, De Silva AP, Stephens T, De Alwis S, Mahipala PG, Sigera PC, Munasinghe S, Weeratunga P, Ranasinghe D et al. 2017. Closing the theory to practice gap for newly qualified doctors: evaluation of a peer-delivered practical skills training course for newly qualified doctors in preparation for clinical practice. Postgrad Med J, 93 (1104), pp. 592-596. | Show Abstract | Read more

PURPOSE: The Good Intern Programme (GIP) in Sri Lanka has been implemented to bridge the 'theory to practice gap' of doctors preparing for their internship. This paper evaluates the impact of a 2-day peer-delivered Acute Care Skills Training (ACST) course as part of the GIP. STUDY DESIGN: The ACST course was developed by an interprofessional faculty, including newly graduated doctors awaiting internship (pre-intern), focusing on the recognition and management of common medical and surgical emergencies. Course delivery was entirely by pre-intern doctors to their peers. Knowledge was evaluated by a pre- and post-course multiple choice test. Participants' confidence (post-course) and 12 acute care skills (pre- and post-course) were assessed using Likert scale-based questions. A subset of participants provided feedback on the peer learning experience. RESULTS: Seventeen courses were delivered by a faculty consisting of eight peer trainers over 4 months, training 320 participants. The mean (SD) multiple choice questionnaire score was 71.03 (13.19) pre-course compared with 77.98 (7.7) post-course (p<0.05). Increased overall confidence in managing ward emergencies was reported by 97.2% (n=283) of respondents. Participants rated their post-course skills to be significantly higher (p<0.05) than pre-course in all 12 assessed skills. Extended feedback on the peer learning experience was overwhelmingly positive and 96.5% would recommend the course to a colleague. CONCLUSIONS: A peer-delivered ACST course was extremely well received and can improve newly qualified medical graduates' knowledge, skills and confidence in managing medical and surgical emergencies. This peer-based model may have utility beyond pre-interns and beyond Sri Lanka.

Näsström E, Parry CM, Vu Thieu NT, Maude RR, de Jong HK, Fukushima M, Rzhepishevska O, Marks F, Panzner U, Im J et al. 2017. Reproducible diagnostic metabolites in plasma from typhoid fever patients in Asia and Africa. Elife, 6 | Show Abstract | Read more

Salmonella Typhi is the causative agent of typhoid. Typhoid is diagnosed by blood culture, a method that lacks sensitivity, portability and speed. We have previously shown that specific metabolomic profiles can be detected in the blood of typhoid patients from Nepal (Näsström et al., 2014). Here, we performed mass spectrometry on plasma from Bangladeshi and Senegalese patients with culture confirmed typhoid fever, clinically suspected typhoid, and other febrile diseases including malaria. After applying supervised pattern recognition modelling, we could significantly distinguish metabolite profiles in plasma from the culture confirmed typhoid patients. After comparing the direction of change and degree of multivariate significance, we identified 24 metabolites that were consistently up- or down regulated in a further Bangladeshi/Senegalese validation cohort, and the Nepali cohort from our previous work. We have identified and validated a metabolite panel that can distinguish typhoid from other febrile diseases, providing a new approach for typhoid diagnostics.

Imwong M, Suwannasin K, Kunasol C, Sutawong K, Mayxay M, Rekol H, Smithuis FM, Hlaing TM, Tun KM, van der Pluijm RW et al. 2017. The spread of artemisinin-resistant Plasmodium falciparum in the Greater Mekong subregion: a molecular epidemiology observational study. Lancet Infect Dis, 17 (5), pp. 491-497. | Show Abstract | Read more

BACKGROUND: Evidence suggests that the PfKelch13 mutations that confer artemisinin resistance in falciparum malaria have multiple independent origins across the Greater Mekong subregion, which has motivated a regional malaria elimination agenda. We aimed to use molecular genotyping to assess antimalarial drug resistance selection and spread in the Greater Mekong subregion. METHODS: In this observational study, we tested Plasmodium falciparum isolates from Myanmar, northeastern Thailand, southern Laos, and western Cambodia for PfKelch13 mutations and for Pfplasmepsin2 gene amplification (indicating piperaquine resistance). We collected blood spots from patients with microscopy or rapid test confirmed uncomplicated falciparum malaria. We used microsatellite genotyping to assess genetic relatedness. FINDINGS: As part of studies on the epidemiology of artemisinin-resistant malaria between Jan 1, 2008, and Dec 31, 2015, we collected 434 isolates. In 2014-15, a single long PfKelch13 C580Y haplotype (-50 to +31·5 kb) lineage, which emerged in western Cambodia in 2008, was detected in 65 of 88 isolates from northeastern Thailand, 86 of 111 isolates from southern Laos, and 14 of 14 isolates from western Cambodia, signifying a hard transnational selective sweep. Pfplasmepsin2 amplification occurred only within this lineage, and by 2015 these closely related parasites were found in ten of the 14 isolates from Cambodia and 15 of 15 isolates from northeastern Thailand. C580Y mutated parasites from Myanmar had a different genetic origin. INTERPRETATION: Our results suggest that the dominant artemisinin-resistant P falciparum C580Y lineage probably arose in western Cambodia and then spread to Thailand and Laos, outcompeting other parasites and acquiring piperaquine resistance. The emergence and spread of fit artemisinin-resistant P falciparum parasite lineages, which then acquire partner drug resistance across the Greater Mekong subregion, threatens regional malaria control and elimination goals. Elimination of falciparum malaria from this region should be accelerated while available antimalarial drugs still remain effective. FUNDING: The Wellcome Trust and the Bill and Melinda Gates Foundation.

Plewes K, Kingston HWF, Ghose A, Maude RJ, Herdman MT, Leopold SJ, Ishioka H, Hasan MMU, Haider MS, Alam S et al. 2017. Cell-free hemoglobin mediated oxidative stress is associated with acute kidney injury and renal replacement therapy in severe falciparum malaria: an observational study. BMC Infect Dis, 17 (1), pp. 313. | Show Abstract | Read more

BACKGROUND: Intravascular hemolysis is an intrinsic feature of severe malaria pathophysiology but the pathogenic role of cell-free hemoglobin-mediated oxidative stress in severe malaria associated acute kidney injury (AKI) is unknown. METHODS: As part of a prospective observational study, enrolment plasma cell-free hemoglobin (CFH), lipid peroxidation markers (F2-isoprostanes (F2-IsoPs) and isofurans (IsoFs)), red cell deformability, and serum creatinine were quantified in Bangladeshi patients with severe falciparum malaria (n = 107), uncomplicated malaria (n = 80) and sepsis (n = 28). The relationships between these indices and kidney function and clinical outcomes were examined. RESULTS: AKI was diagnosed at enrolment in 58% (62/107) of consecutive patients with severe malaria, defined by an increase in creatinine ≥1.5 times expected baseline. Severe malaria patients with AKI had significantly higher plasma cell-free hemoglobin (geometric mean CFH: 8.8 μM; 95% CI, 6.2-12.3 μM), F2-isoprostane (56.7 pg/ml; 95% CI, 45.3-71.0 pg/ml) and isofuran (109.2 pg/ml; 95% CI, 85.1-140.1 pg/ml) concentrations on enrolment compared to those without AKI (CFH: 5.1 μM; 95% CI, 4.0-6.6 μM; P = 0.018; F2-IsoPs: 27.8 pg/ml; 95% CI, 23.7-32.7 pg/ml; P < 0.001; IsoFs: 41.7 pg/ml; 95% CI, 30.2-57.6 pg/ml; P < 0.001). Cell-free hemoglobin correlated with markers of hemolysis, parasite burden (P. falciparum histidine rich protein 2 (PfHRP2)), and F2-IsoPs. Plasma F2-IsoPs and IsoFs inversely correlated with pH, positively correlated with creatinine, PfHRP2 and fractional excretion of sodium, and were higher in patients later requiring hemodialysis. Plasma F2-IsoP concentrations also inversely correlated with red cell deformability and were higher in fatal cases. Mixed effects modeling including an interaction term for CFH and time showed that F2-IsoPs, IsoFs, PfHRP2, CFH, and red cell rigidity were independently associated with increasing creatinine over 72 h. Multivariable logistic regression showed that admission F2-IsoPs, IsoFs and red cell deformability were associated with the need for subsequent hemodialysis. CONCLUSIONS: Cell-free hemoglobin and lipid peroxidation are associated with acute kidney injury and disease severity in falciparum malaria, suggesting a pathophysiological role in renal tubular injury. Evaluation of adjunctive therapies targeting cell-free hemoglobin-mediated oxidative stress is warranted.

Srisutham S, Saralamba N, Malleret B, Rénia L, Dondorp AM, Imwong M. 2017. Four human Plasmodium species quantification using droplet digital PCR. PLoS One, 12 (4), pp. e0175771. | Show Abstract | Read more

Droplet digital polymerase chain reaction (ddPCR) is a partial PCR based on water-oil emulsion droplet technology. It is a highly sensitive method for detecting and delineating minor alleles from complex backgrounds and provides absolute quantification of DNA targets. The ddPCR technology has been applied for detection of many pathogens. Here the sensitive assay utilizing ddPCR for detection and quantification of Plasmodium species was investigated. The assay was developed for two levels of detection, genus specific for all Plasmodium species and for specific Plasmodium species detection. The ddPCR assay was developed based on primers and probes specific to the Plasmodium genus 18S rRNA gene. Using ddPCR for ultra-sensitive P. falciparum assessment, the lower level of detection from concentrated DNA obtained from a high volume (1 mL) blood sample was 11 parasites/mL. For species identification, in particular for samples with mixed infections, a duplex reaction was developed for detection and quantification P. falciparum/ P. vivax and P. malariae/ P. ovale. Amplification of each Plasmodium species in the duplex reaction showed equal sensitivity to singleplex single species detection. The duplex ddPCR assay had higher sensitivity to identify minor species in 32 subpatent parasitaemia samples from Cambodia, and performed better than real-time PCR. The ddPCR assay shows high sensitivity to assess very low parasitaemia of all human Plasmodium species. This provides a useful research tool for studying the role of the asymptomatic parasite reservoir for transmission in regions aiming for malaria elimination.

Dondorp AM, Limmathurotsakul D, Ashley EA. 2018. What's wrong in the control of antimicrobial resistance in critically ill patients from low- and middle-income countries? Intensive Care Med, 44 (1), pp. 79-82. | Read more

Plewes K, Soontarawirat I, Ghose A, Bancone G, Kingston HWF, Herdman MT, Leopold SJ, Ishioka H, Faiz MA, Anstey NM et al. 2017. Genotypic and phenotypic characterization of G6PD deficiency in Bengali adults with severe and uncomplicated malaria. Malar J, 16 (1), pp. 134. | Show Abstract | Read more

BACKGROUND: Control of malaria increasingly involves administration of 8-aminoquinolines, with accompanying risk of haemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Few data on the prevalence and genotypic basis of G6PD deficiency are available from Bangladesh, where malaria remains a major problem in the South (Chittagong Division). The aim of this study was to determine the prevalence of G6PD deficiency, and associated G6PD genotypes, in adults with falciparum malaria in southern Bangladesh. METHODS: G6PD status was assessed via a combination of fluorescent spot testing (FST) and genotyping in 141 Bengali patients admitted with falciparum malaria to two centres in Chittagong Division from 2012 to 2014. In addition, an analysis of genomic data from 1000 Genomes Project was carried out among five healthy Indian subcontinent populations. RESULTS: One male patient with uncomplicated malaria was found to have G6PD deficiency on FST and a genotype associated with deficiency (hemizygous Orissa variant). In addition, there were two female patients heterozygous for deficiency variants (Orissa and Kerala-Kalyan). These three patients had a relatively long duration of symptoms prior to admission compared to G6PD normal cases, possibly suggesting an interaction with parasite multiplication rate. In addition, one of 27 healthy local controls was deficient on FST and hemizygous for the Mahidol variant of G6PD deficiency. Examination of 1000 Genomes Project sequencing data across the Indian subcontinent showed that 19/723 chromosomes (2.63%) carried a variant associated with deficiency. In the Bengali from Bangladesh 1000 Genomes population, three of 130 chromosomes (2.31%) carried deficient alleles; this included single chromosomes carrying the Kerala-Kalyan and Orissa variants. CONCLUSIONS: In line with other recent work, G6PD deficiency is uncommon in Bengalis in Bangladesh. Further studies of particular ethnic groups are needed to evaluate the potential risk of wide deployment of primaquine in malaria control efforts in Bangladesh.

Schultz MJ, Dunser MW, Dondorp AM, Adhikari NKJ, Iyer S, Kwizera A, Lubell Y, Papali A, Pisani L, Riviello BD et al. 2017. Current challenges in the management of sepsis in ICUs in resource-poor settings and suggestions for the future. Intensive Care Med, 43 (5), pp. 612-624. | Show Abstract | Read more

BACKGROUND: Sepsis is a major reason for intensive care unit (ICU) admission, also in resource-poor settings. ICUs in low- and middle-income countries (LMICs) face many challenges that could affect patient outcome. AIM: To describe differences between resource-poor and resource-rich settings regarding the epidemiology, pathophysiology, economics and research aspects of sepsis. We restricted this manuscript to the ICU setting even knowing that many sepsis patients in LMICs are treated outside an ICU. FINDINGS: Although many bacterial pathogens causing sepsis in LMICs are similar to those in high-income countries, resistance patterns to antimicrobial drugs can be very different; in addition, causes of sepsis in LMICs often include tropical diseases in which direct damaging effects of pathogens and their products can sometimes be more important than the response of the host. There are substantial and persisting differences in ICU capacities around the world; not surprisingly the lowest capacities are found in LMICs, but with important heterogeneity within individual LMICs. Although many aspects of sepsis management developed in rich countries are applicable in LMICs, implementation requires strong consideration of cost implications and the important differences in resources. CONCLUSIONS: Addressing both disease-specific and setting-specific factors is important to improve performance of ICUs in LMICs. Although critical care for severe sepsis is likely cost-effective in LMIC setting, more detailed evaluation at both at a macro- and micro-economy level is necessary. Sepsis management in resource-limited settings is a largely unexplored frontier with important opportunities for research, training, and other initiatives for improvement.

Mercado CEG, Ekapirat N, Dondorp AM, Maude RJ. 2017. An assessment of national surveillance systems for malaria elimination in the Asia Pacific. Malar J, 16 (1), pp. 127. | Show Abstract | Read more

BACKGROUND: Heads of Government from Asia and the Pacific have committed to a malaria-free region by 2030. In 2015, the total number of confirmed cases reported to the World Health Organization by 22 Asia Pacific countries was 2,461,025. However, this was likely a gross underestimate due in part to incidence data not being available from the wide variety of known sources. There is a recognized need for an accurate picture of malaria over time and space to support the goal of elimination. A survey was conducted to gain a deeper understanding of the collection of malaria incidence data for surveillance by National Malaria Control Programmes in 22 countries identified by the Asia Pacific Leaders Malaria Alliance. METHODS: In 2015-2016, a short questionnaire on malaria surveillance was distributed to 22 country National Malaria Control Programmes (NMCP) in the Asia Pacific. It collected country-specific information about the extent of inclusion of the range of possible sources of malaria incidence data and the role of the private sector in malaria treatment. The findings were used to produce recommendations for the regional heads of government on improving malaria surveillance to inform regional efforts towards malaria elimination. RESULTS: A survey response was received from all 22 target countries. Most of the malaria incidence data collected by NMCPs originated from government health facilities, while many did not collect comprehensive data from mobile and migrant populations, the private sector or the military. All data from village health workers were included by 10/20 countries and some by 5/20. Other sources of data included by some countries were plantations, police and other security forces, sentinel surveillance sites, research or academic institutions, private laboratories and other government ministries. Malaria was treated in private health facilities in 19/21 countries, while anti-malarials were available in private pharmacies in 16/21 and private shops in 6/21. Most countries use primarily paper-based reporting. CONCLUSIONS: Most collected malaria incidence data in the Asia Pacific is from government health facilities while data from a wide variety of other known sources are often not included in national surveillance databases. In particular, there needs to be a concerted regional effort to support inclusion of data on mobile and migrant populations and the private sector. There should also be an emphasis on electronic reporting and data harmonization across organizations. This will provide a more accurate and up to date picture of the true burden and distribution of malaria and will be of great assistance in helping realize the goal of malaria elimination in the Asia Pacific by 2030.

Haniffa R, Lubell Y, Cooper BS, Mohanty S, Alam S, Karki A, Pattnaik R, Maswood A, Haque R, Pangeni R et al. 2017. Impact of a structured ICU training programme in resource-limited settings in Asia. PLoS One, 12 (3), pp. e0173483. | Show Abstract | Read more

OBJECTIVE: To assess the impact on ICU performance of a modular training program in three resource-limited general adult ICUs in India, Bangladesh, and Nepal. METHOD: A modular ICU training programme was evaluated using performance indicators from June 2009 to June 2012 using an interrupted time series design with an 8 to 15 month pre-intervention and 18 to 24 month post-intervention period. ICU physicians and nurses trained in Europe and the USA provided training for ICU doctors and nurses. The training program consisted of six modules on basic intensive care practices of 2-3 weeks each over 20 months. The performance indicators consisting of ICU mortality, time to ICU discharge, rate at which patients were discharged alive from the ICU, discontinuation of mechanical ventilation or vasoactive drugs and duration of antibiotic use were extracted. Stepwise changes and changes in trends associated with the intervention were analysed. RESULTS: Pre-Training ICU mortality in Rourkela (India), and Patan (Nepal) Chittagong (Bangladesh), was 28%, 41% and 62%, respectively, compared to 30%, 18% and 51% post-intervention. The intervention was associated with a stepwise reduction in cumulative incidence of in-ICU mortality in Chittagong (adjusted subdistribution hazard ratio [aSHR] (95% CI): 0.62 (0.40, 0.97), p = 0.03) and Patan (aSHR 0.16 (0.06, 0.41), p<0.001), but not in Rourkela (aSHR: 1.17 (0.75, 1.82), p = 0.49). The intervention was associated with earlier discontinuation of vasoactive drugs at Rourkela (adjusted hazard ratio for weekly change [aHR] 1.08 (1.03, 1.14), earlier discontinuation of mechanical ventilation in Chittagong (aHR 2.97 (1.24, 7.14), p = 0.02), and earlier ICU discharge in Patan (aHR 1.87 (1.02, 3.43), p = 0.04). CONCLUSION: This structured training program was associated with a decrease in ICU mortality in two of three sites and improvement of other performance indicators. A larger cluster randomised study assessing process outcomes and longer-term indicators is warranted.

Menard D, Dondorp A. 2017. Antimalarial Drug Resistance: A Threat to Malaria Elimination. Cold Spring Harb Perspect Med, 7 (7), pp. a025619-a025619. | Show Abstract | Read more

Increasing antimalarial drug resistance once again threatens effective antimalarial drug treatment, malaria control, and elimination. Artemisinin combination therapies (ACTs) are first-line treatment for uncomplicated falciparum malaria in all endemic countries, yet partial resistance to artemisinins has emerged in the Greater Mekong Subregion. Concomitant emergence of partner drug resistance is now causing high ACT treatment failure rates in several areas. Genetic markers for artemisinin resistance and several of the partner drugs have been established, greatly facilitating surveillance. Single point mutations in the gene coding for the Kelch propeller domain of the K13 protein strongly correlate with artemisinin resistance. Novel regimens and strategies using existing antimalarial drugs will be needed until novel compounds can be deployed. Elimination of artemisinin resistance will imply elimination of all falciparum malaria from the same areas. In vivax malaria, chloroquine resistance is an increasing problem.

Saiwaew S, Sritabal J, Piaraksa N, Keayarsa S, Ruengweerayut R, Utaisin C, Sila P, Niramis R, Udomsangpetch R, Charunwatthana P et al. 2017. Effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum infected erythrocytes. PLoS One, 12 (3), pp. e0172718. | Show Abstract | Read more

In severe falciparum malaria cytoadherence of parasitised red blood cells (PRBCs) to vascular endothelium (causing sequestration) and to uninfected red cells (causing rosette formation) contribute to microcirculatory flow obstruction in vital organs. Heparin can reverse the underlying ligand-receptor interactions, but may increase the bleeding risks. As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Sevuparin has been evaluated recently in patients with uncomplicated falciparum malaria, and is currently investigated in a clinical trial for sickle cell disease. The effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum isolates from Thailand were investigated. Trophozoite stages of P. falciparum-infected RBCs (Pf-iRBCs) were cultured from 49 patients with malaria. Pf-iRBCs were treated with sevuparin at 37°C and assessed in rosetting and in cytoadhesion assays with human dermal microvascular endothelial cells (HDMECs) under static and flow conditions. The proportion of Pf-iRBCs forming rosettes ranged from 6.5% to 26.0% (median = 12.2%). Rosetting was dose dependently disrupted by sevuparin (50% disruption by 250 μg/mL). Overall 57% of P. falciparum isolates bound to HDMECs under static conditions; median (interquartile range) Pf-iRBC binding was 8.5 (3.0-38.0) Pf-iRBCs/1000 HDMECs. Sevuparin in concentrations ≥ 100 μg/mL inhibited cytoadherence. Sevuparin disrupts P. falciparum rosette formation in a dose dependent manner and inhibits cytoadherence to endothelial cells. The data support assessment of sevuparin as an adjunctive treatment to the standard therapy in severe falciparum malaria.

Sahan K, Pell C, Smithuis F, Phyo AK, Maung SM, Indrasuta C, Dondorp AM, White NJ, Day NPJ, von Seidlein L, Cheah PY. 2017. Community engagement and the social context of targeted malaria treatment: a qualitative study in Kayin (Karen) State, Myanmar. Malar J, 16 (1), pp. 75. | Show Abstract | Read more

BACKGROUND: The spread of artemisinin-resistance in Plasmodium falciparum is a threat to current global malaria control initiatives. Targeted malaria treatment (TMT), which combines mass anti-malarial administration with conventional malaria prevention and control measures, has been proposed as a strategy to tackle this problem. The effectiveness of TMT depends on high levels of population coverage and is influenced by accompanying community engagement activities and the local social context. The article explores how these factors influenced attitudes and behaviours towards TMT in Kayin (Karen) State, Myanmar. METHODS: Semi-structured interviews were conducted with villagers from study villages (N = 31) and TMT project staff (N = 14) between March and July 2015. RESULTS: Community engagement consisted of a range of activities to communicate the local malaria situation (including anti-malarial drug resistance and asymptomatic malaria), the aims of the TMT project, and its potential benefits. Community engagement was seen by staff as integral to the TMT project as a whole and not a sub-set of activities. Attitudes towards TMT (including towards community engagement) showed that developing trusting relationships helped foster participation. After initial wariness, staff received hospitality and acceptance among villagers. Offering healthcare alongside TMT proved mutually beneficial for the study and villagers. A handful of more socially-mobile and wealthy community members were reluctant to participate. The challenges of community engagement included time constraints and the isolation of the community with its limited infrastructure and a history of conflict. CONCLUSIONS: Community engagement had to be responsive to the local community even though staff faced time constraints. Understanding the social context of engagement helped TMT to foster respectful and trusting relationships. The complex relationship between the local context and community engagement complicated evaluation of the community strategy. Nonetheless, the project did record high levels of population coverage.

Dondorp AM, Smithuis FM, Woodrow C, Seidlein LV. 2017. How to Contain Artemisinin- and Multidrug-Resistant Falciparum Malaria. Trends Parasitol, 33 (5), pp. 353-363. | Show Abstract | Read more

In the Greater Mekong subregion (GMS), artemisinin resistance is increasingly compounded by partner drug resistance, causing high failure rates of artemisinin combination therapies in some areas. For its containment, an accelerated elimination strategy will be needed. This includes high-quality implementation of conventional malaria control measures: early case management with quality artemisinin combination therapies (avoiding artesunate monotherapies) and single gametocytocidal low dose of primaquine, vector control and surveillance. Village health workers (VHWs) play a key role in the provision of community-based services which have to reach even the most remote populations. Additional, more aggressive, approaches will be important to accelerate malaria elimination, which could include mass drug administrations, potentially in combination with ivermectin and vaccination, mass screening and treatment with novel diagnostics, reactive case detection, and other measures.

Ataide R, Ashley EA, Powell R, Chan J-A, Malloy MJ, O'Flaherty K, Takashima E, Langer C, Tsuboi T, Dondorp AM et al. 2017. Host immunity to Plasmodium falciparum and the assessment of emerging artemisinin resistance in a multinational cohort. Proc Natl Acad Sci U S A, 114 (13), pp. 3515-3520. | Show Abstract | Read more

Artemisinin-resistant falciparum malaria, defined by a slow-clearance phenotype and the presence of kelch13 mutants, has emerged in the Greater Mekong Subregion. Naturally acquired immunity to malaria clears parasites independent of antimalarial drugs. We hypothesized that between- and within-population variations in host immunity influence parasite clearance after artemisinin treatment and the interpretation of emerging artemisinin resistance. Antibodies specific to 12 Plasmodium falciparum sporozoite and blood-stage antigens were determined in 959 patients (from 11 sites in Southeast Asia) participating in a multinational cohort study assessing parasite clearance half-life (PCt1/2) after artesunate treatment and kelch13 mutations. Linear mixed-effects modeling of pooled individual patient data assessed the association between antibody responses and PCt1/2.P. falciparum antibodies were lowest in areas where the prevalence of kelch13 mutations and slow PCt1/2 were highest [Spearman ρ = -0.90 (95% confidence interval, -0.97, -0.65), and Spearman ρ = -0.94 (95% confidence interval, -0.98, -0.77), respectively]. P. falciparum antibodies were associated with faster PCt1/2 (mean difference in PCt1/2 according to seropositivity, -0.16 to -0.65 h, depending on antigen); antibodies have a greater effect on the clearance of kelch13 mutant compared with wild-type parasites (mean difference in PCt1/2 according to seropositivity, -0.22 to -0.61 h faster in kelch13 mutants compared with wild-type parasites). Naturally acquired immunity accelerates the clearance of artemisinin-resistant parasites in patients with falciparum malaria and may confound the current working definition of artemisinin resistance. Immunity may also play an important role in the emergence and transmission potential of artemisinin-resistant parasites.

Tripura R, Peto TJ, Veugen CC, Nguon C, Davoeung C, James N, Dhorda M, Maude RJ, Duanguppama J, Patumrat K et al. 2017. Submicroscopic Plasmodium prevalence in relation to malaria incidence in 20 villages in western Cambodia. Malar J, 16 (1), pp. 56. | Show Abstract | Read more

BACKGROUND: Cambodia has seen a marked reduction in the incidence of Plasmodium falciparum over the past decade without a corresponding decline in Plasmodium vivax incidence. It is unknown to what extent local transmission is sustained by a chain of clinical and sub-clinical infections or by continued re-introduction via migration. Using an ultrasensitive molecular technique, 20 villages in western Cambodia were surveyed to detect the low season prevalence of P. falciparum and P. vivax and local treatment records were reviewed. METHODS: During March to May 2015 cross-sectional surveys were conducted in 20 villages in Battambang, western Cambodia. Demographic and epidemiological data and venous blood samples were collected from 50 randomly selected adult volunteers in each village. Blood was tested for Plasmodium infections by rapid diagnostic test (RDT), microscopy and high volume (0.5 ml packed red blood cell) quantitative polymerase chain reaction (uPCR). Positive samples were analysed by nested PCR to determine the Plasmodium species. Malaria case records were collected from the Provincial Health Department and village malaria workers to determine incidence and migration status. RESULTS: Among the 1000 participants, 91 (9.1%) were positive for any Plasmodium infection by uPCR, seven (0.7%) by microscopy, and two (0.2%) by RDT. uPCR P. vivax prevalence was 6.6%, P. falciparum 0.7%, and undetermined Plasmodium species 1.8%. Being male (adjusted OR 2.0; 95% CI 1.2-3.4); being a young adult <30 years (aOR 2.1; 95% CI 1.3-3.4); recent forest travel (aOR 2.8; 95% CI 1.6-4.8); and, a history of malaria (aOR 5.2; 95% CI 2.5-10.7) were independent risk factors for parasitaemia. Of the clinical malaria cases diagnosed by village malaria workers, 43.9% (297/634) and 38.4% (201/523) were among migrants in 2013 and in 2014, respectively. Plasmodium vivax prevalence determined by uPCR significantly correlated with vivax malaria incidences in both 2014 and 2015 (p = 0.001 and 0.002, respectively), whereas no relationship was observed in falciparum malaria (p = 0.36 and p = 0.59, respectively). DISCUSSION: There was heterogeneity in the malaria parasite reservoir between villages, and Plasmodium prevalence correlated with subsequent malaria incidence. The association was attributable chiefly to P. vivax infections, which were nine-fold more prevalent than P. falciparum infections. In the absence of a radical cure with 8-aminoquinolines, P. vivax transmission will continue even as P. falciparum prevalence declines. Migration was associated with over a third of incident cases of clinical malaria. Trial registration (NCT01872702). Registered 4 June 2013.

Nguyen T-N, Thu PNH, Hung NT, Son DH, Tien NT, Van Dung N, Quang HH, Seidlein LV, Cheah PY, Dondorp AM et al. 2017. Community perceptions of targeted anti-malarial mass drug administrations in two provinces in Vietnam: a quantitative survey. Malar J, 16 (1), pp. 17. | Show Abstract | Read more

BACKGROUND: As part of a targeted malaria elimination project, mass drug administrations (MDAs) were conducted in Vietnam. The impact of MDAs on malaria transmission depends largely on the efficacy of the anti-malarial drug regimen, the malaria epidemiology in the site and the population coverage. To explore why some people participate in MDAs and others do not, a quantitative survey of the villagers' perceptions was undertaken in Vietnam. METHODS: In 2013/2014 MDAs were conducted in a village in Binh Phuoc province and a village in Ninh Thuan province. Within three months of the drug administration, 59 respondents in a village in Binh Phuoc and 79 respondents in a village in Ninh Thuan were randomly selected and interviewed. RESULTS: Comprehension of the purpose of the intervention was of paramount importance for participation in the intervention. Respondents aware that the intervention aims to protect against malaria were significantly more likely to participate than respondents who were unaware of the MDA's purpose. Secondly, how and by whom villagers were informed was critical for participation. There was a strong association between sensitization by an informant such as a member of the local health team with participation in the intervention. CONCLUSIONS: The study suggests several approaches to increase participation in mass drug administration campaigns. Training trustworthy informants to sensitize the study population is critical to maximize village participation in this setting. To achieve high coverage the entire community must understand and agree with the intervention.

Jeeyapant A, Kingston HW, Plewes K, Maude RJ, Hanson J, Herdman MT, Leopold SJ, Ngernseng T, Charunwatthana P, Phu NH et al. 2017. Defining Surrogate Endpoints for Clinical Trials in Severe Falciparum Malaria. PLoS One, 12 (1), pp. e0169307. | Show Abstract | Read more

BACKGROUND: Clinical trials in severe falciparum malaria require a large sample size to detect clinically meaningful differences in mortality. This means few interventions can be evaluated at any time. Using a validated surrogate endpoint for mortality would provide a useful alternative allowing a smaller sample size. Here we evaluate changes in coma score and plasma lactate as surrogate endpoints for mortality in severe falciparum malaria. METHODS: Three datasets of clinical studies in severe malaria were re-evaluated: studies from Chittagong, Bangladesh (adults), the African 'AQUAMAT' trial comparing artesunate and quinine (children), and the Vietnamese 'AQ' study (adults) comparing artemether with quinine. The absolute change, relative change, slope of the normalization over time, and time to normalization were derived from sequential measurements of plasma lactate and coma score, and validated for their use as surrogate endpoint, including the proportion of treatment effect on mortality explained (PTE) by these surrogate measures. RESULTS: Improvements in lactate concentration or coma scores over the first 24 hours of admission, were strongly prognostic for survival in all datasets. In hyperlactataemic patients in the AQ study (n = 173), lower mortality with artemether compared to quinine closely correlated with faster reduction in plasma lactate concentration, with a high PTE of the relative change in plasma lactate at 8 and 12 hours of 0.81 and 0.75, respectively. In paediatric patients enrolled in the 'AQUAMAT' study with cerebral malaria (n = 785), mortality was lower with artesunate compared to quinine, but this was not associated with faster coma recovery. CONCLUSIONS: The relative changes in plasma lactate concentration assessed at 8 or 12 hours after admission are valid surrogate endpoints for severe malaria studies on antimalarial drugs or adjuvant treatments aiming at improving the microcirculation. Measures of coma recovery are not valid surrogate endpoints for mortality.

Leang R, Khu NH, Mukaka M, Debackere M, Tripura R, Kheang ST, Chy S, Kak N, Buchy P, Tarantola A et al. 2016. Erratum to: An optimised age-based dosing regimen for single low-dose primaquine for blocking malaria transmission in Cambodia. BMC Med, 14 (1), pp. 213. | Show Abstract | Read more

© 2016 The Author(s). After publication of the original article [1], it came to the authors' attention that there was an error in the PQ pharmacokinetics sub-section of the Background section. The following sentence is affected: "There is no PK interaction between PQ and either artesunate-pyronaridine [76] or mefloquine [69, 77]; no PK interaction data exist for PQ and artemetherlumefantrine (AL)." This sentence should have read as follows: "AS pyronaridine increased PQ exposure by 15% without affecting significantly cPQ exposure [76]. There is no PK interaction between PQ and mefloquine [69, 77]; no PK interaction data exist for PQ and artemetherlumefantrine (AL).".

Thwaites CL, Lundeg G, Dondorp AM, sepsis in resource-limited settings–expert consensus recommendations group* of the European Society of Intensive Care Medicine (ESICM) and the Mahidol-Oxford Research Unit (MORU) in Bangkok, Thailand. 2016. Infection management in patients with sepsis and septic shock in resource-limited settings. Intensive Care Med, 42 (12), pp. 2117-2118. | Read more

Parker DM, Landier J, von Seidlein L, Dondorp A, White L, Hanboonkunupakarn B, Maude RJ, Nosten FH. 2016. Limitations of malaria reactive case detection in an area of low and unstable transmission on the Myanmar-Thailand border. Malar J, 15 (1), pp. 571. | Show Abstract | Read more

BACKGROUND: Reactive case detection is an approach that has been proposed as a tool for malaria elimination in low-transmission settings. It is an intuitively justified approach based on the concept of space-time clustering of malaria cases. When an index malaria clinical case is detected, it triggers reactive screening and treatment in the index house and neighbouring houses. However, the efficacy of this approach at varying screening radii and malaria prevalence remains ill defined. METHODS: Data were obtained from a detailed demographic and geographic surveillance study in four villages on the Myanmar-Thailand border. Clinical cases were recorded at village malaria clinics and were linked back to patients' residencies. These data were used to simulate the efficacy of reactive case detection for clinical cases using rapid diagnostic tests (RDT). Simulations took clinical cases in a given month and tabulated the number of cases that would have been detected in the following month at varying screening radii around the index houses. Simulations were run independently for both falciparum and vivax malaria. Each simulation of a reactive case detection effort was run in comparison with a strategy using random selection of houses for screening. RESULTS: In approximately half of the screenings for falciparum and 10% for vivax it would have been impossible to detect any malaria cases regardless of the screening strategy because the screening would have occurred during times when there were no cases. When geographically linked cases were present in the simulation, reactive case detection would have only been successful at detecting most malaria cases using larger screening radii (150-m radius and above). At this screening radius and above, reactive case detection does not perform better than random screening of an equal number of houses in the village. Screening within very small radii detects only a very small proportion of cases, but despite this low performance is better than random screening with the same sample size. CONCLUSIONS: The results of these simulations indicate that reactive case detection for clinical cases using RDTs has limited ability in halting transmission in regions of low and unstable transmission. This is linked to high spatial heterogeneity of cases, acquisition of malaria infections outside the village, as well missing asymptomatic infections. When cases are few and sporadic, reactive case detection would result in major time and budgetary losses.

Stephens T, De Silva AP, Beane A, Welch J, Sigera C, De Alwis S, Athapattu P, Dharmagunawardene D, Peiris L, Siriwardana S et al. 2017. Capacity building for critical care training delivery: Development and evaluation of the Network for Improving Critical care Skills Training (NICST) programme in Sri Lanka. Intensive Crit Care Nurs, 39 pp. 28-36. | Show Abstract | Read more

OBJECTIVES: To deliver and evaluate a short critical care nurse training course whilst simultaneously building local training capacity. RESEARCH METHODOLOGY: A multi-modal short course for critical care nursing skills was delivered in seven training blocks, from 06/2013-11/2014. Each training block included a Train the Trainer programme. The project was evaluated using Kirkpatrick's Hierarchy of Learning. There was a graded hand over of responsibility for course delivery from overseas to local faculty between 2013 and 2014. SETTING: Sri Lanka. MAIN OUTCOME MEASURES: Participant learning assessed through pre/post course Multi-Choice Questionnaires. RESULTS: A total of 584 nurses and 29 faculty were trained. Participant feedback was consistently positive and each course demonstrated a significant increase (p≤0.0001) in MCQ scores. There was no significant difference MCQ scores (p=0.186) between overseas faculty led and local faculty led courses. CONCLUSIONS: In a relatively short period, training with good educational outcomes was delivered to nearly 25% of the critical care nursing population in Sri Lanka whilst simultaneously building a local faculty of trainers. Through use of a structured Train the Trainer programme, course outcomes were maintained following the handover of training responsibility to Sri Lankan faculty. The focus on local capacity building increases the possibility of long term course sustainability.

Dondorp AM, Hoang MNT, Mer M, Sepsis in Resource-Limited Settings-Expert Consensus Recommendations Group of the European Society of Intensive Care Medicine (ESICM) and the Mahidol-Oxford Research Unit (MORU) in Bangkok, Thailand. 2017. Recommendations for the management of severe malaria and severe dengue in resource-limited settings. Intensive Care Med, 43 (11), pp. 1683-1685. | Read more

Dondorp AM. 2017. New genetic marker for piperaquine resistance in Plasmodium falciparum. Lancet Infect Dis, 17 (2), pp. 119-121. | Read more



European Pubmed Central

Adhikari B, James N, Newby G, von Seidlein L, White NJ, Day NPJ, Dondorp AM, Pell C, Cheah PY. 2016. Community engagement and population coverage in mass anti-malarial administrations: a systematic literature review. Malar J, 15 (1), pp. 523. | Show Abstract | Read more

BACKGROUND: Mass anti-malarial administration has been proposed as a key component of the malaria elimination strategy in South East Asia. The success of this approach depends on the local malaria epidemiology, nature of the anti-malarial regimen and population coverage. Community engagement is used to promote population coverage but little research has systematically analysed its impact. This systematic review examines population coverage and community engagement in programmes of mass anti-malarial drug administration. METHODS: This review builds on a previous review that identified 3049 articles describing mass anti-malarial administrations published between 1913 and 2011. Further search and application of a set of criteria conducted in the current review resulted in 51 articles that were retained for analysis. These 51 papers described the population coverage and/or community engagement in mass anti-malarial administrations. Population coverage was quantitatively assessed and a thematic analysis was conducted on the community engagement activities. RESULTS: The studies were conducted in 26 countries: in diverse healthcare and social contexts where various anti-malarial regimens under varied study designs were administered. Twenty-eight articles reported only population coverage; 12 described only community engagement activities; and 11 community engagement and population coverage. Average population coverage was 83% but methods of calculating coverage were frequently unclear or inconsistent. Community engagement activities included providing health education and incentives, using community structures (e.g. existing hierarchies or health infrastructure), mobilizing human resources, and collaborating with government at some level (e.g. ministries of health). Community engagement was often a process involving various activities throughout the duration of the intervention. CONCLUSION: The mean population coverage was over 80% but incomplete reporting of calculation methods limits conclusions and comparisons between studies. Various community engagement activities and approaches were described, but many articles contained limited or no details. Other factors relevant to population coverage, such as the social, cultural and study context were scarcely reported. Further research is needed to understand the factors that influence population coverage and adherence in mass anti-malarial administrations and the role community engagement activities and approaches play in satisfactory participation.

Leang R, Khu NH, Mukaka M, Debackere M, Tripura R, Kheang ST, Chy S, Kak N, Buchy P, Tarantola A et al. 2016. An optimised age-based dosing regimen for single low-dose primaquine for blocking malaria transmission in Cambodia. BMC Med, 14 (1), pp. 171. | Show Abstract | Read more

BACKGROUND: In 2012, the World Health Organization recommended the addition of single low-dose primaquine (SLDPQ, 0.25 mg base/kg body weight) to artemisinin combination therapies to block the transmission of Plasmodium falciparum without testing for glucose-6-phosphate dehydrogenase deficiency. The targeted group was non-pregnant patients aged ≥ 1 year (later changed to ≥ 6 months) with acute uncomplicated falciparum malaria, primarily in countries with artemisinin-resistant P. falciparum (ARPf). No dosing regimen was suggested, leaving malaria control programmes and clinicians in limbo. Therefore, we designed a user-friendly, age-based SLDPQ regimen for Cambodia, the country most affected by ARPf. METHODS: By reviewing primaquine's pharmacology, we defined a therapeutic dose range of 0.15-0.38 mg base/kg (9-22.5 mg in a 60-kg adult) for a therapeutic index of 2.5. Primaquine doses (1-20 mg) were tested using a modelled, anthropometric database of 28,138 Cambodian individuals (22,772 healthy, 4119 with malaria and 1247 with other infections); age distributions were: 0.5-4 years (20.0 %, n = 5640), 5-12 years (9.1 %, n = 2559), 13-17 years (9.1 %, n = 2550), and ≥ 18 years (61.8 %, n = 17,389). Optimal age-dosing groups were selected according to calculated mg base/kg doses and proportions of individuals receiving a therapeutic dose. RESULTS: Four age-dosing bands were defined: (1) 0.5-4 years, (2) 5-9 years, (3) 10-14 years, and (4) ≥15 years to receive 2.5, 5, 7.5, and 15 mg of primaquine base, resulting in therapeutic doses in 97.4 % (5494/5640), 90.5 % (1511/1669), 97.7 % (1473/1508), and 95.7 % (18,489/19,321) of individuals, respectively. Corresponding median (1st-99th centiles) mg base/kg doses of primaquine were (1) 0.23 (0.15-0.38), (2) 0.29 (0.18-0.45), (3) 0.27 (0.15-0.39), and (4) 0.29 (0.20-0.42). CONCLUSIONS: This age-based SLDPQ regimen could contribute substantially to malaria elimination and requires urgent evaluation in Cambodia and other countries with similar anthropometric characteristics. It guides primaquine manufacturers on suitable tablet strengths and doses for paediatric-friendly formulations. Development of similar age-based dosing recommendations for Africa is needed.

Grist EPM, Flegg JA, Humphreys G, Mas IS, Anderson TJC, Ashley EA, Day NPJ, Dhorda M, Dondorp AM, Faiz MA et al. 2016. Optimal health and disease management using spatial uncertainty: a geographic characterization of emergent artemisinin-resistant Plasmodium falciparum distributions in Southeast Asia. Int J Health Geogr, 15 (1), pp. 37. | Show Abstract | Read more

BACKGROUND: Artemisinin-resistant Plasmodium falciparum malaria parasites are now present across much of mainland Southeast Asia, where ongoing surveys are measuring and mapping their spatial distribution. These efforts require substantial resources. Here we propose a generic 'smart surveillance' methodology to identify optimal candidate sites for future sampling and thus map the distribution of artemisinin resistance most efficiently. METHODS: The approach uses the 'uncertainty' map generated iteratively by a geostatistical model to determine optimal locations for subsequent sampling. RESULTS: The methodology is illustrated using recent data on the prevalence of the K13-propeller polymorphism (a genetic marker of artemisinin resistance) in the Greater Mekong Subregion. CONCLUSION: This methodology, which has broader application to geostatistical mapping in general, could improve the quality and efficiency of drug resistance mapping and thereby guide practical operations to eliminate malaria in affected areas.

Maude RR, Ghose A, Samad R, de Jong HK, Fukushima M, Wijedoru L, Hassan MU, Hossain MA, Karim MR, Sayeed AA et al. 2016. A prospective study of the importance of enteric fever as a cause of non-malarial febrile illness in patients admitted to Chittagong Medical College Hospital, Bangladesh. BMC Infect Dis, 16 (1), pp. 567. | Show Abstract | Read more

BACKGROUND: Fever is a common cause of hospital admission in Bangladesh but causative agents, other than malaria, are not routinely investigated. Enteric fever is thought to be common. METHODS: Adults and children admitted to Chittagong Medical College Hospital with a temperature of ≥38.0 °C were investigated using a blood smear for malaria, a blood culture, real-time PCR to detect Salmonella Typhi, S. Paratyphi A and other pathogens in blood and CSF and an NS1 antigen dengue ELISA. RESULTS: We enrolled 300 febrile patients with a negative malaria smear between January and June 2012: 156 children (aged ≤15 years) and 144 adults with a median (interquartile range) age of 13 (5-31) years and median (IQR) illness duration before admission of five (2-8) days. Clinical enteric fever was diagnosed in 52 patients (17.3 %), lower respiratory tract infection in 48 (16.0 %), non-specific febrile illness in 48 (16.0 %), a CNS infection in 37 patients (12.3 %), urinary sepsis in 23 patients (7.7 %), an upper respiratory tract infection in 21 patients (7.0 %), and diarrhea or dysentery in 21 patients (7.0 %). Malaria was still suspected in seven patients despite a negative microscopy test. S. Typhi was detected in blood by culture or PCR in 34 (11.3 %) of patients. Of note Rickettsia typhi and Orientia tsutsugamushi were detected by PCR in two and one patient respectively. Twenty-nine (9 %) patients died during their hospital admission (15/160 (9.4 %) of children and 14/144 (9.7 %) adults). Two of 52 (3.8 %) patients with enteric fever, 5/48 (10.4 %) patients with lower respiratory tract infections, and 12/37 (32.4 %) patients with CNS infection died. CONCLUSION: Enteric fever was confirmed in 11.3 % of patients admitted to this hospital in Bangladesh with non-malaria fever. Lower respiratory tract and CNS infections were also common. CNS infections in this location merit more detailed study due to the high mortality.

Saralamba N, Nakeesathit S, Mayxay M, Newton PN, Osorio L, Kim J-R, White NJ, Day NPJ, Dondorp AM, Imwong M. 2016. Geographic distribution of amino acid mutations in DHFR and DHPS in Plasmodium vivax isolates from Lao PDR, India and Colombia. Malar J, 15 (1), pp. 484. | Show Abstract | Read more

BACKGROUND: Non-synonymous mutations in dhfr and dhps genes in Plasmodium vivax are associated with sulfadoxine-pyrimethamine (SP) resistance. The present study aimed to assess the prevalence of point mutations in P. vivax dhfr (pvdhfr) and P. vivax dhps (pvdhps) genes in three countries: Lao PDR, India and Colombia. METHODS: Samples from 203 microscopically diagnosed vivax malaria were collected from the three countries. Five codons at positions 13, 57, 58, 61, and 117 of pvdhfr and two codons at positions 383 and 553 of pvdhps were examined by polymerase chain reaction-restriction fragment length polymorphism methodology. RESULTS: The largest number of 58R/117 N double mutations in pvdhfr was observed in Colombia (94.3 %), while the corresponding wild-type amino acids were found at high frequencies in Lao PDR during 2001-2004 (57.8 %). Size polymorphism analysis of the tandem repeats within pvdhfr revealed that 74.3 % of all the isolates carried the type B variant. Eighty-nine per cent of all the isolates examined carried wild-type pvdhps A383 and A553. CONCLUSIONS: Although SP is not generally used to treat P. vivax infections, mutations in dhfr and dhps that confer antifolate resistance in P. vivax are common. The data strongly suggest that, when used primarily to treat falciparum malaria, SP can exert a substantial selective pressure on P. vivax populations, and this can lead to point mutations in dhfr and dhps. Accurate data on the global geographic distribution of dhfr and dhps genotypes should help to inform anti-malarial drug-use policies.

Cheah PY, Parker M, Dondorp AM. 2016. Development of drugs for severe malaria in children. Int Health, 8 (5), pp. 313-316. | Show Abstract | Read more

Over 90% of deaths attributable to malaria are in African children under 5 years old. Yet, new treatments are often tested primarily in adult patients and extrapolations have proven to be sometimes invalid, especially in dosing regimens. For studies in severe malaria an additional complication is that the decline in severe malaria in adult patients precludes sufficiently powered trials in adults, before the intervention can be tested in the ultimate target group, paediatric severe malaria. In this paper we propose an alternative pathway to the development of drugs for use in paediatric severe malaria. We argue that following the classical phase I and II studies, small safety and efficacy studies using well-chosen surrogate endpoints in adult severe malaria be conducted, instead of larger mortality endpoint trials. If the drug appears safe and promising small pilot studies in paediatric severe malaria using the same endpoints can follow. Finally, with carefully observed safeguards in place to ensure high ethical standards, promising candidate interventions can be taken forward into mortality endpoint, well-powered, large paediatric studies in African children with severe malaria. Given the available research capacity, limited numbers of prudently selected interventions can be studied in phase III trials, and adaptive designs should be considered.

Falq G, Van Den Bergh R, De Smet M, Etienne W, Nguon C, Rekol H, Imwong M, Dondorp A, Kindermans J-M. 2016. Assessing the asymptomatic reservoir and dihydroartemisinin-piperaquine effectiveness in a low transmission setting threatened by artemisinin resistant Plasmodium falciparum. Malar J, 15 (1), pp. 446. | Show Abstract | Read more

BACKGROUND: In Cambodia, elimination of artemisinin resistance through direct elimination of the Plasmodium falciparum parasite may be the only strategy. Prevalence and incidence at district and village levels were assessed in Chey Saen district, Preah Vihear province, North of Cambodia. Molecular and clinical indicators for artemisinin resistance were documented. METHODS: A cross sectional prevalence survey was conducted at village level in the district of Chey Saen from September to October 2014. Plasmodium spp. was assessed with high volume quantitative real-time polymerase chain reaction (qPCR). Plasmodium falciparum-positive samples were screened for mutations in the k13-propeller domain gene. Treatment effectiveness was established after 28 days (D28) using the same qPCR technique. Data from the provincial surveillance system targeting symptomatic cases, supported by Médecins Sans Frontières (MSF), were used to assess incidence. RESULTS: District P. falciparum prevalence was of 0.74 % [0.41; 1.21]; village prevalence ranged from 0 to 4.6 % [1.4; 10.5]. The annual incidence of P. falciparum was 16.8 cases per 1000 inhabitants in the district; village incidence ranged from 1.3 to 54.9 for 1000 inhabitants. Two geographical clusters with high number of cases were identified by both approaches. The marker for artemisinin resistance was found in six samples out of the 11 tested (55 %). 34.9 % of qPCR blood analysis of symptomatic patients were still positive at D28. CONCLUSIONS: The overall low prevalence of P. falciparum was confirmed in Chey Saen district in Cambodia, while there were important variations between villages. Symptomatic cases had a different pattern and were likely acquired outside the villages. It illustrates the importance of prevalence surveys in targeting interventions for elimination. Mutations in the k13-propeller domain gene (C580Y), conferring artemisinin resistance, were highly prevalent in both symptomatic and asymptomatic cases (realizing the absolute figures remain low). Asymptomatic individuals could be an additional reservoir for artemisinin resistance. The low effectiveness of dihydroartemisinin-piperaquine (DHA-PPQ) for symptomatic cases indicates that PPQ is no longer able to complement the reduced potency of DHA to treat falciparum malaria and highlights the need for an alternative first-line treatment.

Sigera PC, Tunpattu TMUS, Jayashantha TP, De Silva AP, Athapattu PL, Dondorp A, Haniffa R. 2016. National Profile of Physical Therapists in Critical Care Units of Sri Lanka: Lower Middle-Income Country. Phys Ther, 96 (7), pp. 933-939. | Show Abstract | Read more

BACKGROUND: The availability and role of physical therapists in critical care is variable in resource-poor settings, including lower middle-income countries. OBJECTIVE: The aim of this study was to determine: (1) the availability of critical care physical therapist services, (2) the equipment and techniques used and needed, and (3) the training and continuous professional development of physical therapists. METHODS: All physical therapists working in critical care units (CCUs) of state hospitals in Sri Lanka were contacted. The study tool used was an interviewer-administered telephone questionnaire. RESULTS: The response rate was 100% (N=213). Sixty-one percent of the physical therapists were men. Ninety-four percent of the respondents were at least diploma holders in physical therapy, and 6% had non-physical therapy degrees. Most (n=145, 68%) had engaged in some continuous professional development in the past year. The majority (n=119, 56%) attended to patients after referral from medical staff. Seventy-seven percent, 98%, and 96% worked at nights, on weekends, and on public holidays, respectively. Physical therapists commonly perform manual hyperinflation, breathing exercises, manual airway clearance techniques, limb exercises, mobilization, positioning, and postural drainage in the CCUs. Lack of specialist training, lack of adequate physical therapy staff numbers, a heavy workload, and perceived lack of infection control in CCUs were the main difficulties they identified. LIMITATIONS: Details on the proportions of time spent by the physical therapists in the CCUs, wards, or medical departments were not collected. CONCLUSIONS: The availability of physical therapist services in CCUs in Sri Lanka, a lower middle-income country, was comparable to that in high-income countries, as per available literature, in terms of service availability and staffing, although the density of physical therapists remained very low, critical care training was limited, and resource limitations to physical therapy practices were evident.

Peto TJ, Tripura R, Lee SJ, Althaus T, Dunachie S, Nguon C, Dhorda M, Promnarate C, Chalk J, Imwong M et al. 2016. Association between Subclinical Malaria Infection and Inflammatory Host Response in a Pre-Elimination Setting. PLoS One, 11 (7), pp. e0158656. | Show Abstract | Read more

BACKGROUND: Subclinical infections in endemic areas of Southeast Asia sustain malaria transmission. These asymptomatic infections might sustain immunity against clinical malaria and have been considered benign for the host, but if they are associated with chronic low-grade inflammation this could be harmful. We conducted a case-control study to explore the association between subclinical malaria and C-reactive protein (CRP), an established biomarker of inflammation. METHODS: Blood samples from asymptomatic villagers in Pailin, Western Cambodia were tested for malaria by high-volume ultra-sensitive polymerase chain reaction (uPCR) to determine the Plasmodium species. Plasma CRP concentration was measured in 328 individuals with parasitaemia (cases) and compared with: i) the same individual's value at the first time point when they had no detectable parasites (n = 282); and ii) age- sex- and village-matched controls (n = 328) free of Plasmodium infection. Plasma CRP concentrations were compared against thresholds of 3mg/L and 10mg/L. Subgroup analysis was carried out for cases with P vivax and P falciparum mono-infections. RESULTS: Median plasma CRP level for all samples was 0.59mg/L (interquartile range: 0.24-1.64mg/L). CRP concentrations were higher in parasitaemic individuals compared with same-person-controls (p = 0.050); and matched-controls (p = 0.025). 4.9% of samples had CRP concentrations above 10mg/L and 14.6% were above 3mg/L. Cases were more likely to have plasma CRP concentrations above these thresholds than age/sex matched controls, odds ratio 3.5 (95%CI 1.5-9.8) and 1.8 (95%CI 1.1-2.9), respectively. Amongst cases, parasite density and CRP were positively correlated (p<0.001), an association that remained significant when controlling for age and fever. Individuals with P.vivax mono-infections had the highest plasma CRP concentrations with the greatest association with parasitaemia. DISCUSSION: In this setting persistent malaria infections in asymptomatic individuals were associated with moderately elevated plasma CRP concentrations; chiefly evident in cases with P.vivax mono-infections. As well as interrupting malaria transmission within the community, treatment of asymptomatic malaria infections, in particular radical cure of vivax malaria, may benefit the health of infected individuals.

Thwaites CL, Lundeg G, Dondorp AM, sepsis in resource-limited settings–expert consensus recommendations group of the European Society of Intensive Care Medicine (ESICM) and the Mahidol-Oxford Research Unit (MORU) in Bangkok, Thailand. 2016. Recommendations for infection management in patients with sepsis and septic shock in resource-limited settings. Intensive Care Med, 42 (12), pp. 2040-2042. | Read more

Phommasone K, Adhikari B, Henriques G, Pongvongsa T, Phongmany P, von Seidlein L, White NJ, Day NPJ, M Dondorp A, Newton PN et al. 2016. Asymptomatic Plasmodium infections in 18 villages of southern Savannakhet Province, Lao PDR (Laos). Malar J, 15 (1), pp. 296. | Show Abstract | Read more

BACKGROUND: A large fraction of Plasmodium infections do not cause clinical signs and symptoms of disease and persist at densities in blood that are not detectable by microscopy or rapid diagnostic tests. These infections may be critical as a transmission reservoir in areas of low malaria endemicity. Understanding the epidemiology of these infections would be helpful for malaria elimination. METHODS: A cross-sectional survey was conducted in Thapangthong and Nong Districts of Savannakhet Province, Lao PDR, to determine the prevalence of parasitaemia. A total of 888 blood samples were collected from afebrile volunteers aged ≥15 years in 18 villages during March and July 2015. Plasmodium infections were diagnosed by rapid diagnostic tests (RDT) and high volume, ultra-sensitive quantitative polymerase chain reaction (uPCR). RESULTS: uPCR detected Plasmodium infections in 175 of 888 samples (20 %). The species distribution was Plasmodium falciparum 3.6 % (32/888), Plasmodium vivax 11.1 % (99/888), mixed infections with P. falciparum and P. vivax 1.6 % (14/888) and Plasmodium of undetermined species 3.4 % (30/888). RDT identified only 2 % (18/888) positive cases. Using uPCR as reference, the sensitivity and specificity of RDTs were 28 and 100 %, respectively, in detecting P. falciparum infections, and 3 and 99 % in detecting asymptomatic P. vivax infections. The K13 kelch propeller domain C580Y mutation, associated with reduced susceptibility to artemisinin derivatives, was found in 75 % (12/18) of P. falciparum isolates from Thapangthong and in 7 % (2/28) from Nong (p < 0.001). In a multivariate analysis, males were more likely to have P. vivax infections [adjusted odds ratio (aOR) 4.76 (95 % CI 2.84-8.00)] while older villagers were at lower risk for parasitaemia [aOR for increasing age 0.98 (95 % CI 0.96-0.99)]. CONCLUSION: There is a high prevalence of asymptomatic Plasmodium infections in southern Savannakhet. Artemisinin-resistant P. falciparum strains form an increasing proportion of the parasite population in Thapangthong District and are already present in the more remote Nong District. This worrying trend has wider implications for Laos and could reverse the gains achieved by the successful control of malaria in Laos and the Greater Mekong Sub-region (GMS). Rapid elimination of P. falciparum has to be a top priority in Laos as well as in the wider GMS.



European Pubmed Central

WWARN Gametocyte Study Group. 2016. Gametocyte carriage in uncomplicated Plasmodium falciparum malaria following treatment with artemisinin combination therapy: a systematic review and meta-analysis of individual patient data. BMC Med, 14 (1), pp. 79. | Show Abstract | Read more

BACKGROUND: Gametocytes are responsible for transmission of malaria from human to mosquito. Artemisinin combination therapy (ACT) reduces post-treatment gametocyte carriage, dependent upon host, parasite and pharmacodynamic factors. The gametocytocidal properties of antimalarial drugs are important for malaria elimination efforts. An individual patient clinical data meta-analysis was undertaken to identify the determinants of gametocyte carriage and the comparative effects of four ACTs: artemether-lumefantrine (AL), artesunate/amodiaquine (AS-AQ), artesunate/mefloquine (AS-MQ), and dihydroartemisinin-piperaquine (DP). METHODS: Factors associated with gametocytaemia prior to, and following, ACT treatment were identified in multivariable logistic or Cox regression analysis with random effects. All relevant studies were identified through a systematic review of PubMed. Risk of bias was evaluated based on study design, methodology, and missing data. RESULTS: The systematic review identified 169 published and 9 unpublished studies, 126 of which were shared with the WorldWide Antimalarial Resistance Network (WWARN) and 121 trials including 48,840 patients were included in the analysis. Prevalence of gametocytaemia by microscopy at enrolment was 12.1 % (5887/48,589), and increased with decreasing age, decreasing asexual parasite density and decreasing haemoglobin concentration, and was higher in patients without fever at presentation. After ACT treatment, gametocytaemia appeared in 1.9 % (95 % CI, 1.7-2.1) of patients. The appearance of gametocytaemia was lowest after AS-MQ and AL and significantly higher after DP (adjusted hazard ratio (AHR), 2.03; 95 % CI, 1.24-3.12; P = 0.005 compared to AL) and AS-AQ fixed dose combination (FDC) (AHR, 4.01; 95 % CI, 2.40-6.72; P < 0.001 compared to AL). Among individuals who had gametocytaemia before treatment, gametocytaemia clearance was significantly faster with AS-MQ (AHR, 1.26; 95 % CI, 1.00-1.60; P = 0.054) and slower with DP (AHR, 0.74; 95 % CI, 0.63-0.88; P = 0.001) compared to AL. Both recrudescent (adjusted odds ratio (AOR), 9.05; 95 % CI, 3.74-21.90; P < 0.001) and new (AOR, 3.03; 95 % CI, 1.66-5.54; P < 0.001) infections with asexual-stage parasites were strongly associated with development of gametocytaemia after day 7. CONCLUSIONS: AS-MQ and AL are more effective than DP and AS-AQ FDC in preventing gametocytaemia shortly after treatment, suggesting that the non-artemisinin partner drug or the timing of artemisinin dosing are important determinants of post-treatment gametocyte dynamics.

Govindasamy G, Barber BE, Ghani SA, William T, Grigg MJ, Borooah S, Dhillon B, Dondorp AM, Yeo TW, Anstey NM, Maude RJ. 2016. Retinal Changes in Uncomplicated and Severe Plasmodium knowlesi Malaria. J Infect Dis, 213 (9), pp. 1476-1482. | Show Abstract | Read more

BACKGROUND: Plasmodium knowlesi causes severe malaria, but its pathogenesis is poorly understood. Retinal changes provide insights into falciparum malaria pathogenesis but have not been studied in knowlesi malaria. METHODS: An observational study was conducted in Malaysian adults hospitalized with severe (n = 20) and nonsevere (n = 24) knowlesi malaria using indirect ophthalmoscopy (n = 44) and fundus photography (n = 29). RESULTS: The patients' median age was 44 years (range, 18-74 years). No coma or deaths occurred. Photography detected retinal changes in 11 of 12 patients (92%) with severe and 14 of 17 (82%) with nonsevere knowlesi malaria. Nonspecific retinal whitening occurred in 3 (35%) and 5 (29%) patients with severe and nonsevere disease, respectively; hemorrhages in 2 (17%) and 3 (18%); loss of retinal pigment epithelium in 1 (8%) and 4 (24%); and drusen in 9 (71%) and 12 (75%). All changes were mild, with no significant differences between severe and nonsevere disease. Patients with retinal hemorrhages had lower platelet counts than those without (median, 22 vs 43 × 10(9)/L; P= .04). CONCLUSIONS: The paucity of specific retinal findings associated with disease severity in knowlesi malaria contrasts with the retinopathy of severe adult falciparum malaria with and without coma, suggesting that falciparum-like microvascular sequestration in the brain is not a major component in severe knowlesi malaria pathogenesis.

Wattanakul T, Teerapong P, Plewes K, Newton PN, Chierakul W, Silamut K, Chotivanich K, Ruengweerayut R, White NJ, Dondorp AM, Tarning J. 2016. Pharmacokinetic properties of intramuscular versus oral syrup paracetamol in Plasmodium falciparum malaria. Malar J, 15 (1), pp. 244. | Show Abstract | Read more

BACKGROUND: Fever is an inherent symptom of malaria in both adults and children. Paracetamol (acetaminophen) is the recommended antipyretic as it is inexpensive, widely available and has a good safety profile, but patients may not be able to take the oral drug reliably. A comparison between the pharmacokinetics of oral syrup and intramuscular paracetamol given to patients with acute falciparum malaria and high body temperature was performed. METHODS: A randomized, open-label, two-treatment, crossover, pharmacokinetic study of paracetamol dosed orally and intramuscularly was conducted. Twenty-one adult patients with uncomplicated falciparum malaria were randomized to receive a single 600 mg dose of paracetamol either as syrup or intramuscular injection on day 0 followed by a single dose administered by the alternative route on day 1. Paracetamol plasma concentrations were quantified frequently and modelled simultaneously using nonlinear mixed-effects modelling. The final population pharmacokinetic model was used for dose optimization simulations. Relationships between paracetamol concentrations with temperature and parasite half-life were investigated using linear and non-linear regression analyses. RESULTS: The population pharmacokinetic properties of paracetamol were best described by a two-compartment disposition model, with zero-order and first-order absorption for intramuscular and oral syrup administration, respectively. The relative bioavailability of oral syrup was 84.4 % (95 % CI 68.2-95.1 %) compared to intramuscular administration. Dosing simulations showed that 1000 mg of intramuscular or oral syrup administered six-hourly reached therapeutic steady state concentrations for antipyresis, but more favourable concentration-time profiles were achieved with a loading dose of 1500 mg, followed by a 1000 mg maintenance dose. This ensured that maximum therapeutic concentrations were reached rapidly during the first 6 h. No significant relationships between paracetamol concentrations and temperature or parasite half-life were found. CONCLUSIONS: Paracetamol plasma concentrations after oral syrup and intramuscular administration in patients with acute falciparum malaria were described successfully by a two-compartment disposition model. Relative oral bioavailability compared to intramuscular dosing was estimated as 84.4 % (95 % CI 68.2-95.1 %). Dosing simulations showed that a loading dose followed by six-hourly dosing intervals reduced the time delay to reach therapeutic drug levels after both routes of administration. The safety and efficacy of loading dose paracetamol antipyretic regimens now needs to be established in larger studies.

Peto TJ, Kloprogge SE, Tripura R, Nguon C, Sanann N, Yok S, Heng C, Promnarate C, Chalk J, Song N et al. 2016. History of malaria treatment as a predictor of subsequent subclinical parasitaemia: a cross-sectional survey and malaria case records from three villages in Pailin, western Cambodia. Malar J, 15 (1), pp. 240. | Show Abstract | Read more

BACKGROUND: Treatment of the sub-clinical reservoir of malaria, which may maintain transmission, could be an important component of elimination strategies. The reliable detection of asymptomatic infections with low levels of parasitaemia requires high-volume quantitative polymerase chain reaction (uPCR), which is impractical to conduct on a large scale. It is unknown to what extent sub-clinical parasitaemias originate from recent or older clinical episodes. This study explored the association between clinical history of malaria and subsequent sub-clinical parasitaemia. METHODS: In June 2013 a cross-sectional survey was conducted in three villages in Pailin, western Cambodia. Demographic and epidemiological data and blood samples were collected. Blood was tested for malaria by high-volume qPCR. Positive samples were analysed by nested PCR to determine the Plasmodium species. To identify previous episodes of malaria, case records were collected from village malaria workers and local health facilities and linked to study participants. RESULTS: Among 1343 participants, 40/122 (32.8 %) with a history of clinical malaria were parasitaemic during the cross-sectional survey, compared to 172/1221 (14.1 %) without this history (p < 0.001). Among the 212 parasitaemic participants in the survey, 40 (18.9 %) had a history of clinical malaria, compared to 87 out of 1131 (7.7 %) parasite-negative participants; p < 0.001, adjusted OR 3.3 (95 % CI; 2.1-5.1). A history of Plasmodium vivax was associated with sub-clinical P. vivax parasitaemia in the survey (p < 0.001), but this association was not seen with Plasmodium falciparum (p = 0.253); only three participants had both P. falciparum parasites in the survey and a clinical history of P. falciparum. CONCLUSIONS: A clinical episode of vivax malaria was associated with subsequent sub-clinical parasitaemia. Treatment of P. vivax with artemisinin-based combination therapy without primaquine often resulted in recurrent episodes. Targeting individuals with a history of clinical malaria will be insufficient to eliminate the sub-clinical reservoir as they constitute a minority of parasitaemias.

Nakeesathit S, Saralamba N, Pukrittayakamee S, Dondorp A, Nosten F, White NJ, Imwong M. 2016. Limited Polymorphism of the Kelch Propeller Domain in Plasmodium malariae and P. ovale Isolates from Thailand. Antimicrob Agents Chemother, 60 (7), pp. 4055-4062. | Show Abstract | Read more

Artemisinin resistance in Plasmodium falciparum, the agent of severe malaria, is currently a major obstacle to malaria control in Southeast Asia. A gene named "kelch13" has been associated with artemisinin resistance in P. falciparum The orthologue of the kelch gene in P. vivax was identified and a small number of mutations were found in previous studies. The kelch orthologues in the other two human malaria parasites, P. malariae and P. ovale, have not yet been studied. Therefore, in this study, the orthologous kelch genes of P. malariae, P. ovale wallikeri, and P. ovale curtisi were isolated and analyzed for the first time. The homologies of the kelch genes of P. malariae and P. ovale were 84.8% and 82.7%, respectively, compared to the gene in P. falciparum kelch polymorphisms were studied in 13 P. malariae and 5 P. ovale isolates from Thailand. There were 2 nonsynonymous mutations found in these samples. One mutation was P533L, which was found in 1 of 13 P. malariae isolates, and the other was K137R, found in 1 isolate of P. ovale wallikeri (n = 4). This result needs to be considered in the context of widespread artemisinin used within the region; their functional consequences for artemisinin sensitivity in P. malariae and P. ovale will need to be elucidated.



European Pubmed Central

Imwong M, Stepniewska K, Tripura R, Peto TJ, Lwin KM, Vihokhern B, Wongsaen K, von Seidlein L, Dhorda M, Snounou G et al. 2016. Numerical Distributions of Parasite Densities During Asymptomatic Malaria. J Infect Dis, 213 (8), pp. 1322-1329. | Show Abstract | Read more

BACKGROUND: Asymptomatic parasitemia is common even in areas of low seasonal malaria transmission, but the true proportion of the population infected has not been estimated previously because of the limited sensitivity of available detection methods. METHODS: Cross-sectional malaria surveys were conducted in areas of low seasonal transmission along the border between eastern Myanmar and northwestern Thailand and in western Cambodia. DNA was quantitated by an ultrasensitive polymerase chain reaction (uPCR) assay (limit of accurate detection, 22 parasites/mL) to characterize parasite density distributions for Plasmodium falciparum and Plasmodium vivax, and the proportions of undetected infections were imputed. RESULTS: The prevalence of asymptomatic malaria as determined by uPCR was 27.5% (1303 of 4740 people tested). Both P. vivax and P. falciparum density distributions were unimodal and log normal, with modal values well within the quantifiable range. The estimated proportions of all parasitemic individuals identified by uPCR were >70% among individuals infected with P. falciparum and >85% among those infected with P. vivax. Overall, 83% of infections were predicted to be P. vivax infections, 13% were predicted to be P. falciparum infections, and 4% were predicted to be mixed infections. Geometric mean parasite densities were similar; 5601 P. vivax parasites/mL and 5158 P. falciparum parasites/mL. CONCLUSIONS: This uPCR method identified most infected individuals in malaria-endemic areas. Malaria parasitemia persists in humans at levels that optimize the probability of generating transmissible gametocyte densities without causing illness.

Beane A, Stephens T, Silva APD, Welch J, Sigera C, De Alwis S, Athapattu P, Dharmagunawardene D, Peiris L, Siriwardana S et al. 2016. A sustainable approach to training nurses in acute care skills in a resource limited setting (Network for Intensive Care Skills Training, NICST). Resuscitation, 101 pp. e1-e2. | Read more

Herdman MT, Maude RJ, Chowdhury MS, Kingston HWF, Jeeyapant A, Samad R, Karim R, Dondorp AM, Hossain MA. 2016. The Relationship between Poverty and Healthcare Seeking among Patients Hospitalized with Acute Febrile Illnesses in Chittagong, Bangladesh. PLoS One, 11 (4), pp. e0152965. | Show Abstract | Read more

Delays in seeking appropriate healthcare can increase the case fatality of acute febrile illnesses, and circuitous routes of care-seeking can have a catastrophic financial impact upon patients in low-income settings. To investigate the relationship between poverty and pre-hospital delays for patients with acute febrile illnesses, we recruited a cross-sectional, convenience sample of 527 acutely ill adults and children aged over 6 months, with a documented fever ≥38.0 °C and symptoms of up to 14 days' duration, presenting to a tertiary referral hospital in Chittagong, Bangladesh, over the course of one year from September 2011 to September 2012. Participants were classified according to the socioeconomic status of their households, defined by the Oxford Poverty and Human Development Initiative's multidimensional poverty index (MPI). 51% of participants were classified as multidimensionally poor (MPI>0.33). Median time from onset of any symptoms to arrival at hospital was 22 hours longer for MPI poor adults compared to non-poor adults (123 vs. 101 hours) rising to a difference of 26 hours with adjustment in a multivariate regression model (95% confidence interval 7 to 46 hours; P = 0.009). There was no difference in delays for children from poor and non-poor households (97 vs. 119 hours; P = 0.394). Case fatality was 5.9% vs. 0.8% in poor and non-poor individuals respectively (P = 0.001)-5.1% vs. 0.0% for poor and non-poor adults (P = 0.010) and 6.4% vs. 1.8% for poor and non-poor children (P = 0.083). Deaths were attributed to central nervous system infection (11), malaria (3), urinary tract infection (2), gastrointestinal infection (1) and undifferentiated sepsis (1). Both poor and non-poor households relied predominantly upon the (often informal) private sector for medical advice before reaching the referral hospital, but MPI poor participants were less likely to have consulted a qualified doctor. Poor participants were more likely to attribute delays in decision-making and travel to a lack of money (P<0.001), and more likely to face catastrophic expenditure of more than 25% of monthly household income (P<0.001). We conclude that multidimensional poverty is associated with greater pre-hospital delays and expenditure in this setting. Closer links between health and development agendas could address these consequences of poverty and streamline access to adequate healthcare.

Tun KM, Jeeyapant A, Imwong M, Thein M, Aung SSM, Hlaing TM, Yuentrakul P, Promnarate C, Dhorda M, Woodrow CJ et al. 2016. Parasite clearance rates in Upper Myanmar indicate a distinctive artemisinin resistance phenotype: a therapeutic efficacy study. Malar J, 15 (1), pp. 185. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance in Plasmodium falciparum extends across Southeast Asia where it is associated with worsening partner drug resistance and a decline in the efficacy of frontline artemisinin-based combination therapy. Dihydroartemisinin-piperaquine (DP) is an essential component of preventive and curative treatment in the region, but its therapeutic efficacy has fallen in Cambodia. METHODS: A prospective clinical and parasitological evaluation of DP was conducted at two sites in Upper Myanmar between August 2013 and December 2014, enrolling 116 patients with acute uncomplicated falciparum malaria. Patients received DP orally for 3 days together with primaquine 0.25 mg/kg on admission. Parasite clearance half-lives based on 6 hourly blood smears, and day 42 therapeutic responses were assessed as well as parasite K13 genotypes. RESULTS: Median parasite clearance half-life was prolonged, and clearance half-life was greater than 5 h in 21% of patients. Delayed parasite clearance was significantly associated with mutations in the propeller region of the parasite k13 gene. The k13 F446I mutation was found in 25.4% of infections and was associated with a median clearance half-life of 4.7 h compared with 2.7 h for infections without k13 mutations (p < 0.001). There were no failures after 42 days of follow-up, although 18% of patients had persistent parasitaemia on day 3. CONCLUSION: The dominant k13 mutation observed in Upper Myanmar, F446I, appears to be associated with an intermediate rate of parasite clearance compared to other common mutations described elsewhere in the Greater Mekong Subregion. Discerning this phenotype requires relatively detailed clearance measurements, highlighting the importance of methodology in assessing artemisinin resistance.

Tripura R, Peto TJ, Chalk J, Lee SJ, Sirithiranont P, Nguon C, Dhorda M, von Seidlein L, Maude RJ, Day NPJ et al. 2016. Persistent Plasmodium falciparum and Plasmodium vivax infections in a western Cambodian population: implications for prevention, treatment and elimination strategies. Malar J, 15 (1), pp. 181. | Show Abstract | Read more

BACKGROUND: Subclinical Plasmodium parasitaemia is an important reservoir for the transmission and persistence of malaria, particularly in low transmission areas. METHODS: Using ultrasensitive quantitative PCR (uPCR) for the detection of parasitaemia, the entire population of three Cambodian villages in Pailin province were followed for 1 year at three-monthly intervals. A cohort of adult participants found initially to have asymptomatic malaria parasitaemia was followed monthly over the same period. RESULTS: The initial cross sectional survey in June 2013 (M0) of 1447 asymptomatic residents found that 32 (2.2%) had Plasmodium falciparum, 48 (3.3%) had P. vivax, 4 (0.3%) had mixed infections and in 142/1447 (9.8%) malaria was detected but there was insufficient DNA to identify the species (Plasmodium. species). Polymorphisms in the 'K13-propeller' associated with reduced susceptibility to artemisinin derivatives (C580Y) were found in 17/32 (51%) P. falciparum strains. Monthly follow-up without treatment of 24 adult participants with asymptomatic mono or mixed P. falciparum infections found that 3/24 (13%) remained parasitaemic for 2-4 months, whereas the remaining 21/24 (87%) participants had cleared their parasitaemia after 1 month. In contrast, 12/34 (35%) adult participants with P. vivax mono-infection at M0 had malaria parasites (P. vivax or P. sp.) during four or more of the following 11 monthly surveys. CONCLUSIONS: This longitudinal survey in a low transmission setting shows limited duration of P. falciparum carriage, but prolonged carriage of P. vivax infections. Radical treatment of P. vivax infections by 8-aminoquinoline regimens may be required to eliminate all malaria from Cambodia. Trial registration NCT01872702.



European Pubmed Central

MalariaGEN Plasmodium falciparum Community Project. 2016. Genomic epidemiology of artemisinin resistant malaria. Elife, 5 (MARCH2016), | Show Abstract | Read more

The current epidemic of artemisinin resistant Plasmodium falciparum in Southeast Asia is the result of a soft selective sweep involving at least 20 independent kelch13 mutations. In a large global survey, we find that kelch13 mutations which cause resistance in Southeast Asia are present at low frequency in Africa. We show that African kelch13 mutations have originated locally, and that kelch13 shows a normal variation pattern relative to other genes in Africa, whereas in Southeast Asia there is a great excess of non-synonymous mutations, many of which cause radical amino-acid changes. Thus, kelch13 is not currently undergoing strong selection in Africa, despite a deep reservoir of variations that could potentially allow resistance to emerge rapidly. The practical implications are that public health surveillance for artemisinin resistance should not rely on kelch13 data alone, and interventions to prevent resistance must account for local evolutionary conditions, shown by genomic epidemiology to differ greatly between geographical regions.

Ishioka H, Ghose A, Charunwatthana P, Maude R, Plewes K, Kingston H, Intharabut B, Woodrow C, Chotivanich K, Sayeed AA et al. 2016. Sequestration and Red Cell Deformability as Determinants of Hyperlactatemia in Falciparum Malaria. J Infect Dis, 213 (5), pp. 788-793. | Show Abstract | Read more

BACKGROUND: Hyperlactatemia is a strong predictor of mortality in severe falciparum malaria. Sequestered parasitized erythrocytes and reduced uninfected red blood cell deformability (RCD) compromise microcirculatory flow, leading to anaerobic glycolysis. METHODS: In a cohort of patients with falciparum malaria hospitalized in Chittagong, Bangladesh, bulk RCD was measured using a laser diffraction technique, and parasite biomass was estimated from plasma concentrations of Plasmodium falciparum histidine-rich protein 2 (PfHRP2). A multiple linear regression model was constructed to examine their associations with plasma lactate concentrations. RESULTS: A total of 286 patients with falciparum malaria were studied, of whom 224 had severe malaria, and 70 died. Hyperlactatemia (lactate level, ≥ 4 mmol/L) was present in 111 cases. RCD at shear stresses of 1.7 Pa and 30 Pa was reduced significantly in patients who died, compared with survivors, individuals with uncomplicated malaria, or healthy individuals (P < .05, for all comparisons). Multiple linear regression analysis showed that the plasma PfHRP2 level, parasitemia level, total bilirubin level, and RCD at a shear stress of 1.7 Pa were each independently correlated with plasma lactate concentrations (n = 278; R(2) = 0.35). CONCLUSIONS: Sequestration of parasitized red blood cells and reduced RCD both contribute to decreased microcirculatory flow in severe disease.

Leang R, Canavati SE, Khim N, Vestergaard LS, Borghini Fuhrer I, Kim S, Denis MB, Heng P, Tol B, Huy R et al. 2016. Efficacy and Safety of Pyronaridine-Artesunate for Treatment of Uncomplicated Plasmodium falciparum Malaria in Western Cambodia. Antimicrob Agents Chemother, 60 (7), pp. 3884-3890. | Show Abstract | Read more

Pyronaridine-artesunate efficacy for the treatment of uncomplicated Plasmodium falciparum malaria was assessed in an area of artemisinin resistance in western Cambodia. This nonrandomized, single-arm, observational study was conducted between 2014 and 2015. Eligible patients were adults or children with microscopically confirmed P. falciparum infection and fever. Patients received pyronaridine-artesunate once daily for 3 days, dosed according to body weight. The primary outcome was an adequate clinical and parasitological response (ACPR) on day 42, estimated by using Kaplan-Meier analysis, PCR adjusted to exclude reinfection. One hundred twenty-three patients were enrolled. Day 42 PCR-crude ACPRs were 87.2% (95% confidence interval [CI], 79.7 to 92.6%) for the overall study, 89.8% (95% CI, 78.8 to 95.3%) for Pursat, and 82.1% (95% CI, 68.4 to 90.2%) for Pailin. Day 42 PCR-adjusted ACPRs were 87.9% (95% CI, 80.6 to 93.2%) for the overall study, 89.8% (95% CI, 78.8 to 95.3%) for Pursat, and 84.0% (95% CI, 70.6 to 91.7%) for Pailin (P = 0.353 by a log rank test). Day 28 PCR-crude and -adjusted ACPRs were 93.2% (95% CI, 82.9 to 97.4%) and 88.1% (95% CI, 75.3 to 94.5%) for Pursat and Pailin, respectively. A significantly lower proportion of patients achieved day 3 parasite clearance in Pailin (56.4% [95% CI, 43.9 to 69.6%]) than in Pursat (86.7% [95% CI, 76.8 to 93.8%]; P = 0.0019). Fever clearance was also extended at Pailin versus Pursat (P < 0.0001). Most patients (95.9% [116/121]) harbored P. falciparum kelch13 C580Y mutant parasites. Pyronaridine-artesunate was well tolerated; mild increases in hepatic transaminase levels were consistent with data from previous reports. Pyronaridine-artesunate efficacy was below the World Health Organization-recommended threshold at day 42 for medicines with a long half-life (90%) for first-line treatment of P. falciparum malaria in western Cambodia despite high efficacy elsewhere in Asia and Africa. (This study has been registered at under registration number NCT02389439.).

Awab GR, Imwong M, Pukrittayakamee S, Alim F, Hanpithakpong W, Tarning J, Dondorp AM, Day NPJ, White NJ, Woodrow CJ. 2016. Clinical trials of artesunate plus sulfadoxine-pyrimethamine for Plasmodium falciparum malaria in Afghanistan: maintained efficacy a decade after introduction. Malar J, 15 (1), pp. 121. | Show Abstract | Read more

BACKGROUND: Combination therapy with artesunate plus sulfadoxine-pyrimethamine (SP) was adopted as recommended treatment for Plasmodium falciparum infection in Afghanistan in 2003. METHODS: A series of prospective clinical studies examining the efficacy of artesunate plus sulfadoxine-pyrimethamine (AS + SP) against P. falciparum were undertaken in sentinel sites in Afghanistan from 2007 to 2014, accompanied by relevant molecular studies. The first study was a randomized trial of AS + SP versus dihydroartemisinin-piperaquine, while two subsequent studies were standard therapeutic efficacy studies of AS + SP. RESULTS: Three hundred and three patients were enrolled across four provinces in the north and east of the country. Curative efficacy was high in all the trials, with an adequate clinical and parasitological response (ACPR) of more than 95 % in all groups and trial stages. Genotyping for drug-resistance alleles at dhfr indicated fixation of the S108 N mutation and a prevalence of the C59R mutation of approximately 95 % across all sites. Other mutations in dhfr and dhps remained rare or absent entirely, although five isolates from the first trial carried the dhps triple mutant SGEGA haplotype. In the last study undertaken in 2012-2014 the K13 artemisinin resistance marker was examined; only two of 60 successfully sequenced samples carried a K13-propeller mutation. CONCLUSIONS: These data confirm maintained efficacy 10 years after introduction of artesunate plus SP as combination treatment of P. falciparum in Afghanistan. The molecular data indicate that despite a substantial fall in incidence, resistance has not developed to artemisinins, or intensified to the ACT partner drug components. Trial Registration NCT00682578, NCT01115439 and NCT01707199.

Canavati SE, Lawford HLS, Fatunmbi BS, Lek D, Top-Samphor N, Leang R, Dondorp AM, Huy R, Kazadi WM. 2016. Establishing research priorities for malaria elimination in the context of the emergency response to artemisinin resistance framework-the Cambodian approach. Malar J, 15 (1), pp. 120. | Show Abstract | Read more

BACKGROUND: Countries of the greater Mekong subregion have made a transition from malaria control to an aim for falciparum and vivax malaria elimination. The elimination of falciparum malaria will have to be achieved against a background of increasing artemisinin and multi-drug resistance. This ambitious goal requires an operational research (OR) agenda that addresses the dynamic challenges encountered on the path to elimination, which will need to be flexible and developed in close relation with the cambodian national programme for parasitology, entomology and malaria control (CNM). In Cambodia, a number of meetings with stakeholders were convened by the CNM and emergency response to artemisinin resistance (ERAR) hub, producing an initial list of priority OR topics. The process and outcome of these meetings are described, which could serve as a template for other countries in the region. METHODS: A landscaping exercise was conducted to gather all past, on-going and planned malaria focussed OR activities conducted by the cambodian research consortium in Cambodia and categorized according to research theme. The six themes included (1) malaria epidemiology, surveillance and response, (2) malaria case management, (3) malaria vector control, (4) malaria behavioural issues, (5) malaria clinical studies, and (6) other vector-borne diseases (dengue, neglected tropical diseases, soil-transmitted helminths). The different themes were discussed in small focus groups, which made an initial prioritization list which was then presented to a plenary group for further discussion. This produced a list of research questions ranked according to priority. RESULTS: OR priorities produced by the thematic groups were discussed in the plenary meeting and given a priority score by group voting. A list of 17 OR questions were developed, finalized and listed, which included questions on surveillance, active case detection and treatment efficacy. CONCLUSION: This paper describes ERAR's work on supporting Cambodia's transition to malaria elimination by identifying national operational research priorities. ERAR has initiated and currently plays a critical role in the development of country specific research agendas for malaria elimination. The first example of this has been the described exercise in Cambodia, which could serve a template for setting OR priorities in the wider region.

Dondorp AM, Iyer SS, Schultz MJ. 2016. Critical Care in Resource-Restricted Settings. JAMA, 315 (8), pp. 753-754. | Read more

Canavati SE, Lawford HLS, Fatunmbi BS, Lek D, Leang R, Top Samphor N, Dondorp AM, Huy R, Kazadi WM. 2016. The Cambodia Research Consortium: expediting research for malaria elimination with the emergency response to artemisinin resistance framework. Malar J, 15 (1), pp. 5. | Show Abstract | Read more

This commentary offers insight into how to best address barriers that may hinder the translation of malaria research findings into policy. It also proposes viable methods of implementing these policies in Cambodia. Currently, a wide range of malaria research is being conducted by in-country stakeholders, including Cambodia's National Programme for Parasitology, Entomology and Malaria Control's (CNM), non-governmental organizations, and academic institutions. Coordinating research amongst these partners, as well as within the Ministry of Health, is a challenge. Results are rarely disseminated widely and seldom inform programme and policy decisions. CNM and its research partners have severely limited access to each other's databases. This lack of accessibility, timeliness, engagement and cooperation between CNM and its partners greatly impacts overall research efficiency in this field, and is stifling innovation both within and beyond CNM. Cambodia has set a goal to eradicate all forms of malaria by 2030. As countries approach the elimination phase, there is a greater need for sharing research-generated evidence amongst partners, in order to ensure that appropriate and impactful activities are conducted. The Cambodian Research Consortium was established to serve as a framework for partners, stakeholders and researchers to share research projects, information and results, and to promote the goals of CNM. The sharing of malaria research results will help to inform prevention, control and elimination activities in the country. It will also determine and address the country's operational research needs, and could potentially become a framework model to be used in other countries aiming to transition from malaria control to elimination.

Wihokhoen B, Dondorp AM, Turner P, Woodrow CJ, Imwong M. 2016. Use of Blood Smears and Dried Blood Spots for Polymerase Chain Reaction-Based Detection and Quantification of Bacterial Infection and Plasmodium falciparum in Severely Ill Febrile African Children. Am J Trop Med Hyg, 94 (2), pp. 322-326. | Show Abstract | Read more

Molecular approaches offer a means of testing archived samples stored as dried blood spots in settings where standard blood cultures are not possible. Peripheral blood films are one suggested source of material, although the sensitivity of this approach has not been well defined. Thin blood smears and dried blood spots from a severe pediatric malaria study were assessed using specific polymerase chain reaction (PCR) primers to detect non-typhoidal Salmonella (NTS; MisL gene), Streptococcus pneumoniae (lytA), and Plasmodium falciparum (18S rRNA). Of 16 cases of NTS and S. pneumoniae confirmed on blood culture, none were positive by PCR using DNA extracts from blood films or dried blood spots. In contrast, four of 36 dried blood spots and two of 178 plasma samples were PCR positive for S. pneumoniae, despite negative bacterial blood cultures, suggesting false positives. Quantitative assessment revealed that the effective concentration of P. falciparum DNA in blood films was three log orders of magnitude lower than for dried blood spots. The P. falciparum kelch13 gene could not be amplified from blood films. These findings question the value of blood PCR-based approaches for detection of NTS and S. pneumoniae, and show that stored blood films are an inefficient method of studying P. falciparum.

de Haan F, Onyamboko MA, Fanello CI, Woodrow CJ, Lubell Y, Boon WPC, Dondorp AM. 2015. Exploring health practitioners' acceptability of a prospective semi-quantitative pfHRP2 device to define severe malaria in the Democratic Republic of Congo. Malar J, 14 (1), pp. 503. | Show Abstract | Read more

BACKGROUND: A rapid diagnostic tool is being developed to discern severely ill children with severe malaria from children who are ill with alternative febrile diseases but have coincidental peripheral blood parasitaemia. The device semi-quantitatively measures plasma pfHRP2 and has the potential to reduce mortality in children with severe febrile illnesses by improving diagnosis. The aim of this study is to identify contributing and inhibiting factors that affect healthcare practitioners' acceptability of this prospective diagnostic device in a high malaria transmission setting in the Democratic Republic of Congo. METHODS: Data were collected qualitatively by conducting semi-structured interviews with a purposeful sample of health professionals in Kinshasa, capital of Democratic Republic of Congo. In total, 11 interviews were held with professionals at four different institutes. RESULTS: Four key findings emerged: (1) Congolese practitioners perceive the semi-quantitative pfHRP2 device as a welcome intervention as they recognize the limited reliability of their current diagnostic and therapeutic approaches to severe febrile illnesses; (2) compatibility of the semi-quantitative pfHRP2 device with clinical equipment and competences of Congolese health practitioners is considered to be limited, especially in rural settings; (3) a formal training programme is crucial for correct understanding and application of the semi-quantitative pfHRP2 device; and, (4) provision of evidence to practitioners, and support from health authorities would be important to establish confidence in the semi-quantitative pfHRP2 device. CONCLUSIONS: Congolese practitioners perceive the prospective semi-quantitative pfHRP2 device as a welcome addition to their clinical equipment. The device could improve current diagnostic work-up of severe febrile illness, which might consequently improve treatment choices. However, despite this recognized potential, several hurdles and drivers need to be taken into account when implementing this device in DR Congo.

IMPROV Study Group. 2015. Improving the radical cure of vivax malaria (IMPROV): a study protocol for a multicentre randomised, placebo-controlled comparison of short and long course primaquine regimens. BMC Infect Dis, 15 (1), pp. 558. | Show Abstract | Read more

BACKGROUND: Plasmodium vivax malaria is a major cause of morbidity and recognised as an important contributor to mortality in some endemic areas. The current recommended treatment regimen for the radical cure of P. vivax includes a schizontocidal antimalarial, usually chloroquine, combined with a 14 day regimen of primaquine. The long treatment course frequently results in poor adherence and effectiveness. Shorter courses of higher daily doses of primaquine have the potential to improve adherence and thus effectiveness without compromising safety. The proposed multicentre randomised clinical trial aims to provide evidence across a variety of endemic settings on the safety and efficacy of high dose short course primaquine in glucose-6-phosphate-dehydrogenase (G6PD) normal patients. DESIGN: This study is designed as a placebo controlled, double blinded, randomized trial in four countries: Indonesia, Vietnam, Afghanistan and Ethiopia. G6PD normal patients diagnosed with vivax malaria are randomized to receive either 7 or 14 days high dose primaquine or placebo. G6PD deficient (G6PDd) patients are allocated to weekly primaquine doses for 8weeks. All treatment is directly observed and recurrent episodes are treated with the same treatment than allocated at the enrolment episode. Patients are followed daily until completion of treatment, weekly until 8 weeks and then monthly until 1 year after initiation of the treatment. The primary endpoint is the incidence rate (per person year) of symptomatic recurrent P. vivax parasitaemia over 12 months of follow-up, for all individuals, controlling for site, comparing the 7 versus 14-day primaquine treatment arms. Secondary endpoints are other efficacy measures such as incidence risk at different time points. Further endpoints are risks of haemolysis and severe adverse events. DISCUSSION: This study has been approved by relevant institutional ethics committees in the UK and Australia, and all participating countries. Results will be disseminated to inform P. vivax malaria treatment policy through peer-reviewed publications and academic presentations. Findings will contribute to a better understanding of the risks and benefits of primaquine which is crucial in persuading policy makers as well as clinicians of the importance of radical cure of vivax malaria, contributing to decreased transmission and a reduce parasite reservoir. TRIAL REGISTRATION: Identifier: NCT01814683 . Registered March 18, 2013.

Plewes K, Maude RJ, Ghose A, Dondorp AM. 2015. Severe falciparum malaria complicated by prolonged haemolysis and rhinomaxillary mucormycosis after parasite clearance: a case report. BMC Infect Dis, 15 (1), pp. 555. | Show Abstract | Read more

BACKGROUND: Severe falciparum malaria may be complicated by prolonged haemolysis and recurrent fever after parasite clearance. However, their respective etiologies are unclear and challenging to diagnose. We report the first case of severe falciparum malaria followed by prolonged haemolytic anaemia and rhinomaxillary mucormycosis in a previously healthy adult male. CASE PRESENTATION: A 30-year old Bangladeshi man was admitted with severe falciparum malaria complicated by hyperlactataemia and haemoglobinuria. Prior to admission he was treated with intravenous quinine and upon admission received intravenous artesunate and empiric ceftriaxone. Thirty hours later the peripheral parasitaemia cleared with resolution of fever and haemoglobinuria. Despite parasite clearance, on day 3 the patient developed recurrent fever and acute haemolytic anaemia requiring seven blood transfusions over six days with no improvement of his haemoglobin or haemoglobinuria. On day 10, he was treated with high-dose dexamethasone and meropenem with discontinuation of the ceftriaxone. Two days later the haemoglobinuria resolved. Ceftriaxone-induced haemolysis was the suspected final diagnosis. On day 16, the patient had progressively worsening right-sided facial pain and swelling; a necrotic ulceration of the hard palate was observed. Rhinomaxillary mucormycosis was diagnosed supported by microscopy findings. The patient initially responded to treatment with urgent surgical debridement, itraconazole, followed by two weeks of amphotericin B deoxycholate, however was subsequently lost to follow up. CONCLUSIONS: This case highlights the range of potential alternative aetiologies of acute, prolonged haemolysis and recurrent fever following parasite clearance in severe falciparum malaria. It emphasizes the importance of a high degree of suspicion for alternative causes of haemolysis in order to avoid unnecessary treatments, including blood transfusion and steroids. It is critical to consider and identify common invasive bacterial and rare opportunistic co-infections as a cause of fever in severe malaria patients remaining febrile after parasite clearance to promote antimicrobial stewardship and prompt emergency care.

Slater HC, Ross A, Ouédraogo AL, White LJ, Nguon C, Walker PGT, Ngor P, Aguas R, Silal SP, Dondorp AM et al. 2015. Assessing the impact of next-generation rapid diagnostic tests on Plasmodium falciparum malaria elimination strategies. Nature, 528 (7580), pp. S94-101. | Show Abstract | Read more

Mass-screen-and-treat and targeted mass-drug-administration strategies are being considered as a means to interrupt transmission of Plasmodium falciparum malaria. However, the effectiveness of such strategies will depend on the extent to which current and future diagnostics are able to detect those individuals who are infectious to mosquitoes. We estimate the relationship between parasite density and onward infectivity using sensitive quantitative parasite diagnostics and mosquito feeding assays from Burkina Faso. We find that a diagnostic with a lower detection limit of 200 parasites per microlitre would detect 55% of the infectious reservoir (the combined infectivity to mosquitoes of the whole population weighted by how often each individual is bitten) whereas a test with a limit of 20 parasites per microlitre would detect 83% and 2 parasites per microlitre would detect 95% of the infectious reservoir. Using mathematical models, we show that increasing the diagnostic sensitivity from 200 parasites per microlitre (equivalent to microscopy or current rapid diagnostic tests) to 2 parasites per microlitre would increase the number of regions where transmission could be interrupted with a mass-screen-and-treat programme from an entomological inoculation rate below 1 to one of up to 4. The higher sensitivity diagnostic could reduce the number of treatment rounds required to interrupt transmission in areas of lower prevalence. We predict that mass-screen-and-treat with a highly sensitive diagnostic is less effective than mass drug administration owing to the prophylactic protection provided to uninfected individuals by the latter approach. In low-transmission settings such as those in Southeast Asia, we find that a diagnostic tool with a sensitivity of 20 parasites per microlitre may be sufficient for targeted mass drug administration because this diagnostic is predicted to identify a similar village population prevalence compared with that currently detected using polymerase chain reaction if treatment levels are high and screening is conducted during the dry season. Along with other factors, such as coverage, choice of drug, timing of the intervention, importation of infections, and seasonality, the sensitivity of the diagnostic can play a part in increasing the chance of interrupting transmission.

Hoogendijk AJ, Blok DC, Garcia Laorden MI, Kager LM, Lede IO, Rahman W, Afroz R, Bresser P, van der Zee JS, Ghose A et al. 2015. Soluble and cell-associated triggering receptor expressed on myeloid cells-1 and -2 in patients with pulmonary tuberculosis. J Infect, 71 (6), pp. 706-709. | Read more

Nguyen TD, Olliaro P, Dondorp AM, Baird JK, Lam HM, Farrar J, Thwaites GE, White NJ, Boni MF. 2015. Optimum population-level use of artemisinin combination therapies: a modelling study. Lancet Glob Health, 3 (12), pp. e758-e766. | Show Abstract | Read more

BACKGROUND: Artemisinin combination therapies (ACTs) are used worldwide as first-line treatment against confirmed or suspected Plasmodium falciparum malaria. Despite the success of ACTs at reducing the global burden of malaria, emerging resistance to artemisinin threatens these gains. Countering onset of resistance might need deliberate tactics aimed at slowing the reduction in ACT effectiveness. We assessed optimum use of ACTs at the population level, specifically focusing on a strategy of multiple first-line therapies (MFT), and comparing it with strategies of cycling or sequential use of single first-line ACTs. METHODS: With an individual-based microsimulation of regional malaria transmission, we looked at how to apply a therapy as widely as possible without accelerating reduction of efficacy by drug resistance. We compared simultaneous distribution of artemether-lumefantrine, artesunate-amodiaquine, and dihydroartemisinin-piperaquine (ie, MFT) against strategies in which these ACTs would be cycled or used sequentially, either on a fixed schedule or when population-level efficacy reaches the WHO threshold of 10% treatment failure. The main assessment criterion was total number of treatment failures per 100 people per year. Additionally, we analysed the benefits of including a single non-ACT therapy in an MFT strategy, and did sensitivity analyses in which we varied transmission setting, treatment coverage, partner-drug half-life, fitness cost of drug resistance, and the relation between drug concentration and resistance evolution. FINDINGS: Use of MFT was predicted to reduce the long-term number of treatment failures compared with strategies in which a single first-line ACT is recommended. This result was robust to various epidemiological, pharmacological, and evolutionary features of malaria transmission. Inclusion of a single non-ACT therapy in an MFT strategy would have substantial benefits in reduction of pressure on artemisinin resistance evolution, delaying its emergence and slowing its spread. INTERPRETATION: Adjusting national antimalarial treatment guidelines to encourage simultaneous use of MFT is likely to extend the useful therapeutic life of available antimalarial drugs, resulting in long-term beneficial outcomes for patients. FUNDING: Wellcome Trust, UK Medical Research Council, Li Ka Shing Foundation.

Beane A, Stephens T, De Silva AP, Adikaram M, De Alwis S, Athapattu P, Sigera C, Peiris L, Siriwardana S, Jayasinghe K et al. 2015. A collaborative approach to training ward nurses in acute care skills in resource limited settings: the nursing intensive care skills training (nicts) project. Intensive Care Med Exp, 3 (Suppl 1), pp. A445. | Read more

Stephens T, Beane A, De Silva AP, Welch J, Sigera C, De Alwis S, Athapattu P, Peiris L, Siriwardana S, Jayasinghe K et al. 2015. Capacity building for critical care skills training provision in resource limited settings: the nursing intensive care skills training (nicst) project. Intensive Care Med Exp, 3 (Suppl 1), pp. A444. | Read more

Imwong M, Jindakhad T, Kunasol C, Sutawong K, Vejakama P, Dondorp AM. 2015. An outbreak of artemisinin resistant falciparum malaria in Eastern Thailand. Sci Rep, 5 (1), pp. 17412. | Show Abstract | Read more

Artemisinin resistant falciparum malaria is an increasing problem in Southeast Asia, but has not been associated with increased transmission of the disease, yet. During a recent outbreak in 2014 in Ubon Ratchatani, Eastern Thailand, parasites from 101 patients with falciparum malaria were genotyped for antimalarial drug resistance markers. Mutations in the Kelch13 marker for artemisinin resistance were present in 93% of samples, mainly C580Y from 2 major clusters as identified by microsatellite typing. Resistance markers for antifolates and chloroquine were also highly prevalent. Most strains (91%) carried single copy number PfMDR1, suggesting sustained sensitivity to mefloquine, the partner drug in the local first-line artemisinin combination therapy (ACT). The high prevalence of artemisinin resistance in this recent malaria outbreak suggests but does not prove a causative role in increased transmission. Careful monitoring of ACT efficacy and additional genetic epidemiological studies are warranted to guide the public health response to the outbreak.



European Pubmed Central

Cheeseman IH, Miller B, Tan JC, Tan A, Nair S, Nkhoma SC, De Donato M, Rodulfo H, Dondorp A, Branch OH et al. 2016. Population Structure Shapes Copy Number Variation in Malaria Parasites. Mol Biol Evol, 33 (3), pp. 603-620. | Show Abstract | Read more

If copy number variants (CNVs) are predominantly deleterious, we would expect them to be more efficiently purged from populations with a large effective population size (Ne) than from populations with a small Ne. Malaria parasites (Plasmodium falciparum) provide an excellent organism to examine this prediction, because this protozoan shows a broad spectrum of population structures within a single species, with large, stable, outbred populations in Africa, small unstable inbred populations in South America and with intermediate population characteristics in South East Asia. We characterized 122 single-clone parasites, without prior laboratory culture, from malaria-infected patients in seven countries in Africa, South East Asia and South America using a high-density single-nucleotide polymorphism/CNV microarray. We scored 134 high-confidence CNVs across the parasite exome, including 33 deletions and 102 amplifications, which ranged in size from <500 bp to 59 kb, as well as 10,107 flanking, biallelic single-nucleotide polymorphisms. Overall, CNVs were rare, small, and skewed toward low frequency variants, consistent with the deleterious model. Relative to African and South East Asian populations, CNVs were significantly more common in South America, showed significantly less skew in allele frequencies, and were significantly larger. On this background of low frequency CNV, we also identified several high-frequency CNVs under putative positive selection using an FST outlier analysis. These included known adaptive CNVs containing rh2b and pfmdr1, and several other CNVs (e.g., DNA helicase and three conserved proteins) that require further investigation. Our data are consistent with a significant impact of genetic structure on CNV burden in an important human pathogen.

Lubell Y, Blacksell SD, Dunachie S, Tanganuchitcharnchai A, Althaus T, Watthanaworawit W, Paris DH, Mayxay M, Peto TJ, Dondorp AM et al. 2015. Performance of C-reactive protein and procalcitonin to distinguish viral from bacterial and malarial causes of fever in Southeast Asia. BMC Infect Dis, 15 (1), pp. 511. | Show Abstract | Read more

BACKGROUND: Poor targeting of antimicrobial drugs contributes to the millions of deaths each year from malaria, pneumonia, and other tropical infectious diseases. While malaria rapid diagnostic tests have improved use of antimalarial drugs, there are no similar tests to guide the use of antibiotics in undifferentiated fevers. In this study we estimate the diagnostic accuracy of two well established biomarkers of bacterial infection, procalcitonin and C-reactive protein (CRP) in discriminating between common viral and bacterial infections in malaria endemic settings of Southeast Asia. METHODS: Serum procalcitonin and CRP levels were measured in stored serum samples from febrile patients enrolled in three prospective studies conducted in Cambodia, Laos and, Thailand. Of the 1372 patients with a microbiologically confirmed diagnosis, 1105 had a single viral, bacterial or malarial infection. Procalcitonin and CRP levels were compared amongst these aetiological groups and their sensitivity and specificity in distinguishing bacterial infections and bacteraemias from viral infections were estimated using standard thresholds. RESULTS: Serum concentrations of both biomarkers were significantly higher in bacterial infections and malaria than in viral infections. The AUROC for CRP in discriminating between bacterial and viral infections was 0.83 (0.81-0.86) compared with 0.74 (0.71-0.77) for procalcitonin (p < 0.0001). This relative advantage was evident in all sites and when stratifying patients by age and admission status. For CRP at a threshold of 10 mg/L, the sensitivity of detecting bacterial infections was 95% with a specificity of 49%. At a threshold of 20 mg/L sensitivity was 86% with a specificity of 67%. For procalcitonin at a low threshold of 0.1 ng/mL the sensitivity was 90% with a specificity of 39%. At a higher threshold of 0.5 ng/ul sensitivity was 60% with a specificity of 76%. CONCLUSION: In samples from febrile patients with mono-infections from rural settings in Southeast Asia, CRP was a highly sensitive and moderately specific biomarker for discriminating between viral and bacterial infections. Use of a CRP rapid test in peripheral health settings could potentially be a simple and affordable measure to better identify patients in need of antibacterial treatment and part of a global strategy to combat the emergence of antibiotic resistance.

Herdman MT, Sriboonvorakul N, Leopold SJ, Douthwaite S, Mohanty S, Hassan MMU, Maude RJ, Kingston HWF, Plewes K, Charunwatthana P et al. 2015. Erratum to: the role of previously unmeasured organic acids in the pathogenesis of severe malaria. Crit Care, 19 (1), pp. 382. | Read more

Imwong M, Nguyen TN, Tripura R, Peto TJ, Lee SJ, Lwin KM, Suangkanarat P, Jeeyapant A, Vihokhern B, Wongsaen K et al. 2015. The epidemiology of subclinical malaria infections in South-East Asia: findings from cross-sectional surveys in Thailand-Myanmar border areas, Cambodia, and Vietnam. Malar J, 14 (1), pp. 381. | Show Abstract | Read more

BACKGROUND: The importance of the submicroscopic reservoir of Plasmodium infections for malaria elimination depends on its size, which is generally considered small in low transmission settings. The precise estimation of this reservoir requires more sensitive parasite detection methods. The prevalence of asymptomatic, sub-microscopic malaria was assessed by a sensitive, high blood volume quantitative real-time polymerase chain reaction method in three countries of the Greater Mekong Sub-region. METHODS: Cross-sectional surveys were conducted in three villages in western Cambodia, four villages along the Thailand-Myanmar border and four villages in southwest Vietnam. Malaria parasitaemia was assessed by Plasmodium falciparum/pan malaria rapid diagnostic tests (RDTs), microscopy and a high volume ultra-sensitive real-time polymerase chain reaction (HVUSqPCR: limit of detection 22 parasites/mL). All villagers older than 6 months were invited to participate. RESULTS: A census before the surveys identified 7355 residents in the study villages. Parasite prevalence was 224/5008 (4 %) by RDT, 229/5111 (5 %) by microscopy, and 988/4975 (20 %) when assessed by HVUSqPCR. Of these 164 (3 %) were infected with P. falciparum, 357 (7 %) with Plasmodium vivax, 56 (1 %) with a mixed infection, and 411 (8 %) had parasite densities that were too low for species identification. A history of fever, male sex, and age of 15 years or older were independently associated with parasitaemia in a multivariate regression model stratified by site. CONCLUSION: Light microscopy and RDTs identified only a quarter of all parasitaemic participants. The asymptomatic Plasmodium reservoir is considerable, even in low transmission settings. Novel strategies are needed to eliminate this previously under recognized reservoir of malaria transmission.

Sinha I, Ekapirat N, Dondorp AM, Woodrow CJ. 2015. Use of a rapid test to assess plasma Plasmodium falciparum HRP2 and guide management of severe febrile illness. Malar J, 14 (1), pp. 362. | Show Abstract | Read more

BACKGROUND: Plasma Plasmodium falciparum histidine-rich protein-2 (PfHRP2) is the most accurate biomarker for severe malaria, but its measurement by ELISA has been considered too unwieldy to incorporate into clinical management. METHODS: Plasma samples covering a wide range of PfHRP2 concentrations were applied to rapid diagnostic tests (RDTs). RDTs were read by eye and digital capture, and PfHRP2 concentrations were measured via serial dilution with results compared to ELISA readings. RESULTS: The Paracheck (®) brand showed the strongest correlation (r(2) = 0.963) as well as the lowest inter-observer variability (combined kappa across band intensities for three observers = 0.938). Plasma PfHRP2 measurement via serial dilution showed minimal bias compared to ELISA and acceptable limits of agreement. Three different dilutions of a well characterized set of admission samples from uncomplicated and severe malaria patients studied in a low transmission setting gave an area under the receiver operator characteristic curve of 0.844 in terms of identifying severe malaria. CONCLUSIONS: These studies show that plasma PfHRP2 can be assessed via a single RDT, with application of a plasma dilution of 1:5 or 1:10 providing useful diagnostic information to assist in patient management or clinical trial inclusion.

WWARN Parasite Clearance Study Group, Abdulla S, Ashley EA, Bassat Q, Bethell D, Björkman A, Borrmann S, D'Alessandro U, Dahal P, Day NP et al. 2015. Baseline data of parasite clearance in patients with falciparum malaria treated with an artemisinin derivative: an individual patient data meta-analysis. Malar J, 14 (1), pp. 359. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance in Plasmodium falciparum manifests as slow parasite clearance but this measure is also influenced by host immunity, initial parasite biomass and partner drug efficacy. This study collated data from clinical trials of artemisinin derivatives in falciparum malaria with frequent parasite counts to provide reference parasite clearance estimates stratified by location, treatment and time, to examine host factors affecting parasite clearance, and to assess the relationships between parasite clearance and risk of recrudescence during follow-up. METHODS: Data from 24 studies, conducted from 1996 to 2013, with frequent parasite counts were pooled. Parasite clearance half-life (PC1/2) was estimated using the WWARN Parasite Clearance Estimator. Random effects regression models accounting for study and site heterogeneity were used to explore factors affecting PC1/2 and risk of recrudescence within areas with reported delayed parasite clearance (western Cambodia, western Thailand after 2000, southern Vietnam, southern Myanmar) and in all other areas where parasite populations are artemisinin sensitive. RESULTS: PC1/2 was estimated in 6975 patients, 3288 of whom also had treatment outcomes evaluate d during 28-63 days follow-up, with 93 (2.8 %) PCR-confirmed recrudescences. In areas with artemisinin-sensitive parasites, the median PC1/2 following three-day artesunate treatment (4 mg/kg/day) ranged from 1.8 to 3.0 h and the proportion of patients with PC1/2 >5 h from 0 to 10 %. Artesunate doses of 4 mg/kg/day decreased PC1/2 by 8.1 % (95 % CI 3.2-12.6) compared to 2 mg/kg/day, except in populations with delayed parasite clearance. PC1/2 was longer in children and in patients with fever or anaemia at enrolment. Long PC1/2 (HR = 2.91, 95 % CI 1.95-4.34 for twofold increase, p < 0.001) and high initial parasitaemia (HR = 2.23, 95 % CI 1.44-3.45 for tenfold increase, p < 0.001) were associated independently with an increased risk of recrudescence. In western Cambodia, the region with the highest prevalence of artemisinin resistance, there was no evidence for increasing PC1/2 since 2007. CONCLUSIONS: Several factors affect PC1/2. As substantial heterogeneity in parasite clearance exists between locations, early detection of artemisinin resistance requires reference PC1/2 data. Studies with frequent parasite count measurements to characterize PC1/2 should be encouraged. In western Cambodia, where PC1/2 values are longest, there is no evidence for recent emergence of higher levels of artemisinin resistance.

Herdman MT, Sriboonvorakul N, Leopold SJ, Douthwaite S, Mohanty S, Hassan MMU, Maude RJ, Kingston HWF, Plewes K, Charunwatthana P et al. 2015. The role of previously unmeasured organic acids in the pathogenesis of severe malaria. Crit Care, 19 (1), pp. 317. | Show Abstract | Read more

INTRODUCTION: Severe falciparum malaria is commonly complicated by metabolic acidosis. Together with lactic acid (LA), other previously unmeasured acids have been implicated in the pathogenesis of falciparum malaria. METHODS: In this prospective study, we characterised organic acids in adults with severe falciparum malaria in India and Bangladesh. Liquid chromatography-mass spectrometry was used to measure organic acids in plasma and urine. Patients were followed until recovery or death. RESULTS: Patients with severe malaria (n=138), uncomplicated malaria (n=102), sepsis (n=32) and febrile encephalopathy (n=35) were included. Strong ion gap (mean ± SD) was elevated in severe malaria (8.2 mEq/L ± 4.5) and severe sepsis (8.6 mEq/L ± 7.7) compared with uncomplicated malaria (6.0 mEq/L ± 5.1) and encephalopathy (6.6 mEq/L ± 4.7). Compared with uncomplicated malaria, severe malaria was characterised by elevated plasma LA, hydroxyphenyllactic acid (HPLA), α-hydroxybutyric acid and β-hydroxybutyric acid (all P<0.05). In urine, concentrations of methylmalonic, ethylmalonic and α-ketoglutaric acids were also elevated. Multivariate logistic regression showed that plasma HPLA was a strong independent predictor of death (odds ratio [OR] 3.5, 95 % confidence interval [CI] 1.6-7.5, P=0.001), comparable to LA (OR 3.5, 95 % CI 1.5-7.8, P=0.003) (combined area under the receiver operating characteristic curve 0.81). CONCLUSIONS: Newly identified acids, in addition to LA, are elevated in patients with severe malaria and are highly predictive of fatal outcome. Further characterisation of their sources and metabolic pathways is now needed.

Imwong M, Tun KM, Hlaing TM, Grist EP, Guerin P, Smithuis F, Dondorp AM, Day NP, Nosten F, White N, Woodrow CJ. 2015. Artemisinin resistance in Myanmar--Authors' reply. Lancet Infect Dis, 15 (9), pp. 1002-1003. | Read more

Nguyen TD, Olliaro P, Dondorp A, Baird JK, Lam HM, Farrar J, Thwaites GE, White NJ, Boni MF. 2015. Optimal population-level deployment of artemisinin combination therapies TROPICAL MEDICINE & INTERNATIONAL HEALTH, 20 pp. 182-182.

Tanner M, Greenwood B, Whitty CJM, Ansah EK, Price RN, Dondorp AM, von Seidlein L, Baird JK, Beeson JG, Fowkes FJI et al. 2015. Malaria eradication and elimination: views on how to translate a vision into reality. BMC Med, 13 (1), pp. 167. | Show Abstract | Read more

Although global efforts in the past decade have halved the number of deaths due to malaria, there are still an estimated 219 million cases of malaria a year, causing more than half a million deaths. In this forum article, we asked experts working in malaria research and control to discuss the ways in which malaria might eventually be eradicated. Their collective views highlight the challenges and opportunities, and explain how multi-factorial and integrated processes could eventually make malaria eradication a reality.

Guyant P, Corbel V, Guérin PJ, Lautissier A, Nosten F, Boyer S, Coosemans M, Dondorp AM, Sinou V, Yeung S, White N. 2015. Past and new challenges for malaria control and elimination: the role of operational research for innovation in designing interventions. Malar J, 14 (1), pp. 279. | Show Abstract | Read more

This meeting report presents the outcomes of a workshop held in Bangkok on December 1st 2014, where the following challenges were discussed: the threat of resistance to artemisinin and artemisinin-based combination therapy in the Greater Mekong Sub-region (GMS) and in Africa; access to treatment for most at risk and hard to reach population; insecticide resistance, residual and outdoors transmission. The role of operational research and the interactions between research institutions, National Malaria Control Programmes, Civil Society Organizations, and of financial and technical partners to address those challenges and to accelerate translation of research into policies and programmes were debated. The threat and the emergency of the artemisinin resistance spread and independent emergence in the GMS was intensely debated as it is now close to the border of India. The need for key messages, based on scientific evidence and information available and disseminated without delay, was highlighted as crucial for an effective and urgent response.

Parry CM, Thieu NTV, Dolecek C, Karkey A, Gupta R, Turner P, Dance D, Maude RR, Ha V, Tran CN et al. 2015. Erratum for Parry et al., Clinically and microbiologically derived azithromycin susceptibility breakpoints for Salmonella enterica serovars Typhi and Paratyphi A. Antimicrob Agents Chemother, 59 (7), pp. 4364. | Read more

Ringwald P, Dondorp AM. 2015. Severe Malaria Not Responsive to Artemisinin Derivatives in Man Returning from Angola to Vietnam. Emerg Infect Dis, 21 (7), pp. 1264-1265. | Read more

Garcia-Laorden MI, Blok DC, Kager LM, Hoogendijk AJ, van Mierlo GJ, Lede IO, Rahman W, Afroz R, Ghose A, Visser CE et al. 2015. Increased intra- and extracellular granzyme expression in patients with tuberculosis. Tuberculosis (Edinb), 95 (5), pp. 575-580. | Show Abstract | Read more

Tuberculosis (TB) is an important cause of morbidity and mortality worldwide. Granzymes (gzms) are proteases mainly found in cytotoxic lymphocytes, but also extracellularly. While the role of gzms in target cell death has been widely characterized, considerable evidence points towards broader roles related to infectious and inflammatory responses. To investigate the expression of the gzms in TB, intracellular gzms A, B and K were measured by flow cytometry in lymphocyte populations from peripheral blood mononuclear cells from 18 TB patients and 12 healthy donors from Bangladesh, and extracellular levels of gzmA and B were measured in serum from 58 TB patients and 31 healthy controls. TB patients showed increased expression of gzmA in CD8(+) T, CD4(+) T and CD56(+) T, but not NK, cells, and of gzmB in CD8(+) T cells, when compared to controls. GzmK expression was not altered in TB patients in any lymphocyte subset. The extracellular levels of gzmA and, to a lesser extent, of gzmB, were increased in TB patients, but did not correlate with intracellular gzm expression in lymphocyte subsets. Our results reveal enhanced intra- and extracellular expression of gzmA and B in patients with pulmonary TB, suggesting that gzms are part of the host response to tuberculosis.

Maude RR, de Jong HK, Wijedoru L, Fukushima M, Ghose A, Samad R, Hossain MA, Karim MR, Faiz MA, Parry CM, CMCH Typhoid Study Group. 2015. The diagnostic accuracy of three rapid diagnostic tests for typhoid fever at Chittagong Medical College Hospital, Chittagong, Bangladesh. Trop Med Int Health, 20 (10), pp. 1376-1384. | Show Abstract | Read more

OBJECTIVE: To determine the diagnostic accuracy of three rapid diagnostic tests (RDTs) for typhoid fever in febrile hospitalised patients in Bangladesh. METHODS: Febrile adults and children admitted to Chittagong Medical College Hospital, Bangladesh, were investigated with Bact/Alert(®) blood cultures and real-time PCR to detect Salmonella enterica Typhi and Paratyphi A and assays for Rickettsia, leptospirosis and dengue fever. Acute serum samples were examined with the LifeAssay (LA) Test-it™ Typhoid IgM lateral flow assay detecting IgM antibodies against S. Typhi O antigen, CTKBiotech Onsite Typhoid IgG/IgM Combo Rapid-test cassette lateral flow assay detecting IgG and IgM antibodies against S. Typhi O and H antigens and SD Bioline line assay for IgG and IgM antibodies against S. Typhi proteins. RESULTS: In 300 malaria smear-negative febrile patients [median (IQR) age of 13.5 (5-31) years], 34 (11.3%) had confirmed typhoid fever: 19 positive by blood culture for S. Typhi (three blood PCR positive) and 15 blood culture negative but PCR positive for S. Typhi in blood. The respective sensitivity and specificity of the three RDTs in patients using a composite reference standard of blood culture and/or PCR-confirmed typhoid fever were 59% and 61% for LifeAssay, 59% and 74% for the CTK IgM and/or IgG, and 24% and 96% for the SD Bioline RDT IgM and/or IgG. The LifeAssay RDT had a sensitivity of 63% and a specificity of 91% when modified with a positive cut-off of ≥2+ and analysed using a Bayesian latent class model. CONCLUSIONS: These typhoid RDTs demonstrated moderate diagnostic accuracies, and better tests are needed.

Plewes K, Haider MS, Kingston HWF, Yeo TW, Ghose A, Hossain MA, Dondorp AM, Turner GDH, Anstey NM. 2015. Severe falciparum malaria treated with artesunate complicated by delayed onset haemolysis and acute kidney injury. Malar J, 14 (1), pp. 246. | Show Abstract | Read more

BACKGROUND: Severe falciparum malaria may be complicated by haemolysis after parasite clearance, however the mechanisms remain unclear. Recent reports describe a pattern of delayed onset haemolysis among non-immune travellers with hyperparasitaemia treated with intravenous artesunate, termed post-artesunate delayed haemolysis (PADH). The occurrence and clinical impact of PADH following severe malaria infections in areas of unstable transmission are unknown. CASE: A 45-year-old Bangladeshi male was initially admitted to a local hospital with severe falciparum malaria complicated by hyperparasitaemia and treated with intravenous artesunate. Twenty days from his first presentation he was readmitted with delayed onset haemolytic anaemia and acute kidney injury. Multiple blood transfusions and haemodialysis were required. Renal biopsy revealed acute tubular injury and haem pigment nephropathy. His haemoglobin and renal function recovered to baseline after 62 days from his second admission. DISCUSSION: This case highlights the differential diagnosis of post-malaria delayed onset haemolysis, including the recently described syndrome of post-artemisinin delayed haemolysis. The pathophysiology contributing to acute kidney injury in this patient and the limited treatment options are discussed. CONCLUSIONS: This report describes PADH complicated by acute kidney injury in an adult patient living in a malaria hypoendemic region who subsequently required blood transfusions and haemodialysis. This case emphasizes the importance of routine follow up of haemoglobin and renal function in artesunate-treated patients who have recovered from severe malaria.

Worldwide Antimalarial Resistance Network (WWARN) AL Dose Impact Study Group. 2015. The effect of dose on the antimalarial efficacy of artemether-lumefantrine: a systematic review and pooled analysis of individual patient data. Lancet Infect Dis, 15 (6), pp. 692-702. | Show Abstract | Read more

BACKGROUND: Artemether-lumefantrine is the most widely used artemisinin-based combination therapy for malaria, although treatment failures occur in some regions. We investigated the effect of dosing strategy on efficacy in a pooled analysis from trials done in a wide range of malaria-endemic settings. METHODS: We searched PubMed for clinical trials that enrolled and treated patients with artemether-lumefantrine and were published from 1960 to December, 2012. We merged individual patient data from these trials by use of standardised methods. The primary endpoint was the PCR-adjusted risk of Plasmodium falciparum recrudescence by day 28. Secondary endpoints consisted of the PCR-adjusted risk of P falciparum recurrence by day 42, PCR-unadjusted risk of P falciparum recurrence by day 42, early parasite clearance, and gametocyte carriage. Risk factors for PCR-adjusted recrudescence were identified using Cox's regression model with frailty shared across the study sites. FINDINGS: We included 61 studies done between January, 1998, and December, 2012, and included 14,327 patients in our analyses. The PCR-adjusted therapeutic efficacy was 97·6% (95% CI 97·4-97·9) at day 28 and 96·0% (95·6-96·5) at day 42. After controlling for age and parasitaemia, patients prescribed a higher dose of artemether had a lower risk of having parasitaemia on day 1 (adjusted odds ratio [OR] 0·92, 95% CI 0·86-0·99 for every 1 mg/kg increase in daily artemether dose; p=0·024), but not on day 2 (p=0·69) or day 3 (0·087). In Asia, children weighing 10-15 kg who received a total lumefantrine dose less than 60 mg/kg had the lowest PCR-adjusted efficacy (91·7%, 95% CI 86·5-96·9). In Africa, the risk of treatment failure was greatest in malnourished children aged 1-3 years (PCR-adjusted efficacy 94·3%, 95% CI 92·3-96·3). A higher artemether dose was associated with a lower gametocyte presence within 14 days of treatment (adjusted OR 0·92, 95% CI 0·85-0·99; p=0·037 for every 1 mg/kg increase in total artemether dose). INTERPRETATION: The recommended dose of artemether-lumefantrine provides reliable efficacy in most patients with uncomplicated malaria. However, therapeutic efficacy was lowest in young children from Asia and young underweight children from Africa; a higher dose regimen should be assessed in these groups. FUNDING: Bill & Melinda Gates Foundation.

Hanson J, Lee SJ, Hossain MA, Anstey NM, Charunwatthana P, Maude RJ, Kingston HWF, Mishra SK, Mohanty S, Plewes K et al. 2015. Microvascular obstruction and endothelial activation are independently associated with the clinical manifestations of severe falciparum malaria in adults: an observational study. BMC Med, 13 (1), pp. 122. | Show Abstract | Read more

BACKGROUND: Microvascular obstruction and endothelial dysfunction have both been linked to tissue hypoperfusion in falciparum malaria, but their relative contributions to the disease's pathogenesis and outcome are unknown. METHODS: Microvascular blood flow was quantified in adults with severe falciparum malaria on their admission to hospital; plasma biomarkers of endothelial function were measured simultaneously. The relationship between these indices and the patients' clinical findings and in-hospital course was examined. RESULTS: Microvascular obstruction was observed in 119/142 (84 %) patients; a median (interquartile range (IQR)) of 14.9 % (6.6-34.9 %) of capillaries were obstructed in patients that died versus 8.3 % (1.7-26.6 %) in survivors (P = 0.039). The proportion of obstructed capillaries correlated with the estimated parasite biomass (rs = 0.25, P = 0.004) and with plasma lactate (rs = 0.38, P <0.0001), the strongest predictor of death in the series. Plasma angiopoietin-2 (Ang-2) concentrations were markedly elevated suggesting widespread endothelial activation; the median (IQR) Ang-2 concentration was 21.9 ng/mL (13.4-29.4 ng/mL) in patients that died versus 14.9 ng/mL (9.8-29.3 ng/mL) in survivors (P = 0.035). Ang-2 concentrations correlated with estimated parasite biomass (rs = 0.35, P <0.001) and plasma lactate (rs = 0.37, P <0.0001). Microvascular obstruction and Ang-2 concentrations were not significantly correlated with each other (rs = 0.17, P = 0.06), but were independently associated with plasma lactate (P <0.001 and P = 0.002, respectively). CONCLUSIONS: Microvascular obstruction and systemic endothelial activation are independently associated with plasma lactate, the strongest predictor of death in adults with falciparum malaria. This supports the hypothesis that the two processes make an independent contribution to the pathogenesis and clinical manifestations of the disease.

Hanson J, Phu NH, Hasan MU, Charunwatthana P, Plewes K, Maude RJ, Prapansilp P, Kingston HWF, Mishra SK, Mohanty S et al. 2015. The clinical implications of thrombocytopenia in adults with severe falciparum malaria: a retrospective analysis. BMC Med, 13 (1), pp. 97. | Show Abstract | Read more

BACKGROUND: Thrombocytopenia is a common finding in adults with severe falciparum malaria, but its clinical and prognostic utility is incompletely defined. METHODS: Clinical and laboratory data from 647 adults with severe falciparum malaria were analysed retrospectively to determine the relationship between a patient's platelet count on admission to hospital and their subsequent clinical course. RESULTS: On admission, 614 patients (94.9%) were thrombocytopenic (platelet count <150 × 10(9)/L) and 328 (50.7%) had a platelet count <50 × 10(9)/L. The admission platelet count was inversely correlated with parasite biomass (estimated from plasma PfHRP2 concentrations, rs = -0.28, P = 0.003), the degree of microvascular sequestration (measured with orthogonal polarizing spectral imaging, rs = -0.31, P = 0.001) and disease severity (the number of World Health Organization severity criteria satisfied by the patient, rs = -0.21, P <0.001). Platelet counts were lower on admission in the patients who died (median: 30 (interquartile range 22 to 52) × 10(9)/L versus 50 (34 to 78) × 10(9)/L in survivors; P <0.001), but did not predict outcome independently from other established laboratory and clinical prognostic indices. The 39 patients (6%) with profound thrombocytopenia (platelet count <20 × 10(9)/L) were more likely to die (odds ratio: 5.00, 95% confidence interval: 2.56 to 9.75) than patients with higher platelet counts, but these high-risk patients could be identified more rapidly with simple bedside clinical assessment. The admission platelet count did not reliably identify the 50 patients (7.7%) with major bleeding during the study. CONCLUSIONS: Thrombocytopenia is a marker of disease severity in adults with falciparum malaria, but has limited utility in prognostication, triage and management.

Deen J, Dondorp AM, White NJ. 2015. Treatment of Ebola. N Engl J Med, 372 (17), pp. 1673-1674. | Read more

Mbengue A, Bhattacharjee S, Pandharkar T, Liu H, Estiu G, Stahelin RV, Rizk SS, Njimoh DL, Ryan Y, Chotivanich K et al. 2015. A molecular mechanism of artemisinin resistance in Plasmodium falciparum malaria. Nature, 520 (7549), pp. 683-687. | Show Abstract | Read more

Artemisinins are the cornerstone of anti-malarial drugs. Emergence and spread of resistance to them raises risk of wiping out recent gains achieved in reducing worldwide malaria burden and threatens future malaria control and elimination on a global level. Genome-wide association studies (GWAS) have revealed parasite genetic loci associated with artemisinin resistance. However, there is no consensus on biochemical targets of artemisinin. Whether and how these targets interact with genes identified by GWAS, remains unknown. Here we provide biochemical and cellular evidence that artemisinins are potent inhibitors of Plasmodium falciparum phosphatidylinositol-3-kinase (PfPI3K), revealing an unexpected mechanism of action. In resistant clinical strains, increased PfPI3K was associated with the C580Y mutation in P. falciparum Kelch13 (PfKelch13), a primary marker of artemisinin resistance. Polyubiquitination of PfPI3K and its binding to PfKelch13 were reduced by the PfKelch13 mutation, which limited proteolysis of PfPI3K and thus increased levels of the kinase, as well as its lipid product phosphatidylinositol-3-phosphate (PI3P). We find PI3P levels to be predictive of artemisinin resistance in both clinical and engineered laboratory parasites as well as across non-isogenic strains. Elevated PI3P induced artemisinin resistance in absence of PfKelch13 mutations, but remained responsive to regulation by PfKelch13. Evidence is presented for PI3P-dependent signalling in which transgenic expression of an additional kinase confers resistance. Together these data present PI3P as the key mediator of artemisinin resistance and the sole PfPI3K as an important target for malaria elimination.



European Pubmed Central

von Seidlein L, Dondorp A. 2015. Fighting fire with fire: mass antimalarial drug administrations in an era of antimalarial resistance. Expert Rev Anti Infect Ther, 13 (6), pp. 715-730. | Show Abstract | Read more

The emergence and spread of antimalarial resistance has been a major liability for malaria control. The spread of chloroquine-resistant Plasmodium falciparum strains had catastrophic consequences for people in malaria-endemic regions, particularly in sub-Saharan Africa. The recent emergence of artemisinin-resistant P. falciparum strains is of highest concern. Current efforts to contain artemisinin resistance have yet to show success. In the absence of more promising plans, it has been suggested to eliminate falciparum malaria from foci of artemisinin resistance using a multipronged approach, including mass drug administrations. The use of mass drug administrations is controversial as it increases drug pressure. Based on current knowledge it is difficult to conceptualize how targeted malaria elimination could contribute to artemisinin resistance, provided a full treatment course is ensured.

White LJ, Flegg JA, Phyo AP, Wiladpai-ngern JH, Bethell D, Plowe C, Anderson T, Nkhoma S, Nair S, Tripura R et al. 2015. Defining the in vivo phenotype of artemisinin-resistant falciparum malaria: a modelling approach. PLoS Med, 12 (4), pp. e1001823. | Show Abstract | Read more

BACKGROUND: Artemisinin-resistant falciparum malaria has emerged in Southeast Asia, posing a major threat to malaria control. It is characterised by delayed asexual-stage parasite clearance, which is the reference comparator for the molecular marker 'Kelch 13' and in vitro sensitivity tests. However, current cut-off values denoting slow clearance based on the proportion of individuals remaining parasitaemic on the third day of treatment ('day-3'), or on peripheral blood parasite half-life, are not well supported. We here explore the parasite clearance distributions in an area of artemisinin resistance with the aim refining the in vivo phenotypic definitions. METHODS AND FINDINGS: Data from 1,518 patients on the Thai-Myanmar and Thai-Cambodian borders with parasite half-life assessments after artesunate treatment were analysed. Half-lives followed a bimodal distribution. A statistical approach was developed to infer the characteristics of the component distributions and their relative contribution to the composite mixture. A model representing two parasite subpopulations with geometric mean (IQR) parasite half-lives of 3.0 (2.4-3.9) hours and 6.50 (5.7-7.4) hours was consistent with the data. For individual patients, the parasite half-life provided a predicted likelihood of an artemisinin-resistant infection which depends on the population prevalence of resistance in that area. Consequently, a half-life where the probability is 0.5 varied between 3.5 and 5.5 hours. Using this model, the current 'day-3' cut-off value of 10% predicts the potential presence of artemisinin-resistant infections in most but not all scenarios. These findings are relevant to the low-transmission setting of Southeast Asia. Generalisation to a high transmission setting as in regions of Sub-Saharan Africa will need additional evaluation. CONCLUSIONS: Characterisation of overlapping distributions of parasite half-lives provides quantitative insight into the relationship between parasite clearance and artemisinin resistance, as well as the predictive value of the 10% cut-off in 'day-3' parasitaemia. The findings are important for the interpretation of in vitro sensitivity tests and molecular markers for artemisinin resistance and for contextualising the 'day 3' threshold to account for initial parasitaemia and sample size.

Dogovski C, Xie SC, Burgio G, Bridgford J, Mok S, McCaw JM, Chotivanich K, Kenny S, Gnädig N, Straimer J et al. 2015. Targeting the cell stress response of Plasmodium falciparum to overcome artemisinin resistance. PLoS Biol, 13 (4), pp. e1002132. | Show Abstract | Read more

Successful control of falciparum malaria depends greatly on treatment with artemisinin combination therapies. Thus, reports that resistance to artemisinins (ARTs) has emerged, and that the prevalence of this resistance is increasing, are alarming. ART resistance has recently been linked to mutations in the K13 propeller protein. We undertook a detailed kinetic analysis of the drug responses of K13 wild-type and mutant isolates of Plasmodium falciparum sourced from a region in Cambodia (Pailin). We demonstrate that ART treatment induces growth retardation and an accumulation of ubiquitinated proteins, indicative of a cellular stress response that engages the ubiquitin/proteasome system. We show that resistant parasites exhibit lower levels of ubiquitinated proteins and delayed onset of cell death, indicating an enhanced cell stress response. We found that the stress response can be targeted by inhibiting the proteasome. Accordingly, clinically used proteasome inhibitors strongly synergize ART activity against both sensitive and resistant parasites, including isogenic lines expressing mutant or wild-type K13. Synergy is also observed against Plasmodium berghei in vivo. We developed a detailed model of parasite responses that enables us to infer, for the first time, in vivo parasite clearance profiles from in vitro assessments of ART sensitivity. We provide evidence that the clinical marker of resistance (delayed parasite clearance) is an indirect measure of drug efficacy because of the persistence of unviable parasites with unchanged morphology in the circulation, and we suggest alternative approaches for the direct measurement of viability. Our model predicts that extending current three-day ART treatment courses to four days, or splitting the doses, will efficiently clear resistant parasite infections. This work provides a rationale for improving the detection of ART resistance in the field and for treatment strategies that can be employed in areas with ART resistance.

Parry CM, Thieu NTV, Dolecek C, Karkey A, Gupta R, Turner P, Dance D, Maude RR, Ha V, Tran CN et al. 2015. Clinically and microbiologically derived azithromycin susceptibility breakpoints for Salmonella enterica serovars Typhi and Paratyphi A. Antimicrob Agents Chemother, 59 (5), pp. 2756-2764. | Show Abstract | Read more

Azithromycin is an effective treatment for uncomplicated infections with Salmonella enterica serovar Typhi and serovar Paratyphi A (enteric fever), but there are no clinically validated MIC and disk zone size interpretative guidelines. We studied individual patient data from three randomized controlled trials (RCTs) of antimicrobial treatment in enteric fever in Vietnam, with azithromycin used in one treatment arm, to determine the relationship between azithromycin treatment response and the azithromycin MIC of the infecting isolate. We additionally compared the azithromycin MIC and the disk susceptibility zone sizes of 1,640 S. Typhi and S. Paratyphi A clinical isolates collected from seven Asian countries. In the RCTs, 214 patients who were treated with azithromycin at a dose of 10 to 20 mg/ml for 5 to 7 days were analyzed. Treatment was successful in 195 of 214 (91%) patients, with no significant difference in response (cure rate, fever clearance time) with MICs ranging from 4 to 16 μg/ml. The proportion of Asian enteric fever isolates with an MIC of ≤ 16 μg/ml was 1,452/1,460 (99.5%; 95% confidence interval [CI], 98.9 to 99.7) for S. Typhi and 207/240 (86.3%; 95% CI, 81.2 to 90.3) (P < 0.001) for S. Paratyphi A. A zone size of ≥ 13 mm to a 5-μg azithromycin disk identified S. Typhi isolates with an MIC of ≤ 16 μg/ml with a sensitivity of 99.7%. An azithromycin MIC of ≤ 16 μg/ml or disk inhibition zone size of ≥ 13 mm enabled the detection of susceptible S. Typhi isolates that respond to azithromycin treatment. Further work is needed to define the response to treatment in S. Typhi isolates with an azithromycin MIC of >16 μg/ml and to determine MIC and disk breakpoints for S. Paratyphi A.

Blok DC, Kager LM, Hoogendijk AJ, Lede IO, Rahman W, Afroz R, Bresser P, van der Zee JS, Ghose A, Visser CE et al. 2015. Expression of inhibitory regulators of innate immunity in patients with active tuberculosis. BMC Infect Dis, 15 (1), pp. 98. | Show Abstract | Read more

BACKGROUND: Tuberculosis (TB) is an important cause of morbidity and mortality worldwide. Toll-like-receptors (TLRs) are important for the recognition of the causative agent Mycobacterium tuberculosis. Negative regulation of TLRs is necessary to control deleterious inflammatory damage, but could provide a means of immune evasion by M. tuberculosis as well. METHODS: To obtain insight in the extent of expression of inhibitory regulators of immunity in patients with active TB, peripheral-blood-mononuclear-cells (PBMCs) and plasma were obtained from 54 TB patients and 29 healthy blood donors from Chittagong, Bangladesh. Bilateral alveolar macrophages were obtained from an infected versus a contralateral normal lung segment of 9 patients. Statistical analyses were performed using Mann-Whitney U and Wilcoxon matched pairs testing. Correlations were calculated using the Spearman rho test. RESULTS: PBMCs harvested from TB patients demonstrated increased mRNA expression of IL-1-receptor-associated-kinase-M, suppressor-of-cytokine-signalling-3 and Toll-interacting-protein. Flow cytometry revealed enhanced expression of IL-1-receptor-like-1 (ST2) on lymphocytes. Plasma soluble ST2 was elevated in patients with TB and correlated with established TB biomarkers, most strongly with soluble interleukin-2 receptor subunit α and interleukin-8. Alveolar macrophage mRNA expression of negative TLR regulators did not differ between the infected and contralateral lung side. CONCLUSION: These results show enhanced expression of distinct negative regulators of innate immunity in PBMCs of patients with TB and identify plasma soluble ST2 as a potential novel biomarker for TB disease activity.

Tun KM, Imwong M, Lwin KM, Win AA, Hlaing TM, Hlaing T, Lin K, Kyaw MP, Plewes K, Faiz MA et al. 2015. Spread of artemisinin-resistant Plasmodium falciparum in Myanmar: a cross-sectional survey of the K13 molecular marker. Lancet Infect Dis, 15 (4), pp. 415-421. | Show Abstract | Read more

BACKGROUND: Emergence of artemisinin resistance in southeast Asia poses a serious threat to the global control of Plasmodium falciparum malaria. Discovery of the K13 marker has transformed approaches to the monitoring of artemisinin resistance, allowing introduction of molecular surveillance in remote areas through analysis of DNA. We aimed to assess the spread of artemisinin-resistant P falciparum in Myanmar by determining the relative prevalence of P falciparum parasites carrying K13-propeller mutations. METHODS: We did this cross-sectional survey at malaria treatment centres at 55 sites in ten administrative regions in Myanmar, and in relevant border regions in Thailand and Bangladesh, between January, 2013, and September, 2014. K13 sequences from P falciparum infections were obtained mainly by passive case detection. We entered data into two geostatistical models to produce predictive maps of the estimated prevalence of mutations of the K13 propeller region across Myanmar. FINDINGS: Overall, 371 (39%) of 940 samples carried a K13-propeller mutation. We recorded 26 different mutations, including nine mutations not described previously in southeast Asia. In seven (70%) of the ten administrative regions of Myanmar, the combined K13-mutation prevalence was more than 20%. Geospatial mapping showed that the overall prevalence of K13 mutations exceeded 10% in much of the east and north of the country. In Homalin, Sagaing Region, 25 km from the Indian border, 21 (47%) of 45 parasite samples carried K13-propeller mutations. INTERPRETATION: Artemisinin resistance extends across much of Myanmar. We recorded P falciparum parasites carrying K13-propeller mutations at high prevalence next to the northwestern border with India. Appropriate therapeutic regimens should be tested urgently and implemented comprehensively if spread of artemisinin resistance to other regions is to be avoided. FUNDING: Wellcome Trust-Mahidol University-Oxford Tropical Medicine Research Programme and the Bill & Melinda Gates Foundation.

Miotto O, Amato R, Ashley EA, MacInnis B, Almagro-Garcia J, Amaratunga C, Lim P, Mead D, Oyola SO, Dhorda M et al. 2015. Genetic architecture of artemisinin-resistant Plasmodium falciparum. Nat Genet, 47 (3), pp. 226-234. | Show Abstract | Read more

We report a large multicenter genome-wide association study of Plasmodium falciparum resistance to artemisinin, the frontline antimalarial drug. Across 15 locations in Southeast Asia, we identified at least 20 mutations in kelch13 (PF3D7_1343700) affecting the encoded propeller and BTB/POZ domains, which were associated with a slow parasite clearance rate after treatment with artemisinin derivatives. Nonsynonymous polymorphisms in fd (ferredoxin), arps10 (apicoplast ribosomal protein S10), mdr2 (multidrug resistance protein 2) and crt (chloroquine resistance transporter) also showed strong associations with artemisinin resistance. Analysis of the fine structure of the parasite population showed that the fd, arps10, mdr2 and crt polymorphisms are markers of a genetic background on which kelch13 mutations are particularly likely to arise and that they correlate with the contemporary geographical boundaries and population frequencies of artemisinin resistance. These findings indicate that the risk of new resistance-causing mutations emerging is determined by specific predisposing genetic factors in the underlying parasite population.

Vellinga NAR, Boerma EC, Koopmans M, Donati A, Dubin A, Shapiro NI, Pearse RM, Machado FR, Fries M, Akarsu-Ayazoglu T et al. 2015. International study on microcirculatory shock occurrence in acutely ill patients. Crit Care Med, 43 (1), pp. 48-56. | Show Abstract | Read more

OBJECTIVES: Microcirculatory alterations are associated with adverse outcome in subsets of critically ill patients. The prevalence and significance of microcirculatory alterations in the general ICU population are unknown. We studied the prevalence of microcirculatory alterations in a heterogeneous ICU population and its predictive value in an integrative model of macro- and microcirculatory variables. DESIGN: Multicenter observational point prevalence study. SETTING: The Microcirculatory Shock Occurrence in Acutely ill Patients study was conducted in 36 ICUs worldwide. PATIENTS: A heterogeneous ICU population consisting of 501 patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Demographic, hemodynamic, and laboratory data were collected in all ICU patients who were 18 years old or older. Sublingual Sidestream Dark Field imaging was performed to determine the prevalence of an abnormal capillary microvascular flow index (< 2.6) and its additional value in predicting hospital mortality. In 501 patients with a median Acute Physiology and Chronic Health Evaluation II score of 15 (10-21), a Sequential Organ Failure Assessment score of 5 (2-8), and a hospital mortality of 28.4%, 17% exhibited an abnormal capillary microvascular flow index. Tachycardia (heart rate > 90 beats/min) (odds ratio, 2.71; 95% CI, 1.67-4.39; p < 0.001), mean arterial pressure (odds ratio, 0.979; 95% CI, 0.963-0.996; p = 0.013), vasopressor use (odds ratio, 1.84; 95% CI, 1.11-3.07; p = 0.019), and lactate level more than 1.5 mEq/L (odds ratio, 2.15; 95% CI, 1.28-3.62; p = 0.004) were independent risk factors for hospital mortality, but not abnormal microvascular flow index. In reference to microvascular flow index, a significant interaction was observed with tachycardia. In patients with tachycardia, the presence of an abnormal microvascular flow index was an independent, additive predictor for in-hospital mortality (odds ratio, 3.24; 95% CI, 1.30-8.06; p = 0.011). This was not true for nontachycardic patients nor for the total group of patients. CONCLUSIONS: In a heterogeneous ICU population, an abnormal microvascular flow index was present in 17% of patients. This was not associated with mortality. However, in patients with tachycardia, an abnormal microvascular flow index was independently associated with an increased risk of hospital death.

Sathpathi S, Mohanty AK, Satpathi P, Mishra SK, Behera PK, Patel G, Dondorp AM. 2014. Comparing Leishman and Giemsa staining for the assessment of peripheral blood smear preparations in a malaria-endemic region in India. Malar J, 13 (1), pp. 512. | Show Abstract | Read more

BACKGROUND: Microscopy of peripheral blood thin and thick films remains the reference for malaria diagnosis. Although Giemsa staining is most commonly used, the Leishman staining method provides better visualization of the nuclear chromatin pattern of cells. It is less well known whether accuracy of parasitaemia assessment is equally accurate with the latter method. METHODS: Peripheral blood thin and thick smears from consecutive febrile patients admitted to Ispat General hospital, Rourkela, Odhisa, India, were stained with Giemsa and Leishman stain. Methods were compared for species identification, parasite quantification, and ability for identification of alternative diagnoses. RESULTS: Blood films from 1,180 fever patients were compared according to staining method, of which 111 were identified as parasitaemic using Giemsa and 110 with Leishman staining. The Kappa value as a measure of agreement between methods was 0.995 (p < 0.001), and the log10parasitaemia between methods were strongly correlated (r2 = 0.9981). In parasite negative patients, thin smear assessment contributed to making a diagnosis in 276/1,180 (23%) of cases. These assessments were better made in Leishman-stained preparations, especially for the assessment of morphological changes in red and white cells. CONCLUSION: Leishman's staining method for thin and thick smears is a good alternative to Giemsa's stain for identifying Plasmodium parasites. The Leishman method is superior for visualization of red and white blood cell morphology.

Brown TS, Jacob CG, Silva JC, Takala-Harrison S, Djimdé A, Dondorp AM, Fukuda M, Noedl H, Nyunt MM, Kyaw MP et al. 2015. Plasmodium falciparum field isolates from areas of repeated emergence of drug resistant malaria show no evidence of hypermutator phenotype. Infect Genet Evol, 30 pp. 318-322. | Show Abstract | Read more

Multiple transcontinental waves of drug resistance in Plasmodium falciparum have originated in Southeast Asia before spreading westward, first into the rest of Asia and then to sub-Saharan Africa. In vitro studies have suggested that hypermutator P. falciparum parasites may exist in Southeast Asia and that an increased rate of acquisition of new mutations in these parasites may explain the repeated emergence of drug resistance in Southeast Asia. This study is the first to test the hypermutator hypothesis using field isolates. Using genome-wide SNP data from human P. falciparum infections in Southeast Asia and West Africa and a test for relative rate differences we found no evidence of increased relative substitution rates in P. falciparum isolates from Southeast Asia. Instead, we found significantly increased substitution rates in Mali and Bangladesh populations relative to those in populations from Southeast Asia. Additionally we found no association between increased relative substitution rates and parasite clearance following treatment with artemisinin derivatives.

Mok S, Ashley EA, Ferreira PE, Zhu L, Lin Z, Yeo T, Chotivanich K, Imwong M, Pukrittayakamee S, Dhorda M et al. 2015. Drug resistance. Population transcriptomics of human malaria parasites reveals the mechanism of artemisinin resistance. Science, 347 (6220), pp. 431-435. | Show Abstract | Read more

Artemisinin resistance in Plasmodium falciparum threatens global efforts to control and eliminate malaria. Polymorphisms in the kelch domain-carrying protein K13 are associated with artemisinin resistance, but the underlying molecular mechanisms are unknown. We analyzed the in vivo transcriptomes of 1043 P. falciparum isolates from patients with acute malaria and found that artemisinin resistance is associated with increased expression of unfolded protein response (UPR) pathways involving the major PROSC and TRiC chaperone complexes. Artemisinin-resistant parasites also exhibit decelerated progression through the first part of the asexual intraerythrocytic development cycle. These findings suggest that artemisinin-resistant parasites remain in a state of decelerated development at the young ring stage, whereas their up-regulated UPR pathways mitigate protein damage caused by artemisinin. The expression profiles of UPR-related genes also associate with the geographical origin of parasite isolates, further suggesting their role in emerging artemisinin resistance in the Greater Mekong Subregion.

White NJ, Ashley EA, Recht J, Delves MJ, Ruecker A, Smithuis FM, Eziefula AC, Bousema T, Drakeley C, Chotivanich K et al. 2014. Assessment of therapeutic responses to gametocytocidal drugs in Plasmodium falciparum malaria. Malar J, 13 (1), pp. 483. | Show Abstract | Read more

Indirect clinical measures assessing anti-malarial drug transmission-blocking activity in falciparum malaria include measurement of the duration of gametocytaemia, the rate of gametocyte clearance or the area under the gametocytaemia-time curve (AUC). These may provide useful comparative information, but they underestimate dose-response relationships for transmission-blocking activity. Following 8-aminoquinoline administration P. falciparum gametocytes are sterilized within hours, whereas clearance from blood takes days. Gametocytaemia AUC and clearance times are determined predominantly by the more numerous female gametocytes, which are generally less drug sensitive than the minority male gametocytes, whereas transmission-blocking activity and thus infectivity is determined by the more sensitive male forms. In choosing doses of transmission-blocking drugs there is no substitute yet for mosquito-feeding studies.

Rahimi BA, Thakkinstian A, White NJ, Sirivichayakul C, Dondorp AM, Chokejindachai W. 2014. Severe vivax malaria: a systematic review and meta-analysis of clinical studies since 1900. Malar J, 13 (1), pp. 481. | Show Abstract | Read more

BACKGROUND: Malaria caused by Plasmodium vivax was long considered to have a low mortality, but recent reports from some geographical areas suggest that severe and complicated vivax malaria may be more common than previously thought. METHODS: The primary objective of this systematic review and meta-analysis was to describe the reported clinical characteristics and the geographical variation in prevalence of reported severe vivax malaria and its change over time derived from English-language articles published since 1900. Medline and Scopus databases were searched for original papers on severe vivax malaria, using as inclusion criteria modified 2010 WHO criteria for the diagnosis of severe falciparum malaria. Articles before 1949 were identified through reference lists in journals, textbooks, and personal collections of colleagues. RESULTS: A total of 77 studies with reported severe vivax malaria and 63 studies with no reported severe vivax malaria (totaling 46,411 and 6,753 vivax malaria patients, respectively) were included. The 77 studies with reported severe vivax malaria were mainly from India (n = 33), USA (n = 8), Indonesia (n = 6), and Pakistan (n = 6). Vivax endemic countries not reporting severe vivax malaria beyond individual case reports included: the Greater Mekong Sub-region, China, North Korea, Bangladesh, Afghanistan, Middle East (except Qatar), the horn of Africa, and Madagascar. Only 17/77 reports were from before 2000. Vivax mono-infection was confirmed by PCR in 14 studies and co-morbidities were ruled out in 23 studies. Among the 77 studies reporting severe vivax malaria, severe thrombocytopenia (<50,000/mm3) was the most common "severe" manifestation (888/45,775 with pooled prevalence of 8.6%). The case fatality was 0.3% (353/46,411). Severity syndromes varied widely between different geographical areas, with severe anaemia being most prominent in areas of high transmission and chloroquine resistance. CONCLUSION: Plasmodium vivax can cause severe and even fatal disease, but there is a recent increase in reports over the past 15 years with larger series restricted to a limited number of geographical areas. The biological basis of these variations is currently not known. More detailed epidemiological studies are needed which dissociate causation from association to refine the definition and estimate the prevalence of severe vivax malaria.

Lubell Y, Dondorp A, Guérin PJ, Drake T, Meek S, Ashley E, Day NPJ, White NJ, White LJ. 2014. Artemisinin resistance--modelling the potential human and economic costs. Malar J, 13 (1), pp. 452. | Show Abstract | Read more

BACKGROUND: Artemisinin combination therapy is recommended as first-line treatment for falciparum malaria across the endemic world and is increasingly relied upon for treating vivax malaria where chloroquine is failing. Artemisinin resistance was first detected in western Cambodia in 2007, and is now confirmed in the Greater Mekong region, raising the spectre of a malaria resurgence that could undo a decade of progress in control, and threaten the feasibility of elimination. The magnitude of this threat has not been quantified. METHODS: This analysis compares the health and economic consequences of two future scenarios occurring once artemisinin-based treatments are available with high coverage. In the first scenario, artemisinin combination therapy (ACT) is largely effective in the management of uncomplicated malaria and severe malaria is treated with artesunate, while in the second scenario ACT are failing at a rate of 30%, and treatment of severe malaria reverts to quinine. The model is applied to all malaria-endemic countries using their specific estimates for malaria incidence, transmission intensity and GDP. The model describes the direct medical costs for repeated diagnosis and retreatment of clinical failures as well as admission costs for severe malaria. For productivity losses, the conservative friction costing method is used, which assumes a limited economic impact for individuals that are no longer economically active until they are replaced from the unemployment pool. RESULTS: Using conservative assumptions and parameter estimates, the model projects an excess of 116,000 deaths annually in the scenario of widespread artemisinin resistance. The predicted medical costs for retreatment of clinical failures and for management of severe malaria exceed US$32 million per year. Productivity losses resulting from excess morbidity and mortality were estimated at US$385 million for each year during which failing ACT remained in use as first-line treatment. CONCLUSIONS: These 'ballpark' figures for the magnitude of the health and economic threat posed by artemisinin resistance add weight to the call for urgent action to detect the emergence of resistance as early as possible and contain its spread from known locations in the Mekong region to elsewhere in the endemic world.

Hanson J, Anstey NM, Bihari D, White NJ, Day NP, Dondorp AM. 2014. The fluid management of adults with severe malaria. Crit Care, 18 (6), pp. 642. | Show Abstract | Read more

Fluid resuscitation has long been considered a key intervention in the treatment of adults with severe falciparum malaria. Profound hypovolemia is common in these patients and has the potential to exacerbate the acidosis and acute kidney injury that are independent predictors of death. However, new microvascular imaging techniques have shown that disease severity correlates more strongly with obstruction of the microcirculation by parasitized erythrocytes--a process termed sequestration. Fluid loading has little effect on sequestration and increases the risk of complications, particularly pulmonary edema, a condition that can develop suddenly and unpredictably and that is frequently fatal in this population. Accordingly, even if a patient is clinically hypovolemic, if there is an adequate blood pressure and urine output, there may be little advantage in infusing intravenous fluid beyond a maintenance rate of 1 to 2 mL/kg per hour. The optimal agent for fluid resuscitation remains uncertain; significant anemia requires blood transfusion, but colloid solutions may be associated with harm and should be avoided. The preferred crystalloid is unclear, although the use of balanced solutions requires investigation. There are fewer data to guide the fluid management of severe vivax and knowlesi malaria, although a similar conservative strategy would appear prudent.

Zaloumis SG, Tarning J, Krishna S, Price RN, White NJ, Davis TME, McCaw JM, Olliaro P, Maude RJ, Kremsner P et al. 2014. Population pharmacokinetics of intravenous artesunate: a pooled analysis of individual data from patients with severe malaria. CPT Pharmacometrics Syst Pharmacol, 3 (11), pp. e145. | Show Abstract | Read more

There are ~660,000 deaths from severe malaria each year. Intravenous artesunate (i.v. ARS) is the first-line treatment in adults and children. To optimize the dosing regimen of i.v. ARS, the largest pooled population pharmacokinetic study to date of the active metabolite dihydroartemisinin (DHA) was performed. The pooled dataset consisted of 71 adults and 195 children with severe malaria, with a mixture of sparse and rich sampling within the first 12 h after drug administration. A one-compartment model described the population pharmacokinetics of DHA adequately. Body weight had the greatest impact on DHA pharmacokinetics, resulting in lower DHA exposure for smaller children (6-10 kg) than adults. Post hoc estimates of DHA exposure were not significantly associated with parasitological outcomes. Comparable DHA exposure in smaller children and adults after i.v. ARS was achieved under a dose modification for intramuscular ARS proposed in a separate analysis of children.

Zaloumis SG, Tarning J, Krishna S, Price RN, White NJ, Davis TME, McCaw JM, Olliaro P, Maude RJ, Kremsner P et al. 2014. Population Pharmacokinetics of Intravenous Artesunate: A Pooled Analysis of Individual Data From Patients With Severe Malaria. CPT Pharmacometrics Syst Pharmacol, 3 (11), pp. 1-9. | Show Abstract | Read more

There are ~660,000 deaths from severe malaria each year. Intravenous artesunate (i.v. ARS) is the first-line treatment in adults and children. To optimize the dosing regimen of i.v. ARS, the largest pooled population pharmacokinetic study to date of the active metabolite dihydroartemisinin (DHA) was performed. The pooled dataset consisted of 71 adults and 195 children with severe malaria, with a mixture of sparse and rich sampling within the first 12 h after drug administration. A one-compartment model described the population pharmacokinetics of DHA adequately. Body weight had the greatest impact on DHA pharmacokinetics, resulting in lower DHA exposure for smaller children (6-10 kg) than adults. Post hoc estimates of DHA exposure were not significantly associated with parasitological outcomes. Comparable DHA exposure in smaller children and adults after i.v. ARS was achieved under a dose modification for intramuscular ARS proposed in a separate analysis of children. CPT Pharmacometrics Syst. Pharmacol. (2014) 3, e145; doi:10.1038/psp.2014.43; published online 05 November 2014.

Kager LM, Blok DC, Lede IO, Rahman W, Afroz R, Bresser P, van der Zee JS, Ghose A, Visser CE, de Jong MD et al. 2015. Pulmonary tuberculosis induces a systemic hypercoagulable state. J Infect, 70 (4), pp. 324-334. | Show Abstract | Read more

OBJECTIVES: Human tuberculosis (TB) remains an important cause of death globally. Bangladesh is one of the most affected countries. We aimed to investigate the impact of pulmonary TB on pro- and anticoagulant mechanisms. METHODS: This prospective study was conducted in Chittagong, Bangladesh. We performed an in-depth analysis of coagulation activation and inhibition in plasma obtained from 64 patients with primary lung TB and 11 patients with recurrent lung TB and compared these with 37 healthy controls. Additionally, in nine patients coagulation activation was studied in bronchoalveolar lavage fluid (BALF) harvested from the site of infection and compared with BALF from a contralateral unaffected lung subsegment. RESULTS: Relative to uninfected controls, primary and recurrent TB were associated with a systemic net procoagulant state, as indicated by enhanced activation of coagulation (elevated plasma levels of thrombin-antithrombin complexes, D-dimer and fibrinogen) together with impaired anticoagulant mechanisms (reduced plasma levels of antithrombin, protein C activity, free protein S, and protein C inhibitor). Activation of coagulation did not correlate with plasma concentrations of established TB biomarkers. Coagulation activation could not be detected at the primary site of infection in a subset of TB patients. CONCLUSIONS: Pulmonary TB is associated with a systemic hypercoagulable state.

Imwong M, Woodrow CJ, Hendriksen ICE, Veenemans J, Verhoef H, Faiz MA, Mohanty S, Mishra S, Mtove G, Gesase S et al. 2015. Plasma concentration of parasite DNA as a measure of disease severity in falciparum malaria. J Infect Dis, 211 (7), pp. 1128-1133. | Show Abstract | Read more

In malaria-endemic areas, Plasmodium falciparum parasitemia is common in apparently healthy children and severe malaria is commonly misdiagnosed in patients with incidental parasitemia. We assessed whether the plasma Plasmodium falciparum DNA concentration is a useful datum for distinguishing uncomplicated from severe malaria in African children and Asian adults. P. falciparum DNA concentrations were measured by real-time polymerase chain reaction (PCR) in 224 African children (111 with uncomplicated malaria and 113 with severe malaria) and 211 Asian adults (100 with uncomplicated malaria and 111 with severe malaria) presenting with acute falciparum malaria. The diagnostic accuracy of plasma P. falciparum DNA concentrations in identifying severe malaria was 0.834 for children and 0.788 for adults, similar to that of plasma P. falciparum HRP2 levels and substantially superior to that of parasite densities (P < .0001). The diagnostic accuracy of plasma P. falciparum DNA concentrations plus plasma P. falciparum HRP2 concentrations was significantly greater than that of plasma P. falciparum HRP2 concentrations alone (0.904 for children [P = .004] and 0.847 for adults [P = .003]). Quantitative real-time PCR measurement of parasite DNA in plasma is a useful method for diagnosing severe falciparum malaria on fresh or archived plasma samples.

Haniffa R, De Silva AP, Iddagoda S, Batawalage H, De Silva STGR, Mahipala PG, Dondorp A, de Keizer N, Jayasinghe S. 2014. A cross-sectional survey of critical care services in Sri Lanka: a lower middle-income country. J Crit Care, 29 (5), pp. 764-768. | Show Abstract | Read more

PURPOSE: To describe the extent and variation of critical care services in Sri Lanka as a first step towards the development of a nationwide critical care unit (CCU) registry. MATERIALS AND METHODS: A cross-sectional survey was conducted in all state CCUs by telephone or by visits to determine administration, infrastructure, equipment, staffing, and overall patient outcomes. RESULTS: There were 99 CCUs with 2.5 CCU beds per 100000 population and 13 CCU beds per 1 000 hospital beds. The median number of beds per CCU was 5. The overall admissions were 194 per 100000 population per year. The overall bed turnover was 76.5 per unit per year, with CCU mortality being 17%. Most CCUs were headed by an anesthetist. There were a total of 790 doctors (1.6 per bed), 1,989 nurses (3.9 per bed), and 626 health care assistants (1.2 per bed). Majority (87.9%) had 1:1 nurse-to-patient ratio, although few (11.4%) nurses had received formal intensive care unit training. All CCUs had basic infrastructure (electricity, running water, piped oxygen) and basic equipment (such as electronic monitoring and infusion pumps). CONCLUSION: Sri Lanka, a lower middle-income country has an extensive network of critical care facilities but with inequalities in its distribution and facilities.

Maude RJ, Ahmed BUMW, Rahman AHMW, Rahman R, Majumder MI, Menezes DB, Abu Sayeed A, Hughes L, MacGillivray TJ, Borooah S et al. 2014. Retinal changes in visceral leishmaniasis by retinal photography. BMC Infect Dis, 14 (1), pp. 527. | Show Abstract | Read more

BACKGROUND: In visceral leishmaniasis (VL), retinal changes have previously been noted but not described in detail and their clinical and pathological significance are unknown. A prospective observational study was undertaken in Mymensingh, Bangladesh aiming to describe in detail visible changes in the retina in unselected patients with VL. METHODS: Patients underwent assessment of visual function, indirect and direct ophthalmoscopy and portable retinal photography. The photographs were assessed by masked observers including assessment for vessel tortuosity using a semi-automated system. RESULTS: 30 patients with VL were enrolled, of whom 6 (20%) had abnormalities. These included 5 with focal retinal whitening, 2 with cotton wool spots, 2 with haemorrhages, as well as increased vessel tortuosity. Visual function was preserved. CONCLUSIONS: These changes suggest a previously unrecognized retinal vasculopathy. An inflammatory aetiology is plausible such as a subclinical retinal vasculitis, possibly with altered local microvascular autoregulation, and warrants further investigation.

Maude RJ, Nguon C, Ly P, Bunkea T, Ngor P, Canavati de la Torre SE, White NJ, Dondorp AM, Day NPJ, White LJ, Chuor CM. 2014. Spatial and temporal epidemiology of clinical malaria in Cambodia 2004-2013. Malar J, 13 (1), pp. 385. | Show Abstract | Read more

BACKGROUND: Artemisinin-resistant Plasmodium falciparum malaria has recently been identified on the Thailand-Cambodia border and more recently in parts of Thailand, Myanmar and Vietnam. There is concern that if this resistance were to spread, it would severely hamper malaria control and elimination efforts worldwide. Efforts are currently underway to intensify malaria control activities and ultimately eliminate malaria from Cambodia. To support these efforts, it is crucial to have a detailed picture of disease burden and its major determinants over time. METHODS: An analysis of spatial and temporal data on clinical malaria in Cambodia collected by the National Centre for Parasitology, Entomology and Malaria Control (CNM) and the Department of Planning and Health Information, Ministry of Health Cambodia from 2004 to 2013 is presented. RESULTS: There has been a marked decrease of 81% in annual cases due to P. falciparum since 2009 coinciding with a rapid scale-up in village malaria workers (VMWs) and insecticide-treated bed nets (ITNs). Concurrently, the number of cases with Plasmodium vivax has greatly increased. It is estimated that there were around 112,000 total cases in 2012, 2.8 times greater than the WHO estimate for that year, and 68,000 in 2013 (an annual parasite incidence (API) of 4.6/1000). With the scale-up of VMWs, numbers of patients presenting to government facilities did not fall and it appears likely that those who saw VMWs had previously accessed healthcare in the private sector. Malaria mortality has decreased, particularly in areas with VMWs. There has been a marked decrease in cases in parts of western Cambodia, especially in Pailin and Battambang Provinces. In the northeast, the fall in malaria burden has been more modest, this area having the highest API in 2013. CONCLUSION: The clinical burden of falciparum malaria in most areas of Cambodia has greatly decreased from 2009 to 2013, associated with roll-out of ITNs and VMWs. Numbers of cases with P. vivax have increased. Possible reasons for these trends are discussed and areas requiring further study are highlighted. Although malaria surveillance data are prone to collection bias and tend to underestimate disease burden, the finding of similar trends in two independent datasets in this study greatly increased the robustness of the findings.

Maude RJ, Nguon C, Dondorp AM, White LJ, White NJ. 2014. The diminishing returns of atovaquone-proguanil for elimination of Plasmodium falciparum malaria: modelling mass drug administration and treatment. Malar J, 13 (1), pp. 380. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance is a major threat to current efforts to eliminate Plasmodium falciparum malaria which rely heavily on the continuing efficacy of artemisinin combination therapy (ACT). It has been suggested that ACT should not be used in mass drug administration (MDA) in areas where artemisinin-resistant P. falciparum is prevalent, and that atovaquone-proguanil (A-P) might be a preferable alternative. However, a single point mutation in the cytochrome b gene confers high level resistance to atovaquone, and such mutant parasites arise frequently during treatment making A-P a vulnerable tool for elimination. METHODS: A deterministic, population level, mathematical model was developed based on data from Cambodia to explore the possible effects of large-scale use of A-P compared to dihydroartemisinin-piperaquine ACT for mass drug administration and/or treatment of P. falciparum malaria, with and without adjunctive primaquine (PQ) and long-lasting insecticide-treated bed nets (LLIN). The aim was local elimination. RESULTS: The model showed the initial efficacy of ACT and A-P for MDA to be similar. However, each round of A-P MDA resulted in rapid acquisition and spread of atovaquone resistance. Even a single round of MDA could compromise efficacy sufficient to preclude its use for treatment or prophylaxis. A switch to A-P for treatment of symptomatic episodes resulted in a complete loss of efficacy in the population within four to five years of its introduction. The impact of MDA was temporary and a combination of maintained high coverage with ACT treatment for symptomatic individuals and LLIN was necessary for elimination. CONCLUSION: For malaria elimination, A-P for MDA or treatment of symptomatic cases should be avoided. A combined strategy of high coverage with ACT for treatment of symptomatic episodes, LLIN and ACT + P MDA would be preferable.

Takala-Harrison S, Jacob CG, Arze C, Cummings MP, Silva JC, Dondorp AM, Fukuda MM, Hien TT, Mayxay M, Noedl H et al. 2015. Independent emergence of artemisinin resistance mutations among Plasmodium falciparum in Southeast Asia. J Infect Dis, 211 (5), pp. 670-679. | Show Abstract | Read more

BACKGROUND: The emergence of artemisinin-resistant Plasmodium falciparum in Southeast Asia threatens malaria treatment efficacy. Mutations in a kelch protein encoded on P. falciparum chromosome 13 (K13) have been associated with resistance in vitro and in field samples from Cambodia. METHODS: P. falciparum infections from artesunate efficacy trials in Bangladesh, Cambodia, Laos, Myanmar, and Vietnam were genotyped at 33 716 genome-wide single-nucleotide polymorphisms (SNPs). Linear mixed models were used to test associations between parasite genotypes and parasite clearance half-lives following artesunate treatment. K13 mutations were tested for association with artemisinin resistance, and extended haplotypes on chromosome 13 were examined to determine whether mutations arose focally and spread or whether they emerged independently. RESULTS: The presence of nonreference K13 alleles was associated with prolonged parasite clearance half-life (P = 1.97 × 10(-12)). Parasites with a mutation in any of the K13 kelch domains displayed longer parasite clearance half-lives than parasites with wild-type alleles. Haplotype analysis revealed both population-specific emergence of mutations and independent emergence of the same mutation in different geographic areas. CONCLUSIONS: K13 appears to be a major determinant of artemisinin resistance throughout Southeast Asia. While we found some evidence of spreading resistance, there was no evidence of resistance moving westward from Cambodia into Myanmar.

Maude RR, Maude RJ, Ghose A, Amin MR, Islam MB, Ali M, Bari MS, Majumder MI, Tanganuchitcharnchai A, Dondorp AM et al. 2014. Serosurveillance of Orientia tsutsugamushi and Rickettsia typhi in Bangladesh. Am J Trop Med Hyg, 91 (3), pp. 580-583. | Show Abstract | Read more

Scrub and murine typhus infections are under-diagnosed causes of febrile illness across the tropics, and it is not known how common they are in Bangladesh. We conducted a prospective seroepidemiologic survey across six major teaching hospitals in Bangladesh by using an IgM enzyme-linked immunosorbent assay. Results indicated recent exposure (287 of 1,209, 23.7% seropositive for Orientia tsutsugamushi and 805 of 1,209, 66.6% seropositive for Rickettsia typhi). Seropositive rates were different in each region. However, there was no geographic clustering of seropositive results for both organisms. There was no difference between those from rural or urban areas. Rickettsia typhi seroreactivity was positively correlated with age. Scrub typhus and murine typhus should be considered as possible causes of infection in Bangladesh.

Dondorp AM, Haniffa R. 2014. Critical care and severe sepsis in resource poor settings. Trans R Soc Trop Med Hyg, 108 (8), pp. 453-454. | Read more

Lubell Y, White L, Varadan S, Drake T, Yeung S, Cheah PY, Maude RJ, Dondorp A, Day NPJ, White NJ, Parker M. 2014. Ethics, economics, and the use of primaquine to reduce falciparum malaria transmission in asymptomatic populations. PLoS Med, 11 (8), pp. e1001704. | Show Abstract | Read more

Yoel Lubell and colleagues consider ethical and economic perspectives on mass drug administration of primaquine to limit transmission of P. falciparum malaria. Please see later in the article for the Editors' Summary.

Ashley EA, Dhorda M, Fairhurst RM, Amaratunga C, Lim P, Suon S, Sreng S, Anderson JM, Mao S, Sam B et al. 2014. Spread of artemisinin resistance in Plasmodium falciparum malaria. N Engl J Med, 371 (5), pp. 411-423. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance in Plasmodium falciparum has emerged in Southeast Asia and now poses a threat to the control and elimination of malaria. Mapping the geographic extent of resistance is essential for planning containment and elimination strategies. METHODS: Between May 2011 and April 2013, we enrolled 1241 adults and children with acute, uncomplicated falciparum malaria in an open-label trial at 15 sites in 10 countries (7 in Asia and 3 in Africa). Patients received artesunate, administered orally at a daily dose of either 2 mg per kilogram of body weight per day or 4 mg per kilogram, for 3 days, followed by a standard 3-day course of artemisinin-based combination therapy. Parasite counts in peripheral-blood samples were measured every 6 hours, and the parasite clearance half-lives were determined. RESULTS: The median parasite clearance half-lives ranged from 1.9 hours in the Democratic Republic of Congo to 7.0 hours at the Thailand-Cambodia border. Slowly clearing infections (parasite clearance half-life >5 hours), strongly associated with single point mutations in the "propeller" region of the P. falciparum kelch protein gene on chromosome 13 (kelch13), were detected throughout mainland Southeast Asia from southern Vietnam to central Myanmar. The incidence of pretreatment and post-treatment gametocytemia was higher among patients with slow parasite clearance, suggesting greater potential for transmission. In western Cambodia, where artemisinin-based combination therapies are failing, the 6-day course of antimalarial therapy was associated with a cure rate of 97.7% (95% confidence interval, 90.9 to 99.4) at 42 days. CONCLUSIONS: Artemisinin resistance to P. falciparum, which is now prevalent across mainland Southeast Asia, is associated with mutations in kelch13. Prolonged courses of artemisinin-based combination therapies are currently efficacious in areas where standard 3-day treatments are failing. (Funded by the U.K. Department of International Development and others; number, NCT01350856.).

Onyamboko MA, Fanello CI, Wongsaen K, Tarning J, Cheah PY, Tshefu KA, Dondorp AM, Nosten F, White NJ, Day NPJ. 2014. Randomized comparison of the efficacies and tolerabilities of three artemisinin-based combination treatments for children with acute Plasmodium falciparum malaria in the Democratic Republic of the Congo. Antimicrob Agents Chemother, 58 (9), pp. 5528-5536. | Show Abstract | Read more

An open-label, randomized controlled trial was carried out in 2011-2012 in the Democratic Republic of the Congo to test the efficacy, safety, and tolerability of the artemisinin-based combination treatments dihydroartemisinin-piperaquine, amodiaquine-artesunate, and artemether-lumefantrine. Six hundred eighty-four children aged 3 to 59 months with uncomplicated Plasmodium falciparum malaria were randomly allocated to each study arm. Children were hospitalized for 3 days, given supervised treatment, and followed up weekly for 42 days. All regimens were well tolerated and rapidly effective. The median parasitemia clearance half-life was 2.2 h, and half-lives were similar between arms (P=0.19). The PCR-uncorrected cure rates by day 42 were 73.0% for amodiaquine-artesunate, 70.2% for artemether-lumefantrine, and 86.3% for dihydroartemisinin-piperaquine (P=0.001). Early treatment failure occurred in three patients (0.5%), one in each arm. The PCR-corrected cure rates were 93.4% for amodiaquine-artesunate, 92.7% for artemether-lumefantrine, and 94.3% for dihydroartemisinin-piperaquine (P=0.78). The last provided a longer posttreatment prophylactic effect than did the other two treatments. The day 7 plasma concentration of piperaquine was below 30 ng/ml in 47% of the children treated with dihydroartemisinin-piperaquine, and the day 7 lumefantrine concentration was below 280 ng/ml in 37.0% of children who received artemether-lumefantrine. Thus, although cure rates were all satisfactory, they could be improved by increasing the dose. (This study has been registered with the International Standard Randomized Controlled Trial Number Register [] under registration no. ISRCTN20984426.).

Imwong M, Hanchana S, Malleret B, Rénia L, Day NPJ, Dondorp A, Nosten F, Snounou G, White NJ. 2014. High-throughput ultrasensitive molecular techniques for quantifying low-density malaria parasitemias. J Clin Microbiol, 52 (9), pp. 3303-3309. | Show Abstract | Read more

The epidemiology of malaria in "low-transmission" areas has been underestimated. Molecular detection methods have revealed higher prevalences of malaria than conventional microscopy or rapid diagnostic tests, but these typically evaluate finger-prick capillary blood samples (∼5 μl) and therefore cannot detect parasite densities of <200/ml. Their use underestimates true parasite carriage rates. To characterize the epidemiology of malaria in low-transmission settings and plan elimination strategies, more sensitive quantitative PCR (qPCR) is needed to identify and quantify low-density malaria parasitemias. A highly sensitive "high-volume" quantitative PCR (qPCR) method based on Plasmodium sp. 18S RNA was adapted for blood sample volumes of ≥250 μl and scaled for high throughput. The methods were validated by assessment of the analytical sensitivity and specificity, diagnostic sensitivity, and specificity, efficiency, precision, analytical and diagnostic accuracies, limit of detection, root cause analysis of false positives, and robustness. The high-volume qPCR method based on Plasmodium sp. 18S RNA gave high PCR efficiency of 90 to 105%. Concentrations of parasite DNA from large volumes of blood gave a consistent analytical detection limit (LOD) of 22 parasites/ml (95% CI, 21.79 to 74.9), which is some 2,500 times more sensitive than conventional microscopy and 50 times more sensitive than currently used PCR methods from filter paper blood spots. The diagnostic specificity was 99.75%. Using automated procedures it was possible to process 700 blood samples per week. A very sensitive and specific high-throughput high-volume qPCR method for the detection of low-density parasitemias (>20 parasites/ml) was developed and validated.

Woodrow CJ, Dondorp AM. 2014. Parasite burden and severity of malaria in Tanzanian children. N Engl J Med, 371 (5), pp. 481-482. | Read more

Maude RJ, Kingston HWF, Joshi S, Mohanty S, Mishra SK, White NJ, Dondorp AM. 2014. Reversibility of retinal microvascular changes in severe falciparum malaria. Am J Trop Med Hyg, 91 (3), pp. 493-495. | Show Abstract | Read more

Malarial retinopathy allows detailed study of central nervous system vascular pathology in living patients with severe malaria. An adult with cerebral malaria is described who had prominent retinal whitening with corresponding retinal microvascular obstruction, vessel dilatation, increased vascular tortuosity, and blood retinal barrier leakage with decreased visual acuity, all of which resolved on recovery. Additional study of these features and their potential role in elucidating the pathogenesis of cerebral malaria is warranted.

Das D, Cheah PY, Akter F, Paul D, Islam A, Sayeed AA, Samad R, Rahman R, Hossain A, Dondorp A et al. 2014. Participants' perceptions and understanding of a malaria clinical trial in Bangladesh. Malar J, 13 (1), pp. 217. | Show Abstract | Read more

BACKGROUND: Existing evidence suggests that there is often limited understanding among participants in clinical trials about the informed consent process, resulting in their providing consent without really understanding the purpose of the study, specific procedures, and their rights. The objective of the study was to determine the subjects' understanding of research, perceptions of voluntariness and motivations for participation in a malaria clinical trial. METHODS: In this study semi-structured interviews of adult clinical trial participants with uncomplicated falciparum malaria were conducted in Ramu Upazila Health Complex, in Bangladesh. RESULTS: Of 16 participants, the vast majority (81%) were illiterate. All subjects had a 'therapeutic misconception' i.e. the trial was perceived to be conducted primarily for the benefit of individual patients when in fact the main objective was to provide information to inform public health policy. From the patients' perspective, getting well from their illness was their major concern. Poor actual understanding of trial specific procedures was reported despite participants' satisfaction with treatment and nursing care. CONCLUSION: There is frequently a degree of overlap between research and provision of clinical care in malaria research studies. Patients may be motivated to participate to research without a good understanding of the principal objectives of the study despite a lengthy consent process. The findings suggest that use of a standard consent form following the current ICH-GCP guidelines does not result in achieving fully informed consent and the process should be revised, simplified and adapted to individual trial settings.

Maude RJ, Barkhof F, Hassan MU, Ghose A, Hossain A, Abul Faiz M, Choudhury E, Rashid R, Abu Sayeed A, Charunwatthana P et al. 2014. Magnetic resonance imaging of the brain in adults with severe falciparum malaria. Malar J, 13 (1), pp. 177. | Show Abstract | Read more

BACKGROUND: Magnetic resonance imaging (MRI) allows detailed study of structural and functional changes in the brain in patients with cerebral malaria. METHODS: In a prospective observational study in adult Bangladeshi patients with severe falciparum malaria, MRI findings in the brain were correlated with clinical and laboratory parameters, retinal photography and optic nerve sheath diameter (ONSD) ultrasound (a marker of intracranial pressure). RESULTS: Of 43 enrolled patients, 31 (72%) had coma and 12 (28%) died. MRI abnormalities were present in 79% overall with mostly mild changes in a wide range of anatomical sites. There were no differences in MRI findings between patients with cerebral and non-cerebral or fatal and non-fatal disease. Subtle diffuse cerebral swelling was common (n = 22/43), but mostly without vasogenic oedema or raised intracranial pressure (ONSD). Also seen were focal extracellular oedema (n = 11/43), cytotoxic oedema (n = 8/23) and mildly raised brain lactate on magnetic resonance spectroscopy (n = 5/14). Abnormalities were much less prominent than previously described in Malawian children. Retinal whitening was present in 36/43 (84%) patients and was more common and severe in patients with coma. CONCLUSION: Cerebral swelling is mild and not specific to coma or death in adult severe falciparum malaria. This differs markedly from African children. Retinal whitening, reflecting heterogeneous obstruction of the central nervous system microcirculation by sequestered parasites resulting in small patches of ischemia, is associated with coma and this process is likely important in the pathogenesis.

Tanomsing N, Mayxay M, Newton PN, Nosten F, Dolecek C, Hien TT, White NJ, Day NPJ, Dondorp AM, Imwong M. 2014. Genetic variability of Plasmodium malariae dihydropteroate synthase (dhps) in four Asian countries. PLoS One, 9 (4), pp. e93942. | Show Abstract | Read more

The dihydropteroate synthase (dhps) genes of 44 P. malariae strains from four Asian countries were isolated. Only a limited number of polymorphisms were observed. Comparison with homologous mutations in other Plasmodium species showed that these polymorphisms are unlikely to be associated with sulfadoxine resistance.

Chotivanich K, Tripura R, Das D, Yi P, Day NPJ, Pukrittayakamee S, Chuor CM, Socheat D, Dondorp AM, White NJ. 2014. Laboratory detection of artemisinin-resistant Plasmodium falciparum. Antimicrob Agents Chemother, 58 (6), pp. 3157-3161. | Show Abstract | Read more

Conventional 48-h in vitro susceptibility tests have low sensitivity in identifying artemisinin-resistant Plasmodium falciparum, defined phenotypically by low in vivo parasite clearance rates. We hypothesized originally that this discrepancy was explained by a loss of ring-stage susceptibility and so developed a simple field-adapted 24-h trophozoite maturation inhibition (TMI) assay focusing on the ring stage and compared it to the standard 48-h schizont maturation inhibition (WHO) test. In Pailin, western Cambodia, where artemisinin-resistant P. falciparum is prevalent, the TMI test mean (95% confidence interval) 50% inhibitory concentration (IC50) for artesunate was 6.8 (5.2 to 8.3) ng/ml compared with 1.5 (1.2 to 1.8) ng/ml for the standard 48-h WHO test (P = 0.001). TMI IC50s correlated significantly with the in vivo responses to artesunate (parasite clearance time [r = 0.44, P = 0.001] and parasite clearance half-life [r = 0.46, P = 0.001]), whereas the standard 48-h test values did not. On continuous culture of two resistant isolates, the artemisinin-resistant phenotype was lost after 6 weeks (IC50s fell from 10 and 12 ng/ml to 2.7 and 3 ng/ml, respectively). Slow parasite clearance in falciparum malaria in western Cambodia results from reduced ring-stage susceptibility.

Plewes K, Royakkers AA, Hanson J, Hasan MMU, Alam S, Ghose A, Maude RJ, Stassen PM, Charunwatthana P, Lee SJ et al. 2014. Correlation of biomarkers for parasite burden and immune activation with acute kidney injury in severe falciparum malaria. Malar J, 13 (1), pp. 91. | Show Abstract | Read more

BACKGROUND: Acute kidney injury (AKI) complicating severe Plasmodium falciparum malaria occurs in up to 40% of adult patients. The case fatality rate reaches 75% in the absence of renal replacement therapy (RRT). The precise pathophysiology of AKI in falciparum malaria remains unclear. Histopathology shows acute tubular necrosis with localization of host monocytes and parasitized red blood cells in the microvasculature. This study explored the relationship of plasma soluble urokinase-type plasminogen activator receptor (suPAR), as a proxy-measure of mononuclear cell activation, and plasma P. falciparum histidine rich protein 2 (PfHRP2), as a measure of sequestered parasite burden, with AKI in severe malaria. METHODS: Admission plasma suPAR and PfHRP2 concentrations were assessed in Bangladeshi adults with severe falciparum malaria (n=137). Patients were stratified according to AKI severity based on admission creatinine clearance. RESULTS: A total of 106 (77%) patients had AKI; 32 (23%), 42 (31%) and 32 (23%) were classified into 'mild, 'moderate' and 'severe' AKI groups, respectively. Plasma suPAR and PfHRP2 concentrations increased with AKI severity (test-for-trend P <0.0001) and correlated with other markers of renal dysfunction. Admission plasma suPAR and PfHRP2 concentrations were higher in patients who later required RRT (P <0.0001 and P=0.0004, respectively). In a multivariate analysis, both increasing suPAR and PfHRP2 were independently associated with increasing urine neutrophil gelatinase-associated lipocalin concentration, a marker of acute tubular necrosis (β=16.54 (95% CI 6.36-26.71) and β=0.07 (0.02-0.11), respectively). CONCLUSIONS: Both sequestered parasite burden and immune activation contribute to the pathogenesis of AKI in severe falciparum malaria.

White NJ, Pukrittayakamee S, Hien TT, Faiz MA, Mokuolu OA, Dondorp AM. 2014. Malaria (vol 383, pg 723, 2014) LANCET, 383 (9918), pp. 696-696. | Read more

Jamornthanyawat N, Awab GR, Tanomsing N, Pukrittayakamee S, Yamin F, Dondorp AM, Day NPJ, White NJ, Woodrow CJ, Imwong M. 2014. A population survey of the glucose-6-phosphate dehydrogenase (G6PD) 563C>T (Mediterranean) mutation in Afghanistan. PLoS One, 9 (2), pp. e88605. | Show Abstract | Read more

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common inherited enzyme defect and an important problem in areas with Plasmodium vivax infection because of the risk of haemolysis following administration of primaquine to treat the liver forms of the parasite. We undertook a genotypic survey of 713 male individuals across nine provinces of Afghanistan in which malaria is found, four in the north and five in the east. RFLP typing at nucleotide position 563 detected 40 individuals with the Mediterranean mutation 563C>T, an overall prevalence of 5.6%. This varied according to self-reported ethnicity, with prevalence in the Pashtun/Pashai group of 33/369 (8.9%) compared to 7/344 individuals in the rest of the population (2.0%; p<0.001, Chi-squared test). Multivariate analysis of ethnicity and geographical location indicated an adjusted odds ratio of 3.50 (95% CI 1.36-9.02) for the Pashtun/Pashai group, while location showed only a trend towards higher prevalence in eastern provinces (adjusted odds ratio = 1.73, 0.73-4.13). Testing of known polymorphic markers (1311C>T in exon 11, and C93T in intron XI) in a subset of 82 individuals wild-type at C563 revealed a mixture of 3 haplotypes in the background population and was consistent with data from the 1000 Genomes Project and published studies. By comparison individuals with G6PD deficiency showed a highly skewed haplotype distribution, with 95% showing the CT haplotype, a finding consistent with relatively recent appearance and positive selection of the Mediterranean variant in Afghanistan. Overall, the data confirm that the Mediterranean variant of G6PD is common in many ethnic groups in Afghanistan, indicating that screening for G6PD deficiency is required in all individuals before radical treatment of P. vivax with primaquine.

Hanson J, Lee SJ, Mohanty S, Faiz MA, Anstey NM, Price RN, Charunwatthana P, Yunus EB, Mishra SK, Tjitra E et al. 2014. Rapid clinical assessment to facilitate the triage of adults with falciparum malaria, a retrospective analysis. PLoS One, 9 (1), pp. e87020. | Show Abstract | Read more

BACKGROUND: Most adults dying from falciparum malaria will die within 48 hours of their hospitalisation. An essential component of early supportive care is the rapid identification of patients at greatest risk. In resource-poor settings, where most patients with falciparum malaria are managed, decisions regarding patient care must frequently be made using clinical evaluation alone. METHODS: We retrospectively analysed 4 studies of 1801 adults with severe falciparum malaria to determine whether the presence of simple clinical findings might assist patient triage. RESULTS: If present on admission, shock, oligo-anuria, hypo- or hyperglycaemia, an increased respiratory rate, a decreased Glasgow Coma Score and an absence of fever were independently predictive of death. The variables were used to construct a simple clinical algorithm. When applied to the 1801 patients, this algorithm's positive predictive value for survival to 48 hours was 99.4 (95% confidence interval (CI) 97.8-99.9) and for survival to discharge 96.9% (95% CI 94.3-98.5). In the 712 patients receiving artesunate, the algorithm's positive predictive value for survival to 48 hours was 100% (95% CI 97.3-100) and to discharge was 98.5% (95% CI 94.8-99.8). CONCLUSIONS: Simple clinical findings are closely linked to the pathophysiology of severe falciparum malaria in adults. A basic algorithm employing these indices can facilitate the triage of patients in settings where intensive care services are limited. Patients classified as low-risk by this algorithm can be safely managed initially on a general ward whilst awaiting senior clinical review and laboratory data.

Maude RR, Amir Hossain M, Hassan MU, Osbourne S, Langan K, Sayeed A, Karim MR, Samad R, Borooah S, Dhillon B et al. 2014. Correction: Transorbital Sonographic Evaluation of Normal Optic Nerve Sheath Diameter in Healthy Volunteers in Bangladesh PLoS ONE, 9 (1), | Read more

White NJ, Pukrittayakamee S, Hien TT, Faiz MA, Mokuolu OA, Dondorp AM. 2014. Erratum: Malaria (The Lancet (2014) 383 (723-735)) The Lancet, 383 (9918), pp. 696.

Sriboonvorakul N, Leepipatpiboon N, Dondorp AM, Pouplin T, White NJ, Tarning J, Lindegardh N. 2013. Liquid chromatographic-mass spectrometric method for simultaneous determination of small organic acids potentially contributing to acidosis in severe malaria. J Chromatogr B Analyt Technol Biomed Life Sci, 941 pp. 116-122. | Show Abstract | Read more

Acidosis is an important cause of mortality in severe falciparum malaria. Lactic acid is a major contributor to metabolic acidosis, but accounts for only one-quarter of the strong anion gap. Other unidentified organic acids have an independent strong prognostic significance for a fatal outcome. In this study, a simultaneous bio-analytical method for qualitative and quantitative assessment in plasma and urine of eight small organic acids potentially contributing to acidosis in severe malaria was developed and validated. High-throughput strong anion exchange solid-phase extraction in a 96-well plate format was used for sample preparation. Hydrophilic interaction liquid chromatography (HILIC) coupled to negative mass spectroscopy was utilized for separation and detection. Eight possible small organic acids; l-lactic acid (LA), α-hydroxybutyric acid (aHBA), β-hydroxybutyric acid (bHBA), p-hydroxyphenyllactic acid (pHPLA), malonic acid (MA), methylmalonic acid (MMA), ethylmalonic acid (EMA) and α-ketoglutaric acid (aKGA) were analyzed simultaneously using a ZIC-HILIC column with an isocratic elution containing acetonitrile and ammonium acetate buffer. This method was validated according to U.S. Food and Drug Administration guidelines with additional validation procedures for endogenous substances. Accuracy for all eight acids ranged from 93.1% to 104.0%, and the within-day and between-day precisions (i.e. relative standard deviations) were lower than 5.5% at all tested concentrations. The calibration ranges were: 2.5-2500μg/mL for LA, 0.125-125μg/mL for aHBA, 7.5-375μg/mL for bHBA, 0.1-100μg/mL for pHPLA, 1-1000μg/mL for MA, 0.25-250μg/mL for MMA, 0.25-100μg/mL for EMA, and 30-1500μg/mL for aKGA. Clinical applicability was demonstrated by analyzing plasma and urine samples from five patients with severe falciparum malaria; five acids had increased concentrations in plasma (range LA=177-1169μg/mL, aHBA=4.70-38.4μg/mL, bHBA=7.70-38.0μg/mL, pHPLA=0.900-4.30μg/mL and aKGA=30.2-32.0) and seven in urine samples (range LA=11.2-513μg/mL, aHBA=1.50-69.5μg/mL, bHBA=8.10-111μg/mL, pHPLA=4.30-27.7μg/mL, MMA=0.300-13.3μg/mL, EMA=0.300-48.1μg/mL and aKGA=30.4-107μg/mL). In conclusion, a novel bioanalytical method was developed and validated which allows for simultaneous quantification of eight small organic acids in plasma and urine. This new method may be a useful tool for the assessment of acidosis in patients with severe malaria, and other conditions complicated by acidosis.

WorldWide Antimalarial Resistance Network (WWARN) DP Study Group. 2013. The effect of dosing regimens on the antimalarial efficacy of dihydroartemisinin-piperaquine: a pooled analysis of individual patient data. PLoS Med, 10 (12), pp. e1001564. | Show Abstract | Read more

BACKGROUND: Dihydroartemisinin-piperaquine (DP) is increasingly recommended for antimalarial treatment in many endemic countries; however, concerns have been raised over its potential under dosing in young children. We investigated the influence of different dosing schedules on DP's clinical efficacy. METHODS AND FINDINGS: A systematic search of the literature was conducted to identify all studies published between 1960 and February 2013, in which patients were enrolled and treated with DP. Principal investigators were approached and invited to share individual patient data with the WorldWide Antimalarial Resistance Network (WWARN). Data were pooled using a standardised methodology. Univariable and multivariable risk factors for parasite recrudescence were identified using a Cox's regression model with shared frailty across the study sites. Twenty-four published and two unpublished studies (n = 7,072 patients) were included in the analysis. After correcting for reinfection by parasite genotyping, Kaplan-Meier survival estimates were 97.7% (95% CI 97.3%-98.1%) at day 42 and 97.2% (95% CI 96.7%-97.7%) at day 63. Overall 28.6% (979/3,429) of children aged 1 to 5 years received a total dose of piperaquine below 48 mg/kg (the lower limit recommended by WHO); this risk was 2.3-2.9-fold greater compared to that in the other age groups and was associated with reduced efficacy at day 63 (94.4% [95% CI 92.6%-96.2%], p<0.001). After adjusting for confounding factors, the mg/kg dose of piperaquine was found to be a significant predictor for recrudescence, the risk increasing by 13% (95% CI 5.0%-21%) for every 5 mg/kg decrease in dose; p = 0.002. In a multivariable model increasing the target minimum total dose of piperaquine in children aged 1 to 5 years old from 48 mg/kg to 59 mg/kg would halve the risk of treatment failure and cure at least 95% of patients; such an increment was not associated with gastrointestinal toxicity in the ten studies in which this could be assessed. CONCLUSIONS: DP demonstrates excellent efficacy in a wide range of transmission settings; however, treatment failure is associated with a lower dose of piperaquine, particularly in young children, suggesting potential for further dose optimisation.

Maude RR, Hossain MA, Hassan MU, Osbourne S, Sayeed KLA, Karim MR, Samad R, Borooah S, Dhillon B, Day NPJ et al. 2013. Transorbital sonographic evaluation of normal optic nerve sheath diameter in healthy volunteers in Bangladesh. PLoS One, 8 (12), pp. e81013. | Show Abstract | Read more

INTRODUCTION: Measurement of optic nerve sheath diameter (ONSD) by ultrasound is increasingly used as a marker to detect raised intracranial pressure (ICP). ONSD varies with age and there is no clear consensus between studies for an upper limit of normal. Knowledge of normal ONSD in a healthy population is essential to interpret this measurement. METHODS: In a prospective observational study, ONSD was measured using a 15 MHz ultrasound probe in healthy volunteers in Chittagong, Bangladesh. The aims were to determine the normal range of ONSD in healthy Bangladeshi adults and children, compare measurements in males and females, horizontal and vertical beam orientations and left and right eyes in the same individual and to determine whether ONSD varies with head circumference independent of age. RESULTS: 136 subjects were enrolled, 12.5% of whom were age 16 or under. Median ONSD was 4.41 mm with 95% of subjects in the range 4.25-4.75 mm. ONSD was bimodally distributed. There was no relationship between ONSD and age (≥4 years), gender, head circumference, and no difference in left vs right eye or horizontal vs vertical beam. CONCLUSIONS: Ultrasonographic ONSD in Bangladeshi healthy volunteers has a narrow bimodal distribution independent of age (≥4 years), gender and head circumference. ONSD >4.75 mm in this population should be considered abnormal.

Flegg JA, Guérin PJ, Nosten F, Ashley EA, Phyo AP, Dondorp AM, Fairhurst RM, Socheat D, Borrmann S, Björkman A et al. 2013. Optimal sampling designs for estimation of Plasmodium falciparum clearance rates in patients treated with artemisinin derivatives. Malar J, 12 (1), pp. 411. | Show Abstract | Read more

BACKGROUND: The emergence of Plasmodium falciparum resistance to artemisinins in Southeast Asia threatens the control of malaria worldwide. The pharmacodynamic hallmark of artemisinin derivatives is rapid parasite clearance (a short parasite half-life), therefore, the in vivo phenotype of slow clearance defines the reduced susceptibility to the drug. Measurement of parasite counts every six hours during the first three days after treatment have been recommended to measure the parasite clearance half-life, but it remains unclear whether simpler sampling intervals and frequencies might also be sufficient to reliably estimate this parameter. METHODS: A total of 2,746 parasite density-time profiles were selected from 13 clinical trials in Thailand, Cambodia, Mali, Vietnam, and Kenya. In these studies, parasite densities were measured every six hours until negative after treatment with an artemisinin derivative (alone or in combination with a partner drug). The WWARN Parasite Clearance Estimator (PCE) tool was used to estimate "reference" half-lives from these six-hourly measurements. The effect of four alternative sampling schedules on half-life estimation was investigated, and compared to the reference half-life (time zero, 6, 12, 24 (A1); zero, 6, 18, 24 (A2); zero, 12, 18, 24 (A3) or zero, 12, 24 (A4) hours and then every 12 hours). Statistical bootstrap methods were used to estimate the sampling distribution of half-lives for parasite populations with different geometric mean half-lives. A simulation study was performed to investigate a suite of 16 potential alternative schedules and half-life estimates generated by each of the schedules were compared to the "true" half-life. The candidate schedules in the simulation study included (among others) six-hourly sampling, schedule A1, schedule A4, and a convenience sampling schedule at six, seven, 24, 25, 48 and 49 hours. RESULTS: The median (range) parasite half-life for all clinical studies combined was 3.1 (0.7-12.9) hours. Schedule A1 consistently performed the best, and schedule A4 the worst, both for the individual patient estimates and for the populations generated with the bootstrapping algorithm. In both cases, the differences between the reference and alternative schedules decreased as half-life increased. In the simulation study, 24-hourly sampling performed the worst, and six-hourly sampling the best. The simulation study confirmed that more dense parasite sampling schedules are required to accurately estimate half-life for profiles with short half-life (≤ three hours) and/or low initial parasite density (≤ 10,000 per μL). Among schedules in the simulation study with six or fewer measurements in the first 48 hours, a schedule with measurements at times (time windows) of 0 (0-2), 6 (4-8), 12 (10-14), 24 (22-26), 36 (34-36) and 48 (46-50) hours, or at times 6, 7 (two samples in time window 5-8), 24, 25 (two samples during time 23-26), and 48, 49 (two samples during time 47-50) hours, until negative most accurately estimated the "true" half-life. For a given schedule, continuing sampling after two days had little effect on the estimation of half-life, provided that adequate sampling was performed in the first two days and the half-life was less than three hours. If the measured parasitaemia at two days exceeded 1,000 per μL, continued sampling for at least once a day was needed for accurate half-life estimates. CONCLUSIONS: This study has revealed important insights on sampling schedules for accurate and reliable estimation of Plasmodium falciparum half-life following treatment with an artemisinin derivative (alone or in combination with a partner drug). Accurate measurement of short half-lives (rapid clearance) requires more dense sampling schedules (with more than twice daily sampling). A more intensive sampling schedule is, therefore, recommended in locations where P. falciparum susceptibility to artemisinins is not known and the necessary resources are available. Counting parasite density at six hours is important, and less frequent sampling is satisfactory for estimating long parasite half-lives in areas where artemisinin resistance is present.

Kager LM, Weehuizen TA, Wiersinga WJ, Roelofs JJTH, Meijers JCM, Dondorp AM, van 't Veer C, van der Poll T. 2013. Endogenous α2-antiplasmin is protective during severe gram-negative sepsis (melioidosis). Am J Respir Crit Care Med, 188 (8), pp. 967-975. | Show Abstract | Read more

RATIONALE: α2-Antiplasmin (A2AP) is a major inhibitor of fibrinolysis by virtue of its capacity to inhibit plasmin. Although the fibrinolytic system is strongly affected by infection, the functional role of A2AP in the host response to sepsis is unknown. OBJECTIVES: To study the role of A2AP in melioidosis, a common form of community-acquired sepsis in Southeast Asia and Northern Australia caused by the gram-negative bacterium Burkholderia pseudomallei. METHODS: In a single-center observational study A2AP was measured in patients with culture-proven septic melioidosis. Wild-type and A2AP-deficient (A2AP(-/-)) mice were intranasally infected with B. pseudomallei to induce severe pneumosepsis (melioidosis). Parameters of inflammation and coagulation were measured, and survival studies were performed. MEASUREMENTS AND MAIN RESULTS: Patients with melioidosis showed elevated A2AP plasma levels. Likewise, A2AP levels in plasma and lung homogenates were elevated in mice infected with B. pseudomallei. A2AP-deficient (A2AP(-/-)) mice had a strongly disturbed host response during experimental melioidosis as reflected by enhanced bacterial growth at the primary site of infection accompanied by increased dissemination to distant organs. In addition, A2AP(-/-) mice showed more severe lung pathology and injury together with an increased accumulation of neutrophils and higher cytokine levels in lung tissue. A2AP deficiency further was associated with exaggerated systemic inflammation and coagulation, increased distant organ injury, and enhanced lethality. CONCLUSIONS: This study is the first to identify A2AP as a protective mediator during gram-negative (pneumo)sepsis by limiting bacterial growth, inflammation, tissue injury, and coagulation.

Hanson J, Lam SWK, Alam S, Pattnaik R, Mahanta KC, Uddin Hasan M, Mohanty S, Mishra S, Cohen S, Day N et al. 2013. The reliability of the physical examination to guide fluid therapy in adults with severe falciparum malaria: an observational study. Malar J, 12 (1), pp. 348. | Show Abstract | Read more

BACKGROUND: Adults with severe malaria frequently require intravenous fluid therapy to restore their circulating volume. However, fluid must be delivered judiciously as both under- and over-hydration increase the risk of complications and, potentially, death. As most patients will be cared for in a resource-poor setting, management guidelines necessarily recommend that physical examination should guide fluid resuscitation. However, the reliability of this strategy is uncertain. METHODS: To determine the ability of physical examination to identify hypovolaemia, volume responsiveness, and pulmonary oedema, clinical signs and invasive measures of volume status were collected independently during an observational study of 28 adults with severe malaria. RESULTS: The physical examination defined volume status poorly. Jugular venous pressure (JVP) did not correlate with intravascular volume as determined by global end diastolic volume index (GEDVI; r(s) = 0.07, p = 0.19), neither did dry mucous membranes (p = 0.85), or dry axillae (p = 0.09). GEDVI was actually higher in patients with decreased tissue turgor (p < 0.001). Poor capillary return correlated with GEDVI, but was present infrequently (7% of observations) and, therefore, insensitive. Mean arterial pressure (MAP) correlated with GEDVI (rs = 0.16, p = 0.002), but even before resuscitation patients with a low GEDVI had a preserved MAP. Anuria on admission was unrelated to GEDVI and although liberal fluid resuscitation led to a median hourly urine output of 100 ml in 19 patients who were not anuric on admission, four (21%) developed clinical pulmonary oedema subsequently. MAP was unrelated to volume responsiveness (p = 0.71), while a low JVP, dry mucous membranes, dry axillae, increased tissue turgor, prolonged capillary refill, and tachycardia all had a positive predictive value for volume responsiveness of ≤50%. Extravascular lung water ≥11 ml/kg indicating pulmonary oedema was present on 99 of the 353 times that it was assessed during the study, but was identified on less than half these occasions by tachypnoea, chest auscultation, or an elevated JVP. A clear chest on auscultation and a respiratory rate <30 breaths/minute could exclude pulmonary oedema on 82% and 72% of occasions respectively. CONCLUSIONS: Findings on physical examination correlate poorly with true volume status in adults with severe malaria and must be used with caution to guide fluid therapy. TRIAL REGISTRATION: identifier: NCT00692627.

Maude RJ, Silamut K, Plewes K, Charunwatthana P, Ho M, Abul Faiz M, Rahman R, Hossain MA, Hassan MU, Bin Yunus E et al. 2014. Randomized controlled trial of levamisole hydrochloride as adjunctive therapy in severe falciparum malaria with high parasitemia. J Infect Dis, 209 (1), pp. 120-129. | Show Abstract | Read more

BACKGROUND: Cytoadherence and sequestration of erythrocytes containing mature stages of Plasmodium falciparum are central to the pathogenesis of severe malaria. The oral anthelminthic drug levamisole inhibits cytoadherence in vitro and reduces sequestration of late-stage parasites in uncomplicated falciparum malaria treated with quinine. METHODS: Fifty-six adult patients with severe malaria and high parasitemia admitted to a referral hospital in Bangladesh were randomized to receive a single dose of levamisole hydrochloride (150 mg) or no adjuvant to antimalarial treatment with intravenous artesunate. RESULTS: Circulating late-stage parasites measured as the median area under the parasite clearance curves were 2150 (interquartile range [IQR], 0-28 025) parasites/µL × hour in patients treated with levamisole and 5489 (IQR, 192-25 848) parasites/µL × hour in controls (P = .25). The "sequestration ratios" at 6 and 12 hours for all parasite stages and changes in microvascular blood flow did not differ between treatment groups (all P > .40). The median time to normalization of plasma lactate (<2 mmol/L) was 24 (IQR, 12-30) hours with levamisole vs 28 (IQR, 12-36) hours without levamisole (P = .15). CONCLUSIONS: There was no benefit of a single-dose of levamisole hydrochloride as adjuvant to intravenous artesunate in the treatment of adults with severe falciparum malaria. Rapid parasite killing by intravenous artesunate might obscure the effects of levamisole.

Lim P, Dek D, Try V, Eastman RT, Chy S, Sreng S, Suon S, Mao S, Sopha C, Sam B et al. 2013. Ex vivo susceptibility of Plasmodium falciparum to antimalarial drugs in western, northern, and eastern Cambodia, 2011-2012: association with molecular markers. Antimicrob Agents Chemother, 57 (11), pp. 5277-5283. | Show Abstract | Read more

In 2008, dihydroartemisinin (DHA)-piperaquine (PPQ) became the first-line treatment for uncomplicated Plasmodium falciparum malaria in western Cambodia. Recent reports of increased treatment failure rates after DHA-PPQ therapy in this region suggest that parasite resistance to DHA, PPQ, or both is now adversely affecting treatment. While artemisinin (ART) resistance is established in western Cambodia, there is no evidence of PPQ resistance. To monitor for resistance to PPQ and other antimalarials, we measured drug susceptibilities for parasites collected in 2011 and 2012 from Pursat, Preah Vihear, and Ratanakiri, in western, northern, and eastern Cambodia, respectively. Using a SYBR green I fluorescence assay, we calculated the ex vivo 50% inhibitory concentrations (IC50s) of 310 parasites to six antimalarials: chloroquine (CQ), mefloquine (MQ), quinine (QN), PPQ, artesunate (ATS), and DHA. Geometric mean IC50s (GMIC50s) for all drugs (except PPQ) were significantly higher in Pursat and Preah Vihear than in Ratanakiri (P ≤ 0.001). An increased copy number of P. falciparum mdr1 (pfmdr1), an MQ resistance marker, was more prevalent in Pursat and Preah Vihear than in Ratanakiri and was associated with higher GMIC50s for MQ, QN, ATS, and DHA. An increased copy number of a chromosome 5 region (X5r), a candidate PPQ resistance marker, was detected in Pursat but was not associated with reduced susceptibility to PPQ. The ex vivo IC50 and pfmdr1 copy number are important tools in the surveillance of multidrug-resistant (MDR) parasites in Cambodia. While MDR P. falciparum is prevalent in western and northern Cambodia, there is no evidence for PPQ resistance, suggesting that DHA-PPQ treatment failures result mainly from ART resistance.

Pasaribu AP, Chokejindachai W, Sirivichayakul C, Tanomsing N, Chavez I, Tjitra E, Pasaribu S, Imwong M, White NJ, Dondorp AM. 2013. A randomized comparison of dihydroartemisinin-piperaquine and artesunate-amodiaquine combined with primaquine for radical treatment of vivax malaria in Sumatera, Indonesia. J Infect Dis, 208 (11), pp. 1906-1913. | Show Abstract | Read more

BACKGROUND: A high prevalence of chloroquine-resistant Plasmodium vivax in Indonesia has shifted first-line treatment to artemisinin-based combination therapies, combined with primaquine (PQ) for radical cure. Which combination is most effective and safe remains to be established. METHODS: We conducted a prospective open-label randomized comparison of 14 days of PQ (0.25 mg base/kg) plus either artesunate-amodiaquine (AAQ + PQ) or dihydroartemisinin-piperaquine (DHP + PQ) for the treatment of uncomplicated monoinfection P. vivax malaria in North Sumatera, Indonesia. Patients were randomized and treatments were given without prior testing for G6PD status. The primary outcome was parasitological failure at day 42. Patients were followed up to 1 year. RESULTS: Between December 2010 and April 2012, 331 patients were included. After treatment with AAQ + PQ, recurrent infection occurred in 0 of 167 patients within 42 days and in 15 of 130 (11.5%; 95% confidence interval [CI], 6.6%-18.3%) within a year. With DHP + PQ, this was 1 of 164 (0.6%; 95% CI, 0.01%-3.4%) and 13 of 143 (9.1%; 95% CI, 4.9%-15.0%), respectively (P > .2). Intravascular hemolysis occurred in 5 patients, of which 3 males were hemizygous for the G6PD-Mahidol mutation. Minor adverse events were more frequent with AAQ + PQ. CONCLUSIONS: In North Sumatera, Indonesia, AAQ and DHP, both combined with PQ, were effective for blood-stage parasite clearance of uncomplicated P. vivax malaria. Both treatments were safe, but DHP + PQ was better tolerated. CLINICAL TRIALS REGISTRATION: NCT01288820.

Dondorp AM, Ringwald P. 2013. Artemisinin resistance is a clear and present danger. Trends Parasitol, 29 (8), pp. 359-360. | Read more

Newton PN, Stepniewska K, Dondorp A, Silamut K, Chierakul W, Krishna S, Davis TME, Suputtamongkol Y, Angus B, Pukrittayakamee S et al. 2013. Prognostic indicators in adults hospitalized with falciparum malaria in Western Thailand. Malar J, 12 (1), pp. 229. | Show Abstract | Read more

BACKGROUND: Severe malaria remains a major cause of death and morbidity amongst adults in the Asiatic tropics. METHODS: A retrospective analysis of the clinical and laboratory data of 988 adult patients, hospitalized with Plasmodium falciparum malaria and prospectively recruited to malaria studies in western Thailand between 1986 and 2002, was performed to assess the factors associated with a fatal outcome. Different severity scores and classifications for defining severe malaria were compared and, using multiple logistic regression, simple models for predicting mortality developed. RESULTS: The proportion of patients fulfilling the WHO 2000 definition of severe malaria was 78.1%, and their mortality was 10%. Mortality in patients given parenteral artesunate or artemether (16/317, 5%) was lower than in those given parenteral quinine (59/442, 13%) (P < 0.001). Models using parameter sets based on WHO 1990, 2000 and Adapted AQ criteria plus blood smear parasite-stage assessment gave the best mortality prediction. A malaria prognostic index (MPI), derived from the dataset using five clinical or laboratory variables gave similar prognostic accuracy. CONCLUSIONS: The mortality of severe malaria in adults has fallen and the switch from quinine to artesunate has probably been an important contributor. Prognostic indices based on WHO 2000 definitions, and other simpler indices based on fewer variables, provide clinically useful predictions of outcome in Asian adults with severe malaria.

Kager LM, Schouten M, Wiersinga WJ, de Boer JD, Lattenist LCW, Roelofs JJTH, Meijers JCM, Levi M, Dondorp AM, Esmon CT et al. 2013. Overexpression of the endothelial protein C receptor is detrimental during pneumonia-derived gram-negative sepsis (Melioidosis). PLoS Negl Trop Dis, 7 (7), pp. e2306. | Show Abstract | Read more

BACKGROUND: The endothelial protein C receptor (EPCR) enhances anticoagulation by accelerating activation of protein C to activated protein C (APC) and mediates anti-inflammatory effects by facilitating APC-mediated signaling via protease activated receptor-1. We studied the role of EPCR in the host response during pneumonia-derived sepsis instigated by Burkholderia (B.) pseudomallei, the causative agent of melioidosis, a common form of community-acquired Gram-negative (pneumo)sepsis in South-East Asia. METHODOLOGY/PRINCIPAL FINDINGS: Soluble EPCR was measured in plasma of patients with septic culture-proven melioidosis and healthy controls. Experimental melioidosis was induced by intranasal inoculation of B. pseudomallei in wild-type (WT) mice and mice with either EPCR-overexpression (Tie2-EPCR) or EPCR-deficiency (EPCR(-/-)). Mice were sacrificed after 24, 48 or 72 hours. Organs and plasma were harvested to measure colony forming units, cellular influxes, cytokine levels and coagulation parameters. Plasma EPCR-levels were higher in melioidosis patients than in healthy controls and associated with an increased mortality. Tie2-EPCR mice demonstrated enhanced bacterial growth and dissemination to distant organs during experimental melioidosis, accompanied by increased lung damage, neutrophil influx and cytokine production, and attenuated coagulation activation. EPCR(-/-) mice had an unremarkable response to B. pseudomallei infection as compared to WT mice, except for a difference in coagulation activation in plasma. CONCLUSION/SIGNIFICANCE: Increased EPCR-levels correlate with accelerated mortality in patients with melioidosis. In mice, transgenic overexpression of EPCR aggravates outcome during Gram-negative pneumonia-derived sepsis caused by B. pseudomallei, while endogenous EPCR does not impact on the host response. These results add to a better understanding of the regulation of coagulation during severe (pneumo)sepsis.

Hendriksen ICE, Mtove G, Kent A, Gesase S, Reyburn H, Lemnge MM, Lindegardh N, Day NPJ, von Seidlein L, White NJ et al. 2013. Population pharmacokinetics of intramuscular artesunate in African children with severe malaria: implications for a practical dosing regimen. Clin Pharmacol Ther, 93 (5), pp. 443-450. | Show Abstract | Read more

Parenteral artesunate (ARS) is the drug of choice for the treatment of severe malaria. Pharmacokinetics data on intramuscular ARS are limited with respect to the main treatment group that carries the highest mortality, namely, critically ill children with severe malaria. A population pharmacokinetic study of ARS and dihydroartemisinin (DHA) was conducted from sparse sampling in 70 Tanzanian children of ages 6 months to 11 years. All the children had been admitted with severe falciparum malaria and were treated with intramuscular ARS (2.4 mg/kg at 0, 12, and 24 h). Venous plasma concentration-time profiles were characterized using nonlinear mixed-effects modeling (NONMEM). A one-compartment disposition model accurately described first-dose population pharmacokinetics of ARS and DHA. Body weight significantly affected clearance and apparent volume of distribution (P < 0.001), resulting in lower ARS and DHA exposure levels in smaller children. An adapted dosing regimen including a practical dosing table per weight band is proposed for young children based on the pharmacokinetic model.

Miotto O, Almagro-Garcia J, Manske M, Macinnis B, Campino S, Rockett KA, Amaratunga C, Lim P, Suon S, Sreng S et al. 2013. Multiple populations of artemisinin-resistant Plasmodium falciparum in Cambodia. Nat Genet, 45 (6), pp. 648-655. | Show Abstract | Read more

We describe an analysis of genome variation in 825 P. falciparum samples from Asia and Africa that identifies an unusual pattern of parasite population structure at the epicenter of artemisinin resistance in western Cambodia. Within this relatively small geographic area, we have discovered several distinct but apparently sympatric parasite subpopulations with extremely high levels of genetic differentiation. Of particular interest are three subpopulations, all associated with clinical resistance to artemisinin, which have skewed allele frequency spectra and high levels of haplotype homozygosity, indicative of founder effects and recent population expansion. We provide a catalog of SNPs that show high levels of differentiation in the artemisinin-resistant subpopulations, including codon variants in transporter proteins and DNA mismatch repair proteins. These data provide a population-level genetic framework for investigating the biological origins of artemisinin resistance and for defining molecular markers to assist in its elimination.

White NJ, Turner GDH, Day NPJ, Dondorp AM. 2013. Lethal malaria: Marchiafava and Bignami were right. J Infect Dis, 208 (2), pp. 192-198. | Show Abstract | Read more

One hundred and twenty years ago, the Italian malariologists Marchiafava and Bignami proposed that the fundamental pathological process underlying lethal falciparum malaria was microvascular obstruction. Since then, several alternative hypotheses have been proposed. These formed the basis for adjunctive interventions, which have either been ineffective or harmful. Recent evidence strongly suggests that Marchiafava and Bignami were right.

Awab GR, Pukrittayakamee S, Jamornthanyawat N, Yamin F, Dondorp AM, Day NP, White NJ, Woodrow CJ, Imwong M. 2013. Prevalence of antifolate resistance mutations in Plasmodium falciparum isolates in Afghanistan. Malar J, 12 (1), pp. 96. | Show Abstract | Read more

BACKGROUND: Artesunate plus sulphadoxine-pyrimethamine (AS+SP) is now first-line treatment for Plasmodium falciparum infection in several south Asian countries, including Afghanistan. Molecular studies provide a sensitive means to investigate the current state of drug susceptibility to the SP component, and can also provide information on the likely efficacy of other potential forms of artemisinin-combination therapy. METHODS: During the years 2007 to 2010, 120 blood spots from patients with P. falciparum malaria were obtained in four provinces of Afghanistan. PCR-based methods were used to detect drug-resistance mutations in dhfr, dhps, pfcrt and pfmdr1, as well as to determine copy number of pfmdr1. RESULTS: The majority (95.5%) of infections had a double mutation in the dhfr gene (C59R, S108N); no mutations at dhfr positions 16, 51 or 164 were seen. Most isolates were wild type across the dhps gene, but five isolates from the provinces of Kunar and Nangarhar in eastern Afghanistan had the triple mutation A437G / K540E / A581G; all five cases were successfully treated with three receiving AS+SP and two receiving dihydroartemisinin-piperaquine. All isolates showed the pfcrt SVNMT chloroquine resistance haplotype. Five of 79 isolates had the pfmdr1 N86Y mutation, while 52 had pfmdr1 Y184F; positions 1034, 1042 and 1246 were wild type in all isolates. The pfmdr1 gene was not amplified in any sample. CONCLUSIONS: This study indicates that shortly after the adoption of AS+SP as first-line treatment in Afghanistan, most parasites had a double mutation haplotype in dhfr, and a small number of isolates from eastern Afghanistan harboured a triple mutation haplotype in dhps. The impact of these mutations on the efficacy of AS+SP remains to be assessed in significant numbers of patients, but these results are clearly concerning since they suggest a higher degree of SP resistance than previously detected. Further focused molecular and clinical studies in this region are urgently required.

Hanson JP, Lam SWK, Mohanty S, Alam S, Pattnaik R, Mahanta KC, Hasan MU, Charunwatthana P, Mishra SK, Day NPJ et al. 2013. Fluid resuscitation of adults with severe falciparum malaria: effects on Acid-base status, renal function, and extravascular lung water. Crit Care Med, 41 (4), pp. 972-981. | Show Abstract | Read more

OBJECTIVE: To evaluate the efficacy and safety of liberal fluid resuscitation of adults with severe malaria. DESIGN, SETTING, PATIENTS, AND METHODS: Twenty-eight Bangladeshi and Indian adults with severe falciparum malaria received crystalloid resuscitation guided by transpulmonary thermodilution (PiCCO) in an intensive care setting. Systemic hemodynamics, microvascular indices and measures of acidosis, renal function, and pulmonary edema were followed prospectively. RESULTS: All patients were hypovolemic (global end-diastolic volume index<680 mL/m) on enrollment. Patients received a median (range) 3230 mL (390-7300) of isotonic saline in the first 6 hours and 5450 mL (710-13,720) in the first 24 hours. With resuscitation, acid-base status deteriorated in 19 of 28 (68%), and there was no significant improvement in renal function. Extravascular lung water increased in 17 of 22 liberally resuscitated patients (77%); eight of these patients developed pulmonary edema, five of whom died. All other patients survived. All patients with pulmonary edema during the study were hypovolemic or euvolemic at the time pulmonary edema developed. Plasma lactate was lower in hypovolemic patients before (rs=0.38; p=0.05) and after (rs=0.49; p=0.01) resuscitation but was the strongest predictor of mortality before (chi-square=9.9; p=0.002) and after resuscitation (chi-square=11.1; p<0.001) and correlated with the degree of visualized microvascular sequestration of parasitized erythrocytes at both time points (rs=0.55; p=0.003 and rs=0.43; p=0.03, respectively). Persisting sequestration was evident in 7 of 15 patients (47%) 48 hours after enrollment. CONCLUSIONS: Lactic acidosis--the strongest prognostic indicator in adults with severe falciparum malaria--results from sequestration of parasitized erythrocytes in the microcirculation, not from hypovolemia. Liberal fluid resuscitation has little effect on this sequestration and does not improve acid-base status or renal function. Pulmonary edema--secondary to increased pulmonary vascular permeability--is common, unpredictable, and exacerbated by fluid loading. Liberal fluid replacement of adults with severe malaria should be avoided.

Kolyva C, Kingston H, Tachtsidis I, Mohanty S, Mishra S, Patnaik R, Maude RJ, Dondorp AM, Elwell CE. 2013. Oscillations in cerebral haemodynamics in patients with falciparum malaria. Adv Exp Med Biol, 765 pp. 101-107. | Show Abstract | Read more

Spontaneous oscillations in cerebral haemodynamics studied with near-infrared spectroscopy (NIRS), become impaired in several pathological conditions. We assessed the spectral characteristics of these oscillations in 20 patients with falciparum malaria admitted to Ispat General Hospital, Rourkela, India. Monitoring included continuous frontal lobe NIRS recordings within 24 h of admission (Day 0), together with single measurements of a number of clinical and chemical markers recorded on admission. Seven patients returned for follow-up measurements on recovery (FU). A 2,048 sampling-point segment of oxygenated haemoglobin concentration ([ΔHbO(2)]) data was subjected to Fourier analysis per patient, and power spectral density was derived over the very low frequency (VLF: 0.02-0.04 Hz), low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4 Hz) bands. At Day 0, VLF spectral power was 21.1 ± 16.4, LF power 7.2 ± 4.6 and HF power 2.6 ± 5.0, with VLF power being statistically significantly higher than LF and HF (P < 0.005). VLF power tended to decrease in the severely ill patients and correlated negatively with heart rate (r = 0.57, P < 0.01), while LF power correlated positively with aural body temperature (r = 0.49, P < 0.05). In all but one of the patients who returned for FU measurements, VLF power increased after recovery. This may be related to autonomic dysfunction in severe malaria, a topic of little research to date. The present study demonstrated that application of NIRS in a resource-poor setting is feasible and has potential as a research tool.

Takala-Harrison S, Clark TG, Jacob CG, Cummings MP, Miotto O, Dondorp AM, Fukuda MM, Nosten F, Noedl H, Imwong M et al. 2013. Genetic loci associated with delayed clearance of Plasmodium falciparum following artemisinin treatment in Southeast Asia. Proc Natl Acad Sci U S A, 110 (1), pp. 240-245. | Show Abstract | Read more

The recent emergence of artemisinin-resistant Plasmodium falciparum malaria in western Cambodia could threaten prospects for malaria elimination. Identification of the genetic basis of resistance would provide tools for molecular surveillance, aiding efforts to contain resistance. Clinical trials of artesunate efficacy were conducted in Bangladesh, in northwestern Thailand near the Myanmar border, and at two sites in western Cambodia. Parasites collected from trial participants were genotyped at 8,079 single nucleotide polymorphisms (SNPs) using a P. falciparum-specific SNP array. Parasite genotypes were examined for signatures of recent positive selection and association with parasite clearance phenotypes to identify regions of the genome associated with artemisinin resistance. Four SNPs on chromosomes 10 (one), 13 (two), and 14 (one) were significantly associated with delayed parasite clearance. The two SNPs on chromosome 13 are in a region of the genome that appears to be under strong recent positive selection in Cambodia. The SNPs on chromosomes 10 and 13 lie in or near genes involved in postreplication repair, a DNA damage-tolerance pathway. Replication and validation studies are needed to refine the location of loci responsible for artemisinin resistance and to understand the mechanism behind it; however, two SNPs on chromosomes 10 and 13 may be useful markers of delayed parasite clearance in surveillance for artemisinin resistance in Southeast Asia.

Witkowski B, Khim N, Chim P, Kim S, Ke S, Kloeung N, Chy S, Duong S, Leang R, Ringwald P et al. 2013. Reduced artemisinin susceptibility of Plasmodium falciparum ring stages in western Cambodia. Antimicrob Agents Chemother, 57 (2), pp. 914-923. | Show Abstract | Read more

The declining efficacy of artemisinin derivatives against Plasmodium falciparum in western Cambodia is a major concern. The knowledge gap in the understanding of the mechanisms involved hampers designing monitoring tools. Here, we culture-adapted 20 isolates from Pailin and Ratanakiri (areas of artemisinin resistance and susceptibility in western and eastern Cambodia, respectively) and studied their in vitro response to dihydroartemisinin. No significant difference between the two sets of isolates was observed in the classical isotopic test. However, a 6-h pulse exposure to 700 nM dihydroartemisinin (ring-stage survival assay -RSA]) revealed a clear-cut geographic dichotomy. The survival rate of exposed ring-stage parasites (ring stages) was 17-fold higher in isolates from Pailin (median, 13.5%) than in those from Ratanakiri (median, 0.8%), while exposed mature stages were equally and highly susceptible (0.6% and 0.7%, respectively). Ring stages survived drug exposure by cell cycle arrest and resumed growth upon drug withdrawal. The reduced susceptibility to artemisinin in Pailin appears to be associated with an altered in vitro phenotype of ring stages from Pailin in the RSA.

Hendriksen ICE, Maiga D, Lemnge MM, Mtove G, Gesase S, Reyburn H, Lindegardh N, Day NPJ, von Seidlein L, Dondorp AM et al. 2013. Population pharmacokinetic and pharmacodynamic properties of intramuscular quinine in Tanzanian children with severe Falciparum malaria. Antimicrob Agents Chemother, 57 (2), pp. 775-783. | Show Abstract | Read more

Although artesunate is clearly superior, parenteral quinine is still used widely for the treatment of severe malaria. A loading-dose regimen has been recommended for 30 years but is still often not used. A population pharmacokinetic study was conducted with 75 Tanzanian children aged 4 months to 8 years with severe malaria who received quinine intramuscularly; 69 patients received a loading dose of 20 mg quinine dihydrochloride (salt)/kg of body weight. Twenty-one patients had plasma quinine concentrations detectable at baseline. A zero-order absorption model with one-compartment disposition pharmacokinetics described the data adequately. Body weight was the only significant covariate and was implemented as an allometric function on clearance and volume parameters. Population pharmacokinetic parameter estimates (and percent relative standard errors [%RSE]) of elimination clearance, central volume of distribution, and duration of zero-order absorption were 0.977 liters/h (6.50%), 16.7 liters (6.39%), and 1.42 h (21.5%), respectively, for a typical patient weighing 11 kg. Quinine exposure was reduced at lower body weights after standard weight-based dosing; there was 18% less exposure over 24 h in patients weighing 5 kg than in those weighing 25 kg. Maximum plasma concentrations after the loading dose were unaffected by body weight. There was no evidence of dose-related drug toxicity with the loading dosing regimen. Intramuscular quinine is rapidly and reliably absorbed in children with severe falciparum malaria. Based on these pharmacokinetic data, a loading dose of 20 mg salt/kg is recommended, provided that no loading dose was administered within 24 h and no routine dose was administered within 12 h of admission. (This study has been registered with Current Controlled Trials under registration number ISRCTN 50258054.).

Das D, Tripura R, Phyo AP, Lwin KM, Tarning J, Lee SJ, Hanpithakpong W, Stepniewska K, Menard D, Ringwald P et al. 2013. Effect of high-dose or split-dose artesunate on parasite clearance in artemisinin-resistant falciparum malaria. Clin Infect Dis, 56 (5), pp. e48-e58. | Show Abstract | Read more

BACKGROUND: The emergence of Plasmodium falciparum resistance to artemisinins on the Cambodian and Myanmar-Thai borders poses severe threats to malaria control. We investigated whether increasing or splitting the dose of the short-half-life drug artesunate improves parasite clearance in falciparum malaria in the 2 regions. METHODS: In Pailin, western Cambodia (from 2008 to 2010), and Wang Pha, northwestern Thailand (2009-2010), patients with uncomplicated falciparum malaria were randomized to oral artesunate 6 mg/kg/d as a once-daily or twice-daily dose for 7 days, or artesunate 8 mg/kg/d as a once-daily or twice-daily dose for 3 days, followed by mefloquine. Parasite clearance and recrudescence for up to 63 days of follow-up were assessed. RESULTS: A total of 159 patients were enrolled. Overall median (interquartile range [IQR]) parasitemia half-life (half-life) was 6.03 (4.89-7.28) hours in Pailin versus 3.42 (2.20-4.85) hours in Wang Pha (P = .0001). Splitting or increasing the artesunate dose did not shorten half-life in either site. Pharmacokinetic profiles of artesunate and dihydroartemisinin were similar between sites and did not correlate with half-life. Recrudescent infections occurred in 4 of 79 patients in Pailin and 5 of 80 in Wang Pha and was not different between treatment arms (P = .68). CONCLUSIONS: Increasing the artesunate treatment dose up to 8 mg/kg/d or splitting the dose does not improve parasite clearance in either artemisinin resistant or more sensitive infections with P. falciparum. Clinical Trials Registration. ISRCTN15351875.

Dondorp AM. 2013. Editorial commentary: single-dose primaquine as gametocytocidal treatment in patients with uncomplicated falciparum malaria. Clin Infect Dis, 56 (5), pp. 694-696. | Read more

Hendriksen ICE, White LJ, Veenemans J, Mtove G, Woodrow C, Amos B, Saiwaew S, Gesase S, Nadjm B, Silamut K et al. 2013. Defining falciparum-malaria-attributable severe febrile illness in moderate-to-high transmission settings on the basis of plasma PfHRP2 concentration. J Infect Dis, 207 (2), pp. 351-361. | Show Abstract | Read more

BACKGROUND: In malaria-endemic settings, asymptomatic parasitemia complicates the diagnosis of malaria. Histidine-rich protein 2 (HRP2) is produced by Plasmodium falciparum, and its plasma concentration reflects the total body parasite burden. We aimed to define the malaria-attributable fraction of severe febrile illness, using the distributions of plasma P. falciparum HRP2 (PfHRP2) concentrations from parasitemic children with different clinical presentations. METHODS: Plasma samples were collected from and peripheral blood slides prepared for 1435 children aged 6-60 months in communities and a nearby hospital in northeastern Tanzania. The study population included children with severe or uncomplicated malaria, asymptomatic carriers, and healthy control subjects who had negative results of rapid diagnostic tests. The distributions of plasma PfHRP2 concentrations among the different groups were used to model severe malaria-attributable disease. RESULTS: The plasma PfHRP2 concentration showed a close correlation with the severity of infection. PfHRP2 concentrations of >1000 ng/mL denoted a malaria-attributable fraction of severe disease of 99% (95% credible interval [CI], 96%-100%), with a sensitivity of 74% (95% CI, 72%-77%), whereas a concentration of <200 ng/mL denoted severe febrile illness of an alternative diagnosis in >10% (95% CI, 3%-27%) of patients. Bacteremia was more common among patients in the lowest and highest PfHRP2 concentration quintiles. CONCLUSIONS: The plasma PfHRP2 concentration defines malaria-attributable disease and distinguishes severe malaria from coincidental parasitemia in African children in a moderate-to-high transmission setting.

Hanson J, Dondorp AM, Day NP, White NJ. 2013. Reply to Cunnington et al. J Infect Dis, 207 (2), pp. 370-371. | Read more

Maude RJ, Hasan MU, Hossain MA, Sayeed AA, Kanti Paul S, Rahman W, Maude RR, Vaid N, Ghose A, Amin R et al. 2012. Temporal trends in severe malaria in Chittagong, Bangladesh. Malar J, 11 (1), pp. 323. | Show Abstract | Read more

BACKGROUND: Epidemiological data on malaria in Bangladesh are sparse, particularly on severe and fatal malaria. This hampers the allocation of healthcare provision in this resource-poor setting. Over 85% of the estimated 150,000-250,000 annual malaria cases in Bangladesh occur in Chittagong Division with 80% in the Chittagong Hill Tracts (CHT). Chittagong Medical College Hospital (CMCH) is the major tertiary referral hospital for severe malaria in Chittagong Division. METHODS: Malaria screening data from 22,785 inpatients in CMCH from 1999-2011 were analysed to investigate the patterns of referral, temporal trends and geographical distribution of severe malaria in Chittagong Division, Bangladesh. RESULTS: From 1999 till 2011, 2,394 malaria cases were admitted, of which 96% harboured Plasmodium falciparum and 4% Plasmodium vivax. Infection was commonest in males (67%) between 15 and 34 years of age. Seasonality of malaria incidence was marked with a single peak in P. falciparum transmission from June to August coinciding with peak rainfall, whereas P. vivax showed an additional peak in February-March possibly representing relapse infections. Since 2007 there has been a substantial decrease in the absolute number of admitted malaria cases. Case fatality in severe malaria was 18% from 2008-2011, remaining steady during this period.A travel history obtained in 226 malaria patients revealed only 33% had been to the CHT in the preceding three weeks. Of all admitted malaria patients, only 9% lived in the CHT, and none in the more remote malaria endemic regions near the Indian border. CONCLUSIONS: The overall decline in admitted malaria cases to CMCH suggests recent control measures are successful. However, there are no reliable data on the incidence of severe malaria in the CHT, the most endemic area of Bangladesh, and most of these patients do not reach tertiary health facilities. Improvement of early treatment and simple supportive care for severe malaria in remote areas and implementation of a referral system for cases requiring additional supportive care could be important contributors to further reducing malaria-attributable disease and death in Bangladesh.

Amaratunga C, Sreng S, Suon S, Phelps ES, Stepniewska K, Lim P, Zhou C, Mao S, Anderson JM, Lindegardh N et al. 2012. Artemisinin-resistant Plasmodium falciparum in Pursat province, western Cambodia: a parasite clearance rate study. Lancet Infect Dis, 12 (11), pp. 851-858. | Show Abstract | Read more

BACKGROUND: Artemisinin-resistant Plasmodium falciparum has been reported in Pailin, western Cambodia, detected as a slow parasite clearance rate in vivo. Emergence of this phenotype in western Thailand and possibly elsewhere threatens to compromise the effectiveness of all artemisinin-based combination therapies. Parasite genetics is associated with parasite clearance rate but does not account for all variation. We investigated contributions of both parasite genetics and host factors to the artemisinin-resistance phenotype in Pursat, western Cambodia. METHODS: Between June 19 and Nov 28, 2009, and June 26 and Dec 6, 2010, we enrolled patients aged 10 years or older with uncomplicated falciparum malaria, a density of asexual parasites of at least 10,000 per μL of whole blood, no symptoms or signs of severe malaria, no other cause of febrile illness, and no chronic illness. We gave participants 4 mg/kg artesunate at 0, 24, and 48 h, 15 mg/kg mefloquine at 72 h, and 10 mg/kg mefloquine at 96 h. We assessed parasite density on thick blood films every 6 h until undetectable. The parasite clearance half-life was calculated from the parasite clearance curve. We genotyped parasites with 18 microsatellite markers and patients for haemoglobin E, α-thalassaemia, and a mutation of G6PD, which encodes glucose-6-phosphate dehydrogenase. To account for the possible effects of acquired immunity on half-life, we used three surrogates for increased likelihood of exposure to P falciparum: age, sex, and place of residence. This study is registered with, number NCT00341003. FINDINGS: We assessed 3504 individuals from all six districts of Pursat province seeking treatment for malaria symptoms. We enrolled 168 patients with falciparum malaria who met inclusion criteria. The geometric mean half-life was 5·85 h (95% CI 5·54-6·18) in Pursat, similar to that reported in Pailin (p=0·109). We identified two genetically different parasite clone groups: parasite group 1 (PG1) and parasite group 2 (PG2). Non-significant increases in parasite clearance half-life were seen in patients with haemoglobin E (0·55 h; p=0·078), those of male sex (0·96 h; p=0·064), and in 2010 (0·68 h; p=0·068); PG1 was associated with a significant increase (0·79 h; p=0·033). The mean parasite heritability of half-life was 0·40 (SD 0·17). INTERPRETATION: Heritable artemisinin resistance is established in a second Cambodian province. To accurately identify parasites that are intrinsically susceptible or resistant to artemisinins, future studies should explore the effect of erythrocyte polymorphisms and specific immune responses on half-life variation. FUNDING: Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health.

Ramutton T, Hendriksen ICE, Mwanga-Amumpaire J, Mtove G, Olaosebikan R, Tshefu AK, Onyamboko MA, Karema C, Maitland K, Gomes E et al. 2012. Sequence variation does not confound the measurement of plasma PfHRP2 concentration in African children presenting with severe malaria. Malar J, 11 (1), pp. 276. | Show Abstract | Read more

BACKGROUND: Plasmodium falciparum histidine-rich protein PFHRP2 measurement is used widely for diagnosis, and more recently for severity assessment in falciparum malaria. The Pfhrp2 gene is highly polymorphic, with deletion of the entire gene reported in both laboratory and field isolates. These issues potentially confound the interpretation of PFHRP2 measurements. METHODS: Studies designed to detect deletion of Pfhrp2 and its paralog Pfhrp3 were undertaken with samples from patients in seven countries contributing to the largest hospital-based severe malaria trial (AQUAMAT). The quantitative relationship between sequence polymorphism and PFHRP2 plasma concentration was examined in samples from selected sites in Mozambique and Tanzania. RESULTS: There was no evidence for deletion of either Pfhrp2 or Pfhrp3 in the 77 samples with lowest PFHRP2 plasma concentrations across the seven countries. Pfhrp2 sequence diversity was very high with no haplotypes shared among 66 samples sequenced. There was no correlation between Pfhrp2 sequence length or repeat type and PFHRP2 plasma concentration. CONCLUSIONS: These findings indicate that sequence polymorphism is not a significant cause of variation in PFHRP2 concentration in plasma samples from African children. This justifies the further development of plasma PFHRP2 concentration as a method for assessing African children who may have severe falciparum malaria. The data also add to the existing evidence base supporting the use of rapid diagnostic tests based on PFHRP2 detection.

White NJ, Dondorp AM, Faiz A, Mishra S, Hien TT. 2012. New global estimates of malaria deaths. Lancet, 380 (9841), pp. 559-560. | Read more

Fairhurst RM, Nayyar GML, Breman JG, Hallett R, Vennerstrom JL, Duong S, Ringwald P, Wellems TE, Plowe CV, Dondorp AM. 2012. Artemisinin-resistant malaria: research challenges, opportunities, and public health implications. Am J Trop Med Hyg, 87 (2), pp. 231-241. | Show Abstract | Read more

Artemisinin-based combination therapies are the most effective drugs to treat Plasmodium falciparum malaria. Reduced sensitivity to artemisinin monotherapy, coupled with the emergence of parasite resistance to all partner drugs, threaten to place millions of patients at risk of inadequate treatment of malaria. Recognizing the significance and immediacy of this possibility, the Fogarty International Center and the National Institute of Allergy and Infectious Diseases of the U.S. National Institutes of Health convened a conference in November 2010 to bring together the diverse array of stakeholders responding to the growing threat of artemisinin resistance, including scientists from malarious countries in peril. This conference encouraged and enabled experts to share their recent unpublished data from studies that may improve our understanding of artemisinin resistance. Conference sessions addressed research priorities to forestall artemisinin resistance and fostered collaborations between field- and laboratory-based researchers and international programs, with the aim of translating new scientific evidence into public health solutions. Inspired by this conference, this review summarizes novel findings and perspectives on artemisinin resistance, approaches for translating research data into relevant public health information, and opportunities for interdisciplinary collaboration to combat artemisinin resistance.

Taylor WRJ, Hanson J, Turner GDH, White NJ, Dondorp AM. 2012. Respiratory manifestations of malaria. Chest, 142 (2), pp. 492-505. | Show Abstract | Read more

Respiratory distress develops in up to 25% of adults and 40% of children with severe falciparum malaria. Its diverse causes include respiratory compensation of metabolic acidosis, noncardiogenic pulmonary edema, concomitant pneumonia, and severe anemia. Patients with severe falciparum, vivax, and knowlesi malaria may develop acute lung injury (ALI) and ARDS, often several days after antimalarial drug treatment. ARDS rates, best characterized for severe Plasmodium falciparum, are 5% to 25% in adults and up to 29% in pregnant women; ARDS is rare in young children. ARDS pathophysiology centers on inflammatory-mediated increased capillary permeability or endothelial damage leading to diffuse alveolar damage that can continue after parasite clearance. The role of parasite sequestration in the pulmonary microvasculature is unclear, because sequestration occurs intensely in P falciparum, less so in P knowlesi, and has not been shown convincingly in P vivax. Because early markers of ALI/ARDS are lacking, fluid resuscitation in severe malaria should follow the old adage to "keep them dry." Bacteremia and hospital-acquired pneumonia can complicate severe malaria and may contribute to ALI/ARDS. Mechanical ventilation can save life in ALI/ARDS. Basic critical care facilities are increasingly available in tropical countries. The use of lung-protective ventilation has helped to reduce mortality from malaria-induced ALI/ARDS, but permissive hypercapnia in unconscious patients is not recommended because increased intracranial pressure and cerebral swelling may occur in cerebral malaria. The best antimalarial treatment of severe malaria is IV artesunate.

Hendriksen ICE, Mwanga-Amumpaire J, von Seidlein L, Mtove G, White LJ, Olaosebikan R, Lee SJ, Tshefu AK, Woodrow C, Amos B et al. 2012. Diagnosing severe falciparum malaria in parasitaemic African children: a prospective evaluation of plasma PfHRP2 measurement. PLoS Med, 9 (8), pp. e1001297. | Show Abstract | Read more

BACKGROUND: In African children, distinguishing severe falciparum malaria from other severe febrile illnesses with coincidental Plasmodium falciparum parasitaemia is a major challenge. P. falciparum histidine-rich protein 2 (PfHRP2) is released by mature sequestered parasites and can be used to estimate the total parasite burden. We investigated the prognostic significance of plasma PfHRP2 and used it to estimate the malaria-attributable fraction in African children diagnosed with severe malaria. METHODS AND FINDINGS: Admission plasma PfHRP2 was measured prospectively in African children (from Mozambique, The Gambia, Kenya, Tanzania, Uganda, Rwanda, and the Democratic Republic of the Congo) aged 1 month to 15 years with severe febrile illness and a positive P. falciparum lactate dehydrogenase (pLDH)-based rapid test in a clinical trial comparing parenteral artesunate versus quinine (the AQUAMAT trial, ISRCTN 50258054). In 3,826 severely ill children, Plasmadium falciparum PfHRP2 was higher in patients with coma (p = 0.0209), acidosis (p<0.0001), and severe anaemia (p<0.0001). Admission geometric mean (95%CI) plasma PfHRP2 was 1,611 (1,350-1,922) ng/mL in fatal cases (n = 381) versus 1,046 (991-1,104) ng/mL in survivors (n = 3,445, p<0.0001), without differences in parasitaemia as assessed by microscopy. There was a U-shaped association between log(10) plasma PfHRP2 and risk of death. Mortality increased 20% per log(10) increase in PfHRP2 above 174 ng/mL (adjusted odds ratio [AOR] 1.21, 95%CI 1.05-1.39, p = 0.009). A mechanistic model assuming a PfHRP2-independent risk of death in non-malaria illness closely fitted the observed data and showed malaria-attributable mortality less than 50% with plasma PfHRP2≤174 ng/mL. The odds ratio (OR) for death in artesunate versus quinine-treated patients was 0.61 (95%CI 0.44-0.83, p = 0.0018) in the highest PfHRP2 tertile, whereas there was no difference in the lowest tertile (OR 1.05; 95%CI 0.69-1.61; p = 0.82). A limitation of the study is that some conclusions are drawn from a mechanistic model, which is inherently dependent on certain assumptions. However, a sensitivity analysis of the model indicated that the results were robust to a plausible range of parameter estimates. Further studies are needed to validate our findings. CONCLUSIONS: Plasma PfHRP2 has prognostic significance in African children with severe falciparum malaria and provides a tool to stratify the risk of "true" severe malaria-attributable disease as opposed to other severe illnesses in parasitaemic African children.

Duenser MW, Festic E, Dondorp A, Kissoon N, Ganbat T, Kwizera A, Haniffa R, Baker T, Schultz MJ, Med ESIC. 2012. Point of care ultrasound for sepsis management in resource-limited settings: response to Via et al. INTENSIVE CARE MEDICINE, 38 (8), pp. 1408-1409. | Read more

Maude RR, Maude RJ, Ghose A, Amin MR, Islam MB, Ali M, Bari MS, Majumder MI, Wuthiekanan V, Dondorp AM et al. 2012. Seroepidemiological surveillance of Burkholderia pseudomallei in Bangladesh. Trans R Soc Trop Med Hyg, 106 (9), pp. 576-578. | Show Abstract | Read more

Melioidosis (Burkholderia pseudomallei infection) has yet to be demonstrated systematically in Bangladesh. A prospective, cross-sectional serological survey was conducted in 2010 at six Bangladeshi hospitals. Age, gender, occupation and residential address were recorded. Of 1244 patients, 359 (28.9%) were positive for B. pseudomallei by indirect haemagglutination assay. Farmers had an increased risk of seropositivity (risk ratio=1.4, 95% CI 1.0-1.8; p=0.03). There was no clear geographic clustering of seropositives. Melioidosis should be considered as a possible cause of febrile illness in Bangladesh. Further studies are needed to establish the incidence of clinical disease and distribution of environmental risk.

Kim J-R, Nandy A, Maji AK, Addy M, Dondorp AM, Day NPJ, Pukrittayakamee S, White NJ, Imwong M. 2012. Genotyping of Plasmodium vivax reveals both short and long latency relapse patterns in Kolkata. PLoS One, 7 (7), pp. e39645. | Show Abstract | Read more

BACKGROUND: The Plasmodium vivax that was once prevalent in temperate climatic zones typically had an interval between primary infection and first relapse of 7-10 months, whereas in tropical areas P.vivax infections relapse frequently at intervals of 3-6 weeks. Defining the epidemiology of these two phenotypes from temporal patterns of illness in endemic areas is difficult or impossible, particularly if they overlap. METHODS: A prospective open label comparison of chloroquine (CQ) alone versus CQ plus unobserved primaquine for either 5 days or 14 days was conducted in patients presenting with acute vivax malaria in Kolkata. Patients were followed for 15 months and primary and recurrent infections were genotyped using three polymorphic antigen and up to 8 microsatellite markers. RESULTS: 151 patients were enrolled of whom 47 (31%) had subsequent recurrent infections. Recurrence proportions were similar in the three treatment groups. Parasite genotyping revealed discrete temporal patterns of recurrence allowing differentiation of probable relapse from newly acquired infections. This suggested that 32 of the 47 recurrences were probable relapses of which 22 (69%) were genetically homologous. The majority (81%) of probable relapses occurred within three months (16 homologous, 10 heterologous) and six genetically homologous relapses (19%) were of the long latency (8-10 month interval) phenotype. CONCLUSIONS: With long follow-up to assess temporal patterns of vivax malaria recurrence, genotyping of P.vivax can be used to assess relapse rates. A 14 day unobserved course of primaquine did not prevent relapse. Genotyping indicates that long latency P.vivax is prevalent in West Bengal, and that the first relapses after long latent periods are genetically homologous. TRIAL REGISTRATION: ISRCTN14027467.

Hendriksen ICE, Ferro J, Montoya P, Chhaganlal KD, Seni A, Gomes E, Silamut K, Lee SJ, Lucas M, Chotivanich K et al. 2012. Diagnosis, clinical presentation, and in-hospital mortality of severe malaria in HIV-coinfected children and adults in Mozambique. Clin Infect Dis, 55 (8), pp. 1144-1153. | Show Abstract | Read more

BACKGROUND: Severe falciparum malaria with human immunodeficiency virus (HIV) coinfection is common in settings with a high prevalence of both diseases, but there is little information on whether HIV affects the clinical presentation and outcome of severe malaria. METHODS: HIV status was assessed prospectively in hospitalized parasitemic adults and children with severe malaria in Beira, Mozambique, as part of a clinical trial comparing parenteral artesunate versus quinine (ISRCTN50258054). Clinical signs, comorbidity, complications, and disease outcome were compared according to HIV status. RESULTS: HIV-1 seroprevalence was 11% (74/655) in children under 15 years and 72% (49/68) in adults with severe malaria. Children with HIV coinfection presented with more severe acidosis, anemia, and respiratory distress, and higher peripheral blood parasitemia and plasma Plasmodium falciparum histidine-rich protein-2 (PfHRP2). During hospitalization, deterioration in coma score, convulsions, respiratory distress, and pneumonia were more common in HIV-coinfected children, and mortality was 26% (19/74) versus 9% (53/581) in uninfected children (P < .001). In an age- and antimalarial treatment-adjusted logistic regression model, significant, independent predictors for death were renal impairment, acidosis, parasitemia, and plasma PfHRP2 concentration. CONCLUSIONS: Severe malaria in HIV-coinfected patients presents with higher parasite burden, more complications, and comorbidity, and carries a higher case fatality rate. Early identification of HIV coinfection is important for the clinical management of severe malaria.

Dondorp AM, Maude RJ, Hendriksen ICE, Day NP, White NJ. 2012. Artesunate dosing in severe falciparum malaria. J Infect Dis, 206 (4), pp. 618-619. | Read more



European Pubmed Central

Hanson J, Lam SWK, Mahanta KC, Pattnaik R, Alam S, Mohanty S, Hasan MU, Hossain A, Charunwatthana P, Chotivanich K et al. 2012. Relative contributions of macrovascular and microvascular dysfunction to disease severity in falciparum malaria. J Infect Dis, 206 (4), pp. 571-579. | Show Abstract | Read more

BACKGROUND: Sequestration of parasitized erythrocytes in the microcirculation is considered the central pathophysiological process in severe falciparum malaria. Hypovolemia with reduced oxygen delivery and microvascular obstruction have different implications for patient management; however, their relative contributions to disease severity are uncertain. METHODS: Adult patients (n = 28) with severe Plasmodium falciparum malaria were enrolled in a prospective hemodynamic study. Volume status and oxygen delivery were assessed using transpulmonary thermodilution. Microvascular sequestration was measured using orthogonal polarized spectroscopy. FINDINGS: Duration of therapy before study enrollment was correlated with the amount of directly visualized and quantitated microvascular sequestration (P = .03). The amount of sequestration correlated with plasma lactate (r(s )= 0.55; P = .003) and disease severity (r(s )= 0.41; P = .04). In patients who had received artesunate for <10 hours, sequestration was higher in fatal cases than in survivors: median (range) 45% (32-50) vs 15% (0-40); P = .03). Parasite biomass estimated from plasma P. falciparum histidine-rich protein 2 correlated positively with disease severity (r(s )= 0.48; P = .01) and was significantly higher in patients who died (P = .046). There was no relationship between oxygen delivery and disease severity (P = .64) or outcome (P = .74). INTERPRETATION: Vital organ dysfunction in severe malaria results primarily from sequestration of parasitized erythrocytes in the microvasculature rather than reduction in circulating blood volume and oxygen delivery.

Witkowski B, Sokunmalis K, Kim S, Pheaktra C, Sopheakvatey K, Kloeung N, Khim N, Duong S, Leang R, Ringwald P et al. 2012. In vitro phenotype of reduced susceptibility to artemisinin in Plasmodium falciparum isolates from western Cambodia INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES, 16 pp. E178-E178. | Read more

Dondorp A. 2012. Artemisinin resistance in falciparum malaria INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES, 16 pp. E43-E43. | Read more

Chotivanich K, Mungthin M, Ruengweerayuth R, Udomsangpetch R, Dondorp AM, Singhasivanon P, Pukrittayakamee S, White NJ. 2012. The effects of serum lipids on the in vitro activity of lumefantrine and atovaquone against Plasmodium falciparum. Malar J, 11 (1), pp. 177. | Show Abstract | Read more

BACKGROUND: Lumefantrine and atovaquone are highly lipophilic anti-malarial drugs. As a consequence absorption is increased when the drugs are taken together with a fatty meal, but the free fraction of active drug decreases in the presence of triglyceride-rich plasma lipoproteins. In this study, the consequences of lipidaemia on anti-malarial drug efficacy were assessed in vitro. METHODS: Serum was obtained from non-immune volunteers under fasting conditions and after ingestion of a high fat meal and used in standard Plasmodium falciparum in-vitro susceptibility assays. Anti-malarial drugs, including lumefantrine, atovaquone and chloroquine in five-fold dilutions (range 0.05 ng/ml-1 ug/mL) were diluted in culture medium supplemented with fasting or post-prandial 10% donor serum. The in-vitro drug susceptibility of parasite isolates was determined using the ³H-hypoxanthine uptake inhibition method and expressed as the concentration which gave 50% inhibition of hypoxanthine uptake (IC₅₀). RESULTS: Doubling plasma triglyceride concentrations (from 160 mg/dL to 320 mg/dL), resulted in an approximate doubling of the IC₅₀ for lumefantrine (191 ng/mL to 465 ng/mL, P < 0.01) and a 20-fold increase in the IC₅₀ for atovaquone (0.5 ng/mL to 12 ng/ml; P < 0.01). In contrast, susceptibility to the hydrophilic anti-malarial chloroquine did not change in relation to triglyceride content of the medium. CONCLUSIONS: Lipidaemia reduces the anti-malarial activity of lipophilic anti-malarial drugs. This is an important confounder in laboratory in vitro testing and it could have therapeutic relevance.



European Pubmed Central

Maude RJ, Socheat D, Nguon C, Saroth P, Dara P, Li G, Song J, Yeung S, Dondorp AM, Day NP et al. 2012. Optimising strategies for Plasmodium falciparum malaria elimination in Cambodia: primaquine, mass drug administration and artemisinin resistance. PLoS One, 7 (5), pp. e37166. | Show Abstract | Read more

BACKGROUND: Malaria elimination requires a variety of approaches individually optimized for different transmission settings. A recent field study in an area of low seasonal transmission in South West Cambodia demonstrated dramatic reductions in malaria parasite prevalence following both mass drug administration (MDA) and high treatment coverage of symptomatic patients with artemisinin-piperaquine plus primaquine. This study employed multiple combined strategies and it was unclear what contribution each made to the reductions in malaria. METHOD AND FINDINGS: A mathematical model fitted to the trial results was used to assess the effects of the various components of these interventions, design optimal elimination strategies, and explore their interactions with artemisinin resistance, which has recently been discovered in Western Cambodia. The modelling indicated that most of the initial reduction of P. falciparum malaria resulted from MDA with artemisinin-piperaquine. The subsequent continued decline and near elimination resulted mainly from high coverage with artemisinin-piperaquine treatment. Both these strategies were more effective with the addition of primaquine. MDA with artemisinin combination therapy (ACT) increased the proportion of artemisinin resistant infections, although much less than treatment of symptomatic cases with ACT, and this increase was slowed by adding primaquine. Artemisinin resistance reduced the effectiveness of interventions using ACT when the prevalence of resistance was very high. The main results were robust to assumptions about primaquine action, and immunity. CONCLUSIONS: The key messages of these modelling results for policy makers were: high coverage with ACT treatment can produce a long-term reduction in malaria whereas the impact of MDA is generally only short-term; primaquine enhances the effect of ACT in eliminating malaria and reduces the increase in proportion of artemisinin resistant infections; parasite prevalence is a better surveillance measure for elimination programmes than numbers of symptomatic cases; combinations of interventions are most effective and sustained efforts are crucial for successful elimination.

Smith M, Campino S, Gu Y, Clark TG, Otto TD, Maslen G, Manske M, Imwong M, Dondorp AM, Kwiatkowski DP et al. 2012. An In-Solution Hybridisation Method for the Isolation of Pathogen DNA from Human DNA-rich Clinical Samples for Analysis by NGS. Open Genomics J, 5 (1), pp. 18-29. | Show Abstract | Read more

Studies on DNA from pathogenic organisms, within clinical samples, are often complicated by the presence of large amounts of host, e.g., human DNA. Isolation of pathogen DNA from these samples would improve the efficiency of next-generation sequencing (NGS) and pathogen identification. Here we describe a solution-based hybridisation method for isolation of pathogen DNA from a mixed population. This straightforward and inexpensive technique uses probes made from whole-genome DNA and off-the-shelf reagents. In this study, Escherichia coli DNA was successfully enriched from a mixture of E.coli and human DNA. After enrichment, genome coverage following NGS was significantly higher and the evenness of coverage and GC content were unaffected. This technique was also applied to samples containing a mixture of human and Plasmodium falciparum DNA. The P.falciparum genome is particularly difficult to sequence due to its high AT content (80.6%) and repetitive nature. Post enrichment, a bias in the recovered DNA was observed, with a poorer representation of the AT-rich non-coding regions. This uneven coverage was also observed in pre-enrichment samples, but to a lesser degree. Despite the coverage bias in enriched samples, SNP (single-nucleotide polymorphism) calling in coding regions was unaffected and the majority of samples had over 90% of their coding region covered at 5× depth. This technique shows significant promise as an effective method to enrich pathogen DNA from samples with heavy human contamination, particularly when applied to GC-neutral genomes.

Phyo AP, Nkhoma S, Stepniewska K, Ashley EA, Nair S, McGready R, ler Moo C, Al-Saai S, Dondorp AM, Lwin KM et al. 2012. Emergence of artemisinin-resistant malaria on the western border of Thailand: a longitudinal study. Lancet, 379 (9830), pp. 1960-1966. | Show Abstract | Read more

BACKGROUND: Artemisinin-resistant falciparum malaria has arisen in western Cambodia. A concerted international effort is underway to contain artemisinin-resistant Plasmodium falciparum, but containment strategies are dependent on whether resistance has emerged elsewhere. We aimed to establish whether artemisinin resistance has spread or emerged on the Thailand-Myanmar (Burma) border. METHODS: In malaria clinics located along the northwestern border of Thailand, we measured six hourly parasite counts in patients with uncomplicated hyperparasitaemic falciparum malaria (≥4% infected red blood cells) who had been given various oral artesunate-containing regimens since 2001. Parasite clearance half-lives were estimated and parasites were genotyped for 93 single nucleotide polymorphisms. FINDINGS: 3202 patients were studied between 2001 and 2010. Parasite clearance half-lives lengthened from a geometric mean of 2·6 h (95% CI 2·5-2·7) in 2001, to 3·7 h (3·6-3·8) in 2010, compared with a mean of 5·5 h (5·2-5·9) in 119 patients in western Cambodia measured between 2007 and 2010. The proportion of slow-clearing infections (half-life ≥6·2 h) increased from 0·6% in 2001, to 20% in 2010, compared with 42% in western Cambodia between 2007 and 2010. Of 1583 infections genotyped, 148 multilocus parasite genotypes were identified, each of which infected between two and 13 patients. The proportion of variation in parasite clearance attributable to parasite genetics increased from 30% between 2001 and 2004, to 66% between 2007 and 2010. INTERPRETATION: Genetically determined artemisinin resistance in P falciparum emerged along the Thailand-Myanmar border at least 8 years ago and has since increased substantially. At this rate of increase, resistance will reach rates reported in western Cambodia in 2-6 years. FUNDING: The Wellcome Trust and National Institutes of Health.

Cheeseman IH, Miller BA, Nair S, Nkhoma S, Tan A, Tan JC, Al Saai S, Phyo AP, Moo CL, Lwin KM et al. 2012. A major genome region underlying artemisinin resistance in malaria. Science, 336 (6077), pp. 79-82. | Show Abstract | Read more

Evolving resistance to artemisinin-based compounds threatens to derail attempts to control malaria. Resistance has been confirmed in western Cambodia and has recently emerged in western Thailand, but is absent from neighboring Laos. Artemisinin resistance results in reduced parasite clearance rates (CRs) after treatment. We used a two-phase strategy to identify genome region(s) underlying this ongoing selective event. Geographical differentiation and haplotype structure at 6969 polymorphic single-nucleotide polymorphisms (SNPs) in 91 parasites from Cambodia, Thailand, and Laos identified 33 genome regions under strong selection. We screened SNPs and microsatellites within these regions in 715 parasites from Thailand, identifying a selective sweep on chromosome 13 that shows strong association (P = 10(-6) to 10(-12)) with slow CRs, illustrating the efficacy of targeted association for identifying the genetic basis of adaptive traits.

Dünser MW, Festic E, Dondorp A, Kissoon N, Ganbat T, Kwizera A, Haniffa R, Baker T, Schultz MJ, Global Intensive Care Working Group of European Society of Intensive Care Medicine. 2012. Recommendations for sepsis management in resource-limited settings. Intensive Care Med, 38 (4), pp. 557-574. | Show Abstract | Read more

PURPOSE: To provide clinicians practicing in resource-limited settings with a framework to improve the diagnosis and treatment of pediatric and adult patients with sepsis. METHODS: The medical literature on sepsis management was reviewed. Specific attention was paid to identify clinical evidence on sepsis management from resource-limited settings. RESULTS: Recommendations are grouped into acute and post-acute interventions. Acute interventions include liberal fluid resuscitation to achieve adequate tissue perfusion, normal heart rate and arterial blood pressure, use of epinephrine or dopamine for inadequate tissue perfusion despite fluid resuscitation, frequent measurement of arterial blood pressure in hemodynamically unstable patients, administration of hydrocortisone or prednisolone to patients requiring catecholamines, oxygen administration to achieve an oxygen saturation >90%, semi-recumbent and/or lateral position, non-invasive ventilation for increased work of breathing or hypoxemia despite oxygen therapy, timely administration of adequate antimicrobials, thorough clinical investigation for infectious source identification, fluid/tissue sampling and microbiological work-up, removal, drainage or debridement of the infectious source. Post-acute interventions include regular re-assessment of antimicrobial therapy, administration of antimicrobials for an adequate but not prolonged duration, avoidance of hypoglycemia, pharmacological or mechanical deep vein thrombosis prophylaxis, resumption of oral food intake after resuscitation and regaining of consciousness, careful use of opioids and sedatives, early mobilization, and active weaning of invasive support. Specific considerations for malaria, puerperal sepsis and HIV/AIDS patients with sepsis are included. CONCLUSION: Only scarce evidence exists for the management of pediatric and adult sepsis in resource-limited settings. The presented recommendations may help to improve sepsis management in middle- and low-income countries.

Duenser MW, Festic E, Dondorp A, Kissoon N, Ganbat T, Kwizera A, Haniffa R, Baker T, Schultz MJ, Med ESIC. 2012. Erratum to: Recommendations for sepsis management in resource-limited settings (vol 38, pg 557, 2012) INTENSIVE CARE MEDICINE, 38 (4), pp. 575-576. | Read more

von Seidlein L, Olaosebikan R, Hendriksen ICE, Lee SJ, Adedoyin OT, Agbenyega T, Nguah SB, Bojang K, Deen JL, Evans J et al. 2012. Predicting the clinical outcome of severe falciparum malaria in african children: findings from a large randomized trial. Clin Infect Dis, 54 (8), pp. 1080-1090. | Show Abstract | Read more

BACKGROUND: Data from the largest randomized, controlled trial for the treatment of children hospitalized with severe malaria were used to identify such predictors of a poor outcome from severe malaria. METHODS: African children (<15 years) with severe malaria participated in a randomized comparison of parenteral artesunate and parenteral quinine in 9 African countries. Detailed clinical assessment was performed on admission. Parasite densities were assessed in a reference laboratory. Predictors of death were examined using a multivariate logistic regression model. RESULTS: Twenty indicators of disease severity were assessed, out of which 5 (base deficit, impaired consciousness, convulsions, elevated blood urea, and underlying chronic illness) were associated independently with death. Tachypnea, respiratory distress, deep breathing, shock, prostration, low pH, hyperparasitemia, severe anemia, and jaundice were statistically significant indicators of death in the univariate analysis but not in the multivariate model. Age, glucose levels, axillary temperature, parasite density, heart rate, blood pressure, and blackwater fever were not related to death in univariate models. CONCLUSIONS: Acidosis, cerebral involvement, renal impairment, and chronic illness are key independent predictors for a poor outcome in African children with severe malaria. Mortality is markedly increased in cerebral malaria combined with acidosis. Clinical Trial Registration. ISRCTN50258054.

Ponsford MJ, Medana IM, Prapansilp P, Hien TT, Lee SJ, Dondorp AM, Esiri MM, Day NPJ, White NJ, Turner GDH. 2012. Sequestration and microvascular congestion are associated with coma in human cerebral malaria. J Infect Dis, 205 (4), pp. 663-671. | Show Abstract | Read more

The pathogenesis of coma in severe Plasmodium falciparum malaria remains poorly understood. Obstruction of the brain microvasculature because of sequestration of parasitized red blood cells (pRBCs) represents one mechanism that could contribute to coma in cerebral malaria. Quantitative postmortem microscopy of brain sections from Vietnamese adults dying of malaria confirmed that sequestration in the cerebral microvasculature was significantly higher in patients with cerebral malaria (CM; n = 21) than in patients with non-CM (n = 23). Sequestration of pRBCs and CM was also significantly associated with increased microvascular congestion by infected and uninfected erythrocytes. Clinicopathological correlation showed that sequestration and congestion were significantly associated with deeper levels of premortem coma and shorter time to death. Microvascular congestion and sequestration were highly correlated as microscopic findings but were independent predictors of a clinical diagnosis of CM. Increased microvascular congestion accompanies coma in CM, associated with parasite sequestration in the cerebral microvasculature.

Wongtanachai J, Silamut K, Day NPJ, Dondorp A, Chaisri U. 2012. Effects of antimalarial drugs on movement of Plasmodium falciparum. Southeast Asian J Trop Med Public Health, 43 (1), pp. 1-9. | Show Abstract

In vitro antimalarial drug susceptibility is conventionally assessed by the concentration dependent growth inhibition of Plasmodium in an in vitro culture system. Inhibition of the kinetic properties of the parasites could provide an alternative method to assess in vitro antimalarial drugs sensitivity. In this study we used a novel real time microscopic technique, which does not require fixation and staining of the parasite, to study the effects of antimalarial drugs on the intracellular movement of Plasmodium (P.) falciparum trophozoites. Using real time microscopy movement of P. falciparum pigment within erythrocytes was investigated before and after antimalarial drugs exposure (artesunate, quinine, and piperaquine). For artesunate, the 50% inhibition concentration (IC50) at which movement in half of the trophozoites was abolished was estimated by sigmoid curve fitting. Intra- and inter-observer agreements were also assessed. Healthy unexposed P. falciparum trophozoites in culture showed very active movement of malaria pigment. Quinine and piperaquine had no effect but artesunate did reduce pigment movement which started after 2.5 hours exposure to the drug. The mean (SD) IC50 for artesunate regarding abolishment of pigment movement was 54 (14) ng/ml. Assessments of intra- and inter-rater agreement showed good reproducibility of the technique (Kappa value 0.82 to 0.91). Abolishment of active movement of malaria pigment is an alternative approach to assess drug sensitivity for artesunate. Malaria pigment movement is abolished by artesunate early after exposure, but at concentrations higher than those inhibiting growth.

Dünser MW, Festic E, Dondorp A, Kissoon N, Ganbat T, Kwizera A, Haniffa R, Baker T, Schultz MJ. 2012. Recommendations for sepsis management in resource-limited settings Intensive Care Medicine, pp. 1-18.

Dünser MW, Festic E, Dondorp A, Kissoon N, Ganbat T, Kwizera A, Haniffa R, Baker T, Schultz MJ. 2012. Erratum to: Recommendations for sepsis management in resource-limited settings Intensive Care Medicine, pp. 1-2.

Dünser MW, Festic E, Dondorp A, Kissoon N, Ganbat T, Kwizera A, Haniffa R, Baker T, Schultz MJ. 2012. Point of care ultrasound for sepsis management in resource-limited settings: response to Via et al. Intensive Care Medicine, pp. 1-2.

Maude R, Abu Sayeed A, Beare N, Charunwatthana P, Faiz MA, Hossain A, Bin Yunus E, Hoque MG, Hasan MU, White N et al. 2011. MALARIAL RETINOPATHY IN ADULTS JOURNAL OF INFECTION, 63 (6), pp. 494-495. | Read more


Maude RJ, Hoque G, Hasan MU, Sayeed A, Akter S, Samad R, Alam B, Yunus EB, Rahman R, Rahman W et al. 2011. Timing of enteral feeding in cerebral malaria in resource-poor settings: a randomized trial. PLoS One, 6 (11), pp. e27273. | Show Abstract | Read more

BACKGROUND: Early start of enteral feeding is an established treatment strategy in intubated patients in intensive care since it reduces invasive bacterial infections and length of hospital stay. There is equipoise whether early enteral feeding is also beneficial in non-intubated patients with cerebral malaria in resource poor settings. We hypothesized that the risk of aspiration pneumonia might outweigh the potential benefits of earlier recovery and prevention of hypoglycaemia. METHOD AND FINDINGS: A randomized trial of early (day of admission) versus late (after 60 hours in adults or 36 hours in children) start of enteral feeding was undertaken in patients with cerebral malaria in Chittagong, Bangladesh from May 2008 to August 2009. The primary outcome measures were incidence of aspiration pneumonia, hypoglycaemia and coma recovery time. The trial was terminated after inclusion of 56 patients because of a high incidence of aspiration pneumonia in the early feeding group (9/27 (33%)), compared to the late feeding group (0/29 (0%)), p = 0.001). One patient in the late feeding group, and none in the early group, had hypoglycaemia during admission. There was no significant difference in overall mortality (9/27 (33%) vs 6/29 (21%), p = 0.370), but mortality was 5/9 (56%) in patients with aspiration pneumonia. CONCLUSIONS: In conclusion, early start of enteral feeding is detrimental in non-intubated patients with cerebral malaria in many resource-poor settings. Evidence gathered in resource rich settings is not necessarily transferable to resource-poor settings. TRIAL REGISTRATION: ISRCTN57488577.

Hanson J, Lam SW, Mohanty S, Alam S, Hasan MMU, Lee SJ, Schultz MJ, Charunwatthana P, Cohen S, Kabir A et al. 2011. Central venous catheter use in severe malaria: time to reconsider the World Health Organization guidelines? Malar J, 10 (1), pp. 342. | Show Abstract | Read more

BACKGROUND: To optimize the fluid status of adult patients with severe malaria, World Health Organization (WHO) guidelines recommend the insertion of a central venous catheter (CVC) and a target central venous pressure (CVP) of 0-5 cmH2O. However there are few data from clinical trials to support this recommendation. METHODS: Twenty-eight adult Indian and Bangladeshi patients admitted to the intensive care unit with severe falciparum malaria were enrolled in the study. All patients had a CVC inserted and had regular CVP measurements recorded. The CVP measurements were compared with markers of disease severity, clinical endpoints and volumetric measures derived from transpulmonary thermodilution. RESULTS: There was no correlation between the admission CVP and patient outcome (p = 0.67) or disease severity (p = 0.33). There was no correlation between the baseline CVP and the concomitant extravascular lung water (p = 0.62), global end diastolic volume (p = 0.88) or cardiac index (p = 0.44). There was no correlation between the baseline CVP and the likelihood of a patient being fluid responsive (p = 0.37). On the occasions when the CVP was in the WHO target range patients were usually hypovolaemic and often had pulmonary oedema by volumetric measures. Seven of 28 patients suffered a complication of the CVC insertion, although none were fatal. CONCLUSION: The WHO recommendation for the routine insertion of a CVC, and the maintenance of a CVP of 0-5 cmH2O in adults with severe malaria, should be reconsidered.

Paris DH, Chansamouth V, Nawtaisong P, Löwenberg EC, Phetsouvanh R, Blacksell SD, Lee SJ, Dondorp AM, van der Poll T, Newton PN et al. 2012. Coagulation and inflammation in scrub typhus and murine typhus--a prospective comparative study from Laos. Clin Microbiol Infect, 18 (12), pp. 1221-1228. | Show Abstract | Read more

Scrub typhus (caused by Orientia tsutsugamushi) and murine typhus (caused by Rickettsia typhi) cause up to 28% of febrile episodes in Thailand and Laos. The current understanding of coagulation and inflammation in the pathogenesis of these clinically very similar vasculotropic diseases is limited. This study compared human in vivo changes in 15 coagulation, inflammation and endothelial activation markers in prospectively collected admission and follow-up samples of 121 patients (55 scrub typhus, 55 murine typhus, and 11 typhus-like illness) and 51 healthy controls from Laos. As compared with controls, all but one of the markers assessed were significantly affected in typhus patients; however, the activation patterns differed significantly between scrub and murine typhus patients. The levels of markers of coagulation activation and all inflammatory cytokines, except for interleukin-12, were significantly higher in patients with scrub typhus than in those with murine typhus. In patients with murine typhus, however, the levels of endothelium-derived markers were significantly higher. Anticoagulant factors were inhibited in both typhus patient groups. This is the first study demonstrating that, in scrub typhus, in vivo coagulation activation is prominent and is related to a strong proinflammatory response, whereas in murine typhus, changes in coagulant and fibrinolytic pathways are suggestive of endothelial cell perturbation. These data suggest that, although late-stage endothelial infection is common in both diseases, the in vivo pathogenic mechanisms of R. typhi and O. tsutsugamushi could differ in the early phase of infection and may contribute to disease differentiation.

Mtove G, Amos B, Nadjm B, Hendriksen ICE, Dondorp AM, Mwambuli A, Kim DR, Ochiai RL, Clemens JD, von Seidlein L et al. 2011. Decreasing incidence of severe malaria and community-acquired bacteraemia among hospitalized children in Muheza, north-eastern Tanzania, 2006-2010. Malar J, 10 (1), pp. 320. | Show Abstract | Read more

BACKGROUND: The annual incidence and temporal trend of severe malaria and community-acquired bacteraemia during a four-year period in Muheza, Tanzania was assessed. METHODS: Data on severely ill febrile children aged 2 months to 14 years from three prospective studies conducted at Muheza District Hospital from 2006 to 2010 was pooled and analysed. On admission, each enrolled child had a thin and thick blood film and at least one rapid diagnostic test for falciparum malaria, as well as a blood culture. The annual incidence of bacteraemia and severe malaria among children coming from Muheza was calculated and their temporal trend was assessed. RESULTS: Overall, 1, 898 severe falciparum malaria and 684 bacteraemia cases were included. Of these, 1, 356 (71%) and 482 (71%), respectively, were from the referral population of Muheza. The incidence of falciparum malaria and all-cause bacteraemia in Muheza decreased five-fold and three-fold, respectively, from the first to the fourth year of surveillance (p < 0.0001). During this period, the median ages of children from Muheza admitted with severe malaria increased from 1.7 to 2.5 years (p < 0.0001). The reduction in all-cause bacteraemia was mainly driven by the 11-fold decline in the incidence of non-typhoidal salmonellosis. The annual incidences of Haemophilus influenzae and pneumococcal invasive bacterial infections decreased as well but were much fewer in number. CONCLUSIONS: These results add to the growing evidence of the decline in malaria associated with a decrease in non-typhoidal salmonellosis and possibly other bacteraemias. Malarial prevention and control strategies may provide a greater benefit than the mere reduction of malaria alone.

Dondorp AM, Fairhurst RM, Slutsker L, Macarthur JR, Breman JG, Guerin PJ, Wellems TE, Ringwald P, Newman RD, Plowe CV. 2011. The threat of artemisinin-resistant malaria. N Engl J Med, 365 (12), pp. 1073-1075. | Read more

Medana IM, Day NPJ, Sachanonta N, Mai NTH, Dondorp AM, Pongponratn E, Hien TT, White NJ, Turner GDH. 2011. Coma in fatal adult human malaria is not caused by cerebral oedema. Malar J, 10 (1), pp. 267. | Show Abstract | Read more

BACKGROUND: The role of brain oedema in the pathophysiology of cerebral malaria is controversial. Coma associated with severe Plasmodium falciparum malaria is multifactorial, but associated with histological evidence of parasitized erythrocyte sequestration and resultant microvascular congestion in cerebral vessels. To determine whether these changes cause breakdown of the blood-brain barrier and resultant perivascular or parenchymal cerebral oedema, histology, immunohistochemistry and image analysis were used to define the prevalence of histological patterns of oedema and the expression of specific molecular pathways involved in water balance in the brain in adults with fatal falciparum malaria. METHODS: The brains of 20 adult Vietnamese patients who died of severe malaria were examined for evidence of disrupted vascular integrity. Immunohistochemistry and image analysis was performed on brainstem sections for activation of the vascular endothelial growth factor (VEGF) receptor 2 and expression of the aquaporin 4 (AQP4) water channel protein. Fibrinogen immunostaining was assessed as evidence of blood-brain barrier leakage and perivascular oedema formation. Correlations were performed with clinical, biochemical and neuropathological parameters of severe malaria infection. RESULTS: The presence of oedema, plasma protein leakage and evidence of VEGF signalling were heterogeneous in fatal falciparum malaria and did not correlate with pre-mortem coma. Differences in vascular integrity were observed between brain regions with the greatest prevalence of disruption in the brainstem, compared to the cortex or midbrain. There was a statistically non-significant trend towards higher AQP4 staining in the brainstem of cases that presented with coma (P = .02). CONCLUSIONS: Histological evidence of cerebral oedema or immunohistochemical evidence of localised loss of vascular integrity did not correlate with the occurrence of pre-mortem coma in adults with fatal falciparum malaria. Enhanced expression of AQP4 water channels in the brainstem may, therefore, reflect a mix of both neuropathological or attempted neuroprotective responses to oedema formation.

Mok S, Imwong M, Mackinnon MJ, Sim J, Ramadoss R, Yi P, Mayxay M, Chotivanich K, Liong K-Y, Russell B et al. 2011. Artemisinin resistance in Plasmodium falciparum is associated with an altered temporal pattern of transcription. BMC Genomics, 12 (1), pp. 391. | Show Abstract | Read more

BACKGROUND: Artemisinin resistance in Plasmodium falciparum malaria has emerged in Western Cambodia. This is a major threat to global plans to control and eliminate malaria as the artemisinins are a key component of antimalarial treatment throughout the world. To identify key features associated with the delayed parasite clearance phenotype, we employed DNA microarrays to profile the physiological gene expression pattern of the resistant isolates. RESULTS: In the ring and trophozoite stages, we observed reduced expression of many basic metabolic and cellular pathways which suggests a slower growth and maturation of these parasites during the first half of the asexual intraerythrocytic developmental cycle (IDC). In the schizont stage, there is an increased expression of essentially all functionalities associated with protein metabolism which indicates the prolonged and thus increased capacity of protein synthesis during the second half of the resistant parasite IDC. This modulation of the P. falciparum intraerythrocytic transcriptome may result from differential expression of regulatory proteins such as transcription factors or chromatin remodeling associated proteins. In addition, there is a unique and uniform copy number variation pattern in the Cambodian parasites which may represent an underlying genetic background that contributes to the resistance phenotype. CONCLUSIONS: The decreased metabolic activities in the ring stages are consistent with previous suggestions of higher resilience of the early developmental stages to artemisinin. Moreover, the increased capacity of protein synthesis and protein turnover in the schizont stage may contribute to artemisinin resistance by counteracting the protein damage caused by the oxidative stress and/or protein alkylation effect of this drug. This study reports the first global transcriptional survey of artemisinin resistant parasites and provides insight to the complexities of the molecular basis of pathogens with drug resistance phenotypes in vivo.

Hanson J, Hasan MMU, Royakkers AA, Alam S, Charunwatthana P, Maude RJ, Douthwaite ST, Yunus EB, Mantha ML, Schultz MJ et al. 2011. Laboratory prediction of the requirement for renal replacement in acute falciparum malaria. Malar J, 10 (1), pp. 217. | Show Abstract | Read more

BACKGROUND: Acute renal failure is a common complication of severe malaria in adults, and without renal replacement therapy (RRT), it carries a poor prognosis. Even when RRT is available, delaying its initiation may increase mortality. Earlier identification of patients who will need RRT may improve outcomes. METHOD: Prospectively collected data from two intervention studies in adults with severe malaria were analysed focusing on laboratory features on presentation and their association with a later requirement for RRT. In particular, laboratory indices of acute tubular necrosis (ATN) and acute kidney injury (AKI) that are used in other settings were examined. RESULTS: Data from 163 patients were available for analysis. Whether or not the patients should have received RRT (a retrospective assessment determined by three independent reviewers) was used as the reference. Forty-three (26.4%) patients met criteria for dialysis, but only 19 (44.2%) were able to receive this intervention due to the limited availability of RRT. Patients with impaired renal function on admission (creatinine clearance < 60 ml/min) (n = 84) had their laboratory indices of ATN/AKI analysed. The plasma creatinine level had the greatest area under the ROC curve (AUC): 0.83 (95% confidence interval 0.74-0.92), significantly better than the AUCs for, urinary sodium level, the urea to creatinine ratio (UCR), the fractional excretion of urea (FeUN) and the urinary neutrophil gelatinase-associated lipocalcin (NGAL) level. The AUC for plasma creatinine was also greater than the AUC for blood urea nitrogen level, the fractional excretion of sodium (FeNa), the renal failure index (RFI), the urinary osmolality, the urine to plasma creatinine ratio (UPCR) and the creatinine clearance, although the difference for these variables did not reach statistical significance. CONCLUSIONS: In adult patients with severe malaria and impaired renal function on admission, none of the evaluated laboratory indices was superior to the plasma creatinine level when used to predict a later requirement for renal replacement therapy.

Mohanty S, Mishra SK, Patnaik R, Dutt AK, Pradhan S, Das B, Patnaik J, Mohanty AK, Lee SJ, Dondorp AM. 2011. Brain swelling and mannitol therapy in adult cerebral malaria: a randomized trial. Clin Infect Dis, 53 (4), pp. 349-355. | Show Abstract | Read more

BACKGROUND: Coma is a frequent presentation of severe malaria in adults and an important cause of death. The role of cerebral swelling in its pathogenesis, and the possible benefit of intravenous mannitol therapy to treat this, is uncertain. METHODS: A computed tomographic (CT) scan of the cerebrum and lumbar puncture with measurement of cerebrospinal fluid (CSF) pressure were performed on admission for 126 consecutive adult Indian patients with cerebral malaria. Patients with brain swelling on CT scan were randomized to adjunctive treatment with intravenous mannitol (1.5 g/kg followed by 0.5 g/kg every 8 hours; n = 30) or no adjunctive therapy (n = 31). RESULTS: On CT scan 80 (63%) of 126 patients had cerebral swelling, of whom 36 (29%) had moderate or severe swelling. Extent of brain swelling was not related to coma depth or mortality. CSF pressures were elevated (≥200 mm H(2)O) in 43 (36%) of 120 patients and correlated with CT scan findings (P for trend = .001). Mortality with mannitol therapy was 9 (30%) of 30 versus 4 (13%) of 31 without adjunctive therapy (hazard ratio, 2.4 [95% confidence interval, 0.8-7.3]; P = .11). Median coma recovery time was 90 hours (range, 22-380 hours) with mannitol versus 32 hours (range, 5-168 hours) without (P = .02). CONCLUSIONS: Brain swelling on CT scan is a common finding in adult patients with cerebral malaria but is not related to coma depth or survival. Mannitol therapy as adjunctive treatment for brain swelling in adult cerebral malaria prolongs coma duration and may be harmful.

Maude RJ, Saralamba S, Lewis A, Sherwood D, White NJ, Day NPJ, Dondorp AM, White LJ. 2011. Modelling malaria elimination on the internet. Malar J, 10 (1), pp. 191. | Show Abstract | Read more

BACKGROUND: Unprecedented efforts are underway to eliminate malaria. Mathematical modelling can help to determine the optimal strategies for malaria elimination in different epidemiological settings. This is necessary as there is limited scope for expensive and time-consuming field studies and failure of planned elimination strategies is likely to discourage ongoing investment by funders. However, there has been very little modelling of malaria elimination and little direct involvement of policymakers in its development. There is thus an urgent need for user-friendly and accessible models purpose-designed in collaboration with policymakers to answer pertinent questions arising from the field. RESULTS: An internet site is presented with a simple mathematical modelling platform for population level models of malaria elimination. It is freely accessible to all and designed to be flexible so both the platform and models can be developed through interaction with users. The site is an accessible introduction to modelling for a non-mathematical audience, and lessons learned from the project will help inform future development of mathematical models and improve communication of modelling results. Currently it hosts a simple model of strategies for malaria elimination and this will be developed, and more models added, over time. The iterative process of feedback and development will result in an educational and planning tool for non-modellers to assist with malaria elimination efforts worldwide. CONCLUSIONS: By collaboration with end users, iterative development of mathematical models of malaria elimination through this internet platform will maximize its potential as an educational and public health policy planning tool. It will also assist with preliminary optimisation of local malaria elimination strategies before commitment of valuable resources.



European Pubmed Central

Lubell Y, Riewpaiboon A, Dondorp AM, von Seidlein L, Mokuolu OA, Nansumba M, Gesase S, Kent A, Mtove G, Olaosebikan R et al. 2011. Cost-effectiveness of parenteral artesunate for treating children with severe malaria in sub-Saharan Africa. Bull World Health Organ, 89 (7), pp. 504-512. | Show Abstract | Read more

OBJECTIVE: To explore the cost-effectiveness of parenteral artesunate for the treatment of severe malaria in children and its potential impact on hospital budgets. METHODS: The costs of inpatient care of children with severe malaria were assessed in four of the 11 sites included in the African Quinine Artesunate Malaria Treatment trial, conducted with over 5400 children. The drugs, laboratory tests and intravenous fluids provided to 2300 patients from admission to discharge were recorded, as was the length of inpatient stay, to calculate the cost of inpatient care. The data were matched with pooled clinical outcomes and entered into a decision model to calculate the cost per disability-adjusted life year (DALY) averted and the cost per death averted. FINDINGS: The mean cost of treating severe malaria patients was similar in the two study groups: 63.5 United States dollars (US$) (95% confidence interval, CI: 61.7-65.2) in the quinine arm and US$ 66.5 (95% CI: 63.7-69.2) in the artesunate arm. Children treated with artesunate had 22.5% lower mortality than those treated with quinine and the same rate of neurological sequelae: (artesunate arm: 2.3 DALYs per patient; quinine arm: 3.0 DALYs per patient). Compared with quinine as a baseline, artesunate showed an incremental cost per DALY averted and an incremental cost per death averted of US$ 3.8 and US$ 123, respectively. CONCLUSION: Artesunate is a highly cost-effective and affordable alternative to quinine for treating children with severe malaria. The budgetary implications of adopting artesunate for routine use in hospital-based care are negligible.

Maude RJ, Plewes K, Dimock J, Dondorp AM. 2011. Low-cost portable fluorescein angiography. Br J Ophthalmol, 95 (9), pp. 1213-1215. | Show Abstract | Read more

Fundus fluorescein angiography has great potential as a unique non-invasive tool to investigate in vivo the microvascular pathogenesis of a wide variety of diseases affecting the central nervous system. However, because it requires a bulky and expensive tabletop retinal camera, it is normally limited to cooperative and alert seated patients in well-resourced settings. Recently completed and ongoing studies of the pathogenesis of severe malaria are using fluorescein angiography to examine in detail the postulated central role of microvascular obstruction. We describe a novel method of fluorescein angiography with a portable retinal camera that can be adapted at very low cost for use in sick patients at the bedside. This method greatly expands the scope of potential studies utilising fluorescein angiography.

Hendriksen ICE, Mtove G, Pedro AJ, Gomes E, Silamut K, Lee SJ, Mwambuli A, Gesase S, Reyburn H, Day NPJ et al. 2011. Evaluation of a PfHRP2 and a pLDH-based rapid diagnostic test for the diagnosis of severe malaria in 2 populations of African children. Clin Infect Dis, 52 (9), pp. 1100-1107. | Show Abstract | Read more

BACKGROUND: Rapid diagnostic tests (RDTs) now play an important role in the diagnosis of falciparum malaria in many countries where the disease is endemic. Although these tests have been extensively evaluated in uncomplicated falciparum malaria, reliable data on their performance for diagnosing potentially lethal severe malaria is lacking. METHODS: We compared a Plasmodium falciparum histidine-rich-protein2 (PfHRP₂)-based RDT and a Plasmodium lactate dehydrogenase (pLDH)-based RDT with routine microscopy of a peripheral blood slide and expert microscopy as a reference standard for the diagnosis of severe malaria in 1898 children who presented with severe febrile illness at 2 centers in Mozambique and Tanzania. RESULTS: The overall sensitivity, specificity, positive predictive value, and negative predictive values of the PfHRP₂-based test were 94.0%, 70.9%, 85.4%, and 86.8%, respectively, and for the pLDH-based test, the values were 88.0%, 88.3%, 93.2%, and 80.3%, respectively. At parasite counts < 1000 parasites/μL (n = 173), sensitivity of the pLDH-based test was low (45.7%), compared with that of the PfHRP₂-based test (69.9%). Both RDTs performed better than did the routine slide reading in a clinical laboratory as assessed in 1 of the centers. CONCLUSION: The evaluated PfHRP2-based RDT is an acceptable alternative to routine microscopy for diagnosing severe malaria in African children and performed better than did the evaluated pLDH-based RDT.

Dondorp AM, Fanello CI, von Seidlein L, Day NPJ, White NJ. 2011. Artesunate for severe malaria in African children Reply LANCET, 377 (9772), pp. 1154-1154. | Read more

Nantakomol D, Dondorp AM, Krudsood S, Udomsangpetch R, Pattanapanyasat K, Combes V, Grau GE, White NJ, Viriyavejakul P, Day NPJ, Chotivanich K. 2011. Circulating red cell-derived microparticles in human malaria. J Infect Dis, 203 (5), pp. 700-706. | Show Abstract | Read more

In patients with falciparum malaria, plasma concentrations of cell-derived microparticles correlate with disease severity. Using flow cytometry, we quantified red blood cell-derived microparticles (RMPs) in patients with malaria and identified the source and the factors associated with production. RMP concentrations were increased in patients with Plasmodium falciparum (n = 29; median, 457 RMPs/μL [range, 13-4,342 RMPs/μL]), Plasmodium vivax (n = 5; median, 409 RMPs/μL [range, 281-503/μL]), and Plasmodium malariae (n = 2; median, 163 RMPs/μL [range, 127-200 RMPs/μL]) compared with those in healthy subjects (n = 11; median, 8 RMPs/μL [range, 3-166 RMPs/μL]; P = .01). RMP concentrations were highest in patients with severe falciparum malaria (P = .01). Parasitized red cells produced >10 times more RMPs than did unparasitized cells, but the overall majority of RMPs still derived from uninfected red blood cells (URBCs). In cultures, RMP production increased as the parasites matured. Hemin and parasite products induced RMP production in URBCs, which was inhibited by N-acetylcysteine, suggesting heme-mediated oxidative stress as a pathway for the generation of RMPs.

Lubell Y, Staedke SG, Greenwood BM, Kamya MR, Molyneux M, Newton PN, Reyburn H, Snow RW, D'Alessandro U, English M et al. 2011. Likely health outcomes for untreated acute febrile illness in the tropics in decision and economic models; a Delphi survey. PLoS One, 6 (2), pp. e17439. | Show Abstract | Read more

BACKGROUND: Modelling is widely used to inform decisions about management of malaria and acute febrile illnesses. Most models depend on estimates of the probability that untreated patients with malaria or bacterial illnesses will progress to severe disease or death. However, data on these key parameters are lacking and assumptions are frequently made based on expert opinion. Widely diverse opinions can lead to conflicting outcomes in models they inform. METHODS AND FINDINGS: A Delphi survey was conducted with malaria experts aiming to reach consensus on key parameters for public health and economic models, relating to the outcome of untreated febrile illnesses. Survey questions were stratified by malaria transmission intensity, patient age, and HIV prevalence. The impact of the variability in opinion on decision models is illustrated with a model previously used to assess the cost-effectiveness of malaria rapid diagnostic tests. Some consensus was reached around the probability that patients from higher transmission settings with untreated malaria would progress to severe disease (median 3%, inter-quartile range (IQR) 1-5%), and the probability that a non-malaria illness required antibiotics in areas of low HIV prevalence (median 20%). Children living in low transmission areas were considered to be at higher risk of progressing to severe malaria (median 30%, IQR 10-58%) than those from higher transmission areas (median 13%, IQR 7-30%). Estimates of the probability of dying from severe malaria were high in all settings (medians 60-73%). However, opinions varied widely for most parameters, and did not converge on resurveying. CONCLUSIONS: This study highlights the uncertainty around potential consequences of untreated malaria and bacterial illnesses. The lack of consensus on most parameters, the wide range of estimates, and the impact of variability in estimates on model outputs, demonstrate the importance of sensitivity analysis for decision models employing expert opinion. Results of such models should be interpreted cautiously. The diversity of expert opinion should be recognised when policy options are debated.

Abu Sayeed A, Maude RJ, Hasan MU, Mohammed N, Hoque MG, Dondorp AM, Faiz MA. 2011. Malarial retinopathy in Bangladeshi adults. Am J Trop Med Hyg, 84 (1), pp. 141-147. | Show Abstract | Read more

To establish if assessment of malarial retinopathy in adult malaria using ophthalmoscopy by non-ophthalmologists has clinical and prognostic significance, 210 Bangladeshi adults were assessed by both direct and indirect ophthalmoscopy; 20 of 20 healthy subjects and 20 of 20 patients with vivax malaria showed no retinal changes, whereas in patients with falciparum malaria, indirect ophthalmoscopy revealed malarial retinopathy (predominantly retinal hemorrhages) in 18 of 21 (86%) fatal, 31 of 75 (41%) cerebral, 16 of 64 (25%) non-cerebral but severe, and 1 of 31 (3%) uncomplicated cases. Direct ophthalmoscopy missed retinopathy in one of these cases and found fewer retinal hemorrhages (mean difference = 3.09; 95% confidence interval = 1.50-4.68; P < 0.0001). Severity of retinopathy increased with severity of disease (P for trend < 0.0001), and renal failure, acidosis, and moderate/severe retinopathy were independent predictors of mortality by both ophthalmoscopic techniques. Direct ophthalmoscopy by non-ophthalmologists is an important clinical tool to aid diagnosis and prognosis in adults with severe malaria, and indirect ophthalmoscopy by non-ophthalmologists, although more sensitive, provides minimal additional prognostic information.

Nguyen HP, Hanson J, Bethell D, Nguyen THM, Tran THC, Ly VC, Pham PL, Dinh XS, Dondorp A, White N et al. 2011. A retrospective analysis of the haemodynamic and metabolic effects of fluid resuscitation in Vietnamese adults with severe falciparum malaria. PLoS One, 6 (10), pp. e25523. | Show Abstract | Read more

BACKGROUND: Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults. METHODS: Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation. RESULTS: 43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m(2) (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: -0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (r(s) = 0.7, p<0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO(2)/FiO(2) ratio). There was no correlation between the oxygen delivery (DO(2)) and base deficit at the 63 time-points where they were assessed simultaneously (r(s) = -0.09, p = 0.46). CONCLUSIONS: In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs.

Saralamba S, Pan-Ngum W, Maude RJ, Lee SJ, Tarning J, Lindegårdh N, Chotivanich K, Nosten F, Day NPJ, Socheat D et al. 2011. Intrahost modeling of artemisinin resistance in Plasmodium falciparum. Proc Natl Acad Sci U S A, 108 (1), pp. 397-402. | Show Abstract | Read more

Artemisinin-resistant Plasmodium falciparum malaria has emerged in western Cambodia. Resistance is characterized by prolonged in vivo parasite clearance times (PCTs) following artesunate treatment. The biological basis is unclear. The hypothesis that delayed parasite clearance results from a stage-specific reduction in artemisinin sensitivity of the circulating young asexual parasite ring stages was examined. A mathematical model was developed, describing the intrahost parasite stage-specific pharmacokinetic-pharmacodynamic relationships. Model parameters were estimated using detailed pharmacokinetic and parasite clearance data from 39 patients with uncomplicated falciparum malaria treated with artesunate from Pailin (western Cambodia) where artemisinin resistance was evident and 40 patients from Wang Pha (northwestern Thailand) where efficacy was preserved. The mathematical model reproduced the observed parasite clearance for each patient with an accurate goodness of fit (rmsd: 0.03-0.67 in log(10) scale). The parameter sets that provided the best fits with the observed in vivo data consist of a highly conserved concentration-effect relationship for the trophozoite and schizont parasite stages, but a variable relationship for the ring stages. The model-derived assessment suggests that the efficacy of artesunate on ring stage parasites is reduced significantly in Pailin. This result supports the hypothesis that artemisinin resistance mainly reflects reduced ring-stage susceptibility and predicts that doubling the frequency of dosing will accelerate clearance of artemisinin-resistant parasites.

Dondorp AM, Fanello CI, Hendriksen ICE, Gomes E, Seni A, Chhaganlal KD, Bojang K, Olaosebikan R, Anunobi N, Maitland K et al. 2010. Artesunate versus quinine in the treatment of severe falciparum malaria in African children (AQUAMAT): an open-label, randomised trial. Lancet, 376 (9753), pp. 1647-1657. | Show Abstract | Read more

BACKGROUND: Severe malaria is a major cause of childhood death and often the main reason for paediatric hospital admission in sub-Saharan Africa. Quinine is still the established treatment of choice, although evidence from Asia suggests that artesunate is associated with a lower mortality. We compared parenteral treatment with either artesunate or quinine in African children with severe malaria. METHODS: This open-label, randomised trial was undertaken in 11 centres in nine African countries. Children (<15 years) with severe falciparum malaria were randomly assigned to parenteral artesunate or parenteral quinine. Randomisation was in blocks of 20, with study numbers corresponding to treatment allocations kept inside opaque sealed paper envelopes. The trial was open label at each site, and none of the investigators or trialists, apart from for the trial statistician, had access to the summaries of treatment allocations. The primary outcome measure was in-hospital mortality, analysed by intention to treat. This trial is registered, number ISRCTN50258054. FINDINGS: 5425 children were enrolled; 2712 were assigned to artesunate and 2713 to quinine. All patients were analysed for the primary outcome. 230 (8·5%) patients assigned to artesunate treatment died compared with 297 (10·9%) assigned to quinine treatment (odds ratio [OR] stratified for study site 0·75, 95% CI 0·63-0·90; relative reduction 22·5%, 95% CI 8·1-36·9; p=0·0022). Incidence of neurological sequelae did not differ significantly between groups, but the development of coma (65/1832 [3·5%] with artesunate vs 91/1768 [5·1%] with quinine; OR 0·69 95% CI 0·49-0·95; p=0·0231), convulsions (224/2712 [8·3%] vs 273/2713 [10·1%]; OR 0·80, 0·66-0·97; p=0·0199), and deterioration of the coma score (166/2712 [6·1%] vs 208/2713 [7·7%]; OR 0·78, 0·64-0·97; p=0·0245) were all significantly less frequent in artesunate recipients than in quinine recipients. Post-treatment hypoglycaemia was also less frequent in patients assigned to artesunate than in those assigned to quinine (48/2712 [1·8%] vs 75/2713 [2·8%]; OR 0·63, 0·43-0·91; p=0·0134). Artesunate was well tolerated, with no serious drug-related adverse effects. INTERPRETATION: Artesunate substantially reduces mortality in African children with severe malaria. These data, together with a meta-analysis of all trials comparing artesunate and quinine, strongly suggest that parenteral artesunate should replace quinine as the treatment of choice for severe falciparum malaria worldwide. FUNDING: The Wellcome Trust.

Omodeo-Salè F, Cortelezzi L, Vommaro Z, Scaccabarozzi D, Dondorp AM. 2010. Dysregulation of L-arginine metabolism and bioavailability associated to free plasma heme. Am J Physiol Cell Physiol, 299 (1), pp. C148-C154. | Show Abstract | Read more

Severe Plasmodium falciparum malaria is associated with hypoargininemia, which contributes to impaired systemic and pulmonary nitric oxide (NO) production and endothelial dysfunction. Since intravascular hemolysis is an intrinsic feature of severe malaria, we investigated whether and by which mechanisms free heme [Fe(III)-protoporphyrin IX (FP)] might contribute to the dysregulation of L-arginine (L-Arg) metabolism and bioavailability. Carrier systems "y+" [or cationic amino acid transporter (CAT)] and "y+L" transport L-Arg into red blood cells (RBC), where it is hydrolyzed to ornithine and urea by arginase (isoform I) or converted to NO* and citrulline by endothelial nitric oxide synthase (eNOS). Our results show a significant and dose-dependent impairment of L-Arg transport into RBC pretreated with FP, with a strong inhibition of the system carrier y+L. Despite the impaired L-Arg influx, higher amounts of L-Arg-derived urea are produced by RBC preexposed to FP caused by activation of RBC arginase I. This activation appeared not to be mediated by oxidative modifications of the enzyme. We conclude that L-Arg transport across RBC membrane is impaired and arginase-mediated L-Arg consumption enhanced by free heme. This could contribute to reduced NO production in severe malaria.




Dondorp AM, Yeung S, White L, Nguon C, Day NPJ, Socheat D, von Seidlein L. 2010. Artemisinin resistance: current status and scenarios for containment (vol 8, pg 272, 2010) NATURE REVIEWS MICROBIOLOGY, 8 (7), pp. 530-530. | Read more

Preechapornkul P, Chotivanich K, Imwong M, Dondorp AM, Lee SJ, Day NPJ, White NJ, Pukrittayakamee S. 2010. Optimizing the culture of Plasmodium falciparum in hollow fiber bioreactors. Southeast Asian J Trop Med Public Health, 41 (4), pp. 761-769. | Show Abstract

The hollow fiber bioreactor (HFBR) is a cell culturing system allowing continuous perfusion of medium. It was designed to grow microorganisms in a dynamically altering medium mimicking change in the in vivo intravascular and extravascular compartments. The cell compartment (extra capillary space) and medium compartment (intra capillary space) are connected through pores of semipermeable fiber membranes. These membranes allow exchange of gas and nutrients. We have adapted this system for the ex vivo culture of Plasmodiumfalciparum at high parasite densities. A Thai P. falciparum isolate (TM036) cultured in RPMI, supplemented with 0.5% Albumax II, could be maintained continuously in the system by daily changes of a small volumes of medium. Under optimized conditions the HFBR cultures attained 8% parasitemia in 40% hematocrit, thereby providing a total parasite biomass of 6.0 x 10(9) parasitized erythrocytes. The main problem encountered was clogging of micropores in the hollow fiber system by cellular debris over time. Although 'reverse flushing' partly prevented this, a larger pore size might be needed to overcome this problem. The system opens new possibilities for the study of in vitro drug sensitivity under conditions mimicking in vivo pharmacokinetics, and the selection of anti-malarial drug resistance and associated parasite biological and genomic changes.

Dondorp AM, Yeung S, White L, Nguon C, Day NPJ, Socheat D, Von Seidlein L. 2010. Erratum: Artemisinin resistance: Current status and scenarios for containment (Nature Reviews Microbiology (2010) 8 (272-280)) Nature Reviews Microbiology, 8 (7), pp. 530.

Anderson TJC, Nair S, Nkhoma S, Williams JT, Imwong M, Yi P, Socheat D, Das D, Chotivanich K, Day NPJ et al. 2010. High heritability of malaria parasite clearance rate indicates a genetic basis for artemisinin resistance in western Cambodia. J Infect Dis, 201 (9), pp. 1326-1330. | Show Abstract | Read more

In western Cambodia, malaria parasites clear slowly from the blood after treatment with artemisinin derivatives, but it is unclear whether this results from parasite, host, or other factors specific to this population. We measured heritability of clearance rate by evaluating patients infected with identical or nonidentical parasite genotypes, using methods analogous to human twin studies. A substantial proportion (56%-58%) of the variation in clearance rate is explained by parasite genetics. This has 2 important implications: (1) selection with artemisinin derivatives will tend to drive resistance spread and (2) because heritability is high, the genes underlying parasite clearance rate may be identified by genome-wide association.

Imwong M, Dondorp AM, Nosten F, Yi P, Mungthin M, Hanchana S, Das D, Phyo AP, Lwin KM, Pukrittayakamee S et al. 2010. Exploring the contribution of candidate genes to artemisinin resistance in Plasmodium falciparum. Antimicrob Agents Chemother, 54 (7), pp. 2886-2892. | Show Abstract | Read more

The reduced in vivo sensitivity of Plasmodium falciparum has recently been confirmed in western Cambodia. Identifying molecular markers for artemisinin resistance is essential for monitoring the spread of the resistant phenotype and identifying the mechanisms of resistance. Four candidate genes, including the P. falciparum mdr1 (pfmdr1) gene, the P. falciparum ATPase6 (pfATPase6) gene, the 6-kb mitochondrial genome, and ubp-1, encoding a deubiquitinating enzyme, of artemisinin-resistant P. falciparum strains from western Cambodia were examined and compared to those of sensitive strains from northwestern Thailand, where the artemisinins are still very effective. The artemisinin-resistant phenotype did not correlate with pfmdr1 amplification or mutations (full-length sequencing), mutations in pfATPase6 (full-length sequencing) or the 6-kb mitochondrial genome (full-length sequencing), or ubp-1 mutations at positions 739 and 770. The P. falciparum CRT K76T mutation was present in all isolates from both study sites. The pfmdr1 copy numbers in western Cambodia were significantly lower in parasite samples obtained in 2007 than in those obtained in 2005, coinciding with a local change in drug policy replacing artesunate-mefloquine with dihydroartemisinin-piperaquine. Artemisinin resistance in western Cambodia is not linked to candidate genes, as was suggested by earlier studies.

Awab GR, Pukrittayakamee S, Imwong M, Dondorp AM, Woodrow CJ, Lee SJ, Day NPJ, Singhasivanon P, White NJ, Kaker F. 2010. Dihydroartemisinin-piperaquine versus chloroquine to treat vivax malaria in Afghanistan: an open randomized, non-inferiority, trial. Malar J, 9 (1), pp. 105. | Show Abstract | Read more

BACKGROUND: Afghanistan's national guidelines recommend chloroquine for the treatment of Plasmodium vivax infection, the parasite responsible for the majority of its malaria burden. Chloroquine resistance in P. vivax is emerging in Asia. Therapeutic responses across Afghanistan have not been evaluated in detail. METHODS: Between July 2007 and February 2009, an open-label, randomized controlled trial of chloroquine and dihydroartemisinin-piperaquine in patients aged three months and over with slide-confirmed P. vivax mono-infections was conducted. Consistent with current national guidelines, primaquine was not administered. Subjects were followed up daily during the acute phase of illness (days 0-3) and weekly until day 56. The primary endpoint was the overall cumulative parasitological failure rate at day 56 after the start of treatment, with the hypothesis being that dihydroartemisinin-piperaquine was non-inferior compared to chloroquine (Delta = 5% difference in proportion of failures). RESULTS: Of 2,182 individuals with positive blood films for P. vivax, 536 were enrolled in the trial. The day 28 cure rate was 100% in both treatment groups. Parasite clearance was more rapid with dihydroartemisinin-piperaquine than chloroquine. At day 56, there were more recurrent infections in the chloroquine arm (8.9%, 95% CI 6.0-13.1%) than the dihydroartemisinin-piperaquine arm (2.8%, 95% CI 1.4-5.8%), a difference in cumulative recurrence rate of 6.1% (2-sided 90%CI +2.6 to +9.7%). The log-rank test comparing the survival curves confirmed the superiority of dihydroartemisinin-piperaquine over chloroquine (p = 0.003). Multivariate analysis showed that a lower initial haemoglobin concentration was also independently associated with recurrence. Both regimens were well tolerated and no serious adverse events were reported. CONCLUSIONS: Chloroquine remains an efficacious treatment for the treatment of vivax malaria in Afghanistan. In a setting where radical therapy cannot be administered, dihydroartemisinin-piperaquine provides additional benefit in terms of post-treatment prophylaxis, reducing the incidence of recurrence from 4-8 weeks after treatment.

Dondorp AM, Yeung S, White L, Nguon C, Day NPJ, Socheat D, von Seidlein L. 2010. Artemisinin resistance: current status and scenarios for containment. Nat Rev Microbiol, 8 (4), pp. 272-280. | Show Abstract | Read more

Artemisinin combination therapies are the first-line treatments for uncomplicated Plasmodium falciparum malaria in most malaria-endemic countries. Recently, partial artemisinin-resistant P. falciparum malaria has emerged on the Cambodia-Thailand border. Exposure of the parasite population to artemisinin monotherapies in subtherapeutic doses for over 30 years, and the availability of substandard artemisinins, have probably been the main driving force in the selection of the resistant phenotype in the region. A multifaceted containment programme has recently been launched, including early diagnosis and appropriate treatment, decreasing drug pressure, optimising vector control, targeting the mobile population, strengthening management and surveillance systems, and operational research. Mathematical modelling can be a useful tool to evaluate possible strategies for containment.

Wiersinga WJ, Kager LM, Hovius JWR, van der Windt GJW, de Vos AF, Meijers JCM, Roelofs JJ, Dondorp A, Levi M, Day NP et al. 2010. Urokinase receptor is necessary for bacterial defense against pneumonia-derived septic melioidosis by facilitating phagocytosis. J Immunol, 184 (6), pp. 3079-3086. | Show Abstract | Read more

Urokinase receptor (urokinase-type plasminogen activator receptor [uPAR], CD87), a GPI-anchored protein, is considered to play an important role in inflammation and fibrinolysis. The Gram-negative bacterium Burkholderia pseudomallei is able to survive and replicate within leukocytes and causes melioidosis, an important cause of pneumonia-derived community-acquired sepsis in Southeast Asia. In this study, we investigated the expression and function of uPAR both in patients with septic melioidosis and in a murine model of experimental melioidosis. uPAR mRNA and surface expression was increased in patients with septic melioidosis in/on both peripheral blood monocytes and granulocytes as well as in the pulmonary compartment during experimental pneumonia-derived melioidosis in mice. uPAR-deficient mice intranasally infected with B. pseudomallei showed an enhanced growth and dissemination of B. pseudomallei when compared with wild-type mice, corresponding with increased pulmonary and hepatic inflammation. uPAR knockout mice demonstrated significantly reduced neutrophil migration toward the pulmonary compartment after inoculation with B. pseudomallei. Further in vitro experiments showed that uPAR-deficient macrophages and granulocytes display a markedly impaired phagocytosis of B. pseudomallei. Additional studies showed that uPAR deficiency did not influence hemostatic and fibrinolytic responses during severe melioidosis. These data suggest that uPAR is crucially involved in the host defense against sepsis caused by B. pseudomallei by facilitating the migration of neutrophils toward the primary site of infection and subsequently facilitating the phagocytosis of B. pseudomallei.

Hanson J, Lee SJ, Mohanty S, Faiz MA, Anstey NM, Charunwatthana P, Yunus EB, Mishra SK, Tjitra E, Price RN et al. 2010. A simple score to predict the outcome of severe malaria in adults. Clin Infect Dis, 50 (5), pp. 679-685. | Show Abstract | Read more

BACKGROUND: World Health Organization treatment guidelines recommend that adults with severe malaria be admitted to an intensive care unit (ICU). However, ICU facilities are limited in the resource-poor settings where most malaria occurs. Identification of patients at greater risk of complications may facilitate their triage and resource allocation. METHODS: With use of data from a trial conducted in Southeast Asia (n=868), a logistic regression model was built to identify independent predictors of mortality among adults with severe malaria. A scoring system based on this model was tested in the original dataset and then validated in 2 series from Bangladesh (n=188) and Vietnam (n=292). RESULTS: Acidosis (base deficit) and cerebral malaria (measured as Glasgow Coma Score) were the main independent predictors of outcome. The 5-point Coma Acidosis Malaria (CAM) score was simply derived from these 2 variables. Mortality increased steadily with increasing score. A CAM score <2 predicted survival with a positive predictive value (PPV) of 95.8% (95% confidence interval [CI], 93%- 97.7%). Of the 14 of 331 patients who died with a CAM score <2, 11 (79%) had renal failure and death occurred late after hospital admission (median, 108 h; range, 40-360 h). Substitution of plasma bicarbonate as the measure of acidosis only slightly reduced the prognostic value of the model. Use of respiratory rate was inferior, but a score <2 still predicted survival with a PPV of 92.2% (95% CI, 89.1%-94.7%). CONCLUSIONS: Patients with a CAM score <2 at hospital admission may be safely treated in a general ward, provided that renal function can be monitored.

Maude RJ, Hassan MU, Ghose A, Douthwaite ST, Faiz MA, Dondorp AM. 2010. Studies on severe malaria are still possible and essential. Clin Infect Dis, 50 (2), pp. 281-282. | Read more

Karema C, Imwong M, Fanello CI, Stepniewska K, Uwimana A, Nakeesathit S, Dondorp A, Day NP, White NJ. 2010. Molecular correlates of high-level antifolate resistance in Rwandan children with Plasmodium falciparum malaria. Antimicrob Agents Chemother, 54 (1), pp. 477-483. | Show Abstract | Read more

Antifolate drugs have an important role in the treatment of malaria. Polymorphisms in the genes encoding the dihydrofolate reductase and dihydropteroate synthetase enzymes cause resistance to the antifol and sulfa drugs, respectively. Rwanda has the highest levels of antimalarial drug resistance in Africa. We correlated the efficacy of chlorproguanil-dapsone plus artesunate (CPG-DDS+A) and amodiaquine plus sulfadoxine-pyrimethamine (AQ+SP) in children with uncomplicated malaria caused by Plasmodium falciparum parasites with pfdhfr and pfdhps mutations, which are known to confer reduced drug susceptibility, in two areas of Rwanda. In the eastern province, where the cure rates were low, over 75% of isolates had three or more pfdhfr mutations and two or three pfdhps mutations and 11% had the pfdhfr 164-Leu polymorphism. In the western province, where the cure rates were significantly higher (P < 0.001), the prevalence of multiple resistance mutations was lower and the pfdhfr I164L polymorphism was not found. The risk of treatment failure following the administration of AQ+SP more than doubled for each additional pfdhfr resistance mutation (odds ratio [OR] = 2.4; 95% confidence interval [CI] = 1.01 to 5.55; P = 0.048) and each pfdhps mutation (OR = 2.1; 95% CI = 1.21 to 3.54; P = 0.008). The risk of failure following CPG-DDS+A treatment was 2.2 times higher (95% CI = 1.34 to 3.7) for each additional pfdhfr mutation, whereas there was no association with mutations in the pfdhps gene (P = 0.13). The pfdhfr 164-Leu polymorphism is prevalent in eastern Rwanda. Antimalarial treatments with currently available antifol-sulfa combinations are no longer effective in Rwanda because of high-level resistance.

Rahman W, Chotivanich K, Silamut K, Tanomsing N, Hossain A, Faiz MA, Dondorp AM, Maude RJ. 2010. Plasmodium malariae in Bangladesh. Trans R Soc Trop Med Hyg, 104 (1), pp. 78-80. | Show Abstract | Read more

We describe a 32-year-old Bangladeshi male presenting with severe malaria caused by a mono-infection with Plasmodium malariae. Rosetting of infected and uninfected erythrocytes, a putative virulence factor in falciparum malaria, was observed in the blood slide. Severe disease caused by P. malariae is extremely rare. The patient made a rapid recovery with intravenous quinine treatment.

Löwenberg EC, Charunwatthana P, Cohen S, van den Born B-J, Meijers JCM, Yunus EB, Hassan MU, Hoque G, Maude RJ, Nuchsongsin F et al. 2010. Severe malaria is associated with a deficiency of von Willebrand factor cleaving protease, ADAMTS13. Thromb Haemost, 103 (1), pp. 181-187. | Show Abstract | Read more

Severe falciparum malaria remains a major killer in tropical countries. Central in the pathophysiology is mechanical obstruction in the microcirculation caused by cytoadherence and sequestration of parasitized erythrocytes. However, the pathogenesis of many features complicating severe malaria, including coma, renal failure and thrombocytopenia, remains incompletely understood. These disease manifestations are also key features of thrombotic thrombocytopenic purpura, a life-threatening disease strongly associated with a deficiency of the von Willebrand factor (VWF) cleaving protease, ADAMTS13. We measured plasma ADAMTS13 activity, VWF antigen and VWF propeptide levels in 30 patients with severe falciparum malaria, 12 patients with uncomplicated falciparum malaria and 14 healthy Bangladeshi controls. In patients with severe malaria ADAMTS13 activity levels were markedly decreased in comparison to normal controls (mean [95%CI]: 23% [20-26] vs. 64% [55-72]) and VWF antigen and propeptide concentrations were significantly elevated (VWF antigen: 439% [396-481] vs. 64% [46-83]; VWF propeptide: 576% [481-671] vs. 69% [59-78]). In uncomplicated malaria VWF levels were also increased compared to healthy controls but ADAMTS13 activity was normal. The results suggest that decreased ADAMTS13 activity in combination with increased VWF concentrations may contribute to the complications in severe malaria.

Maude RJ, Lubell Y, Socheat D, Yeung S, Saralamba S, Pongtavornpinyo W, Cooper BS, Dondorp AM, White NJ, White LJ. 2010. The role of mathematical modelling in guiding the science and economics of malaria elimination. Int Health, 2 (4), pp. 239-246. | Show Abstract | Read more

Unprecedented efforts are now underway to eliminate malaria from many regions. Despite the enormous financial resources committed, if malaria elimination is perceived as failing it is likely that this funding will not be sustained. It is imperative that methods are developed to use the limited data available to design site-specific, cost-effective elimination programmes. Mathematical modelling is a way of including mechanistic understanding to use available data to make predictions. Different strategies can be evaluated much more rapidly than is possible through trial and error in the field. Mathematical modelling has great potential as a tool to guide and inform current elimination efforts. Economic modelling weighs costs against characterised effects or predicted benefits in order to determine the most cost-efficient strategy but has traditionally used static models of disease not suitable for elimination. Dynamic mathematical modelling and economic modelling techniques need to be combined to contribute most effectively to ongoing policy discussions. We review the role of modelling in previous malaria control efforts as well as the unique nature of elimination and the consequent need for its explicit modelling, and emphasise the importance of good disease surveillance. The difficulties and complexities of economic evaluation of malaria control, particularly the end stages of elimination, are discussed.

Monatrakul P, Mungthin M, Dondorp AM, Krudsood S, Udomsangpetch R, Wilairatana P, White NJ, Chotivanich K. 2010. Modulating effects of plasma containing anti-malarial antibodies on in vitro anti-malarial drug susceptibility in Plasmodium falciparum. Malar J, 9 (1), pp. 326. | Show Abstract | Read more

BACKGROUND: The efficacy of anti-malarial drugs is determined by the level of parasite susceptibility, anti-malarial drug bioavailability and pharmacokinetics, and host factors including immunity. Host immunity improves the in vivo therapeutic efficacy of anti-malarial drugs, but the mechanism and magnitude of this effect has not been characterized. This study characterized the effects of 'immune' plasma to Plasmodium falciparumon the in vitro susceptibility of P. falciparum to anti-malarial drugs. METHODS: Titres of antibodies against blood stage antigens (mainly the ring-infected erythrocyte surface antigen [RESA]) were measured in plasma samples obtained from Thai patients with acute falciparum malaria. 'Immune' plasma was selected and its effects on in vitro parasite growth and multiplication of the Thai P. falciparum laboratory strain TM267 were assessed by light microscopy. The in vitro susceptibility to quinine and artesunate was then determined in the presence and absence of 'immune' plasma using the 3H-hypoxanthine uptake inhibition method. Drug susceptibility was expressed as the concentrations causing 50% and 90% inhibition (IC50 and IC90), of 3H-hypoxanthine uptake. RESULTS: Incubation with 'immune' plasma reduced parasite maturation and decreased parasite multiplication in a dose dependent manner. 3H-hypoxanthine incorporation after incubation with 'immune' plasma was decreased significantly compared to controls (median [range]; 181.5 [0 to 3,269] cpm versus 1,222.5 [388 to 5,932] cpm) (p= 0.001). As a result 'immune' plasma reduced apparent susceptibility to quinine substantially; median (range) IC50 6.4 (0.5 to 23.8) ng/ml versus 221.5 (174.4 to 250.4) ng/ml (p = 0.02), and also had a borderline effect on artesunate susceptibility; IC50 0.2 (0.02 to 0.3) ng/ml versus 0.8 (0.2 to 2.3) ng/ml (p = 0.08). Effects were greatest at low concentrations, changing the shape of the concentration-effect relationship. IC90 values were not significantly affected; median (range) IC90 448.0 (65 to > 500) ng/ml versus 368.8 (261 to 501) ng/ml for quinine (p > 0.05) and 17.0 (0.1 to 29.5) ng/ml versus 7.6 (2.3 to 19.5) ng/ml for artesunate (p = 0.4). CONCLUSIONS: 'Immune' plasma containing anti-malarial antibodies inhibits parasite development and multiplication and increases apparent in vitro anti-malarial drug susceptibility of P. falciparum. The IC90 was much less affected than the IC50 measurement.

White NJ, Turner GDH, Medana IM, Dondorp AM, Day NPJ. 2010. The murine cerebral malaria phenomenon. Trends Parasitol, 26 (1), pp. 11-15. | Show Abstract | Read more

P.berghei ANKA infection in CBA or CB57BL/6 mice is used widely as a murine 'model' of human cerebral malaria (HCM), despite markedly different histopathological features. The pathology of the murine model is characterised by marked inflammation with little or no intracerebral sequestration of parasitised erythrocytes, whereas HCM is associated with intense intracerebral sequestration, often with little inflammatory response. There are now more than ten times as many studies each year of the murine model than on HCM. Of 48 adjunctive interventions evaluated in the murine model, 44 (92%) were successful, compared with only 1 (6%) of 17 evaluated in HCM during the same period. The value of the mouse model in identifying pathological processes or therapeutic interventions in human cerebral malaria is questionable.

Dondorp AM, Nosten F, White NJ. 2009. Artemisinin Resistance in Plasmodium falciparum Malaria REPLY NEW ENGLAND JOURNAL OF MEDICINE, 361 (18), pp. 1808-1808.

Dondorp AM, Nosten F, Yi P, Das D, Phyo AP, Tarning J, Lwin KM, Ariey F, Hanpithakong W, Lee SJ et al. 2009. Artemisinin Resistance in Plasmodium falciparum Malaria (vol 361, pg 455, 2009) NEW ENGLAND JOURNAL OF MEDICINE, 361 (17), pp. 1714-1714. | Read more

Dondorp AM, Nosten F, Yi P, Das D, Phyo AP, Tarning J, Lwin KM, Ariey F, Hanpithakpong W, Lee SJ et al. 2009. Artemisinin resistance in Plasmodium falciparum malaria. N Engl J Med, 361 (5), pp. 455-467. | Show Abstract | Read more

BACKGROUND: Artemisinin-based combination therapies are the recommended first-line treatments of falciparum malaria in all countries with endemic disease. There are recent concerns that the efficacy of such therapies has declined on the Thai-Cambodian border, historically a site of emerging antimalarial-drug resistance. METHODS: In two open-label, randomized trials, we compared the efficacies of two treatments for uncomplicated falciparum malaria in Pailin, western Cambodia, and Wang Pha, northwestern Thailand: oral artesunate given at a dose of 2 mg per kilogram of body weight per day, for 7 days, and artesunate given at a dose of 4 mg per kilogram per day, for 3 days, followed by mefloquine at two doses totaling 25 mg per kilogram. We assessed in vitro and in vivo Plasmodium falciparum susceptibility, artesunate pharmacokinetics, and molecular markers of resistance. RESULTS: We studied 40 patients in each of the two locations. The overall median parasite clearance times were 84 hours (interquartile range, 60 to 96) in Pailin and 48 hours (interquartile range, 36 to 66) in Wang Pha (P<0.001). Recrudescence confirmed by means of polymerase-chain-reaction assay occurred in 6 of 20 patients (30%) receiving artesunate monotherapy and 1 of 20 (5%) receiving artesunate-mefloquine therapy in Pailin, as compared with 2 of 20 (10%) and 1 of 20 (5%), respectively, in Wang Pha (P=0.31). These markedly different parasitologic responses were not explained by differences in age, artesunate or dihydroartemisinin pharmacokinetics, results of isotopic in vitro sensitivity tests, or putative molecular correlates of P. falciparum drug resistance (mutations or amplifications of the gene encoding a multidrug resistance protein [PfMDR1] or mutations in the gene encoding sarco-endoplasmic reticulum calcium ATPase6 [PfSERCA]). Adverse events were mild and did not differ significantly between the two treatment groups. CONCLUSIONS: P. falciparum has reduced in vivo susceptibility to artesunate in western Cambodia as compared with northwestern Thailand. Resistance is characterized by slow parasite clearance in vivo without corresponding reductions on conventional in vitro susceptibility testing. Containment measures are urgently needed. ( number, NCT00493363, and Current Controlled Trials number, ISRCTN64835265.)

Maude RJ, Beare NAV, Abu Sayeed A, Chang CC, Charunwatthana P, Faiz MA, Hossain A, Yunus EB, Hoque MG, Hasan MU et al. 2009. The spectrum of retinopathy in adults with Plasmodium falciparum malaria. Trans R Soc Trop Med Hyg, 103 (7), pp. 665-671. | Show Abstract | Read more

A specific retinopathy has been described in African children with cerebral malaria, but in adults this has not been extensively studied. Since the structure and function of the retinal vasculature greatly resembles the cerebral vasculature, study of retinal changes can reveal insights into the pathophysiology of cerebral malaria. A detailed observational study of malarial retinopathy in Bangladeshi adults was performed using high-definition portable retinal photography. Retinopathy was present in 17/27 adults (63%) with severe malaria and 14/20 adults (70%) with cerebral malaria. Moderate or severe retinopathy was more frequent in cerebral malaria (11/20, 55%) than in uncomplicated malaria (3/15, 20%; P=0.039), bacterial sepsis (0/5, 0%; P=0.038) or healthy controls (0/18, 0%; P<0.001). The spectrum of malarial retinopathy was similar to that previously described in African children, but no vessel discolouration was observed. The severity of retinal whitening correlated with admission venous plasma lactate (P=0.046), suggesting that retinal ischaemia represents systemic ischaemia. In conclusion, retinal changes related to microvascular obstruction were common in adults with severe falciparum malaria and correlated with disease severity and coma, suggesting that a compromised microcirculation has important pathophysiological significance in severe and cerebral malaria. Portable retinal photography has potential as a valuable tool to study malarial retinopathy.

Maude RJ, Dondorp AM, Abu Sayeed A, Day NPJ, White NJ, Beare NAV. 2009. The eye in cerebral malaria: what can it teach us? Trans R Soc Trop Med Hyg, 103 (7), pp. 661-664. | Show Abstract | Read more

The pathophysiology of coma in cerebral malaria (CM) is not well understood. Obstruction of microcirculatory flow is thought to play a central role, but other hypotheses include roles for parasite- and host-derived factors such as immune mediators, and for increased blood-brain barrier permeability leading to raised intracranial pressure. The retinal vasculature is a direct extension of the cerebral vasculature. It is the only vascular bed easily accessible for visualisation and provides a unique opportunity to observe vascular pathology and its effect on neurological tissue. A specific retinopathy has been well described in African children with CM and its severity correlates with outcome. This retinopathy has been less well described in adults. The central mechanism causing malarial retinopathy appears to be microvascular obstruction, which has been demonstrated in affected retinas by fluorescein angiography. The presence in a central nervous system tissue of microvascular obstruction strongly supports the hypothesis that the sequestration of erythrocytes in small blood vessels and consequent obstruction of microcirculatory flow is an important mechanism causing coma and death in CM. Despite advances in the antimalarial treatment of severe malaria, its mortality remains approximately 15-20%. Adjunctive treatment targeting sequestration is a promising strategy to further lower mortality.

Maude RJ, Pontavornpinyo W, Saralamba S, Dondorp AM, Day NPJ, White NJ, White LJ. 2009. The role of mathematical modelling in malaria elimination and eradication (Comment on: Can malaria be eliminated?). Trans R Soc Trop Med Hyg, 103 (6), pp. 643-644. | Read more

Preechapornkul P, Imwong M, Chotivanich K, Pongtavornpinyo W, Dondorp AM, Day NPJ, White NJ, Pukrittayakamee S. 2009. Plasmodium falciparum pfmdr1 amplification, mefloquine resistance, and parasite fitness. Antimicrob Agents Chemother, 53 (4), pp. 1509-1515. | Show Abstract | Read more

Mefloquine is widely used in combination with artemisinin derivatives for the treatment of falciparum malaria. Mefloquine resistance in Plasmodium falciparum has been related to increased copy numbers of multidrug-resistant gene 1 (pfmdr1). We studied the ex vivo dynamics of pfmdr1 gene amplification in culture-adapted P. falciparum in relation to mefloquine resistance and parasite fitness. A Thai P. falciparum isolate (isolate TM036) was assessed by the use of multiple genetic markers as a single genotype. Resistance was selected by exposure to stepwise increasing concentrations of mefloquine up to 30 ng/ml in continuous culture. The pfmdr1 gene copy numbers increased as susceptibility to mefloquine declined (P = 0.03). No codon mutations at positions 86, 184, 1034, 1042, and 1246 in the pfmdr1 gene were detected. Two subclones of selected parasites (average copy numbers, 2.3 and 3.1, respectively) showed a fitness disadvantage when they were grown together with the original parasites containing a single pfmdr1 gene copy in the absence of mefloquine; the multiplication rates were 6.3% and 8.7% lower, respectively (P < 0.01). Modeling of the dynamics of the pfmdr1 copy numbers over time in relation to the relative fitness of the parasites suggested that net pfmdr1 gene amplification from one to two copies occurs once in every 10(8) parasites and that amplification from two to three copies occurs once in every 10(3) parasites. pfmdr1 gene amplification in P. falciparum is a frequent event and confers mefloquine resistance. Parasites with multiple copies of the pfmdr1 gene have decreased survival fitness in the absence of drug pressure.

Lubell Y, Yeung S, Dondorp AM, Day NP, Nosten F, Tjitra E, Abul Faiz M, Yunus EB, Anstey NM, Mishra SK et al. 2009. Cost-effectiveness of artesunate for the treatment of severe malaria. Trop Med Int Health, 14 (3), pp. 332-337. | Show Abstract | Read more

OBJECTIVE: To explore the cost-effectiveness of artesunate against quinine based principally on the findings of a large multi-centre trial carried out in Southeast Asia. METHODS: Trial data were used to compare mortality of patients with severe malaria, treated with either artesunate or quinine. This was combined with retrospectively collected cost data to estimate the incremental cost per death averted with the use of artesunate instead of quinine. RESULTS: The incremental cost per death averted using artesunate was approximately 140 USD. Artesunate maintained this high level of cost-effectiveness also when allowing for the uncertainty surrounding the cost and effectiveness assessments. CONCLUSION: This analysis confirms the vast superiority of artesunate for treatment of severe malaria from an economic as well as a clinical perspective.

Pongtavornpinyo W, Hastings IM, Dondorp A, White LJ, Maude RJ, Saralamba S, Day NP, White NJ, Boni MF. 2009. Probability of emergence of antimalarial resistance in different stages of the parasite life cycle. Evol Appl, 2 (1), pp. 52-61. | Show Abstract | Read more

Understanding the evolution of drug resistance in malaria is a central area of study at the intersection of evolution and medicine. Antimalarial drug resistance is a major threat to malaria control and directly related to trends in malaria attributable mortality. Artemisinin combination therapies (ACT) are now recommended worldwide as first line treatment for uncomplicated malaria, and losing them to resistance would be a disaster for malaria control. Understanding the emergence and spread of antimalarial drug resistance in the context of different scenarios of antimalarial drug use is essential for the development of strategies protecting ACTs. In this study, we review the basic mechanisms of resistance emergence and describe several simple equations that can be used to estimate the probabilities of de novo resistance mutations at three stages of the parasite life cycle: sporozoite, hepatic merozoite and asexual blood stages; we discuss the factors that affect parasite survival in a single host in the context of different levels of antimalarial drug use, immunity and parasitaemia. We show that in the absence of drug effects, and despite very different parasite numbers, the probability of resistance emerging at each stage is very low and similar in all stages (for example per-infection probability of 10(-10)-10(-9) if the per-parasite chance of mutation is 10(-10) per asexual division). However, under the selective pressure provided by antimalarial treatment and particularly in the presence of hyperparasitaemia, the probability of resistance emerging in the blood stage of the parasite can be approximately five orders of magnitude higher than in the absence of drugs. Detailed models built upon these basic methods should allow us to assess the relative probabilities of resistance emergence in the different phases of the parasite life cycle.

Wiersinga WJ, van't Veer C, van den Pangaart PS, Dondorp AM, Day NP, Peacock SJ, van der Poll T. 2009. Immunosuppression associated with interleukin-1R-associated-kinase-M upregulation predicts mortality in Gram-negative sepsis (melioidosis). Crit Care Med, 37 (2), pp. 569-576. | Show Abstract | Read more

OBJECTIVES: Sepsis is associated with immunosuppression (characterized by a reduced capacity of circulating monocytes to release proinflammatory cytokines), which has been implicated in late mortality. Melioidosis, caused by the Gram-negative bacterium Burkholderia pseudomallei, is an important cause of community-acquired sepsis in Southeast Asia with a mortality of up to 40%. Previous in vitro and murine studies have suggested a key role for the so-called negative regulators of the toll-like receptor (TLR) signaling pathway in immunosuppression. In this study, we investigated the expression of these negative TLR regulators in patients with septic melioidosis in association with the responsiveness of peripheral blood leukocytes of these patients to lipopolysaccharide and B. pseudomallei. DESIGN: Ex vivo study. SETTING: Academic research laboratory. PATIENTS: Thirty-two healthy controls and 34 patients with sepsis caused by B. pseudomallei. INTERVENTIONS: None. MEASUREMENTS: 1) Plasma cytokine levels; 2) ex vivo cytokine production capacity of whole blood; and 3) purified mononuclear cell-derived messenger RNA (mRNA) levels of key inhibitory molecules of the TLR-signaling cascade were investigated. MAIN RESULTS: In accordance with an immunosuppressed state, whole blood of patients demonstrated a strongly decreased capacity to release the proinflammatory cytokines tumor necrosis factor-[alpha], interleukin-1[beta], and the chemokine interleukin-8 after ex vivo stimulation with lipopolysaccharide or B. pseudomallei. Analysis of myeloid-differentiation-88-short, interleukin-1R-associated-kinase (IRAK)-M, IRAK-1, suppressor-of-cytokine signaling-3, Src-homology-2-domain-containing inositol-5-phosphatase-1, single-immunoglobulin-interleukin-1R-related-molecule, and A20 mRNA expression in purified mononuclear cells showed decreased IRAK-1 and elevated IRAK-M expression in patients with septic melioidosis. Immunosuppression was correlated with mortality; furthermore, patients who eventually died had higher IRAK-M mRNA levels on admission than the patients who survived. CONCLUSIONS: Immunosuppression in sepsis caused by B. pseudomallei is associated with an upregulation of IRAK-M and an indicator of poor outcome.

Charunwatthana P, Abul Faiz M, Ruangveerayut R, Maude RJ, Rahman MR, Roberts LJ, Moore K, Bin Yunus E, Hoque MG, Hasan MU et al. 2009. N-acetylcysteine as adjunctive treatment in severe malaria: a randomized, double-blinded placebo-controlled clinical trial. Crit Care Med, 37 (2), pp. 516-522. | Show Abstract | Read more

OBJECTIVE: Markers of oxidative stress are reported to be increased in severe malaria. It has been suggested that the antioxidant N-acetylcysteine (NAC) may be beneficial in treatment. We studied the efficacy and safety of parenteral NAC as an adjunct to artesunate treatment of severe falciparum malaria. DESIGN: A randomized, double-blind, placebo-controlled trial on the use of high-dose intravenous NAC as adjunctive treatment to artesunate. SETTING: A provincial hospital in Western Thailand and a tertiary referral hospital in Chittagong, Bangladesh. PATIENTS: One hundred eight adult patients with severe falciparum malaria. INTERVENTIONS: Patients were randomized to receive NAC or placebo as an adjunctive treatment to intravenous artesunate. MEASUREMENTS AND MAIN RESULTS: A total of 56 patients were treated with NAC and 52 received placebo. NAC had no significant effect on mortality, lactate clearance times (p = 0.74), or coma recovery times (p = 0.46). Parasite clearance time was increased from 30 hours (range, 6-144 hours) to 36 hours (range, 6-120 hours) (p = 0.03), but this could be explained by differences in admission parasitemia. Urinary F2-isoprostane metabolites, measured as a marker of oxidative stress, were increased in severe malaria compared with patients with uncomplicated malaria and healthy volunteers. Admission red cell rigidity correlated with mortality, but did not improve with NAC. CONCLUSION: Systemic oxidative stress is increased in severe malaria. Treatment with NAC had no effect on outcome in patients with severe falciparum malaria in this setting.

White NJ, Pongtavornpinyo W, Maude RJ, Saralamba S, Aguas R, Stepniewska K, Lee SJ, Dondorp AM, White LJ, Day NPJ. 2009. Hyperparasitaemia and low dosing are an important source of anti-malarial drug resistance. Malar J, 8 (1), pp. 253. | Show Abstract | Read more

BACKGROUND: Preventing the emergence of anti-malarial drug resistance is critical for the success of current malaria elimination efforts. Prevention strategies have focused predominantly on qualitative factors, such as choice of drugs, use of combinations and deployment of multiple first-line treatments. The importance of anti-malarial treatment dosing has been underappreciated. Treatment recommendations are often for the lowest doses that produce "satisfactory" results. METHODS: The probability of de-novo resistant malaria parasites surviving and transmitting depends on the relationship between their degree of resistance and the blood concentration profiles of the anti-malarial drug to which they are exposed. The conditions required for the in-vivo selection of de-novo emergent resistant malaria parasites were examined and relative probabilities assessed. RESULTS: Recrudescence is essential for the transmission of de-novo resistance. For rapidly eliminated anti-malarials high-grade resistance can arise from a single drug exposure, but low-grade resistance can arise only from repeated inadequate treatments. Resistance to artemisinins is, therefore, unlikely to emerge with single drug exposures. Hyperparasitaemic patients are an important source of de-novo anti-malarial drug resistance. Their parasite populations are larger, their control of the infection insufficient, and their rates of recrudescence following anti-malarial treatment are high. As use of substandard drugs, poor adherence, unusual pharmacokinetics, and inadequate immune responses are host characteristics, likely to pertain to each recurrence of infection, a small subgroup of patients provides the particular circumstances conducive to de-novo resistance selection and transmission. CONCLUSION: Current dosing recommendations provide a resistance selection opportunity in those patients with low drug levels and high parasite burdens (often children or pregnant women). Patients with hyperparasitaemia who receive outpatient treatments provide the greatest risk of selecting de-novo resistant parasites. This emphasizes the importance of ensuring that only quality-assured anti-malarial combinations are used, that treatment doses are optimized on the basis of pharmacodynamic and pharmacokinetic assessments in the target populations, and that patients with heavy parasite burdens are identified and receive sufficient treatment to prevent recrudescence.

Hanson J, Hossain A, Charunwatthana P, Hassan MU, Davis TME, Lam SWK, Chubb SAP, Maude RJ, Yunus EB, Haque G et al. 2009. Hyponatremia in severe malaria: evidence for an appropriate anti-diuretic hormone response to hypovolemia. Am J Trop Med Hyg, 80 (1), pp. 141-145. | Show Abstract | Read more

Although hyponatremia occurs in most patients with severe malaria, its pathogenesis, prognostic significance, and optimal management have not been established. Clinical and biochemical data were prospectively collected from 171 consecutive Bangladeshi adults with severe malaria. On admission, 57% of patients were hyponatremic. Plasma sodium and Glasgow Coma Score were inversely related (r(s) = -0.36, P < 0.0001). Plasma antidiuretic hormone concentrations were similar in hyponatremic and normonatremic patients (median, range: 6.1, 2.3-85.3 versus 32.7, 3.0-56.4 pmol/L; P = 0.19). Mortality was lower in hyponatremic than normonatremic patients (31.6% versus 51.4%; odds ratio [95% confidence interval]: 0.44 [0.23-0.82]; P = 0.01 by univariate analysis). Plasma sodium normalized with crystalloid rehydration from (median, range) 127 (123-140) mmol/L on admission to 136 (128-149) mmol/L at 24 hours (P = 0.01). Hyponatremia in adults with severe malaria is common and associated with preserved consciousness and decreased mortality. It likely reflects continued oral hypotonic fluid intake in the setting of hypovolemia and requires no therapy beyond rehydration.

Maude RJ, Plewes K, Faiz MA, Hanson J, Charunwatthana P, Lee SJ, Tärning J, Yunus EB, Hoque MG, Hasan MU et al. 2009. Does artesunate prolong the electrocardiograph QT interval in patients with severe malaria? Am J Trop Med Hyg, 80 (1), pp. 126-132. | Show Abstract | Read more

Several antimalarials can cause significant prolongation of the electrocardiograph QT interval, which can be associated with an increased risk of potentially lethal ventricular arrhythmias. High doses of artemether and artemotil have been associated with QT prolongation in dogs, raising the possibility of a class effect with the artemisinin derivatives. Serial electrocardiograms were recorded, and QTc interval was calculated before and after administration of artesunate by intravenous injection in patients with severe falciparum malaria in Bangladesh. Of 21 adult patients with severe malaria enrolled, 8 (38%) died. The mean QTc interval was unaffected by bolus intravenous artesunate (2.4 mg/kg). In two patients, the QTc interval exceeded 0.5 seconds, but in both cases, an alternative explanation was plausible. No effect was observed on the JTc or PR interval, QRS width, blood pressure, or heart rate. Intravenous artesunate does not have significant cardiovascular effects in patients with severe falciparum malaria.

Maude RJ, Pontavornpinyo W, Saralamba S, Aguas R, Yeung S, Dondorp AM, Day NPJ, White NJ, White LJ. 2009. The last man standing is the most resistant: eliminating artemisinin-resistant malaria in Cambodia. Malar J, 8 (1), pp. 31. | Show Abstract | Read more

BACKGROUND: Artemisinin combination therapy (ACT) is now the recommended first-line treatment for falciparum malaria throughout the world. Initiatives to eliminate malaria are critically dependent on its efficacy. There is recent worrying evidence that artemisinin resistance has arisen on the Thai-Cambodian border. Urgent containment interventions are planned and about to be executed. Mathematical modeling approaches to intervention design are now integrated into the field of malaria epidemiology and control. The use of such an approach to investigate the likely effectiveness of different containment measures with the ultimate aim of eliminating artemisinin-resistant malaria is described. METHODS: A population dynamic mathematical modeling framework was developed to explore the relative effectiveness of a variety of containment interventions in eliminating artemisinin-resistant malaria in western Cambodia. RESULTS: The most effective intervention to eliminate artemisinin-resistant malaria was a switch of treatment from artemisinin monotherapy to ACT (mean time to elimination 3.42 years (95% CI 3.32-3.60 years). However, with this approach it is predicted that elimination of artemisinin-resistant malaria using ACT can be achieved only by elimination of all malaria. This is because the various forms of ACT are more effective against infections with artemisinin-sensitive parasites, leaving the more resistant infections as an increasing proportion of the dwindling parasite population. CONCLUSION: Containment of artemisinin-resistant malaria can be achieved by elimination of malaria from western Cambodia using ACT. The "last man standing" is the most resistant and thus this strategy must be sustained until elimination is truly achieved.

Steenkeste N, Dillies M-A, Khim N, Sismeiro O, Chy S, Lim P, Crameri A, Bouchier C, Mercereau-Puijalon O, Beck H-P et al. 2009. FlexiChip package: an universal microarray with a dedicated analysis software for high-thoughput SNPs detection linked to anti-malarial drug resistance. Malar J, 8 (1), pp. 229. | Show Abstract | Read more

BACKGROUND: A number of molecular tools have been developed to monitor the emergence and spread of anti-malarial drug resistance to Plasmodium falciparum. One of the major obstacles to the wider implementation of these tools is the absence of practical methods enabling high throughput analysis. Here a new Zip-code array is described, called FlexiChip, linked to a dedicated software program, which largely overcomes this problem. METHODS: Previously published microarray probes detecting single-nucleotide polymorphisms (SNP) associated with parasite resistance to anti-malarial drugs (ResMalChip) were adapted for a universal microarray FlexiChip format. To evaluate the overall sensitivity of the FlexiChip package (microarray + software), the results of FlexiChip were compared to ResMalChip microarray, using the same extension probes and with the same PCR products. In both cases, sequence results were used as gold standard to calculate sensitivity and specificity. FlexiChip results obtained with a set of field isolates were then compared to those assessed in an independent reference laboratory. RESULTS: The FlexiChip package gave results identical to the ResMalChip results in 92.7% of samples (kappa coefficient 0.8491, with a standard error 0.021) and had a sensitivity of 95.88% and a specificity of 97.68% compared to the sequencing as the reference method. Moreover the method performed well compared to the results obtained in the reference laboratories, with 99.7% of identical results (kappa coefficient 0.9923, S.E. 0.0523). CONCLUSION: Microarrays could be employed to monitor P. falciparum drug resistance markers with greater cost effectiveness and the possibility for high throughput analysis. The FlexiChip package is a promising tool for use in poor resource settings of malaria endemic countries.

Hsu C-S, Kao J-H. 2009. Peginterferon alfa-2b or alfa-2a with ribavirin for hepatitis C. N Engl J Med, 361 (18), pp. 1808-1809. | Read more

Lindegardh N, Hanpithakpong W, Kamanikom B, Singhasivanon P, Socheat D, Yi P, Dondorp AM, McGready R, Nosten F, White NJ, Day NPJ. 2008. Major pitfalls in the measurement of artemisinin derivatives in plasma in clinical studies. J Chromatogr B Analyt Technol Biomed Life Sci, 876 (1), pp. 54-60. | Show Abstract | Read more

A bioanalytical method for the analysis of artesunate (ARS) and its metabolite dihydroartemisinin (DHA) in human plasma using protein precipitation and liquid chromatography coupled to positive tandem mass spectroscopy was developed. The method was validated according to published US FDA-guidelines and showed excellent performance. However, when it was applied to clinical pharmacokinetic studies in malaria, variable degradation of the artemisinins introduced an unacceptable large source of error, rendering the assay useless. Haemolytic products related to sample collection and malaria infection degraded the compounds. Addition of organic solvents during sample processing and even low volume addition of the internal standard in an organic solvent caused degradation. A solid phase extraction method avoiding organic solvents eliminated problems arising from haemolysis induced degradation. Plasma esterases mediated only approximately 20% of ex vivo hydrolysis of ARS into DHA. There are multiple sources of major preventable error in measuring ARS and DHA in plasma samples from clinical trials. These various pitfalls have undoubtedly contributed to the large inter-subject variation in plasma concentration profiles and derived pharmacokinetic parameters for these important antimalarial drugs.

Hanpithakpong W, Kamanikom B, Dondorp AM, Singhasivanon P, White NJ, Day NPJ, Lindegardh N. 2008. A liquid chromatographic-tandem mass spectrometric method for determination of artesunate and its metabolite dihydroartemisinin in human plasma. J Chromatogr B Analyt Technol Biomed Life Sci, 876 (1), pp. 61-68. | Show Abstract | Read more

A bioanalytical method for the analysis of artesunate and its metabolite dihydroartemisinin in human plasma using high throughput solid-phase extraction in the 96-wellplate format and liquid chromatography coupled to positive tandem mass spectroscopy has been developed and validated. The method was validated according to published FDA guidelines and showed excellent performance. The within-day and between-day precisions expressed as RSD, were lower than 7% at all tested concentrations including the lower limit of quantification. Using 50 microl plasma the calibration range was 1.19-728 ng/ml with a limit of detection at 0.5 ng/ml for artesunate and 1.96-2500 ng/ml with a limit of detection at 0.6 ng/ml for dihydroartemisinin. Using 250 microl of plasma sample the lower limit of quantification was decreased to 0.119 ng/ml for artesunate and 0.196 ng/ml dihydroartemisinin. Validation of over-curve samples in plasma ensured that accurate estimation would be possible with dilution if samples went outside the calibration range. The method was free from matrix effects as demonstrated both graphically and quantitatively.

Maude RJ, Dondorp AM, Faiz MA, Yunus EB, Samad R, Hossain A, Rahman MR. 2008. Malaria in southeast Bangladesh: a descriptive study. Bangladesh Med Res Counc Bull, 34 (3), pp. 87-89. | Show Abstract | Read more

Malaria in Asia is thought to be grossly under-reported and this is evident from previously published statistics from Bangladesh. Malaria screening data from four Upazillas was analysed alongside census data to assess the trends in malaria incidence over time and distribution of malaria by age and gender. Malaria incidence in this area has decreased by around two thirds since 2003, although control measures were not significantly increased until 2005. Malaria occurred in people of all ages with the highest incidence being in young adults. This is consistent with higher occupational exposure in this group. The probability of being screened for malaria decreased with age suggesting significant numbers of adults with malaria may be being missed.

Deen JL, von Seidlein L, Dondorp A. 2008. Therapy of uncomplicated malaria in children: a review of treatment principles, essential drugs and current recommendations. Trop Med Int Health, 13 (9), pp. 1111-1130. | Show Abstract | Read more

Understanding the optimal treatment of uncomplicated malaria in children is challenging because of the availability of new drugs and the shift to combination therapies. This is a review of the guiding principles for the treatment of uncomplicated malaria, the essential anti-malarial drugs for children, and the treatment regimens currently recommended.

Rahman MM, Dondorp AM, Day NPJ, Lindegardh N, Imwong M, Faiz MA, Bangali AM, Kamal ATMM, Karim J, Kaewkungwal J, Singhasivanon P. 2008. Adherence and efficacy of supervised versus non-supervised treatment with artemether/lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in Bangladesh: a randomised controlled trial. Trans R Soc Trop Med Hyg, 102 (9), pp. 861-867. | Show Abstract | Read more

As artemether/lumefantrine is now deployed as the first-line treatment for uncomplicated falciparum malaria in Bangladesh, information on its efficacy and adherence to its use is important. A randomised controlled non-inferiority trial comparing directly observed treatment (DOT) and non-directly observed treatment (NDOT) was conducted in 320 patients with uncomplicated falciparum malaria in Bandarban Hill Tract District, Bangladesh. Both regimens showed similar high levels of PCR-corrected 42-day parasitological and clinical cure rates (99.3% in the NDOT group and 100% in the DOT group; P=0.49). Survival analysis for the time to recurrence of infection showed no difference between treatment groups (log rank, P=0.98). Adherence, as assessed by counting remaining tablets and oral interviews, was 93% in the NDOT group and was confirmed by Day 7 lumefantrine concentrations. Adherence was independent of educational level. Patients with plasma lumefantrine concentrations < 280 ng/ml at Day 7 were at greater risk for re-infection (relative risk 5.62; P=0.027). The efficacy of artemether/lumefantrine for the treatment of uncomplicated falciparum malaria in Bangladesh is high and is similar for DOT and NDOT. Adherence to therapy is high.

Dondorp AM, Lee SJ, Faiz MA, Mishra S, Price R, Tjitra E, Than M, Htut Y, Mohanty S, Yunus EB et al. 2008. The relationship between age and the manifestations of and mortality associated with severe malaria. Clin Infect Dis, 47 (2), pp. 151-157. | Show Abstract | Read more

BACKGROUND: The reported case-fatality rate associated with severe malaria varies widely. Whether age is an independent risk factor is uncertain. METHODS: In a large, multicenter treatment trial conducted in Asia, the presenting manifestations and outcome of severe malaria were analyzed in relation to age. RESULTS: Among 1050 patients with severe malaria, the mortality increased stepwise, from 6.1% in children (age, <10 years) to 36.5% in patients aged >50 years (P<0.001). Compared with adults aged 21-50 years, the decreased risk of death among children (adjusted odds ratio, 0.06; 95% confidence interval, 0.01-0.23; P<0.001) and the increased risk of death among patients aged >50 years (adjusted odds ratio, 1.88; 95% confidence interval, 1.01-3.52; P<0.001) was independent of the variation in presenting manifestations. The incidence of anemia and convulsions decreased with age, whereas the incidence of hyperparasitemia, jaundice, and renal insufficiency increased with age. Coma and metabolic acidosis did not vary with age and were the strongest predictors of a fatal outcome. The number of severity signs at hospital admission also had a strong prognostic value. CONCLUSION: Presenting syndromes in severe malaria depend on age, although the incidence and the strong prognostic significance of coma and acidosis are similar at all ages. Age is an independent risk factor for a fatal outcome of the disease.

Imwong M, Pukrittayakamee S, Pongtavornpinyo W, Nakeesathit S, Nair S, Newton P, Nosten F, Anderson TJC, Dondorp A, Day NPJ, White NJ. 2008. Gene amplification of the multidrug resistance 1 gene of Plasmodium vivax isolates from Thailand, Laos, and Myanmar. Antimicrob Agents Chemother, 52 (7), pp. 2657-2659. | Show Abstract | Read more

Plasmodium vivax mdr1 gene amplification, quantified by real-time PCR, was significantly more common on the western Thailand border (6 of 66 samples), where mefloquine pressure has been intense, than elsewhere in southeast Asia (3 of 149; P = 0.02). Five coding mutations in pvmdr1, independent of gene amplification, were also found.

Nuchsongsin F, Chotivanich K, Charunwatthana P, Fausta OS, Taramelli D, Day NP, White NJ, Dondorp AM. 2008. Effects of malaria heme products on red blood cell deformability (vol 77, pg 617, 2007) AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 78 (5), pp. 847-847.

Dondorp AM. 2008. Clinical significance of sequestration in adults with severe malaria. Transfus Clin Biol, 15 (1-2), pp. 56-57. | Show Abstract | Read more

Reduced microcirculatory flow is a fundamental feature in the pathophysiology of severe Plasmodium falciparum malaria and sequestration of red blood cells containing mature parasites is considered a central cause of this. Direct microscopic observation of the microcirculation in the living patient with severe malaria has enabled us to quantify this phenomenon and link it to severity of disease, supporting the findings of pathology studies. Moreover, the sequestered parasite biomass, calculated from parasite derived plasma PfHRP2 concentrations, strongly correlates with disease severity. Artesunate prevents sequestration by killing ring form parasites, aborting their maturation, which can explain the mortality benefit of this drug compared to quinine in the treatment of adult severe malaria. Levamisole is currently tried as adjunctive treatment in severe malaria targeting sequestration.

Pongtavornpinyo W, Yeung S, Hastings IM, Dondorp AM, Day NPJ, White NJ. 2008. Spread of anti-malarial drug resistance: mathematical model with implications for ACT drug policies. Malar J, 7 (1), pp. 229. | Show Abstract | Read more

BACKGROUND: Most malaria-endemic countries are implementing a change in anti-malarial drug policy to artemisinin-based combination therapy (ACT). The impact of different drug choices and implementation strategies is uncertain. Data from many epidemiological studies in different levels of malaria endemicity and in areas with the highest prevalence of drug resistance like borders of Thailand are certainly valuable. Formulating an appropriate dynamic data-driven model is a powerful predictive tool for exploring the impact of these strategies quantitatively. METHODS: A comprehensive model was constructed incorporating important epidemiological and biological factors of human, mosquito, parasite and treatment. The iterative process of developing the model, identifying data needed, and parameterization has been taken to strongly link the model to the empirical evidence. The model provides quantitative measures of outcomes, such as malaria prevalence/incidence and treatment failure, and illustrates the spread of resistance in low and high transmission settings. The model was used to evaluate different anti-malarial policy options focusing on ACT deployment. RESULTS: The model predicts robustly that in low transmission settings drug resistance spreads faster than in high transmission settings, and treatment failure is the main force driving the spread of drug resistance. In low transmission settings, ACT slows the spread of drug resistance to a partner drug, especially at high coverage rates. This effect decreases exponentially with increasing delay in deploying the ACT and decreasing rates of coverage. In the high transmission settings, however, drug resistance is driven by the proportion of the human population with a residual drug level, which gives resistant parasites some survival advantage. The spread of drug resistance could be slowed down by controlling presumptive drug use and avoiding the use of combination therapies containing drugs with mismatched half-lives, together with reducing malaria transmission through vector control measures. CONCLUSION: This paper has demonstrated the use of a comprehensive mathematical model to describe malaria transmission and the spread of drug resistance. The model is strongly linked to the empirical evidence obtained from extensive data available from various sources. This model can be a useful tool to inform the design of treatment policies, particularly at a time when ACT has been endorsed by WHO as first-line treatment for falciparum malaria worldwide.

Dondorp AM, Ince C, Charunwatthana P, Hanson J, van Kuijen A, Faiz MA, Rahman MR, Hasan M, Bin Yunus E, Ghose A et al. 2008. Direct in vivo assessment of microcirculatory dysfunction in severe falciparum malaria. J Infect Dis, 197 (1), pp. 79-84. | Show Abstract | Read more

BACKGROUND: This study sought to describe and quantify microcirculatory changes in the mucosal surfaces of patients with severe malaria, by direct in vivo observation using orthogonal polarization spectral (OPS) imaging. METHODS: The microcirculation in the rectal mucosa of adult patients with severe malaria was assessed by use of OPS imaging, at admission and then daily. Comparison groups comprised patients with uncomplicated falciparum malaria, patients with bacterial sepsis, and healthy individuals. RESULTS: Erythrocyte velocities were measured directly in 43 adult patients with severe falciparum malaria, of whom 20 died. Microcirculatory blood flow was markedly disturbed, with heterogeneous obstruction that was proportional to severity of disease. Blocked capillaries were found in 29 patients (67%) and were associated with concurrent hyperdynamic blood flow (erythrocyte velocity, >750 mm/s) in adjacent vessels in 27 patients (93%). The proportion of blocked capillaries correlated with the base deficit in plasma and with the concentration of lactate. Abnormalities disappeared when the patients recovered. In healthy individuals and in patients with uncomplicated malaria or sepsis, no stagnant erythrocytes were detected, and, in patients with sepsis, hyperdynamic blood flow was prominent. CONCLUSION: Patients with severe falciparum malaria show extensive microvascular obstruction that is proportional to the severity of the disease. This finding underscores the prominent role that microvascular obstruction plays in the pathophysiology of severe malaria and illustrates the fundamental difference between the microvascular pathophysiology of malaria and that of bacterial sepsis.

Nantakomol D, Chimma P, Day NP, Dondorp AM, Combes V, Krudsood S, Looareesuwan S, White NJ, Pattanapanyasat K, Chotivanich K. 2008. Quantitation of cell-derived microparticles in plasma using flow rate based calibration. Southeast Asian J Trop Med Public Health, 39 (1), pp. 146-153. | Show Abstract

Activation of vascular endothelium and blood cells can result in the formation of microparticles (MPs), which are membrane vesicles with a diameter < 1 microm which can play a pathogenetic role in a variety of infectious and other diseases. In this study, we validated a modified quantitative method called "flow rate based calibration", to measure circulating MPs in plasma of healthy subjects and malaria patients using FACSCalibur flow cytometry. MPs counts obtained from "flow rate based calibration" correlated closely with the standard method (R2 = 0.9, p = 0.001). The median (range) number of MPs in healthy subjects was 163/microl (81-375/microl). We demonstrated a flow rate based calibration for the quantitation of MPs in P. falciparum malaria-infected patients. The median (range) number of MPs was 2,051/microl (222-6,432/microl), n = 28 in patients with falciparum malaria. The number of MPs in plasma from patients with severe falciparum malaria was significantly higher than in uncomplicated falciparum malaria (2,567/microl (366-6,432/microl), n = 18 versus [1,947/microl (222-4,107/microl), n = 10, p < 0.01]. Cellular origin of MPs in malaria patients were mainly derived from red blood cells (35%), platelets (10%), and endothelial cells (5%). There was no significant correlation between the total number of MPs and parasitemia. Flow rate based calibration is a simple, reliable, reproducible method and more affordable to quantitate MPs.




Nantakomol D, Chimma P, Day NP, Dondorp AM, Combes V, Krudsood S, Looareesuwan S, White NJ, Pattanapanyasat K, Chotivanich K. 2008. Quantitation of cell-derived microparticles in plasma using flow rate based calibration Southeast Asian Journal of Tropical Medicine and Public Health, 39 (1), pp. 146-153. | Show Abstract

Activation of vascular endothelium and blood cells can result in the formation of microparticles (MPs), which are membrane vesicles with a diameter < 1 μm which can play a pathogenetic role in a variety of infectious and other diseases. In this study, we validated a modified quantitative method called "flow rate based calibration", to measure circulating MPs in plasma of healthy subjects and malaria patients using FACSCalibur flow cytometry. MPs counts obtained from "flow rate based calibration" correlated closely with the standard method (R 2 =0.9, p=0.001). The median (range) number of MPs in healthy subjects was 163/μl (81-375/μl). We demonstrated a flow rate based calibration for the quantitation of MPs in P. falciparum malaria-infected patients. The median (range) number of MPs was 2,051/μl (222-6,432/μl), n=28 in patients with falciparum malaria. The number of MPs in plasma from patients with severe falciparum malaria was significantly higher than in uncomplicated falciparum malaria (2,567/μl (366-6,432/μl), n=18 versus [1,947/μl (222-4,107/μl), n=10, p<0.01]. Cellular origin of MPs in malaria patients were mainly derived from red blood cells (35%), platelets (10%), and endothelial cells (5%). There was no significant correlation between the total number of MPs and parasitemia. Flow rate based calibration is a simple, reliable, reproducible method and more affordable to quantitate MPs.

Day N, Dondorp AM. 2007. The management of patients with severe malaria. Am J Trop Med Hyg, 77 (6 Suppl), pp. 29-35. | Show Abstract

Severe malaria is a global problem, claiming at least 1 million lives annually. Few adequately powered clinical studies have been directed at improving the management of severe malaria over the years, but this situation is slowly changing. The antimalarial treatment of severe disease is being transformed by the development and deployment of the water-soluble artemisinin derivative artesunate. Parenteral artesunate is now the treatment of choice in low-transmission areas and in the 2nd and 3rd trimesters of pregnancy, and research is underway into whether it should replace quinine as the treatment of choice in African children. Development of good manufacturing practice (GMP) formulations should make parenteral artesunate more widely available in the near future. The development of artesunate suppositories offers another exciting prospect, the ability to treat patients with severe disease in remote rural settings, delaying the evolution of disease and buying them time to reach a health care facility. No adjunctive therapy has been shown to improve the outcome of severe malaria, but most studies have been underpowered. Future trials of interventions shown to be promising in pilot studies should be large and adequately powered. This will require multi-center designs and necessitate close collaboration between groups, as well as agreement on the research agenda. We suggest a list of candidate interventions for debate.

Paris DH, Imwong M, Faiz AM, Hasan M, Yunus EB, Silamut K, Lee SJ, Day NPJ, Dondorp AM. 2007. Loop-mediated isothermal PCR (LAMP) for the diagnosis of falciparum malaria. Am J Trop Med Hyg, 77 (5), pp. 972-976. | Show Abstract | Read more

A recently described loop-mediated isothermal polymerase chain reaction (LAMP) for molecular detection of Plasmodium falciparum was compared with microscopy, PfHRP2-based rapid diagnostic test (RDT), and nested polymerase chain reaction (PCR) as the "gold standard" in 115 Bangladeshi in-patients with fever. DNA extraction for LAMP was conducted by conventional methods or simple heating of the sample; test results were either assessed visually or by gel electrophoresis. Conventional DNA extraction followed by gel electrophoresis had the highest agreement with the reference method (81.7%, kappa = 0.64), with a sensitivity (95% CI) of 76.1% (68.3-83.9%), comparable to RDT and microscopy, but a specificity of 89.6% (84.0-95.2%) compared with 100% for RDT and microscopy. DNA extraction by heat treatment deteriorated specificity to unacceptable levels. LAMP enables molecular diagnosis of falciparum malaria in settings with limited technical resources but will need further optimization. The results are in contrast with a higher accuracy reported in an earlier study comparing LAMP with a non-validated PCR method.

Nuchsongsin F, Chotivanich K, Charunwatthana P, Omodeo-Salè F, Taramelli D, Day NP, White NJ, Dondorp AM. 2007. Effects of malaria heme products on red blood cell deformability. Am J Trop Med Hyg, 77 (4), pp. 617-622. | Show Abstract | Read more

In falciparum malaria, the deformability of the entire erythrocyte population is reduced in proportion to disease severity, and this compromises microcirculatory blood flow through vessels partially obstructed by cytoadherent parasitized erythrocytes. The cause of rigidity of uninfected erythrocytes in not known but could be mediated by malaria heme products. In this study, we show that red blood cell deformability (RBC-D), measured by laser-assisted optical rotational cell analyzer, decreased in a dose-dependent manner after incubation with hemin and hydrogen peroxide but not with hemoglobin or beta-hematin. Hemin also reduced mean red cell volume. Albumin decreased and N-acetylcysteine (NAC) both prevented and reversed rigidity induced by hemin. Hemin-induced oxidative damage of the membrane seems to be a more important contributor to pathology than cell shrinkage because the antioxidant NAC restored RBC-D but not red blood cell volume. The findings suggest novel approaches to the treatment of potentially lethal malaria.

Hanson JP, Dondorp AM, Day NPJ. 2007. Malaria treatment in the United States. JAMA, 298 (12), pp. 1396. | Read more

Lindegårdh N, Dondorp AM, Singhasivanon P, White NJ, Day NPJ. 2007. Validation and application of a liquid chromatographic-mass spectrometric method for determination of artesunate in pharmaceutical samples. J Pharm Biomed Anal, 45 (1), pp. 149-153. | Show Abstract | Read more

A simple and rapid liquid chromatographic-mass spectrometric assay for the evaluation of artesunate in vials for injection has been developed and validated. The content of each vial was dissolved in 3.0 mL of methanol using a SGE analytical syringe (1.0 mL). Each sample was diluted to a theoretical concentration of 1000 ng/mL and analysed in triplicate. Three replicates of calibration standards at concentrations 500, 1000 and 1500 ng/mL were used to construct a calibration curve. Artesunate was analysed by liquid chromatography with atmospheric pressure chemical ionisation (APCI) mass spectrometric (MS) detection on a Hypersil Gold column (100 mm x 4.6 mm) using a mobile phase containing methanol-ammonium acetate 10 mM pH 5.3 (70:30, v/v) at a flow rate of 1 mL/min. The assay was implemented for the analysis of artesunate for injection purchased from Guilin Pharmaceutical Company in China.

Arreesrisom P, Dondorp AM, Looareesuwan S, Udomsangpetch R. 2007. Suppressive effects of the anti-oxidant N-acetylcysteine on the anti-malarial activity of artesunate. Parasitol Int, 56 (3), pp. 221-226. | Show Abstract | Read more

The anti-oxidant drug N-acetylcysteine (NAC) has been proposed as adjunctive treatment in severe falciparum malaria. However, this might inhibit the anti-malarial drug action of the artemisinins, which are thought to exert their parasitocidal action through oxidative damage. We studied the interaction between NAC and artesunate as well as quinine in an in vitro drug sensitivity assay. Combination with NAC reduced the parasitocidal effect of artesunate only within the first 6 h of incubation, whereas no interaction was observed with quinine. Pre-incubation of P. falciparum with NAC resulted in a similar inhibitory effect on the anti-malarial activity of artesunate, whereas no inhibition was observed when NAC was added 2 h after parasite exposure to artesunate. Assessment of parasite maturation inhibition by the standard Giemsa's staining was in accordance with the use of a vital staining. The results herein caution the use of adjunctive treatment for malaria infection. Combination of antagonistic drugs may lead to adverse effects.

Nguansangiam S, Day NPJ, Hien TT, Mai NTH, Chaisri U, Riganti M, Dondorp AM, Lee SJ, Phu NH, Turner GDH et al. 2007. A quantitative ultrastructural study of renal pathology in fatal Plasmodium falciparum malaria. Trop Med Int Health, 12 (9), pp. 1037-1050. | Show Abstract | Read more

OBJECTIVE: To use electron microscopy to examine the role of parasitized red blood cell (PRBC) sequestration in the pathogenesis of acute renal failure in severe falciparum malaria. METHODS: Ultrastructural pathological examination of renal tissues from Southeast Asian adults (n = 63) who died from severe falciparum malaria. Qualitative and quantitative determination of the major pathological features of disease, including PRBC and leukocyte sequestration. Clinico-pathological correlation with the pre-mortem clinical picture and peripheral parasite count. RESULTS: There was a high incidence of malaria-associated renal failure in this population (> 40%) and a correlation between this incidence, severe malarial anaemia and shock. Pathological features included PRBC sequestration in glomerular and tubulo-interstitial vessels, acute tubular damage and mild glomerular hypercellularity resulting from the accumulation of host monocytes within glomerular capillaries. No evidence for an immune complex mediated glomerulonephritis was found. There was a correlation between parasite sequestration in the kidney and pre-mortem renal failure, although overall levels of sequestration were relatively low. Levels of sequestration (Knob+ PRBC) were significantly higher in malaria-associated renal failure than in fatal cases without renal failure (P = 0.005). CONCLUSION: Malaria-associated renal failure is a common and serious complication of severe Plasmodium falciparum malaria in this population, associated with acute tubular injury rather than glomerulonephritis, and linked to localization of host monocytes in the kidney as well as sequestration of PRBCs.

Wiersinga WJ, Wieland CW, van der Windt GJW, de Boer A, Florquin S, Dondorp A, Day NP, Peacock SJ, van der Poll T. 2007. Endogenous interleukin-18 improves the early antimicrobial host response in severe melioidosis. Infect Immun, 75 (8), pp. 3739-3746. | Show Abstract | Read more

Melioidosis is caused by the soil saprophyte Burkholderia pseudomallei and is endemic in Southeast Asia. The pathogenesis of melioidosis is still largely unknown, although gamma interferon (IFN-gamma) seems to play an obligatory role in host defense. Previously, we have shown that IFN-gamma production in melioidosis is controlled in part by interleukin-18 (IL-18). The aim of the present study was to determine the role of IL-18 in the immune response to B. pseudomallei. For this the following investigations were performed. (i) Plasma IL-18 and blood monocyte IL-18 mRNA levels were elevated in 34 patients with culture-proven melioidosis compared to the levels in 32 local healthy controls; in addition, IL-18 binding protein levels were markedly elevated in patients, strongly correlating with mortality. (ii) IL-18 gene-deficient (IL-18 knockout [KO]) mice showed accelerated mortality after intranasal infection with a lethal dose of B. pseudomallei, which was accompanied by enhanced bacterial growth in their lungs, livers, spleens, kidneys, and blood at 24 and 48 h postinfection, compared to wild-type mice. In addition, IL-18 KO mice displayed evidence of enhanced hepatocellular injury and renal insufficiency. Together, these data indicate that the enhanced production of IL-18 in melioidosis is an essential part of a protective immune response to this severe infection.

Dondorp AM, Silamut K, Charunwatthana P, Chuasuwanchai S, Ruangveerayut R, Krintratun S, White NJ, Ho M, Day NPJ. 2007. Levamisole inhibits sequestration of infected red blood cells in patients with falciparum malaria. J Infect Dis, 196 (3), pp. 460-466. | Show Abstract | Read more

BACKGROUND: Sequestration of infected red blood cells (iRBCs) in the microcirculation is central to the pathophysiology of falciparum malaria. It is caused by cytoadhesion of iRBCs to vascular endothelium, mediated through the binding of Plasmodium falciparum erythrocyte membrane protein-1 to several endothelial receptors. Binding to CD36, the major vascular receptor, is stabilized through dephosphorylation of CD36 by an alkaline phosphatase. This is inhibited by the alkaline phosphatase-inhibitor levamisole, resulting in decreased cytoadhesion. METHODS: Patients with uncomplicated falciparum malaria were randomized to receive either quinine treatment alone or treatment with a single 150-mg dose of levamisole as an adjunct to quinine. Peripheral blood parasitemia and parasite stage distribution were monitored closely over time. RESULTS: Compared with those in control subjects, peripheral blood parasitemias of mature P. falciparum parasites increased during the 24 h after levamisole administration (n=21; P=.006). The sequestration ratio (between observed and expected peripheral blood parasitemia) of early trophozoite and midtrophozoite parasites increased after levamisole treatment, with near complete prevention of early trophozoite sequestration and >65% prevention of midtrophozoite sequestration. CONCLUSION: These findings strongly suggest that levamisole decreases iRBC sequestration in falciparum malaria in vivo and should be considered as a potential adjunctive treatment for severe falciparum malaria. TRIAL REGISTRATION: Current Controlled Trials identifier: 15314870.

Wiersinga WJ, Wieland CW, Dessing MC,