Artemisinin Monotherapy Research Articles

Who continues to stock oral artemisinin monotherapy? Results of a provider survey in Myanmar.

BackgroundArtemisinin-based combination therapy (ACT) is a key strategy for global malaria elimination efforts. However, the development of artemisinin-resistant malaria parasites threatens progress and continued usage of oral artemisinin monotherapies (AMT) predisposes the selection of drug resistant strains. This is particularly a problem along the Myanmar/Thailand border. The artemisinin monotherapy replacement programme (AMTR) was established in 2012 to remove oral AMT from stocks in Myanmar, specifically by replacing oral AMT with quality-assured ACT and conducting behavioural change communication activities to the outlets dispensing anti-malarial medications. This study attempts to quantify the characteristics of outlet providers who continue to stock oral AMT despite these concerted efforts.MethodsA cross-sectional survey of all types of private sector outlets that were stocking anti-malarial drugs in 13 townships of Eastern Myanmar was implemented from July to August 2014. A total of 573 outlets were included. Bivariate and multivariable logistic regressions were conducted to assess outlet and provider-level characteristics associated with stocking oral AMT.ResultsIn total, 2939 outlets in Eastern Myanmar were screened for presence of any anti-malarial drugs in August 2014. The study found that 573 (19.5 %) had some kind of oral anti-malarial drug in stock at the time of survey and among them, 96 (16.8 %) stocked oral AMT. In bivariate analyses, compared to health care facilities, itinerant drug vendors, retailers and health workers were less likely to stock oral AMT (33.3 vs 12.9, 10.0, 8.1 %, OR = 0.30, 0.22, 0.18, respectively). Providers who cut blister pack or sell partial courses (40.6 vs 11.7 %, OR 5.18, CI 3.18–8.44) and those who based their stock decision on consumer demand (32.8 vs 12.1 %, OR 3.54, CI 2.21–5.63) were more likely to stock oAMT. Multivariate logistic regressions produced similar significant associations.ConclusionPrivate healthcare facilities and drug shops and providers who prioritize consumers’ demand instead of recommended practices were more likely to stock oral AMT. Malaria elimination strategies should include targeted interventions to effectively reach those outlets.

Correlation between Cyclin Dependent Kinases and Artemisinin-Induced Dormancy in Plasmodium falciparum In Vitro.

BackgroundArtemisinin-induced dormancy provides a plausible explanation for recrudescence following artemisinin monotherapy. This phenomenon shares similarities with cell cycle arrest where cyclin dependent kinases (CDKs) and cyclins play an important role.MethodsTranscription profiles of Plasmodium falciparum CDKs and cyclins before and after dihydroartemisinin (DHA) treatment in three parasite lines, and the effect of CDK inhibitors on parasite recovery from DHA-induced dormancy were investigated.ResultsAfter DHA treatment, parasites enter a dormancy phase followed by a recovery phase. During the dormancy phase parasites up-regulate pfcrk1, pfcrk4, pfcyc2 and pfcyc4, and down-regulate pfmrk, pfpk5, pfpk6, pfcrk3, pfcyc1 and pfcyc3. When entering the recovery phase parasites immediately up-regulate all CDK and cyclin genes. Three CDK inhibitors, olomoucine, WR636638 and roscovitine, produced distinct effects on different phases of DHA-induced dormancy, blocking parasites recovery.ConclusionsThe up-regulation of PfCRK1 and PfCRK4, and down regulation of other CDKs and cyclins correlate with parasite survival in the dormant state. Changes in CDK expression are likely to negatively regulate parasite progression from G1 to S phase. These findings provide new insights into the mechanism of artemisinin-induced dormancy and cell cycle regulation of P. falciparum, opening new opportunities for preventing recrudescence following artemisinin treatment.

Oral artemisinin monotherapy removal from the private sector in Eastern Myanmar between 2012 and 2014.

BackgroundIn 2012 the Artemisinin Monotherapy Therapy Replacement (AMTR) project was implemented in Eastern Myanmar to increase access to subsidized, quality-assured artemisinin combination therapy (ACT) and to remove oral artemisinin monotherapy (AMT) from the private sector. The aim of this paper is to examine changes over time in the private sector anti-malarial landscape and to illustrate the value of complementary interventions in the context of a national ACT subsidy.MethodsThree rounds of cross-sectional malaria medicine outlet surveys were conducted, in 2012, 2013 and 2014. Project intervention areas were selected from the Myanmar Artemisinin Resistance Containment (MARC) area. Provider detailing was implemented in these selected areas. Comparison areas were selected outside of this catchment area, from townships in close proximity to the MARC framework. Within each domain, multi-staged sampling was used to select areas for the survey. Outlets with the potential to sell or distribute anti-malarials in the private sector were screened for eligibility.ResultsThe total number of outlets approached for an interview was as follows in the intervention and comparison areas, respectively: 2012, N = 2046 and 1612; 2013, N = 1636 and 1884; 2014, N = 2939 and 2941. The percentage of pharmacies, general retailers and mobile providers (classed as ‘priority outlets’) with oral AMT in stock on the day of the survey decreased over time in the intervention areas (2012 = 68 %; 2013 = 48 %; 2014 = 10 %). Conversely, quality-assured ACT availability increased among these outlets (2012 = 4 %; 2013 = 62 %; 2014 = 79 %). Relative oral AMT market share among priority outlets also decreased over time (2012 = 44 %; 2013 = 18 %; 2014 = 14 %), while market share of quality-assured ACT increased (2012 = 3 %; 2013 = 59 %; 2014 = 51 %). Among priority outlets in the comparison area, similar trends were observed, though changes over time were less substantial compared to the intervention area. Other outlet types (community health workers and health facilities) performed relatively well over time though modest improvements were also observed.ConclusionThe findings point to the successful design and implementation of a strategy to rapidly remove oral AMT from pharmacies, general retailers and mobile providers and to replace its use with quality-assured ACT. The evidence also highlights the importance of supporting interventions in the context of a high-level subsidy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1292-8) contains supplementary material, which is available to authorized users.

Evidence of successful malaria case management policy implementation in Cambodia: results from national ACTwatch outlet surveys.

BackgroundFor over a decade, Cambodia has implemented a number of policies and innovative strategies to increase access to quality malaria case management services and address the drivers of multi-drug resistance. This paper utilizes outlet survey trend data collected by the ACTwatch project to demonstrate how changes in Cambodian policy and strategies have led to shifts in anti-malarial markets.MethodsAnti-malarial ACTwatch outlet surveys were conducted in Cambodia in 2009 (June–July), 2011 (June–August) and 2013 (September–October). A census of all outlets with the potential to sell or distribute anti-malarials was conducted within a nationally representative sample of communes. Drug information, sales/distribution in the previous week, and retail price were collected for each anti-malarial in stock. Information on availability of malaria blood testing was also collected.ResultsA total of 7833 outlets were enumerated in 2009, 18,584 in 2011, and 16,153 in 2013. The percentage of public health facilities with at least one anti-malarial in stock on the day of the survey increased between 2009 (65.8 %) and 2011 (90.0 %) and remained high in 2013 (82.0 %). Similar trends were found for village malaria workers (VMW). Overall, private sector availability of anti-malarials declined over time and varied by outlet type. By 2013 most anti-malarial stocking public health facilities (81.5 %), VMW (95.4 %), private for-profit health facilities (64.8 %), and pharmacies (71.9 %) had the countries first-line artemisinin-based combination therapy (ACT) treatment in stock. In 2013, 60 % of anti-malarials were delivered through the private sector, 40 % through the public sector, and the most common anti-malarial to be sold or distributed was the first-line ACT, comprising 62.8 % of the national market share. Oral artemisinin monotherapy, which had accounted for 6 % of total anti-malarial market share in 2009, was no longer reportedly sold/distributed in 2013. Malaria blood testing availability remained high over time among public facilities and VMW, with availability over 90 % in 2011 and 2013. Moderate availability was observed in the private sector.ConclusionsContinued implementation of successful public and private sector strategies in support of evolving malaria drug treatment policies will be important to protect the efficacy of anti-malarial medicines and ultimately facilitate malaria elimination in Cambodia by 2025.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-016-1200-2) contains supplementary material, which is available to authorized users.

Effect of policy change on the prescription pattern of antimalarial drugs of doctors in Benin City

This study evaluates the prescriptions of antimalarial medicines before and after the change in the National Antimalarial Policy and ascertain the adherence of prescribers to the change in policy. It's a Retrospective and Descriptive study. The study was carried out in the out-patient department of the University of Benin Teaching Hospital and Central Hospital, both in Benin City, Nigeria. The study examined case records of adult patients (≥ 18yrs) treated for uncomplicated malaria. One in every ten Case cards was sorted via Systematic Sampling. Results showed that prior to the policy change, Artesunate monotherapy was the most prescribed antimalarial(37.3%), followed by Sulphadoxine Pyrimethamine(SP) and Chloroquine(CQ) monotherapies,19.8% and 19.0% respectively. However three years into the change in policy, Artemether/Lumefantrine (AL) was the most prescribed, recording 25.2% as against 0.8% a year prior to the change in policy (2004).This was followed by Artesunate/Amodiaquine (AA) and Artesunate/Mefloquine (AM), 24.3% and 23.6% respectively. Artemisinin monotherapies and non-ACT combinations made up 10.3% and 5.1% of prescribed antimalarials in 2008 respectively. This study showed good adherence of prescribers to the change in antimalarial policy. This is encouraging, however there is need for stiffer regulations regarding Artemisinin monotherapies if success in malaria control must be achieved and the development of resistance prevented. Keywords: National Antimalarial Policy, Artemisinin-based Combination therapy, Plasmodium falciparum

<i>Artemisia annua</i>: A New Version of a Traditional Tea under Randomized, Controlled Clinical Trial for the Treatment of Malaria

Introduction: The traditional antimalarial tea Artemisia annua, indicated for centuries in China to treat fevers, is again arousing interest for the treatment of malaria due to improvements attained in the plant composition by a few Institutions throughout the world, including the State University of Campinas (UNICAMP), Brazil, increasing its principal component by more than 100 times as from standard varieties, giving 1% in artemisinin and an expressive biomass yield such as 2 tons of dried leaves/hectare. Clinical trials carried out with this material in African countries have proven its therapeutic potential for a new generation of Artemisia tea in the treatment of falciparum malaria. In addition to artemisinin, recent studies have identified and quantified other compounds present in the crude extract and characterized their contributions to the anti-malarial efficacy, including their action against chloroquine-resistant strains. The majority of the clinical trials carried out with Artemisia tea in African countries have shown that the control of the parasitaemia is efficient in the initial treatment period, but few trials have followed the patients up to the 28th day. This first clinical trial carried out in Brazil with the A. annua infusion, after toxicological trials that defined the safety of this form of medication. Methods: The therapeutic efficacy of the tea was measured in patients with falciparum malaria over 28 days, comparing it with the current first-line treatment namely artemether-lumefantrine (Coartem?). The trial was carried out in controlled groups according to official protocol approved by the National Ethics in Research Committee (CONEP: 77/ 2011) and a rigorous control of the 17 patients with non-serious cases of falciparum malaria, recruited in the following three municipalities of the State of Para, Brazil: Tucurui, Goianesia do Para and Anajas. The tea group received the infusion prepared in the proportion of 1.25 g of dry leaves of the variety CPQBA with 1% artemisinin for 250 mL of just boiled water, taken every 6 hours for 7 days, giving a total of approximately 175 mg of artemisinin, whilst the artemether-lumefantrine (Coartem?) group received a total of 525 mg of artemisinin equivalent to artemether. Results: The parasitaemia by the tea treatment became negative in the first days, even though it was administered with a dose that was one third of the recommended dose of artemisinin. However, as in the case artemisinin or artesunate monotherapies, 57.1% of the patients treated with the A. annua tea presented type I resistance, with a return of the parasitaemia around the 14th or 21st day. The other patients in the tea group showed type II/III resistance without manifestation of any serious signs or symptoms. In these cases, according to the protocol, the patients were redirected for treatment with artemether-lumefantrin (Coartem?) with subsequent negativity of the parisitaemia. Discussion: The fact that the efficacy of the tea with 1/3 of the dose of artemisinin was similar to that of the full dose of this medication infers that other compounds present in the crude extract, probably flavonoids, had contributed to the negativity of the parasitaemia at the start of the treatment. Considering that the positive control group, where the compound derived from artemisinin (artemether) was associated with another antimalarial agent (lumefantrine), presented excellent efficacy throughout the entire control of the cure, future trials with the A. annua tea should use the same strategy of association with another antimalarial agent, preferably from A. annua itself, in order to extend its therapeutic action during the whole control period. The Artemisia annua tea in the form standardized and used in this research, should not substitute the most efficient treatment, but could be considered as an emergency therapeutic resource in the first hours of symptoms as a function of its availability, anti-inflammatory action and lack of side effects. Other regimes and standardizations deserve investigation, mainly those with a high content of arteannuin B, as occurs in the initial cultivation phase.

Prices and mark-ups on antimalarials: evidence from nationally representative studies in six malaria-endemic countries.

The private for-profit sector is an important source of treatment for malaria. However, private patients face high prices for the recommended treatment for uncomplicated malaria, artemisinin combination therapies (ACTs), which makes them more likely to receive cheaper, less effective non-artemisinin therapies (nATs). This study seeks to better understand consumer antimalarial prices by documenting and exploring the pricing behaviour of retailers and wholesalers. Using data collected in 2009–10, we present survey estimates of antimalarial retail prices, and wholesale- and retail-level price mark-ups from six countries (Benin, Cambodia, the Democratic Republic of Congo, Nigeria, Uganda and Zambia), along with qualitative findings on factors affecting pricing decisions. Retail prices were lowest for nATs, followed by ACTs and artemisinin monotherapies (AMTs). Retailers applied the highest percentage mark-ups on nATs (range: 40% in Nigeria to 100% in Cambodia and Zambia), whereas mark-ups on ACTs (range: 22% in Nigeria to 71% in Zambia) and AMTs (range: 22% in Nigeria to 50% in Uganda) were similar in magnitude, but lower than those applied to nATs. Wholesale mark-ups were generally lower than those at retail level, and were similar across antimalarial categories in most countries. When setting prices wholesalers and retailers commonly considered supplier prices, prevailing market prices, product availability, product characteristics and the costs related to transporting goods, staff salaries and maintaining a property. Price discounts were regularly used to encourage sales and were sometimes used by wholesalers to reward long-term customers. Pricing constraints existed only in Benin where wholesaler and retailer mark-ups are regulated; however, unlicensed drug vendors based in open-air markets did not adhere to the pricing regime. These findings indicate that mark-ups on antimalarials are reasonable. Therefore, improving ACT affordability would be most readily achieved by interventions that reduce commodity prices for retailers, such as ACT subsidies, pooled purchasing mechanisms and cost-effective strategies to increase the distribution coverage area of wholesalers.

Molecular Determinants of Artemisinin Resistance in k13 Gene of Plasmodium falciparum

Artemisinin-based combination therapy (ACT) is the first-line therapy in most malaria endemic countries. An impressive 47% reduction in the global mortality rate between 2000 and 2013 has been achieved by ACT and artemisinin (ART) monotherapy. However, artemisinin resistance (AR) by Plasmodium falciparum (P. falciparum) is now prevalent across south-east Asia (SEA). AR is indicated by delayed parasite clearance of more than 3 days after standard ART treatment and reduced in vitrosusceptibility. Recent work has shown association of AR with mutations in the propeller domain of the kelch gene on chromosome 13 (PF3D7_1343700, k13gene) of P. falciparum. The C580Y mutation of thek13gene is highly prevalent in Cambodia, Myanmar and eastern and western Thailand, while the F446I mutation is predominant in the China-Myanmar border regions as well as in Myanmar. AR has not reached India and Africa, where non-synonymous mutations not associated with delayed parasite clearance are present. Because the location of Myanmar is central between SEA and Africa, a country-specific strategy for Myanmar Artemisinin Resistance Containment (MARC) is necessary. Moreover, regular periodic tracking of prevalent molecular determinants such as C580Y and F446I mutations will be beneficial.

The Other Face of Artesunate: Southern Drug to Treat Northern Diseases

The Other Face of Artesunate: Southern Drug to Treat Northern Diseases

Persistent sub-microscopic parasitaemia after ACT treatment of African children

The efficacy of ACT for treating malaria patients infected with Plasmodium falciparum may be threatened by parasites with reduced responsiveness to artemisinins. Among 298 ACT-treated children from Mbita, Kenya, sub-microscopic persistence of P. falciparum on day 3 post-treatment was associated with subsequent microscopically detected parasitaemia at days 28 or 42. Parasite density post-treatment was measured by duplex probe qPCR at days 1, 2 and 3. DNA sequences of resistance-associated parasite loci pfcrt, pfmdr1, pfubp1 and pfap2mu were determined in the Mbita cohort before treatment, on days 2 and 3 after initiation of treatment and on the day of treatment failure. Among 298 ACT-treated children from Mbita, Kenya, sub-microscopic persistence of P. falciparum on day 3 post-treatment was associated with subsequent microscopically detected parasitaemia at days 28 or 42. Parasites surviving ACT on day 2 or day 3 post-treatment were significantly more likely than the baseline population to carry the wildtype haplotypes of pfcrt (CVMNK at codons 72-76; P < 0.001) and pfmdr1 (NFD at codons 86, 184, 1246; P < 0.001). In contrast, variant alleles of the novel candidate resistance genes pfap2mu (S160N/T; P = 0.006) and pfubp-1 (E1528D; P < 0.001) were significantly more prevalent post-treatment. No genetic similarities were found to parasites with reduced sensitivity to short-course artemisinin monotherapy, recently described in Cambodia. We conclude that, among treated children in western Kenya, certain multi-locus P. falciparum genotypes are more likely to survive ACT at sub-microscopic level, and contribute to onward transmission and subsequent patent recrudescence. These surviving parasites may have an important public health impact that has been overlooked. The possible role of both innate and acquired immune mechanisms in this phenomenon will be discussed.

The medicinal chemistry and drug development of novel antimalarials.

The medicinal chemistry and drug development of novel antimalarials.

Fatty acid synthesis and pyruvate metabolism pathways remain active in dihydroartemisinin-induced dormant ring stages of Plasmodium falciparum.

Artemisinin (ART)-based combination therapy (ACT) is used as the first-line treatment of uncomplicated falciparum malaria worldwide. However, despite high potency and rapid action, there is a high rate of recrudescence associated with ART monotherapy or ACT long before the recent emergence of ART resistance. ART-induced ring-stage dormancy and recovery have been implicated as possible causes of recrudescence; however, little is known about the characteristics of dormant parasites, including whether dormant parasites are metabolically active. We investigated the transcription of 12 genes encoding key enzymes in various metabolic pathways in P. falciparum during dihydroartemisinin (DHA)-induced dormancy and recovery. Transcription analysis showed an immediate downregulation for 10 genes following exposure to DHA but continued transcription of 2 genes encoding apicoplast and mitochondrial proteins. Transcription of several additional genes encoding apicoplast and mitochondrial proteins, particularly of genes encoding enzymes in pyruvate metabolism and fatty acid synthesis pathways, was also maintained. Additions of inhibitors for biotin acetyl-coenzyme A (CoA) carboxylase and enoyl-acyl carrier reductase of the fatty acid synthesis pathways delayed the recovery of dormant parasites by 6 and 4 days, respectively, following DHA treatment. Our results demonstrate that most metabolic pathways are downregulated in DHA-induced dormant parasites. In contrast, fatty acid and pyruvate metabolic pathways remain active. These findings highlight new targets to interrupt recovery of parasites from ART-induced dormancy and to reduce the rate of recrudescence following ART treatment.

Classification SAR Modeling of Diverse Quinolone Compounds for Antimalarial Potency Against Plasmodium falciparum

Both a development of resistance to artemisinin monotherapy and lack of effective vaccine against malaria have created the urgent need for the development of new and efficient antimalarial agents. In this background, we have developed here a linear discriminant analysis (LDA) model and a few 3D-pharmacophore models for the classification of diverse quinolone compounds based on their antimalarial potency against Plasmodium falciparum. The discriminant model shows 70% correct classification for the test set compounds into higher active and lower active analogues. The best pharmacophore model (Hypo-1) with a correlation coefficient of 0.83 shows one hydrogen bond acceptor (HBA) and two ring aromatic (RA) features as the essential structural requirements for antimalarial activity against P falciparum. Both the models may act as in silico filters for a virtual screening and could be utilized for the selection of higher active molecules falling within the applicability of the models.

Plasmodium falciparum founder populations in western Cambodia have reduced artemisinin sensitivity in vitro.

Reduced Plasmodium falciparum sensitivity to short-course artemisinin (ART) monotherapy manifests as a long parasite clearance half-life. We recently defined three parasite founder populations with long half-lives in Pursat, western Cambodia, where reduced ART sensitivity is prevalent. Using the ring-stage survival assay, we show that these founder populations have reduced ART sensitivity in vitro at the early ring stage of parasite development and that a genetically admixed population contains subsets of parasites with normal or reduced ART sensitivity.

Progress toward elimination of malaria in Nigeria: uptake of artemisinin-based combination therapies for the treatment of malaria in households in Benin City.

The Roll Back Malaria (RBM) Partnership converged in Abuja in 2000. In 2005, Nigeria adopted artemisinin-based combination therapies (ACTs) as first-line therapy for uncomplicated malaria. It was determined that by 2010, 80% of persons with malaria would be effectively treated. To describe household practices for malaria treatment in Benin City; to explore demographic characteristics that may influence use of ACTs. Multistage sampling technique was used to select households from each of the three local government areas in Benin City. Adult respondents were interviewed. Household reference persons (HRPs) were defined by International Labour Organization categories. Data were collected between December 2009 and February 2010 and were analyzed using Statistical Package for the Social Sciences Version 16.0, at a significance level of P < 0.05 (2-tailed). Of the 240 households selected, 217 were accessible, and respondents from 90% of these recalled the most recent episode (s) of malaria. One-third of malaria episodes had occurred in children younger than 5 years. ACTs were used in 4.9% of households; sulfadoxine-pyrimethamine was the chief non-ACT antimalarial, followed by artemisinin monotherapies. Patent medicine stores were the most common sources of antimalarial medicines (38.2%), followed by private hospitals (20.3%) and private pharmacies (10.6%). Only 8.3% of households got their medicines from government hospitals. Having a HRP in managerial or professional categories was associated with a 6 times higher odds of using ACTs, compared to other occupational categories [odds ratio (OR) 5.8; confidence interval (CI) 1.470-20.758, P = 0.016]. Fathers' tertiary or higher education was significantly associated with ACT use, but not mothers' (OR 0.054, CI 0.006-0.510; P = 0.011 and OR 0.905, CI 0.195-4.198; P = 0.898, respectively). Ten years after the historic Abuja meeting, only 5% of households in Benin City used ACTs for the treatment of malaria, sourcing medicines chiefly from patent medicine stores and private hospitals. Fathers' level of education was significantly associated with ACT use. Interventions to eliminate malaria from Nigeria should mainstream the men folk and health care providers outside government hospitals, in line with the Nigerian reality.

Clinical Case of Artesunate Resistant Plasmodium falciparum Malaria in Kolkata: A First Report

The World Health Organization has urged to set up artemisinin-based combination therapy (artemisinin and effective antimalarial drug) and gradually pull out oral artemisinin mono-therapies from the making of prescription due to their high recrudescence rates and to reduce the risk of drug resistance. Prescription practices by physicians and the availability of oral artemisinin monotherapies with pharmacists directly affect the pattern of their use as a result the first clinical case report of only artesunate resistant P. falciparum malaria has been found from Kolkata. A significant failure rate of artesunate and SP (9.5%) has recently been observed in the district Jalpaiguri, West Bengal, though no specific mutation has been observed in pfATPase6 gene. In view of the above findings to get a clear picture of artemisinin resistance in P. falciparum a thorough study is required involving in vivo, in vitro and molecular procedures in this vulnerable area.

Novel phenotypic assays for the detection of artemisinin-resistant Plasmodium falciparum malaria in Cambodia: in-vitro and ex-vivo drug-response studies

Artemisinin resistance in Plasmodium falciparum lengthens parasite clearance half-life during artemisinin monotherapy or artemisinin-based combination therapy. Absence of in-vitro and ex-vivo correlates of artemisinin resistance hinders study of this phenotype. We aimed to assess whether an in-vitro ring-stage survival assay (RSA) can identify culture-adapted P falciparum isolates from patients with slow-clearing or fast-clearing infections, to investigate the stage-dependent susceptibility of parasites to dihydroartemisinin in the in-vitro RSA, and to assess whether an ex-vivo RSA can identify artemisinin-resistant P falciparum infections. We culture-adapted parasites from patients with long and short parasite clearance half-lives from a study done in Pursat, Cambodia, in 2010 (registered with ClinicalTrials.gov, number NCT00341003) and used novel in-vitro survival assays to explore the stage-dependent susceptibility of slow-clearing and fast-clearing parasites to dihydroartemisinin. In 2012, we implemented the RSA in prospective parasite clearance studies in Pursat, Preah Vihear, and Ratanakiri, Cambodia (NCT01736319), to measure the ex-vivo responses of parasites from patients with malaria. Continuous variables were compared with the Mann-Whitney U test. Correlations were analysed with the Spearman correlation test. In-vitro survival rates of culture-adapted parasites from 13 slow-clearing and 13 fast-clearing infections differed significantly when assays were done on 0-3 h ring-stage parasites (10·88% vs 0·23%; p=0·007). Ex-vivo survival rates significantly correlated with in-vivo parasite clearance half-lives (n=30, r=0·74, 95% CI 0·50-0·87; p<0·0001). The in-vitro RSA of 0-3 h ring-stage parasites provides a platform for the molecular characterisation of artemisinin resistance. The ex-vivo RSA can be easily implemented where surveillance for artemisinin resistance is needed. Institut Pasteur du Cambodge and the Intramural Research Program, NIAID, NIH.

Patterns of treatment of reported malaria cases during pregnancy in a Nigerian hospital

Prompt and effective case management is one of the control measures for malaria during pregnancy. The objective of the study was to assess treatment patterns of presumed cases of malaria during pregnancy in a Nigerian tertiary health care facility. A cross-sectional study involving immediate postpartum women admitted to the maternity wards of the University of Benin Teaching Hospital was undertaken. History of occurrence and treatment practices of presumed malaria during the immediate past pregnancy were obtained from the women's medical case files and by interview, using a pre-developed data collection form. Two hundred and ninety-seven of the 428 study participants (69.4%) reported a total number of 544 cases of malaria in pregnancy (MiP). More than 85% (n = 469/544) of the reported MiP cases occurred after the first trimester, while 55.5% (302/544) occurred during the second trimester. Among the reported MiP cases, parasite-based diagnosis was done for only 8.6% (n = 47). The use of antimalarial medications was reported in the treatment of 86.6% of the total number of cases. Antimalarial medication was used across the 3 trimesters, including artemisinin-based combination therapy (49.6%), artemisinin monotherapy (15.2%), and other monotherapies, such as sulfadoxine-pyrimethamine, chloroquine, amodiaquine (33.3%), and oral quinine (2%). Sulfadoxine-pyrimethamine and artemisinin derivatives were used in the treatment of 38.8% and 34.7% of first trimester malaria cases, respectively. Parasite-based diagnosis prior to treatment was poorly practiced, and inappropriate antimalarial drug management of MiP was observed. Addressing these observed deficiencies is necessary in order to achieve success in the fight against malaria during pregnancy in Nigeria.

Artemisinin-based combination therapy availability and use in the private sector of five AMFm phase 1 countries

BackgroundIn 2009, the Global Fund to Fight AIDS, Tuberculosis and Malaria established the Affordable Medicines Facility-malaria (AMFm) in order to increase access to quality-assured artemisinin combination therapy (QAACT). AMFm Phase 1, which includes nine pilot programmes in eight countries, was launched in 2009. The objective of this study was to assess anti-malarial stock and purchase patterns at private outlets in five AMFm Phase 1 countries in regard to three of the core AMFm goals: increase the affordability of QAACT, increase the availability of QAACT, and crowd out artemisinin monotherapies and other substandard therapies.MethodsThe study was conducted between April and May 2012 and included interviews with personnel in 598 private pharmaceutical outlets in Ghana, Kenya, Nigeria, Tanzania, and Uganda. Questionnaires were administered at private retail outlets and the data were analyzed to assess within- and between-country differences in QAACT price, availability, and popularity.ResultsAMFm medications were less expensive than their non-AMFm counterparts, yet prices for both types were above country-specific suggested retail prices. Market penetration of AMFm QAACT in both urban and rural areas was high, although stock-outs of both AMFm and non-AMFm products were more common in rural compared with urban outlets in Ghana and Kenya (p = 0.0013). Government recommendation was the most significant factor influencing anti-malarial stock choices in urban (41.5%) and rural (31.9%) outlets. The three top-selling anti-malarials reported for both urban and rural areas in each country were, with the exception of rural Uganda and urban Nigeria, combination therapies.ConclusionsResults from this study indicate that the AMFm has not fully achieved its affordability and crowd-out objectives. Still, the final purchase price of AMFm QAACT was substantially lower than non-AMFm equivalents. Moreover, for both urban and rural areas, AMFm QAACT availability was found to be high, and the various forms of QAACT were the best-selling products among all anti-malarials. These findings suggest a continued need for initiatives like the AMFm that improve the affordability and accessibility of QAACT. Similar programmes may be especially effective if employed in combination with rapid diagnostic testing to ensure the appropriate use of these products.

Slow parasite clearance rates in response to artemether in patients with severe malaria

We recently reported artemisinin-resistant, uncomplicated Plasmodium falciparum malaria in Pursat, western Cambodia.1 Artemisinin resistance manifests as a slow parasite clearance rate (ie, a long parasite clearance half-life). A concern is that parasite clearance rates might be slower in patients with severe malaria2 who receive artemisinin monotherapy parenterally3 until they can take an artemisinin-based drug combination orally. To investigate this possibility, in 2010 we assessed parasite clearance in 30 patients with severe malaria in Pursat, with use of a protocol (ClinicalTrials.gov identifier: {type:clinical-trial,attrs:{text:NCT00341003,term_id:NCT00341003}}NCT00341003) approved by Cambodia’s National Ethics Committee for Health Research and the National Institute for Allergy and Infectious Diseases Institutional Review Board. Adults or parents of child participants gave written informed consent.