Stakeholder perceptions on the deployment of multiple first-line therapies for uncomplicated malaria: a qualitative study in the health district of Kaya, Burkina Faso.

BACKGROUND: In Burkina Faso, malaria remains the first cause of medical consultation and hospitalization in health centres. First-line case management of malaria in the country's health facilities is based on the use of artemisinin-based combination therapy (ACT). To optimize the use of these anti-malarial drugs in the perspective of mitigating the emergence of artemisinin resistance, which is a serious threat to malaria control and elimination, a pilot programme using multiple first-line therapies (MFTs) [three artemisinin-based combinations-pyronaridine-artesunate, dihydroartemisinin-piperaquine and artemether-lumefantrine] has been designed for implementation. As the success of this MFT pilot programme depends on the perceptions of key stakeholders in the health system and community members, the study aimed to assess their perceptions on the implementation of this strategy. METHODS: Semi-structured interviews, including 27 individual in-depth interviews and 41 focus groups discussions, were conducted with key stakeholders including malaria control policymakers and implementers, health system managers, health workers and community members. Volunteers from targets stakeholder groups were randomly selected. All interviews were recorded, transcribed and translated. Content analysis was performed using the qualitative software programme QDA Miner. RESULTS: The interviews revealed a positive perception of stakeholders on the implementation of the planned MFT programme. They saw the strategy as an opportunity to strengthen the supply of anti-malarial drugs and improve the management of fever and malaria. However, due to lack of experience with the products, health workers and care givers expressed some reservations about the effectiveness and side-effect profiles of the two anti-malarial drugs included as first-line therapy in the MFT programme (pyronaridine-artesunate, dihydroartemisinin-piperaquine). Questions were raised about the appropriateness of segmenting the population into three groups and assigning a specific drug to each group. CONCLUSION: The adherence of both populations and key stakeholders to the MFT implementation strategy will likely depend on the efficacy of the proposed drugs, the absence of, or low frequency of, side-effects, the cost of drugs and availability of the different combinations.

Attitudes, practices, and determinants of community care-seeking behaviours for fever/malaria episodes in the context of the implementation of multiple first-line therapies for uncomplicated malaria in the health district of Kaya, Burkina Faso.

BACKGROUND: Malaria case management relies on World Health Organization (WHO)-recommended artemisinin-based combination therapy (ACT), and a continuous understanding of local community knowledge, attitudes, and practices may be a great support for the success of malaria disease control efforts. In this context, this study aimed to identify potential facilitators or barriers at the community level to inform a health district-wide implementation of multiple first-line therapies (MFT) as a new strategy for uncomplicated malaria case management. METHODS: A community-based cross-sectional study using a mixed-method design was carried out from November 2018 to February 2019, in the health district (HD) of Kaya in Burkina Faso. Quantitative data were collected using a standardized questionnaire from 1394 individuals who had fever/malaria episodes four weeks prior to the survey. In addition, 23 focus group discussions (FGDs) were conducted targeting various segments of the community. Logistic regression models were used to assess the predictors of community care-seeking behaviours. RESULTS: Overall, 98% (1366/1394) of study participants sought advice or treatment, and 66.5% did so within 24 h of fever onset. 76.4% of participants preferred to seek treatment from health centres as the first recourse to care, 5.8% were treated at home with remaining drug stock, and 2.3% preferred traditional healers. Artemether-lumefantrine (AL) was by far the most used anti-malarial drug (98.2%); reported adherence to the 3-day treatment regimen was 84.3%. Multivariate analysis identified less than 5 km distance travelled for care (AOR = 2.7; 95% CI 2.1-3.7) and education/schooling (AOR = 1.8; 95% CI 1.3-2.5) as determinants of prompt care-seeking for fever. Geographical proximity (AOR = 1.5, 95% CI 1.2-2.1), having a child under five (AOR = 4.6, 95% CI 3.2-6.7), being pregnant (AOR = 6.5, 95% CI 1.9-22.5), and living in an urban area (AOR = 2.8, 95% CI 1.8-4.2) were significant predictors for visiting health centres. The FGDs showed that participants had good knowledge about malaria symptoms, prevention tools, and effective treatment. Behaviour change regarding malaria treatment and free medication for children under five were the main reasons for participants to seek care at health centres. CONCLUSIONS: The study showed appropriate knowledge about malaria and positive community care-seeking behaviour at health centres for fever/malaria episodes. This could potentially facilitate the implementation of a MFT pilot programme in the district. CLINICALTRIALS: gov Identifier: NCT04265573.

Persistent Submicroscopic Plasmodium falciparum Parasitemia 72 Hours after Treatment with Artemether-Lumefantrine Predicts 42-Day Treatment Failure in Mali and Burkina Faso.

A recent randomized controlled trial, the WANECAM (West African Network for Clinical Trials of Antimalarial Drugs) trial, conducted at seven centers in West Africa, found that artemether-lumefantrine, artesunate-amodiaquine, pyronaridine-artesunate, and dihydroartemisinin-piperaquine all displayed good efficacy. However, artemether-lumefantrine was associated with a shorter interval between clinical episodes than the other regimens. In a further comparison of these therapies, we identified cases of persisting submicroscopic parasitemia by quantitative PCR (qPCR) at 72 h posttreatment among WANECAM participants from 5 sites in Mali and Burkina Faso, and we compared treatment outcomes for this group to those with complete parasite clearance by 72 h. Among 552 evaluable patients, 17.7% had qPCR-detectable parasitemia at 72 h during their first treatment episode. This proportion varied among sites, reflecting differences in malaria transmission intensity, but did not differ among pooled drug treatment groups. However, patients who received artemether-lumefantrine and were qPCR positive at 72 h were significantly more likely to have microscopically detectable recurrent Plasmodium falciparum parasitemia by day 42 than those receiving other regimens and experienced, on average, a shorter interval before the next clinical episode. Haplotypes of pfcrt and pfmdr1 were also evaluated in persisting parasites. These data identify a possible threat to the parasitological efficacy of artemether-lumefantrine in West Africa, over a decade since it was first introduced on a large scale.

A randomized, double-blind, phase 2b study to investigate the efficacy, safety, tolerability and pharmacokinetics of a single-dose regimen of ferroquine with artefenomel in adults and children with uncomplicated Plasmodium falciparum malaria.

BACKGROUND: For uncomplicated Plasmodium falciparum malaria, highly efficacious single-dose treatments are expected to increase compliance and improve treatment outcomes, and thereby may slow the development of resistance. The efficacy and safety of a single-dose combination of artefenomel (800 mg) plus ferroquine (400/600/900/1200 mg doses) for the treatment of uncomplicated P. falciparum malaria were evaluated in Africa (focusing on children ≤ 5 years) and Asia. METHODS: The study was a randomized, double-blind, single-dose, multi-arm clinical trial in patients aged > 6 months to < 70 years, from six African countries and Vietnam. Patients were followed up for 63 days to assess treatment efficacy, safety and pharmacokinetics. The primary efficacy endpoint was the polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR) at Day 28 in the Per-Protocol [PP] Set comprising only African patients ≤ 5 years. The exposure-response relationship for PCR-adjusted ACPR at Day 28 and prevalence of kelch-13 mutations were explored. RESULTS: A total of 373 patients were treated: 289 African patients ≤ 5 years (77.5%), 64 African patients > 5 years and 20 Asian patients. None of the treatment arms met the target efficacy criterion for PCR-adjusted ACPR at Day 28 (lower limit of 95% confidence interval [CI] > 90%). PCR-adjusted ACPR at Day 28 [95% CI] in the PP Set ranged from 78.4% [64.7; 88.7%] to 91.7% [81.6; 97.2%] for the 400 mg to 1200 mg ferroquine dose. Efficacy rates were low in Vietnamese patients, ranging from 20 to 40%. A clear relationship was found between drug exposure (artefenomel and ferroquine concentrations at Day 7) and efficacy (primary endpoint), with higher concentrations of both drugs resulting in higher efficacy. Six distinct kelch-13 mutations were detected in parasite isolates from 10/272 African patients (with 2 mutations known to be associated with artemisinin resistance) and 18/20 Asian patients (all C580Y mutation). Vomiting within 6 h of initial artefenomel administration was common (24.6%) and associated with lower drug exposures. CONCLUSION: The efficacy of artefenomel/ferroquine combination was suboptimal in African children aged ≤ 5 years, the population of interest, and vomiting most likely had a negative impact on efficacy. Trial registration ClinicalTrials.gov, NCT02497612. Registered 14 Jul 2015, https://clinicaltrials.gov/ct2/show/NCT02497612?term=NCT02497612&draw=2&rank=1.

Extended spectrum beta-lactamase and fluoroquinolone resistance genes among Escherichia coli and Salmonella isolates from children with diarrhea, Burkina Faso.

BACKGROUND: The emergence and spread of multidrug-resistant gram-negative bacteria (MDR) has become a major public health concern worldwide. This resistance is caused by enzymes-mediated genes (i.e., extended spectrum beta-lactamases) that are common in certain Enterobacterioceae species. However, the distribution of these genes is poorly documented in Burkina Faso. This study aims to determine the prevalence and distribution of the resistant genes coding for broad spectrum beta-lactamases and quinolones in rural Burkina Faso. METHODS: Multiplex PCR assays were carried out to detect ESBL-encoding genes, including blaOXA, blaTEM, blaCTX-M, blaSHV. The assays also assessed the presence of quinolone resistance gene namely qnrA, qnrB and qnrS in the quinolone-resistance DEC and Salmonella strains. RESULTS: The Extended-Spectrum Beta-Lactamases (ESBL) resistance phenotype was reported in all the E. coli isolates (5/5). Cross-resistance phenotype to quinolones (CRQ) was shown by one Salmonella strain (1/9) and three E. coli (3/5). Cross-resistance phenotypes to fluoroquinolones (CRFQ) were harboured by one Salmonella (1/9) and carbapenemase phenotypes were detected in two E. coli strains (2/5). Whilst the blaOXA genes were detected in 100% (5/5) of E. coli isolates and in 33.33% (3/9) Salmonella isolates. One strain of E. coli (1/5) harbored the blaCTX-M gene and the qnrB gene simultaneously. CONCLUSIONS: This study identified ß-lactam (bla) and quinolone resistance (qnr) genes in multidrug-resistant E. coli and Salmonella spp. in rural Burkina Faso. Our finding which highlighted the enterobacteriaceae strains resistance to ß-lactams and quinolones are of high interest for adequate management of antimicrobial resistant genes outbreak in Burkina Faso.

Biology of Plasmodium falciparum gametocyte sex ratio and implications in malaria parasite transmission.

While significant advances have been made in understanding Plasmodium falciparum gametocyte biology and its relationship with malaria parasite transmission, the gametocyte sex ratio contribution to this process still remains a relevant research question. The present review discusses the biology of sex determination in P. falciparum, the underlying host and parasite factors, the sex specific susceptibility to drugs, the effect of sex ratio dynamics on malaria parasite transmission and the development of gametocyte sex specific diagnosis tools. Despite the inherent differences across several studies and approaches, the emerging picture highlights a potentially relevant contribution of the P. falciparum gametocyte sex ratio in the modulation of malaria parasite transmission. The increasing availability of molecular methods to measure gametocyte sex ratio will enable evaluation of important parameters, such as the impact of drug treatment on gametocyte sex ratio in vitro and in vivo as well as the changes of gametocyte sex ratios in natural infections, key steps towards elucidating how these parameters affect parasite infectiousness to the mosquito vectors.

Novel genotyping tools for investigating transmission dynamics of Plasmodium falciparum.

BACKGROUND: Differentiation between gametocyte-producing Plasmodium falciparum clones depends on both high levels of stage-specific transcripts and high genetic diversity of the selected genotyping marker obtained by a high-resolution typing method. By analyzing consecutive samples of one host, the contribution of each infecting clone to transmission and the dynamics of gametocyte production in multiclone infections can be studied. METHODS: We have evaluated capillary electrophoresis based differentiation of 6 length-polymorphic gametocyte genes. RNA and DNA of 25 µL whole blood from 46 individuals from Burkina Faso were simultaneously genotyped. RESULTS: Highest discrimination power was achieved by pfs230 with 18 alleles, followed by pfg377 with 15 alleles. When assays were performed in parallel on RNA and DNA, 85.7% of all pfs230 samples and 59.5% of all pfg377 samples contained at least one matching genotype in DNA and RNA. CONCLUSIONS: The imperfect detection in both, DNA and RNA, was identified as major limitation for investigating transmission dynamics, owing primarily to the volume of blood processed and the incomplete representation of all clones in the sample tested. Abundant low-density gametocyte carriers impede clone detectability, which may be improved by analyzing larger volumes and detecting initially sequestered gametocyte clones in follow-up samples.

Lessons learned from the use of HRP-2 based rapid diagnostic test in community-wide screening and treatment of asymptomatic carriers of Plasmodium falciparum in Burkina Faso.

BACKGROUND: Rapid diagnostic tests (RDTs) are immune chromatographic tests targeting antigens of one or more Plasmodium species and offer the potential to extend accurate malaria diagnosis in endemic areas. In this study, the performance of Plasmodium falciparum-specific histidine-rich protein-2 (PfHRP-2) RDT in the detection of asymptomatic carriers from a hyperendemic region of Burkina Faso was compared with microscopy to gain further insight on its relevance in community-based interventions. METHODS: The performance of HRP-2 test was evaluated in terms of sensitivity, specificity, positive and negative predictive values, discordant values, likelihood ratios, accuracy, and precision using microscopy as the 'gold standard'. This analysis was carried out in a controlled, parallel, cluster-randomized (18 clusters; 1:1) study in children and adults. The effect of systematic treatment of P. falciparum asymptomatic carriers during three consecutive monthly community screening campaigns on the incidence of symptomatic malaria episodes over a 12-month period was compared with no treatment of asymptomatic carriers. RESULTS: Sensitivity of HRP-2 test in asymptomatic carriers was higher in campaign 1 (92.4%) when compared to campaign 2 (84.0%) and campaign 3 (77.8%). The sensitivity of HRP-2 test increased as parasite density increased across all the age groups. Highest sensitivity (≥97.0%) was recorded at parasite densities of 1,000-4,999/µl, except for children aged 10 to 14 years. The specificity of HRP-2 test was comparable across age groups and highest in campaign 3 (95.9%). The negative predictive values were high across the three campaigns (≥92.7%) while the positive predictive values ranged from 23.2 to 73.8%. False-positive and false-negative rates were high in campaign 1 and campaign 3, respectively. CONCLUSION: The performance of HRP-2 test in detecting asymptomatic carriers of P. falciparum varied by age and parasite density. Although the use of HRP-2 test is beneficial for the diagnosis of acute malaria, its low sensitivity in screening asymptomatic carriers may limit its utility in pre-elimination interventional settings. The use of a practical and more sensitive test such as loop-mediated isothermal amplification in combination with a cost effective HRP-2 test may be worth exploring in such settings.

Schistosomiasis in Burkina Faso: review on 60 years' research.

Schistosomiasis is a common neglected helminthic disease in the tropics and sub-tropics particularly in sub-Saharan countries including Burkina Faso. It is the second world parasitic endemic disease after malaria. The two prevalent species infecting human in Burkina Faso are are Schistosoma haematobium and Schistosoma mansoni which cause respectively the urogenital schistosomiasis and the intestinal schistosomiasis. This review aimed at providing an historical perspective of research on schistosomiasis from 1960 to 2020 and shedding some light on the gaps in knowledge useful for the disease control and the elimination efforts in Burkina Faso. Formal systematic review was not followed for this review. Published studies on the schistosomiasis in Burkina Faso over the period from 1960 to 2020, were search in Medline, PubMed, Google Scholar, EMBASE and the libraries of main universities in Burkina Faso namely: Joseph KI-ZERBO University and Nazi BONI University. The following key words used were: Schistosomiasis, Bilharzia, Bulinus, Biomphalaria, Upper-Volta and Burkina Faso. Over a period of 60 years, a total of 87 scientific research documents were identified. The original scientific research articles represent the majority of the scientific documents found (65.52%). Urinary schistosomiasis was the most common from the documentation. There has been a gradual decrease in the prevalence, more significantly since the implementation of the National Schistosomiasis Control Program (NSCP). The effectiveness of the NSCP could therefore contribute to the elimination of schistosomiasis in Burkina Faso.

Plasmodium falciparum gametocyte production correlates with genetic markers of parasite replication but is not influenced by experimental exposure to mosquito biting.

BACKGROUND: Plasmodium blood-stage parasites balance asexual multiplication with gametocyte development. Few studies link these dynamics with parasite genetic markers in vivo; even fewer in longitudinally monitored infections. Environmental influences on gametocyte formation, such as mosquito exposure, may influence the parasite's investment in gametocyte production. METHODS: We investigated gametocyte production and asexual multiplication in two Plasmodium falciparum infected populations; a controlled human malaria infection (CHMI) study and a 28-day observational study in naturally infected individuals in Burkina Faso with controlled mosquito exposure. We measured gene transcript levels previously related to gametocyte formation (ap2-g, surfin1.2, surfin13.1, gexp-2) or inhibition of asexual multiplication (sir2a) and compared transcript levels to ring-stage parasite and mature gametocyte densities. FINDINGS: Three of the five markers (ap2-g, surfin1.2, surfin13.1) predicted peak gametocytaemia in the CHMI study. An increase in all five markers in natural infections was associated with an increase in mature gametocytes 14 days later; the effect of sir2a on future gametocytes was strongest (fold change = 1.65, IQR = 1.22-2.24, P = 0.004). Mosquito exposure was not associated with markers of gametocyte formation (ap2-g P = 0.277; sir2a P = 0.499) or carriage of mature gametocytes (P = 0.379). INTERPRETATION: All five parasite genetic markers predicted gametocyte formation over a single cycle of gametocyte formation and maturation in vivo; sir2a and ap2-g were most closely associated with gametocyte growth dynamics. We observed no evidence to support the hypothesis that exposure to Anopheles mosquito bites stimulates gametocyte formation. FUNDING: This work was funded by the Bill & Melinda Gates Foundation (INDIE OPP1173572), the European Research Council fellowship (ERC-CoG 864180) and UKRI Medical Research Council (MR/T016272/1) and Wellcome Center (218676/Z/19/Z).

Characterization of Plasmodium Falciparum Resistance Genes to Common Antimalarial Drugs in Semi-urban Areas of Burkina Faso.

INTRODUCTION: Malaria still remains the most frequent parasitic disease on the world with, in 2022, 249 million cases and 608,000 deaths worldwide. Malaria control is compromised by the spread of the parasite's resistance to available antimalarials. The objective of our study is to characterize the Plasmodium falciparum resistance genes to common antimalarial drugs in semi-urban areas of Burkina Faso. MATERIALS AND METHODS: This is a prospective cross-sectional study whose collection took place from June to October 2021 and from June to October 2022 in five health facilities in Burkina Faso. The molecular analysis based on PCR-RFLP took place from January to June 2023 at Centre National de Recherche et de Formation (CNRFP) to determine resistance genes such as Pfcrt, Pfmdr1, Pfdhps, and Pfdhfr. RESULTS: A total of 150 samples were analyzed giving a prevalence of 46.67, 1.33, 0.67, 20, 82, and 4.67%, for Pfcrt 76 T, Pfmdr1 86Y, Pfdhps 437G, Pfdhfr 51I, Pfdhfr 59R, and Pfdhfr 108N mutations, respectively. There are no mutations observed Pfdhps 540E and Pfdhfr 164L positions. However, mutation on Pfdhfr 59R position was the most common. In addition, triple mutation (Pfdhps 437G + Pfdhfr 59R + Pfdhfr 108N) was found with a low frequency which is 0.67%. CONCLUSION: Surveillance of Plasmodium falciparum resistance markers to antimalarial drugs, remains one of the priorities in the context of the control or malaria elimination.

Understanding and maximising the community impact of seasonal malaria chemoprevention in Burkina Faso (INDIE-SMC): study protocol for a cluster randomised evaluation trial.

INTRODUCTION: Seasonal malaria chemoprevention (SMC) involves repeated administrations of sulfadoxine-pyrimethamine plus amodiaquine to children below the age of 5 years during the peak transmission season in areas of seasonal malaria transmission. While highly impactful in reducing Plasmodium falciparum malaria burden in controlled research settings, the impact of SMC on infection prevalence is moderate in real-life settings. It remains unclear what drives this efficacy decay. Recently, the WHO widened the scope for SMC to target all vulnerable populations. The Ministry of Health (MoH) in Burkina Faso is considering extending SMC to children below 10 years old. We aim to assess the impact of SMC on clinical incidence and parasite prevalence and quantify the human infectious reservoir for malaria in this population. METHODS AND ANALYSIS: We will perform a cluster randomised trial in Saponé Health District, Burkina Faso, with three study arms comprising 62 clusters of three compounds: arm 1 (control): SMC in under 5-year-old children, implemented by the MoH without directly observed treatment (DOT) for the full course of SMC; arm 2 (intervention): SMC in under 5-year-old children, with DOT for the full course of SMC; arm 3 (intervention): SMC in under 10-year-old children, with DOT for the full course of SMC. The primary endpoint is parasite prevalence at the end of the malaria transmission season. Secondary endpoints include the impact of SMC on clinical incidence. Factors affecting SMC uptake, treatment adherence, drug concentrations, parasite resistance markers and transmission of parasites will be determined. ETHICS AND DISSEMINATION: The London School of Hygiene & Tropical Medicine's Ethics Committee (29193) and the Burkina Faso National Medical Ethics Committee (Deliberation No 2023-05-104) approved this study. The findings will be presented to the community; disease occurrence data and study outcomes will also be shared with the Burkina Faso MoH. Findings will be published irrespective of their results. TRIAL REGISTRATION NUMBER: NCT05878366.

Variation in haematological parameters in children less than five years of age with asymptomatic Plasmodium infection: implication for malaria field studies.

During the season of high malaria transmission, most children are infected by Plasmodium, which targets red blood cells (RBCs), affecting haematological parameters. To describe these variations, we examined the haematological profiles of two groups of children living in a malaria-endemic area. A cross-sectional survey was conducted at the peak of the malaria transmission season in a rural area of Burkina Faso. After informed consent and clinical examination, blood samples were obtained from the participants for malaria diagnosis and a full blood count. Of the 414 children included in the analysis, 192 were not infected with Plasmodium, whereas 222 were asymptomatic carriers of Plasmodium infection. The mean age of the infected children was 41.8 months (range of 26.4-57.2) compared to 38.8 months (range of 22.4-55.2) for the control group (p = 0.06). The asymptomatic infected children tended to have a significantly lower mean haemoglobin level (10.8 g/dL vs. 10.4 g/dL; p < 0.001), mean lymphocyte count (4592/µL vs. 5141/µL; p = 0.004), mean platelet count (266 x 10³/µL vs. 385 x 10³/µL; p < 0.001) and mean RBC count (4.388 x 10(6)/µL vs. 4.158 x 10(6)/µL; p < 0.001) and a higher mean monocyte count (1403/µL vs. 1192/µL; p < 0.001) compared to the control group. Special attention should be applied when interpreting haematological parameters and evaluating immune responses in asymptomatic infected children living in malaria-endemic areas and enrolled in vaccine trials.

Impact of Plasmodium falciparum infection on DNA methylation of circulating immune cells.

The regulation of immune cell responses to infection is a complex process that involves various molecular mechanisms, including epigenetic regulation. DNA methylation has been shown to play central roles in regulating gene expression and modulating cell response during infection. However, the nature and extent to which DNA methylation is involved in the host immune response in human malaria remains largely unknown. Here, we present a longitudinal study investigating the temporal dynamics of genome-wide in vivo DNA methylation profiles using 189 MethylationEPIC 850 K profiles from 66 children in Burkina Faso, West Africa, sampled three times: before infection, during symptomatic parasitemia, and after malaria treatment. The results revealed major changes in the DNA methylation profiles of children in response to both Plasmodium falciparum infection and malaria treatment, with widespread hypomethylation of CpGs upon infection (82% of 6.8 K differentially methylated regions). We document a remarkable reversal of CpG methylation profiles upon treatment to pre-infection states. These changes implicate divergence in core immune processes, including the regulation of lymphocyte, neutrophil, and myeloid leukocyte function. Integrative DNA methylation-mRNA analysis of a top differentially methylated region overlapping the pro-inflammatory gene TNF implicates DNA methylation of TNF cis regulatory elements in the molecular mechanisms of TNF regulation in human malaria. Our results highlight a central role of epigenetic regulation in mounting the host immune response to P. falciparum infection and in response to malaria treatment.

Feasibility and Acceptability of a Strategy Deploying Multiple First-Line Artemisinin-Based Combination Therapies for Uncomplicated Malaria in the Health District of Kaya, Burkina Faso.

(1) Background: Effective malaria case management relies on World Health Organization (WHO) recommended artemisinin-based combination therapies (ACTs), but partial resistance to artemisinin has emerged and is spreading, threatening malaria control and elimination efforts. The strategy of deploying multiple first-line therapies (MFT) may help mitigate this threat and extend the therapeutic life of current ACTs. (2) Methods: A district-wide pilot quasi-experimental study was conducted, deploying three different ACTs at the public health facility (PHF) level for uncomplicated malaria treatment from December 2019 to December 2020 in the health district (HD) of Kaya, Burkina Faso. Mixed methods, including household and health facility-based quantitative and qualitative surveys, were used to evaluate the pilot programme. (3) Results: A total of 2008 suspected malaria patients were surveyed at PHFs, of which 79.1% were tested by rapid diagnostic test (RDT) with 65.5% positivity rate. In total, 86.1% of the confirmed cases received the appropriate ACT according to the MFT strategy. The adherence level did not differ by study segment (p = 0.19). Overall, the compliance level of health workers (HWs) with MFT strategy was 72.7% (95% CI: 69.7-75.5). The odds of using PHF as the first source of care increased after the intervention (aOR = 1.6; 95% CI, 1.3-1.9), and the reported adherence to the 3-day treatment regimen was 82.1%; (95% CI: 79.6-84.3). Qualitative results showed a high acceptance of the MFT strategy with positive opinions from all stakeholders. (4) Conclusions: Implementing an MFT strategy is operationally feasible and acceptable by stakeholders in the health systems in Burkina Faso. This study provides evidence to support the simultaneous use of multiple first-line artemisinin combination therapies in malaria-endemic countries such as Burkina Faso.

Assessment of the transmission blocking activity of antimalarial compounds by membrane feeding assays using natural Plasmodium falciparum gametocyte isolates from West-Africa.

Antimalarial drugs that can block the transmission of Plasmodium gametocytes to mosquito vectors would be highly beneficial for malaria elimination efforts. Identifying transmission-blocking drugs currently relies on evaluation of their activity against gametocyte-producing laboratory parasite strains and would benefit from a testing pipeline with genetically diverse field isolates. The aims of this study were to develop a pipeline to test drugs against P. falciparum gametocyte field isolates and to evaluate the transmission-blocking activity of a set of novel compounds. Two assays were designed so they could identify both the overall transmission-blocking activity of a number of marketed and experimental drugs by direct membrane feeding assays (DMFA), and then also discriminate between those that are active against the gametocytes (gametocyte killing or sterilizing) or those that block development in the mosquito (sporontocidal). These DMFA assays used venous blood samples from naturally infected Plasmodium falciparum gametocyte carriers and locally reared Anopheles gambiae s.s. mosquitoes. Overall transmission-blocking activity was assessed following a 24 hour incubation of compound with gametocyte infected blood (TB-DMFA). Sporontocidal activity was evaluated following addition of compound directly prior to feeding, without incubation (SPORO-DMFA); Gametocyte viability was retained during 24-hour incubation at 37°C when gametocyte infected red blood cells were reconstituted in RPMI/serum. Methylene-blue, MMV693183, DDD107498, atovaquone and P218 showed potent transmission-blocking activity in the TB-DMFA, and both atovaquone and the novel antifolate P218 were potent inhibitors of sporogonic development in the SPORO-DMA. This work establishes a pipeline for the integral use of field isolates to assess the transmission-blocking capacity of antimalarial drugs to block transmission that should be validated in future studies.

Plasmodium falciparum Genetic Diversity and Resistance Genotype Profile in Infected Placental Samples Collected After Delivery in Ouagadougou.

Purpose: Intermittent preventive treatment with sulfadoxine-pyrimethamine is widely used for the prevention of malaria in pregnant women in Africa. Known resistance cases of sulfadoxine-pyrimethamine during pregnancy need to be follow up to support IPTp implementation in Burkina Faso. However, data on the development and spread of resistance to this molecule are lacking. This study aimed to investigating the genetic diversity of P. falciparum and the mutation prevalence in the dhfr and dhps genes infected from postpartum infected placentas. Patients and Methods: This was a prospective and cross-sectional study conducted between April 2019 and March 2020 in four health districts of Ouagadougou capital city. From the placentas collected after delivery, P. falciparum detection and mps1 and msp2 polymorphism analysis were performed by nested PCR. The resistance profile was checked after analyzing the mutation point on dhfr and dhps genes. Results: PCR-positive samples were estimated at 96% for msp1 and 98% for msp2. The polymorphism analysis showed that the RO33 and 3D7 allelic families were the most widespread with 62.5% and 91.83%, respectively. Multiple infections by msp1 and msp2 were frequent with 12.50% and 92.92%, respectively. The prevalence of individual dhfr mutation point, 51I, 108A, and 59R, was 1.96, 15.68, and 7.84, respectively, and the dhps mutation point, 437G, was 3.92. There is no detected mutation at the point 164L and 540E. The triple (51I+108A+59R) in dhfr and quadruple (51I+108A+59R+ 437G) mutation were not found. Conclusion: The results showed that Plasmodium falciparum has a high genetic diversity of msp1 and msp2. This suggests that dhfr and dhps mutant genotypes are potential early warning factors in the increase in the sulfadoxine-pyrimethamine resistance.

Safety and immunogenicity of BK-SE36/CpG malaria vaccine in healthy Burkinabe adults and children: a phase 1b randomised, controlled, double-blinded, age de-escalation trial.

Background: BK-SE36/CpG is a recombinant blood-stage malaria vaccine candidate based on the N-terminal Plasmodium falciparum serine repeat antigen5 (SE36), adsorbed to aluminium hydroxide gel and reconstituted, prior to administration, with synthetic oligodeoxynucleotides bearing CpG motifs. In healthy Japanese adult males, BK-SE36/CpG was well tolerated. This study assessed its safety and immunogenicity in healthy malaria-exposed African adults and children. Methods: A double-blind, randomised, controlled, age de-escalating clinical trial was conducted in an urban area of Ouagadougou, Burkina Faso. Healthy participants (n=135) aged 21-45 years (Cohort 1), 5-10 years (Cohort 2) and 12-24 months (Cohort 3) were randomised to receive three vaccine doses (Day 0, 28 and 112) of BK-SE36/CpG or rabies vaccine by intramuscular injection. Results: One hundred thirty-four of 135 (99.2%) subjects received all three scheduled vaccine doses. Vaccinations were well tolerated with no related Grade 3 (severe) adverse events (AEs). Pain/limitation of limb movement, headache in adults and fever in younger children (all mild to moderate in intensity) were the most frequently observed local and systemic AEs. Eighty-three of BK-SE36/CpG (91%) recipients and 37 of control subjects (84%) had Grade 1/2 events within 28 days post vaccination. Events considered by the investigator to be vaccine related were experienced by 38% and 14% of subjects in BK-SE36/CpG and control arms, respectively. Throughout the trial, six Grade 3 events (in 4 subjects), not related to vaccination, were recorded in the BK-SE36/CpG arm: 5 events (in 3 subjects) within 28 days of vaccination. All serious adverse events (SAEs) (n=5) were due to severe malaria (52-226 days post vaccination) and not related to vaccination. In all cohorts, BK-SE36/CpG arm had higher antibody titres after Dose 3 than after Dose 2. Younger cohorts had stronger immune responses (12-24-month-old > 5-10 years-old > 21-45 years-old). Sera predominantly reacted to peptides that lie in intrinsically unstructured regions of SE36. In the control arm, there were no marked fold changes in antibody titres and participants' sera reacted poorly to all peptides spanning SE36. Conclusion: BK-SE36/CpG was well-tolerated and immunogenic. These results pave the way for further proof-of-concept studies to demonstrate vaccine efficacy. Clinical trial registration: https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=1921, PACTR201701001921166.

Antibodies to malaria vaccine candidates are associated with chloroquine or sulphadoxine/pyrimethamine treatment efficacy in children in an endemic area of Burkina Faso.

BACKGROUND: Patient immune status is thought to affect the efficacy of anti-malarial chemotherapy. This is a subject of some importance, since evidence of immunity-related interactions may influence our use of chemotherapy in populations with drug resistance, as well as assessment of the value of suboptimal vaccines. The study aim was to investigate relationship between antibodies and anti-malarial drug treatment outcomes. METHODS: Some 248 children aged 0.5 and 15 years were recruited prior to the high malaria transmission season. Venous blood (5 ml) was obtained from each child to measure antibody levels to selected malaria antigens, using ELISA. Blood smears were also performed to assess drug efficacy and malaria infection prevalence. Children were actively followed up to record clinical malaria cases. RESULTS: IgG levels to MSP3 were always higher in the successfully treated group than in the group with treatment failure. The same observation was made for GLURP but the reverse observation was noticed for MSP1-19. Cytophilic and non-cytophilic antibodies were significantly associated with protection against all three antigens, except for IgG4 to MSP1-19 and GLURP. CONCLUSION: Acquired anti-malarial antibodies may play an important role in the efficacy of anti-malarial drugs in younger children more susceptible to the disease.

Haemoglobin variants and Plasmodium falciparum malaria in children under five years of age living in a high and seasonal malaria transmission area of Burkina Faso.

BACKGROUND: Genetic factors play a key role in determining resistance/susceptibility to infectious disease. Susceptibility of the human host to malaria infection has been reported to be influenced by genetic factors, which could be confounders if not taken into account in the assessment of the efficacy of interventions against malaria. This study aimed to assess the relationship between haemoglobin genotypes and malaria in children under five years in a site being characterized for future malaria vaccine trials. METHODS: The study population consisted of 452 children living in four rural villages. Hb genotype was determined at enrolment. Clinical malaria incidence was evaluated over a one-year period using combined active and passive surveillance. Prevalence of infection was evaluated via bi-annual cross-sectional surveys. At each follow-up visit, children received a brief clinical examination and thick and thin blood films were prepared for malaria diagnosis. A clinical malaria was defined as Plasmodium falciparum parasitaemia >2,500 parasites/µl and axillary temperature ≥37.5°C or reported fever over the previous 24 hours. RESULTS: Frequencies of Hb genotypes were 73.2% AA; 15.0% AC; 8.2% AS; 2.2% CC; 1.1% CS and 0.2% SS. Prevalence of infection at enrolment ranged from 61.9%-54.1% among AA, AC and AS children. After one year follow-up, clinical malaria incidence (95% CI) (episodes per person-year) was 1.9 (1.7-2.0) in AA, 1.6 (1.4-2.1) in AC, and 1.7 (1.4-2.0) in AS children. AC genotype was associated with lower incidence of clinical malaria relative to AA genotype among children aged 1-2 years [rate ratio (95% CI) 0.66 (0.42-1.05)] and 2-3 years [rate ratio (95% CI) 0.37 (0.18-0.75)]; an association of opposite direction was however apparent among children aged 3-4 years. AS genotype was associated with lower incidence of clinical malaria relative to AA genotype among children aged 2-3 years [rate ratio (95% CI) 0.63 (0.40-1.01)]. CONCLUSIONS: In this cohort of children, AC or AS genotype was associated with lower risk of clinical malaria relative to AA genotype only among children aged one to three years. It would be advisable for clinical studies of malaria in endemic regions to consider haemoglobin gene differences as a potentially important confounder, particularly among younger children.