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

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

Genetic Diversity of Polymorphic Vaccine Candidate Antigens (Apical Membrane Antigen-1, Merozoite Surface Protein-3, and Erythrocyte Binding Antigen-175) in Plasmodium falciparum Isolates from Western and Central Africa

The malaria vaccine candidate antigens erythrocyte binding antigen 175 (EBA-175), merozoite surface protein 3 (MSP-3), and apical membrane antigen (AMA-1) from Plasmodium falciparum isolates from countries in central and west Africa were assessed for allelic diversity. Samples were collected on filter paper from 600 P. falciparum-infected symptomatic patients in Cameroon, Republic of Congo, Burkina Faso, Ghana, and Senegal and screened for class-specific amplification fragments. Genetic diversity, assessed by mean heterozygosity, was comparable among countries. We detected a clinical increase in eba 175 F-allele frequency from west to east across the study region. No statistical difference in msp-3 allele distribution between countries was observed. The ama-1 3D7 alleles were present at a lower frequency in central Africa than in West Africa. We also detected little to no genetic differentiation among sampling locations. This finding indicates that, at least at the level of resolution offered by restriction fragment length polymorphism analysis, these antigens showed remarkable genetic homogeneity throughout the region sampled, perhaps caused by balancing selection to maintain a diverse array of antigen haplotyes

Clinical Variation of Plasmodium falciparum eba-175

The association between P. falciparum eba-175, ama-1, and msp-3 polymorphism in the pathogenicity of malaria disease was investigated. We therefore compared the prevalence of different alleles between symptomatic and asymptomatic malarial children under five years of age living in Burkina Faso. Blood filter papers were collected during the 2008 malaria transmission season from 228 symptomatic and 199 asymptomatic children under five years of age. All patients were living in the rural area of Saponé at about 50 km from Ouagadougou, the capital city of Burkina Faso. P. falciparum parasite DNA was extracted using QIAGEN kits and the alleles diversity was assessed by a nested PCR. PCR products were then digested by restriction enzymes based on already described polymorphic regions of the eba-175, ama-1, and msp-3 genes. The individual alleles eba-175_FCR3 and msp-3_K1 frequencies were statistically higher (p<0.0001) in the asymptomatic group compared to the symptomatic ones. No statistically significant difference was noted in the prevalence of ama-1-3D7, ama-1-K1, and ama-1-HB3 genotypes between the two groups (p>0.05). The comparative analysis of P. falciparum genotypes indicated that the polymorphism in eba-175 and msp-3 genotypes varied between asymptomatic and symptomatic clinical groups and may contribute to the pathogenesis of malaria

Plasmodium malariae structure and genetic diversity in sub-Saharan Africa determined from microsatellite variants and linked SNPs in orthologues of antimalarial resistance genes

Plasmodium malariae, a neglected human malaria parasite, contributes up to 10% of malaria infections in sub-Saharan Africa (sSA). Though P. malariae infection is considered clinically benign, it presents mostly as coinfections with the dominant P. falciparum. Completion of its reference genome has paved the way to further understand its biology and interactions with the human host, including responses to antimalarial interventions. We characterized 75 P. malariae isolates from seven endemic countries in sSA using highly divergent microsatellites. The P. malariae infections were highly diverse and five subpopulations from three ancestries (independent of origin of isolates) were determined. Sequences of 11 orthologous antimalarial resistance genes, identified low frequency single nucleotide polymorphisms (SNPs), strong linkage disequilibrium between loci that may be due to antimalarial drug selection. At least three sub-populations were detectable from a subset of denoised SNP data from mostly the mitochondrial cytochrome b coding region. This evidence of diversity and selection calls for including P. malariae in malaria genomic surveillance towards improved tools and strategies for malaria elimination

Functional antibodies against Plasmodium falciparum sporozoites are associated with a longer time to qPCR-detected infection among schoolchildren in Burkina Faso.

Background: Individuals living in malaria-endemic regions develop immunity against severe malaria, but it is unclear whether immunity against pre-erythrocytic stages that blocks initiation of blood-stage infection after parasite inoculation develops following continuous natural exposure. Methods: We cleared schoolchildren living in an area (health district of Saponé, Burkina Faso) with highly endemic seasonal malaria of possible sub-patent infections and examined them weekly for incident infections by nested PCR. Plasma samples collected at enrolment were used to quantify antibodies to the pre-eryhrocytic-stage antigens circumsporozoite protein (CSP) and Liver stage antigen 1 (LSA-1). In vitro sporozoite gliding inhibition and hepatocyte invasion inhibition by naturally acquired antibodies were assessed using Plasmodium falciparum NF54 sporozoites. Associations between antibody responses, functional pre-erythrocytic immunity phenotypes and time to infection detected by 18S quantitative PCR were studied. Results: A total of 51 children were monitored. Anti-CSP antibody titres showed a positive association with sporozoite gliding motility inhibition (P<0.0001, Spearman's ρ=0.76). In vitro hepatocyte invasion was inhibited by naturally acquired antibodies (median inhibition, 19.4% [IQR 15.2-40.9%]), and there were positive correlations between invasion inhibition and gliding inhibition (P=0.005, Spearman's ρ=0.67) and between invasion inhibition and CSP-specific antibodies (P=0.002, Spearman's ρ=0.76). Survival analysis indicated longer time to infection in individuals displaying higher-than-median sporozoite gliding inhibition activity (P=0.01), although this association became non-significant after adjustment for blood-stage immunity (P = 0.06). Conclusions: In summary, functional antibodies against the pre-erythrocytic stages of malaria infection are acquired in children who are repeatedly exposed to Plasmodium parasites. This immune response does not prevent them from becoming infected during a malaria transmission season, but might delay the appearance of blood stage parasitaemia. Our approach could not fully separate the effects of pre-erythrocytic-specific and blood-stage-specific antibody-mediated immune responses in vivo; epidemiological studies powered and designed to address this important question should become a research priority

Prevalence of P. falciparum Gametocyte Carrying between Two Sympatric Ethnic Groups Living in Seasonal Malaria Transmission Setting of Burkina Faso after Universal Bed Nets Coverage Campaigns

Aims: This study aimed to compare the prevalence of P. falciparum gametocyte carriage in two sympatric ethnic groups living in seasonal malaria transmission setting in Burkina Faso. Study Design: A cross-sectional survey was conducted from September to November 2017 in children aged from 2 to 12 years and living in Barkoundouba, avillage located at the Northeast part of Ouagadougou, capital city of Burkina Faso. The study participants were subject to clinical examination including axillary temperature. Blood samples were collected from finger pricks to performed RDT and blood smears for malaria diagnosis and on filter paper for molecular detection of the parasite. Any case of fever (temperature ≥ 37.5°C) with RDT positive was treated according to national guideline. Methodology: We included 461 patients in this study. P. falciparum presence and densities were determined by microscopy using Giemsa-stained thick blood smears. The nested PCR was used to confirm the presence of the asexual parasites assessed by the microscopy. Results: P. falciparum prevalence assessed by microscopy was 83 (32.55%) and 103 (50%) for Fulani and Mossi respectively, whereas the prevalence by nested PCR was 88 (39.11%) for Fulani and 121 (68.75%) for Mossi. The gametocyte carriage in the two ethnic groups was: 3.53% for Fulani and 11.65% for Mossi. The prevalence ratio for P. falciparum asymptomatic and gametocyte carriers was 1.5 and 3 in favor of Mossi group respectively. Conclusion: This study showed that the Fulani have a lower prevalence of P. falciparum compared to the Mossi group despite the decrease of parasitemia and prevalence in both groups compared to previous studies

Experimental Study: The Relationship between Plasmodium falciparum Gametocyte Carriage and Mosquitoes Infectiousness in Two Sympatric Ethnic Groups in Burkina Faso

Aims: The lower susceptibility of the Fulani to malaria compared to Mossi was previously described in Burkina Faso in West Africa. The mature gametocyte stage of Plasmodium falciparum is known to be the only stage capable of infecting the mosquito though this process is disrupted by the action of immunity and other factors as well. Our study aims to assess the ability of two sympatric ethnic groups known to have different susceptibility to Plasmodium falciparum malaria, to infect mosquitoes through an experimental membrane feeding assay. Methodology: Study participants were gametocyte carriers aged from 2 to 12 years recruited in the village of Barkoundouba where Fulani and Mossi are living in sympatric. A venous blood was obtained from each participant for direct membrane feeding assay of insectary reared mosquitoes. Blood fed mosquitoes were stored for 7 days with sugar water as the only food source, then dissected for the microscopic detection for oocysts. Results: A total of 1050 mosquitoes were used for the experimental infections. Eight day after feeding, a total of 897 mosquitoes were dissected, 275 from the Fulani and 622 from the Mossi group. With an average of 43 stomachs examined by experimentation, the mosquito infestation rate was 10.5% in Fulani and 13.2% in Mossi group (p=0.569). The fed mosquito rate was 95 % and 95.6% in Fulani and Mossi ethnic group respectively (p=0.241). The rate of survival mosquitoes after the feeding was 96.5% and 87.5% in Fulani and Mossi ethnic group respectively (p=0.088). The proportion of dissected mosquitoes was 100% and 99.2% in Fulani and Mossi ethnic group respectively (p=0.138) leading to an average oocystic load of 249 in Fulani and 21 in Mossi group. The success rate of DMFA in both groups combined was 57.14%. Indeed, this rate was 33.33% and 66.67% in Fulani and Mossi group respectively. Conclusion: Our study showed that there is no significant difference found between the two ethnic group with the fed, survival, dissected and the infested mosquitoes rate. However, the average of oocystic load was higher in Fulani than the Mossi group despite the low infection in Fulani group. There is a need to explore the mechanism underlying such difference between the two ethnic groups

Evaluation of allelic forms of the erythrocyte binding antigen 175 (EBA-175) in Plasmodium falciparum field isolates from Brazilian endemic area

<p>Abstract</p> <p>Background</p> <p>The <it>Plasmodium falciparum </it>Erythrocyte Binding Antigen-175 (EBA-175) is an antigen considered to be one of the leading malaria vaccine candidates. EBA-175 mediates sialic acid-dependent binding to glycophorin A on the erythrocytes playing a crucial role during invasion of the <it>P. falciparum </it>in the host cell. Dimorphic allele segments, termed C-fragment and F-fragment, have been found in high endemicity malaria areas and associations between the dimorphism and severe malaria have been described. In this study, the genetic dimorphism of EBA-175 was evaluated in <it>P. falciparum </it>field isolates from Brazilian malaria endemic area.</p> <p>Methods</p> <p>The study was carried out in rural villages situated near Porto Velho, Rondonia State in the Brazilian Amazon in three time points between 1993 and 2008. The allelic dimorphism of the EBA-175 was analysed by Nested PCR.</p> <p>Results</p> <p>The classical allelic dimorphism of the EBA-175 was identified in the studied area. Overall, C-fragment was amplified in a higher frequency than F-fragment. The same was observed in the three time points where C-fragment was observed in a higher frequency than F-fragment. Single infections (one fragment amplified) were more frequent than mixed infection (two fragments amplified).</p> <p>Conclusions</p> <p>These findings confirm the dimorphism of EBA175, since only the two types of fragments were amplified, C-fragment and F-fragment. Also, the results show the remarkable predominance of CAMP allele in the studied area. The comparative analysis in three time points indicates that the allelic dimorphism of the EBA-175 is stable over time.</p