Evaluation of a novel malaria anti-sporozoite vaccine candidate, R21 in Matrix-M adjuvant, in the UK and Burkina Faso: two phase 1, first-in-human trials.

Background: Malaria remains a substantial public health burden among young children in sub-Saharan Africa and a highly efficacious vaccine eliciting a durable immune response would be a useful tool for controlling malaria. R21 is a malaria vaccine comprising nanoparticles, formed from a circumsporozoite protein and hepatitis B surface antigen (HBsAg) fusion protein, without any unfused HBsAg, and is administered with the saponin-based Matrix-M adjuvant. This study aimed to assess the safety and immunogenicity of the malaria vaccine candidate, R21, administered with or without adjuvant Matrix-M in adults naïve to malaria infection and in healthy adults from malaria endemic areas.

Schistosoma heamatobium tetraspanins TSP-2 and TSP-6 induce Dendritic Cells maturation, cytokine production and T helper cells differentiation in vitro.

Urogenital schistosomiasis caused by Schistosoma haematobium is a major cause of disability in endemic areas. Despite its socio-economic burden, no vaccine exists and the parasite's immunobiology remains underexplored. Genome annotation has revealed over 40 different genes encoding tetraspanins, transmembrane proteins with known immunomodulatory properties in other plathelminthes.

Comparative evaluation of plasma biomarkers of Schistosoma haematobium infection in endemic populations from Burkina Faso.

Infection with Schistosoma haematobium causes urogenital disease associated with organ disfunction, bleeding, pain, and higher susceptibility to infections and cancer. Timely and accurate diagnosis is crucial for prompt and appropriate treatment as well as surveillance efforts, and the use of plasma biomarkers offers important advantages over parasitological examination of urine, including increased sensitivity and the possibility to use the same specimen for multiple investigations. The present study aims to evaluate the diagnostic performance of different plasma biomarkers in endemic populations from Burkina Faso, West Africa.

Longitudinal survey of insecticide resistance in a village of central region of Burkina Faso reveals co-occurrence of 1014F, 1014S and 402L mutations in Anopheles coluzzii and Anopheles arabiensis.

Background: Pyrethroid resistance is one of the major threats for effectiveness of insecticide-treated bed nets (ITNs) in malaria vector control. Genotyping of mutations in the voltage gated sodium channel (VGSC) gene is widely used to easily assess the evolution and spread of pyrethroid target-site resistance among malaria vectors. L1014F and L1014S substitutions are the most common and best characterized VGSC mutations in major African malaria vector species of the Anopheles gambiae complex.

Standing genetic variation and chromosome differences drove rapid ecotype formation in a major malaria mosquito.

Species distributed across heterogeneous environments often evolve locally adapted ecotypes, but understanding of the genetic mechanisms involved in their formation and maintenance in the face of gene flow is incomplete. In Burkina Faso, the major African malaria mosquito comprises two strictly sympatric and morphologically indistinguishable yet karyotypically differentiated forms reported to differ in ecology and behavior. However, knowledge of the genetic basis and environmental determinants of diversification was impeded by lack of modern genomic resources.

The issue is not 'compliance': exploring exposure to malaria vector bites through social dynamics in Burkina Faso.

Credited with averting almost 68% of new cases between 2000 and 2015, insecticide-treated bednets (ITNs) are one of the most efficacious malaria-prevention tools. Their effectiveness, however, depends on if and how they are used, making 'compliance' (and the social factors affecting it) a key area of interest for research on malaria transmission. This article situates the notion of compliance with 'bednet use' within everyday practices in an area of south-west Burkina Faso with high malaria transmission.

Inversion Genotyping in the Complex Using High-Throughput Array and Sequencing Platforms.

Chromosomal inversion polymorphisms have special importance in the complex of malaria vector mosquitoes, due to their role in local adaptation and range expansion. The study of inversions in natural populations is reliant on polytene chromosome analysis by expert cytogeneticists, a process that is limited by the rarity of trained specialists, low throughput, and restrictive sampling requirements. To overcome this barrier, we ascertained tag single nucleotide polymorphisms (SNPs) that are highly correlated with inversion status (inverted or standard orientation).

Distance sampling for epidemiology: an interactive tool for estimating under-reporting of cases from clinic data.

Background: Distance sampling methods are widely used in ecology to estimate and map the abundance of animal and plant populations from spatial survey data. The key underlying concept in distance sampling is the detection function, the probability of detecting the occurrence of an event as a function of its distance from the observer, as well as other covariates that may influence detection. In epidemiology, the burden and distribution of infectious disease is often inferred from cases that are reported at clinics and hospitals.

Antibody response to Schistosoma haematobium and other helminth species in malaria-exposed populations from Burkina Faso.

Infection with helminths in sub-Saharan Africa could modulate the immune response towards Plasmodium falciparum as well as susceptibility to malaria infection and disease. The aim of this study is to assess the antibody responses to helminths species in malaria-exposed populations from Burkina Faso. Plasma samples were collected in rural villages inhabited by Fulani, Mossi and Rimaibe communities, and IgG against parasitic helminths were measured by ELISA.

Unexpectedly high Plasmodium sporozoite rate associated with low human blood index in Anopheles coluzzii from a LLIN-protected village in Burkina Faso.

Despite the effectiveness of mass distribution of long-lasting insecticidal nets (LLINs) in reducing malaria transmission in Africa, in hyperendemic areas such as Burkina Faso the burden of malaria remains high. We here report the results of a 4-month survey on the feeding habits and Plasmodium infection in malaria vectors from a village in Burkina Faso one year following a national LLIN distribution programme. Low values of human blood index (HBI) observed in the major malaria vectors in the area (Anopheles coluzzii: N = 263, 20.

Dissecting functional components of reproductive isolation among closely related sympatric species of the complex.

Explaining how and why reproductive isolation evolves and determining which forms of reproductive isolation have the largest impact on the process of population divergence are major goals in the study of speciation. By studying recent adaptive radiations in incompletely isolated taxa, it is possible to identify barriers involved at early divergence before other confounding barriers emerge after speciation is complete. Sibling species of the complex offer opportunities to provide insights into speciation mechanisms.

The prevalence and distribution of the amyloidogenic transthyretin (TTR) V122I allele in Africa.

Background: Transthyretin (TTR) pV142I (rs76992529-A) is one of the 113 variants in the human TTR gene associated with systemic amyloidosis. It results from a G to A transition at a CG dinucleotide in the codon for amino acid 122 of the mature protein (TTR V122I). The allele frequency is 0.

Evaluation of a protocol for remote identification of mosquito vector species reveals BG-Sentinel trap as an efficient tool for Anopheles gambiae outdoor collection in Burkina Faso.

Background: Feasibility and costs of monitoring efforts aimed to monitor mosquito species are strictly dependent on the presence of skilled entomologists directly in the field. However, in several contexts this is not possible or easy to organize, thus limiting the possibility to obtain crucial information on presence/abundance of potential disease vectors and of new invasive species. Digital imaging approaches could be extremely useful in the frame of medical entomology to overcome this limit.

Novel Insights Into the Protective Role of Hemoglobin S and C Against Plasmodium falciparum Parasitemia.

Although hemoglobin S (HbS) and hemoglobin C (HbC) are well known to protect against severe Plasmodium falciparum malaria, conclusive evidence on their role against infection has not yet been obtained. Here we show, in 2 populations from Burkina Faso (2007-2008), that HbS is associated with a 70% reduction of harboring P. falciparum parasitemia at the heterozygous state (odds ratio [OR] for AS vs AA, 0.

SNP genotyping defines complex gene-flow boundaries among African malaria vector mosquitoes.

Mosquitoes in the Anopheles gambiae complex show rapid ecological and behavioral diversification, traits that promote malaria transmission and complicate vector control efforts. A high-density, genome-wide mosquito SNP-genotyping array allowed mapping of genomic differentiation between populations and species that exhibit varying levels of reproductive isolation. Regions near centromeres or within polymorphic inversions exhibited the greatest genetic divergence, but divergence was also observed elsewhere in the genomes.

IgE antibodies to Plasmodium falciparum and severity of malaria in children of one ethnic group living in Burkina Faso.

Plasmodium falciparum malaria infection induces elevated blood levels of both total immunoglobulin and anti-plasmodial antibodies belonging to different isotypes. We have previously shown that donors living in areas of malaria transmission develop malaria-specific IgE antibodies that are present at highest concentrations in patients with severe disease, suggesting a role for this isotype in malaria pathogenesis. To establish the possible importance of IgE in the course and severity of this disease, we have analyzed a large and homogenous group of African children (age range = 6 months to 15 years) belonging to one ethnic group (Mossi) living in identical epidemiologic conditions in the same urban area (Ougadougo) of Burkina Faso.