Search

The ACE2 gene polymorphisms (rs143936283, rs146676783, and rs4646116) in infected and noninfected persons by SARS-CoV-2 in Burkina Faso. Our cross-sectional study population comprised 137 SARS-CoV-2 infected persons and 181 non-infected persons. Three ACE2 gene polymorphisms rs143936283, rs146676783, and rs4646116, were genotyped using the real-time PCR standard TaqMan allelic discrimination technique. The association between SARS-CoV-2 infection and the polymorphisms were evaluated by a binary logistic regression. There was no association between the polymorphisms rs143936283, rs4646116 haplotypes, and SARS-CoV-2 infection in our study population. However, in the female population, the heterozygous genotype CT of rs146676783 increased by two and half the risk (OR=2.58 95%CI (1.2-5.48), p= 0.014) of being infected by SARS-CoV-2. Additionally, carrying the homozygous minor allele (genotype TT) of rs146676783 increased by more than five and half the risk (OR=5.57 95%CI (1.64-18.78), p=0.006) of being infected by SARS-CoV-2 among females. This study showed that the ACE2 gene variant rs146676783 was associated with an increased risk of being infected by SARS-CoV-2 in females, suggesting a need for further investigation to contribute to a better understanding of the African COVID-19 enigma.

Background: Many rapid antigen kits for SARS-CoV-2 detection have been developed and the results interpreted usually within 30 minutes. Antigen tests are recommended to be used in areas where access to the PCR method is limited, as is the case in Burkina Faso. The aim of this study is to assess the performance of "Standard TM Q COVID-19 Ag Test " in the detection of SARS-CoV-2 antigen. Methods: The evaluation was performed using swabs samples collected between January 26 and March 31, 2021, from 201 subjects previously diagnosed by RT-PCR. The performance of the rapid test “Standard TM Q COVID-19 Ag Test was compared to the RT-PCR test “STANDARD M nCoV real-time detection kit”. Results: Of these 201 samples, 16 were positive for the COVID-19 RT-PCR, and 185 were negative. The sensitivity of the "Standard TM Q COVID-19 Ag Test" was 100% (IC95%: 34.24- 100) in symptomatic subjects with a symptom onset time of 1 to 5 days. This sensitivity decreased to 66.67% (IC95%: 20.77- 93.85) in symptomatic subjects with a symptom onset time of 1 to 7 days. The specificity, it was 95% (IC95%: 83.5-98.62) in all symptomatic subjects and 93.75% (IC95%: 79.85-98.2) in subjects whose symptoms appeared between 1 and 5 days. Conclusion: The " Standard TM Q COVID-19 Ag Test " was better in subjects with delayed symptoms up to 5 days. However, this kit was not suitable for COVID-19 detection in asymptomatic subjects.

Abstract Background The aim of this study was to evaluate the performance of ten (10) SARS-CoV-2 serological rapid diagnostic tests in comparison with the WANTAI SARS-CoV-2 Ab ELISA test in a laboratory setting. Materials and methods Ten (10) SARS-CoV-2 serological rapid diagnostic tests (RDTs) for SARS-CoV-2 IgG/IgM were evaluated with two (2) groups of plasma tested positive for one and negative for the other with the WANTAI SARS-CoV-2 Ab ELISA. The diagnostic performance of the SARS-CoV-2 serological RDTs and their agreement with the reference test were calculated with their 95% confidence intervals. Results The sensitivity of serological RDTs ranged from 27.39 to 61.67% and the specificity from 93.33 to 100% compared to WANTAI SARS-CoV-2 Ab ELISA test. Of all the tests, two tests (STANDARD Q COVID-19 IgM/IgG Combo SD BIOSENSOR and COVID-19 IgG/IgM Rapid Test (Zhejiang Orient Gene Biotech Co., Ltd)) had a sensitivity greater than 50%. In addition, all ten tests had specificity greater than or equal to 93.33% each. The concordance between RDTs and WANTAI SARS-CoV-2 Ab ELISA test ranged from 0.25 to 0.61. Conclusion The SARS-CoV-2 serological RDTs evaluated show low and variable sensitivities compared to the WANTAI SARS-CoV-2 Ab ELISA test, with however a good specificity. These finding may have implications for the interpretation and comparison of COVID-19 seroprevalence studies depending on the type of test used.

The classified forest and partial faunal reserve of Comoé-Léraba belongs to the South Sudanian phytogeographical sector of Burkina Faso and is located in the most humid area of the country. This study aims to present a detailed list of the Comoé-Léraba reserve’s flora for a better knowledge and conservation. Floristic inventories have permitted to record 540 plant species belonging to 342 genera and 91 families, thus representing 26.12% of Burkina Faso’s phytodiversity (2067 species). Fabaceae and Poaceae with 89 and 51 species respectively, were the dominant families. The vegetation is characterized by the dominance of both phanerophytes (45.51%) and therophytes (32.73%). The importance of Guineo–­Con­golian species proves that the Comoé-Léraba flora belongs to the Sudano–Guinean transition sector. Comoé-Léraba also accounts the highest number of exclusive species followed by the reserve of Sahel in the country. Exclusive species bring out its value in flora conservation.

BACKGROUND:Children below six months are reported to be less susceptible to clinical malaria. Maternally derived antibodies and foetal haemoglobin are important putative protective factors. We examined antibodies to Plasmodium falciparum merozoite surface protein 3 (MSP3) and glutamate-rich protein (GLURP), in children in their first two years of life in Burkina Faso and their risk of malaria. METHODS:A cohort of 140 infants aged between four and six weeks was recruited in a stable transmission area of south-western Burkina Faso and monitored for 24 months by active and passive surveillance. Malaria infections were detected by examining blood smears using light microscopy. Enzyme-linked immunosorbent assay was used to quantify total Immunoglobulin G to Plasmodium falciparum antigens MSP3 and two regions of GLURP (R0 and R2) on blood samples collected at baseline, three, six, nine, 12, 18 and 24 months. Foetal haemoglobin and variant haemoglobin fractions were measured at the baseline visit using high pressure liquid chromatography. RESULTS:A total of 79.6% of children experienced one or more episodes of febrile malaria during monitoring. Antibody titres to MSP3 were prospectively associated with an increased risk of malaria while antibody responses to GLURP (R0 and R2) did not alter the risk. Antibody titres to MSP3 were higher among children in areas of high malaria risk. Foetal haemoglobin was associated with delayed first episode of febrile malaria and haemoglobin CC type was associated with reduced incidence of febrile malaria. CONCLUSIONS:We did not find any evidence of association between titres of antibodies to MSP3, GLURP-R0 or GLURP-R2 as measured by enzyme-linked immunosorbent assay and early protection against malaria, although anti-MSP3 antibody titres may reflect increased exposure to malaria and therefore greater risk. Foetal haemoglobin was associated with protection against febrile malaria despite the study limitations and its role is therefore worthy further investigation.

Abstract Greenhouse gas (GHG) emissions from prescribed fires are poorly investigated, resulting in a high uncertainty in GHG budgets. Using, a carbon mass balance approach and experimental prescribed fires in 80 plots, this study assessed carbon emissions and established emission factors (EFs) for carbon dioxides (CO2), carbon monoxide (CO), and methane (CH4) across climate zones and vegetation types. In grass and shrub savannas, fires could burn intensely due to the lower moisture content and continuous spatial distribution of biomass fuel, causing greater carbon emissions with 1.61 ± 0.13 t C ha−1 and 1.01 ± 0.13 t C ha−1, respectively. Despite their low carbon emissions, tree savannas (1658.17 ± 11.13 g kg−1) and woodlands (1629.94 ± 12.23 g kg−1) have the highest EFs, which can be attribute to the high carbon content of biomass fuel in these vegetation types. Vegetation types and their interaction with climate zones have a substantial impact on carbon emissions and carbon species EFs, and should therefore be considered in assessing GHG emissions from fires. The findings from this study provide a useful basis for improving the national measurement, reporting, and verification of GHG emissions and for improving the measurement of the global balance of GHG emissions from fires.

Societal Impact Statement Modern food systems push agriculture to focus on a small number of commercial crops, while there is a very large diversity of untapped edible plants that could be used to address food security and nutrition. Poor and monotonous diets are closely linked to the complex burden of multiple forms of malnutrition and dietary risk. In some contexts, such as West Africa, micronutrient deficiency risks are particularly pronounced. Hence, there is an urgent need to provide people with healthy diets supported by sustainable food systems. Within this context, using nutrition‐sensitive forest landscape restoration to combat environmental degradation could contribute towards ensuring the year‐round availability of nutritious tree‐based food. Summary Diverse diets are important to deliver adequate amounts of the nutrients essential to human health. The consumption of a diversity of food groups is challenging in sub‐Saharan Africa. Trees play an important role in the direct provision of nutritious food items. Forest landscape restoration presents an opportunity to reverse the loss of useful trees, due to degradation, and increase representation of food tree species in the landscape. Here we focused on characterizing the contributions that different food products from trees can make to improving diet diversity in Burkina Faso. A scoring system was developed, based on seasonal availability of edible products and food groups covered, and was integrated into a freely available decision‐making tool that enables carrying out context‐specific, optimal choices of tree species to be considered in forest landscape restoration. Our inventory included 56 food tree species, largely Fabaceae (18 species), providing 81 edible products, mainly fruits (supplied by 79% of tree species), followed by seeds (52%) and leaves (41%). The main food groups represented are ‘Other fruits’ (other than vitamin A‐rich fruits) (covering 52% of the edible products) and dark‐green leafy vegetables (29%). About two thirds of the species listed produce more than a single edible product, a few up to four. A total of 11 species supplied edible products throughout the year. Our results clearly show that seasonal scarcity of food and nutrients in Burkina Faso can be partly mitigated by consuming edible tree products. The methodology can be easily scaled to other geographies.

Agricultural biomass burning plays a critical role in carbon emissions, with implications for climate change. This study aims to assess carbon (C) emissions and establish C, CO, CO2 and CH4 emission factors (EFs) by simultaneously testing the effects of climatic conditions and cropland category on gas emissions. In Burkina Faso, 96 experimental fires were conducted in accordance with farmers’ operations during the land-clearing season in two climatic zones (Sudanian and Sudano-Sahelian) and across two cropland categories (Cropland Remaining Cropland (CC) and Land Converted to Cropland (LC)). The carbon mass balance technique was applied to estimate emissions. Climate zone and cropland category significantly influenced carbon emissions and emission factors (p < 0.05). The Sudanian zone recorded the highest carbon emissions (0.24 ± 0.01 t C ha−1). For cropland category, LC recorded the highest carbon emissions with an average value of 0.27 ± 0.01 t C ha−1. CO2 EFs ranged from 1661.44 ± 3.63 g kg−1 in the Sudanian zone to 1716.51 ± 3.24 g kg−1 in the Sudano-Sahelian zone. EFs showed a dependence on the cropland category, with the highest EFs in CC. Smart agricultural practices limiting cropland expansion and biomass burning need to be promoted. This study provides vital information useful for supporting decision making as part of Nationally Determined Contributions.

Abstract Finding sufficient natural fodder resources to feed livestock has become a challenge for herders in the Sahel zone of Burkina Faso. Despite the existence of pastoral reserves, the issue of fodder shortage remains unsolved. This article highlights the changes in behaviour and the evolution of pastoral practices caused by the scarcity of forage resources. These changes are defined and classified as resilience strategies. Thus, this paper aims to analyse these strategies using new semantics that calls for other forms of perceptions or approach to the questions of pastoralists’ resilience strategies. Interviews (semi-structured and casual conversations), ethnographic observations and ethnobotanical surveys were used to collect data. In rangelands, such high value fodder species as Andropogon gayanus, Pennisetum pedicellatum and Dactyloctenium aegyptium that were abundant herbaceous plants during the last decades are disappearing. Concomitantly, species with lower forage value, such as Senna obtusifolia, which are more resilient to ecological disturbance factors, are colonizing rangelands. Faced with these ecological changes, pastoralists are trying to redefine and reconfigure their practices, and this implies a redefinition of their identity. They use resilience strategies such as mowing grasses, building up fodder bundles, conserving crop residues, exploiting Senna obtusifolia (a previously neglected species), using woody fodder and adapting the type of livestock and the size of the herds to the ability of pastoralists to feed them. Strategies that are older than these are the integration of agriculture with livestock and decollectivized transhumance. It is these resilience strategies that this article exposes and analyses as defence mechanisms of Sahelian pastoralists in the face of the depletion of forage resources in their environments.

Multiple sclerosis (MS) is characterized by the loss of myelin and of myelin-producing oligodendrocytes (OLs) in the central nervous system (CNS). Pro-inflammatory CD4+ Th17 cells are considered pathogenic in MS and are harmful to OLs. We investigated the mechanisms driving human CD4+ T cell-mediated OL cell death. Using fluorescent and brightfield in vitro live imaging, we found that compared to Th2-polarized cells, Th17-polarized cells show greater interactions with primary human OLs and human oligodendrocytic cell line MO3.13, displaying longer duration of contact, lower mean speed, and higher rate of vesicle-like structure formation at the sites of contact. Using single-cell RNA sequencing, we assessed the transcriptomic profile of primary human OLs and Th17-polarized cells in direct contact or separated by an insert. We showed that upon close interaction, OLs upregulate the expression of mRNA coding for chemokines and antioxidant/anti-apoptotic molecules, while Th17-polarized cells upregulate the expression of mRNA coding for chemokines and pro-inflammatory cytokines such as IL-17A, IFN-γ, and granzyme B. We found that secretion of CCL3, CXCL10, IFN-γ, TNFα, and granzyme B is induced upon direct contact in cocultures of human Th17-polarized cells with human OLs. In addition, we validated by flow cytometry and immunofluorescence that granzyme B levels are upregulated in Th17-polarized compared to Th2-polarized cells and are even higher in Th17-polarized cells upon direct contact with OLs or MO3.13 cells compared to Th17-polarized cells separated from OLs by an insert. Moreover, granzyme B is detected in OLs and MO3.13 cells following direct contact with Th17-polarized cells, suggesting the release of granzyme B from Th17-polarized cells into OLs/MO3.13 cells. To confirm granzyme B–mediated cytotoxicity toward OLs, we showed that recombinant human granzyme B can induce OLs and MO3.13 cell death. Furthermore, pretreatment of Th17-polarized cells with a reversible granzyme B blocker (Ac-IEPD-CHO) or a natural granzyme B blocker (serpina3N) improved survival of MO3.13 cells upon coculture with Th17 cells. In conclusion, we showed that human Th17-polarized cells form biologically significant contacts with human OLs and exert direct toxicity by releasing granzyme B.

Introduction Le paludisme demeure un problème majeur de santé publique. Une meilleure connaissance de l’immunologie du paludisme peut contribuer à la recherche vaccinale ainsi qu’à une meilleure connaissance de l’épidémiologie de cette maladie. L’objectif de ce travail était de connaitre l’association entre l’infection palustre et la réponse en anticorps chez les enfants de moins de cinq ans. Matériel et méthodes: Des échantillons et des données parasitologiques collectés au cours de deux enquêtes transversales ont permis de mesurer le niveau des anticorps IgG et des sous classes IgG dirigés contre 5 antigènes de stade érythrocytaire (MSP3, MSP2A, MSP2B, GLURP R0, GLURP R2) de Plasmodium falciparum chez des enfants de moins de cinq ans. Ces données ont également permis d’évaluer l’influence de la parasitémie concomitante sur le niveau des anticorps IgG et des sous classes IgG. Le niveau des anticorps a été mesuré en utilisant la technique ELISA. La goutte épaisse et le frottis mince ont été utilisés pour le diagnostic microscopique quantitatif et qualitatif du paludisme. Résultats : Les résultats de l’étude ont montré que la présence du Plasmodium falciparum était associée à un niveau plus élevé d’anticorps IgG et sous classes IgG. Au-delà d’un certain niveau de charge parasitaire, le niveau d’anticorps baissait, probablement à cause de l’utilisation de ces anticorps. Conclusion : Cette étude a permis de connaitre l’influence de la parasitémie concomitante sur le niveau d’anticorps chez les enfants de moins de cinq ans naturellement exposés à l’infection palustre

Shea tree (Vitellaria paradoxa) is one of the main native oil plants with high economic value in Africa. Its fruits are used for food, medicinal, cultural and exportation purposes. However, the lack of efficient tools to assess annual fruit production of the species limits the sustainable management of its resources. Therefore, production statistics are useful to organize the activities of the shea sector. This study aimed to (i) assess the interannual variation in fruit production along a climatic gradient in Burkina Faso, (ii) examine fruit production patterns according to climatic zones and tree size, (iii) assess the contribution of high-yielding trees in the annual potential production and (iv) develop allometric equations for estimating fruit yields of the species. The yield of 212 trees distributed across three climatic zones was monitored over four successive years. Within each climatic zone, fruit production was significantly different among years. Fruit production was positively and significantly correlated with tree size. The interannual variation in fruit production at tree individual level was higher in drier climatic conditions. The mean interindividual synchrony was less than 50% in each zone, suggesting a large range in fruit production patterns of the species. Annually, more than 55% of the total fruit production was supported by high-yielding trees. The best regression models for estimating fruit yields had R2 values of 69–73% with prediction errors ranging from −7% to 4%. Our findings are useful tools for the planning of rational exploitation of shea tree’s resources and its sustainable management.

Balanites aegyptiaca (L.) Delile is native to semi-arid regions in Africa where it is a well-known and conspicuous component of savannas. The species is highly preferred by local people because of its high socio-economic, cultural and ecological values. However, the species faces multiple environmental challenges such as desertification and human pressure. This study aimed to develop allometric models to predict aboveground biomass (AGB) of B. aegyptiaca in two climatic zones in Burkina Faso. Overall, thirty trees were sampled using destructive method in six study stands along two climatic zones. We assessed the biomass allocation to the different components of trees by computing its fraction. Furthermore, allometric models based on diameter at breast height (dbh) and basal diameter at 20 cm height (D20) were fitted separately as well as combined with crown diameter (CD) and/or tree total height (Ht). For each biomass component, non-linear allometric models were fitted. Branch biomass accounted for 64% of the AGB in the two climatic zones and increased with dbh. No significant difference in carbon content was found. However, biomass allotment (except leaves) varied across climatic zones. Although both dbh and D20 are typically used as independent variables for predicting AGB, the inclusion of the height in the equations did not significantly improve the statistical fits for B. aegyptica. However, adding CD to dbh improved significantly the equations only in the Sudano-Sahelian zone.The established allometric models can provide reliable and accurate estimation of individual tree biomass of the species in areas of similar conditions and may contribute to relevant ecological and economical biomass inventories.

Abstract Background High parasite-specific antibody levels are generally associated with low susceptibility to Plasmodium falciparum malaria. This has been supported by several studies in which clinical malaria cases of P. falciparum malaria were reported to be associated with low antibody avidities. This study was conducted to evaluate the role of age, malaria transmission intensity and incidence of clinical malaria in the induction of protective humoral immune response against P. falciparum malaria in children living in Burkina Faso. Methods We combined levels of IgG and IgG subclasses responses to P. falciparum antigens: Merozoite Surface Protein 3 (MSP3), Merozoite Surface Protein 2a (MSP2a), Merozoite Surface Protein 2b (MSP2b), Glutamate Rich Protein R0 (GLURP R0) and Glutamate Rich Protein R2 (GLURP R2) in plasma samples from 325 children under five (05) years with age, malaria transmission season and malaria incidence. Results We notice higher prevalence of P. falciparum infection in low transmission season compared to high malaria transmission season. While, parasite density was lower in low transmission than high transmission season. IgG against all antigens investigated increased with age. High levels of IgG and IgG subclasses to all tested antigens except for GLURP R2 were associated with the intensity of malaria transmission. IgG to MSP3, MSP2b, GLURP R2 and GLURP R0 were associated with low incidence of malaria. All IgG subclasses were associated with low incidence of P. falciparum malaria, but these associations were stronger for cytophilic IgGs. Conclusions On the basis of the data presented in this study, we conclude that the induction of humoral immune response to tested malaria antigens is related to age, transmission season level and incidence of clinical malaria.

Over the last decades agroforestry parklands in Burkina Faso have come under increasing demographic as well as climatic pressures, which are threatening indigenous tree species that contribute substantially to income generation and nutrition in rural households. Analyzing the threats as well as the species vulnerability to them is fundamental for priority setting in conservation planning. Guided by literature and local experts we selected 16 important food tree species (Acacia macrostachya, Acacia senegal, Adansonia digitata, Annona senegalensis, Balanites aegyptiaca, Bombax costatum, Boscia senegalensis, Detarium microcarpum, Lannea microcarpa, Parkia biglobosa, Sclerocarya birrea, Strychnos spinosa, Tamarindus indica, Vitellaria paradoxa, Ximenia americana, Ziziphus mauritiana) and six key threats to them (overexploitation, overgrazing, fire, cotton production, mining and climate change). We developed a species-specific and spatially explicit approach combining freely accessible datasets, species distribution models (SDMs), climate models and expert survey results to predict, at fine scale, where these threats are likely to have the greatest impact. We find that all species face serious threats throughout much of their distribution in Burkina Faso and that climate change is predicted to be the most prevalent threat in the long term, whereas overexploitation and cotton production are the most important short-term threats. Tree populations growing in areas designated as 'highly threatened' due to climate change should be used as seed sources for ex situ conservation and planting in areas where future climate is predicting suitable habitats. Assisted regeneration is suggested for populations in areas where suitable habitat under future climate conditions coincides with high threat levels due to short-term threats. In the case of Vitellaria paradoxa, we suggest collecting seed along the northern margins of its distribution and considering assisted regeneration in the central part where the current threat level is high due to overexploitation. In the same way, population-specific recommendations can be derived from the individual and combined threat maps of the other 15 food tree species. The approach can be easily transferred to other countries and can be used to analyze general and species specific threats at finer and more local as well as at broader (continental) scales in order to plan more selective and efficient conservation actions in time. The concept can be applied anywhere as long as appropriate spatial data are available as well as knowledgeable experts.

The Arly National Park of southeastern Burkina Faso is in the center of the WAP complex, the largest continuous system of protected areas in West Africa. Although well known for its large mammal populations, its flora has largely been unexplored until recently. The plant species composition is typical for sudanian savanna areas with a high share of grasses and legumes and similar to other protected areas of the complex, the neighbouring Pama reserve and W National Park. It has more species in common with the classified forest of Kou in SW Burkina Faso than with the geographically closer Sahel reserve. The 490 species belong to 280 genera and 83 families. The most important life forms are phanerophytes and therophytes.

INTRODUCTION: for a high quality level diagnosis, mycobacterium culture must comply with the pre-analytical and analytical conditions recommended by the WHO and the country National Tuberculosis Program (NTP). In this study, we determined whether temperature and duration of sputum storage were associated with culture contamination in Burkina Faso. METHODS: sputa were collected in 5 districts labs in Burkina Faso. Temperature and duration of sputum storage were recorded. After the collection, sputa were decontaminated using Petroff modified method, and the pellet was inoculated on LJ media and LJ media supply with 2% sodium pyruvate. Risk of culture contamination associated with temperature and duration of sputum storage was measured by Chi2 test and logistic regression. RESULTS: out of 404 specimens, 61% (246/404) were stored between 2 and 8,C, and 15% (61/404) were processed within three days. The global contamination rate was 24%, with only 8% for samples respecting WHO recommendations, up to 35% for others. Storage at room temperature was associated with a significantly higher risk of contamination compared to storage at 2-8,C (OR 2.24, p=0.001, IC 95%). CONCLUSION: the recommendations about the temperature and the duration of sputum storage before cultures are not completely respected. This leads to high contamination rate of mycobacterium culture. It will be necessary to take logistics measures in peripherals health services or to develop more selective medium for mycobacterium culture in low income countries.