Diversité des insectes actifs au sol dans quatre écosystèmes de bas-fonds du Burkina Faso : importance pour la détermination de bio-indicateurs caractérisant ces milieux

L'action de l’Homme sur l'environnement peut affecter la diversité biologique qui à son tour peut être utilisée comme indicateur de la santé des écosystèmes. Une étude a été menée en 2006 dans quatre (4) MicroBassin-Versants (MBV) du Burkina Faso pour évaluer la diversité des insectes rampants au sol et caractériser chaque écosystème par ses bio-indicateurs les plus significatifs. La diversité taxonomique des espècesd’insectes capturées dans différents sites par des pièges de Barber, leur distribution et leur abondance relative au début et à la fin de la saison des pluies ont ainsi été déterminées. Quatre (4) ordres regroupant treize (13)familles d’insectes, les Carabidae, les Scarabaeidae, les Tenebrionidae, les Cétonidae, les Cérambycidae, les Curculionidae, les Hydrophilidae, les Elateridae, les Staphylinidae, les Chrysomelidae (Coléoptères), lesFormicidae (Hyménoptères), les Gryllidae (Orthoptères) et les Labiduridae (Dermaptères), ont été identifiées dans les MBV étudiés. Les variations climatiques influencent la diversité taxonomique des insectes qui fluctuepar ailleurs dans l’espace et dans le temps. Cinq (5) familles, les Formicidae, les Cicindellidae, les Carabidae, les Scarabaeidae et les Tenebrionidae ont été les plus abondantes et les plus diversifiées en espèces dans chacun des quatre MBV. Ces taxa, qui se sont adaptés aux écosystèmes étudiés, en sont probablement les meilleurs indicateurs. Les résultats obtenus sont discutés en vue de déterminer comment ces groupes majeurs peuvent être utilisés dans l’évaluation et la gestion des écosystèmes qu’ils peuplent

Les risques sanitaires lies a l\u2019utilisation des pesticides dans les bas-fonds rizicoles de la commune de dano, Province du Ioba Burkina Faso

Pesticides are an essential component of agricultural production techniques for pests and weeds control. In Burkina Faso, failure to observe good practices for pesticides use exposes farmers to health risks. The study presents health risks related to pesticide management in rice fields in Dano through a survey of 158 rice farmers working in inland valleys. Socio-demographic characteristics of farmers, the types of pesticides used and their effects on health were documented. Rice farming in Dano is mainly done by an ageing population with an average of over 50 years (60%). In addition, farmers\u2019 education level is low, with an illiteracy rate of 61 and only 32% of farmers attaining primary school education. Risky behaviours of pesticides use are common, especially inadequate of farmer protection, poor practices of storage and re-use of pesticide products. Twelve types of pesticides were identified, of which 40% are not officially registered. The main active components in herbicides are Glyphosate, Paraquat, Bensulfuron methyl and Bispyribac-sodium. Health risks of pesticide use reported by farmers included various poisoning symptoms. To mitigate pesticide poisoning prevalence associated with poor farming practices, awareness campaigns should be conducted to inform farmers to use pesticides safely.Les produits pesticides constituent de nos jours une composante essentielle des techniques de production agricole pour le contr\uf4le des ravageurs et des mauvaises herbes. Au Burkina Faso, le non respect des bonnes pratiques d\u2019utilisation des pesticides pose un v\ue9ritable probl\ue8me de sant\ue9 des populations. L\u2019\ue9tude pr\ue9sente les risques sanitaires de gestion des pesticides agricoles. Une enqu\ueate de terrain a \ue9t\ue9 r\ue9alis\ue9e dans la Commune de Dano aupr\ue8s de 158 producteurs rizicoles. Le questionnaire a port\ue9 sur les caract\ue9ristiques sociod\ue9mographiques des producteurs rizicoles, les types de pesticides utilis\ue9s et leurs effets sur la sant\ue9. L\u2019\ue9tude montre que la riziculture \ue0 Dano est une activit\ue9 principalement exerc\ue9e par une population vieillissante dont les plus de 50 ans repr\ue9sentent pr\ue8s de 60%. De plus, la population est analphab\ue8te \ue0 61% contre 32% des producteurs ayant fr\ue9quent\ue9 l\u2019\ue9cole primaire. Les mauvaises pratiques d\u2019utilisation des pesticides sont fr\ue9quentes et concernent surtout l\u2019insuffisance des \ue9quipements de protection individuels des producteurs, les pratiques de stockage et de r\ue9utilisation des reliquats de pesticides. Douze types de pesticides ont \ue9t\ue9 identifi\ue9s dont 40% ne sont pas homologu\ue9s. Les principales mati\ue8res actives dans les herbicides sont le Glyphosate, le Paraquat, le Bensulfuron methyl et le Bispyribac-sodium. Les effets sanitaires de l\u2019utilisation des pesticides sont ressentis par les producteurs agricoles \ue0 travers divers sympt\uf4mes des intoxications. Pour r\ue9duire la pr\ue9valence des intoxications aux pesticides, des campagnes d\u2019information et de sensibilisation doivent \ueatre men\ue9es \ue0 l\u2019endroit des populations et des producteurs pour une utilisation s\ue9curis\ue9e des pesticides

In silico identification of a candidate synthetic peptide (Tsgf1(18-43)) to monitor human exposure to tsetse flies in West Africa

Background: The analysis of humoral responses directed against the saliva of blood-sucking arthropods was shown to provide epidemiological biomarkers of human exposure to vector-borne diseases. However, the use of whole saliva as antigen presents several limitations such as problems of mass production, reproducibility and specificity. The aim of this study was to design a specific biomarker of exposure to tsetse flies based on the in silico analysis of three Glossina salivary proteins (Ada, Ag5 and Tsgf1) previously shown to be specifically recognized by plasma from exposed individuals. Methodology/Principal Findings: Synthetic peptides were designed by combining several linear epitope prediction methods and Blast analysis. The most specific peptides were then tested by indirect ELISA on a bank of 160 plasma samples from tsetse infested areas and tsetse free areas. Anti-Tsgf1(18-43) specific IgG levels were low in all three control populations (from rural Africa, urban Africa and Europe) and were significantly higher (p < 0.0001) in the two populations exposed to tsetse flies (Guinean HAT foci, and South West Burkina Faso). A positive correlation was also found between Anti-Tsgf1(18-43) IgG levels and the risk of being infected by Trypanosoma brucei gambiense in the sleeping sickness foci of Guinea. Conclusion/Significance: The Tsgf1(18-43) peptide is a suitable and promising candidate to develop a standardize immunoassay allowing large scale monitoring of human exposure to tsetse flies in West Africa. This could provide a new surveillance indicator for tsetse control interventions by HAT control programs

Untreated Human Infections by Trypanosoma brucei gambiense Are Not 100% Fatal

The final outcome of infection by Trypanosoma brucei gambiense, the main agent of sleeping sickness, has always been considered as invariably fatal. While scarce and old reports have mentioned cases of self-cure in untreated patients, these studies suffered from the lack of accurate diagnostic tools available at that time. Here, using the most specific and sensitive tools available to date, we report on a long-term follow-up (15 years) of a cohort of 50 human African trypanosomiasis (HAT) patients from the Ivory Coast among whom 11 refused treatment after their initial diagnosis. In 10 out of 11 subjects who continued to refuse treatment despite repeated visits, parasite clearance was observed using both microscopy and polymerase chain reaction (PCR). Most of these subjects (7/10) also displayed decreasing serological responses, becoming progressively negative to trypanosome variable antigens (LiTat 1.3, 1.5 and 1.6). Hence, in addition to the “classic” lethal outcome of HAT, we show that alternative natural progressions of HAT may occur: progression to an apparently aparasitaemic and asymptomatic infection associated with strong long-lasting serological responses and progression to an apparently spontaneous resolution of infection (with negative results in parasitological tests and PCR) associated with a progressive drop in antibody titres as observed in treated cases. While this study does not precisely estimate the frequency of the alternative courses for this infection, it is noteworthy that in the field national control programs encounter a significant proportion of subjects displaying positive serologic test results but negative results in parasitological testing. These findings demonstrate that a number of these subjects display such infection courses. From our point of view, recognising that trypanotolerance exists in humans, as is now widely accepted for animals, is a major step forward for future research in the field of HAT

Malaria transmission pattern resilience to climatic variability is mediated by insecticide-treated nets

<p>Abstract</p> <p>Background</p> <p>Malaria is an important public-health problem in the archipelago of Vanuatu and climate has been hypothesized as important influence on transmission risk. Beginning in 1988, a major intervention using insecticide-treated bed nets (ITNs) was implemented in the country in an attempt to reduce <it>Plasmodium </it>transmission. To date, no study has addressed the impact of ITN intervention in Vanuatu, how it may have modified the burden of disease, and whether there were any changes in malaria incidence that might be related to climatic drivers.</p> <p>Methods and findings</p> <p>Monthly time series (January 1983 through December 1999) of confirmed <it>Plasmodium falciparum </it>and <it>Plasmodium vivax </it>infections in the archipelago were analysed. During this 17 year period, malaria dynamics underwent a major regime shift around May 1991, following the introduction of bed nets as a control strategy in the country. By February of 1994 disease incidence from both parasites was reduced by at least 50%, when at most 20% of the population at risk was covered by ITNs. Seasonal cycles, as expected, were strongly correlated with temperature patterns, while inter-annual cycles were associated with changes in precipitation. Following the bed net intervention, the influence of environmental drivers of malaria dynamics was reduced by 30–80% for climatic forces, and 33–54% for other factors. A time lag of about five months was observed for the qualitative change ("regime shift") between the two parasites, the change occurring first for <it>P. falciparum</it>. The latter might be explained by interspecific interactions between the two parasites within the human hosts and their distinct biology, since <it>P. vivax </it>can relapse after a primary infection.</p> <p>Conclusion</p> <p>The Vanuatu ITN programme represents an excellent example of implementing an infectious disease control programme. The distribution was undertaken to cover a large, local proportion (~80%) of people in villages where malaria was present. The successful coverage was possible because of the strategy for distribution of ITNs by prioritizing the free distribution to groups with restricted means for their acquisition, making the access to this resource equitable across the population. These results emphasize the need to implement infectious disease control programmes focusing on the most vulnerable populations.</p

Whole-genome sequencing in diverse subjects identifies genetic correlates of leukocyte traits: The NHLBI TOPMed program

Many common and rare variants associated with hematologic traits have been discovered through imputation on large-scale reference panels. However, the majority of genome-wide association studies (GWASs) have been conducted in Europeans, and determining causal variants has proved challenging. We performed a GWAS of total leukocyte, neutrophil, lymphocyte, monocyte, eosinophil, and basophil counts generated from 109,563,748 variants in the autosomes and the X chromosome in the Trans-Omics for Precision Medicine (TOPMed) program, which included data from 61,802 individuals of diverse ancestry. We discovered and replicated 7 leukocyte trait associations, including (1) the association between a chromosome X, pseudo-autosomal region (PAR), noncoding variant located between cytokine receptor genes (CSF2RA and CLRF2) and lower eosinophil count; and (2) associations between single variants found predominantly among African Americans at the S1PR3 (9q22.1) and HBB (11p15.4) loci and monocyte and lymphocyte counts, respectively. We further provide evidence indicating that the newly discovered eosinophil-lowering chromosome X PAR variant might be associated with reduced susceptibility to common allergic diseases such as atopic dermatitis and asthma. Additionally, we found a burden of very rare FLT3 (13q12.2) variants associated with monocyte counts. Together, these results emphasize the utility of whole-genome sequencing in diverse samples in identifying associations missed by European-ancestry-driven GWASs