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Background: Peridomestic animals play a role in maintaining residual transmission of Plasmodium, being alternative blood meal sources for malaria vectors. The blood of animals treated with veterinary formulations of ivermectin show a mosquitocidal effect on malaria vectors, but for a too short period of time to impact Plasmodium transmission. This study proposes to treat cattle with innovative long-acting (six months) injectable formulations of ivermectin as a complementary vector control measure.Methods: The local breeds of cattle were used in two treatment arms (Four cattle injected with two long-acting formulations of ivermectin with the BEPO® technology at the therapeutic dose of 1.2 mg/kg, and two control arms (Four cattle injected with the vehicles of the formulations). The lethality of the formulations was evaluated on 3-5 days old Anopheles coluzzii mosquitoes through direct-skin feeding assays, from one to 210 days after treatments. Formulations’ efficacy was evaluated and compared using Cox proportional hazards survival models, Kaplan-Meier estimates and 4 parameters log-logistic regression on cumulative mortalities. These results were extrapolated to field scenarii using entomological and transmission models, considering different mosquito feeding preferences, hosts abundances, and bed nets uses ratios. Results: Both formulations released mosquitocidal concentrations of ivermectin until 210 days post-treatment (Hazard ratios > 1). The treatments significantly reduced mosquito survival, with the average median survival times of 4-5 days post-feeding. The Lethal Concentrations to kill 50% of the Anopheles (LC50) before they become infectious (10 days after infectious blood meal) were reached until 210 days post injection for both formulations. Modeling showed that administering long-acting ivermectin formulations to calves would significantly decrease Anopheles populations in the fields. The population of infectious vectors may decrease from 35% to 75% depending mostly on the mosquito feeding preference and on the hosts species relative availability.Conclusions: This study shows that, in complement to bed nets, a long-lasting BEPO® formulation of ivermectin injected to cattle could help to decrease field populations of malaria mosquitoes and residual transmission, the impact of this approach being dependant on the field epidemiological context.

SummaryContextIn the current context of residual plasmodium transmission where zoophagic proclivities of Anopheles intervene, we propose to treat peridomestic animals using the endectocide Ivermectin as a complementary approach to bednets. As Ivermectin remanence with classic veterinary compounds is insufficient to induce a significant decrease in vectors’ populations, we developed a long-lasting injectable formulation of ivermectin from the BEPO® technology designed to release insecticidal concentrations of the molecule for 6 months. The work reported here is a proof of concept that using this new technology could help decrease field Anopheles populations.MethodsEight calves were injected with Ivermectin therapeutic doses of 1.2 mg/kg body weight using 2 long lasting formulations (A and B). Efficacy of the product at killing wild derived An. coluzzii has been evaluated by direct-skin feeding assays from 1 to 210 days after injection (DAI). Efficacy on survival was estimated with Cox proportional hazards mixed models and Kaplan meier estimates. To predict efficacy in field-based scenarii, we used a transmission model fed with an entomological model considering different levels for the Anopheles’ zoophagic preference, calves vs humans ratios, and bed net use variables.ResultsThe release at mosquitocidal plasmatic concentrations of Ivermectin during 6 months is confirmed for both formulations (Hazard ratios > 1 for both formulations against their vehicle for 210 days). The Ivermectin concentration allowing to kill 90% of the mosquitoes before the extrinsic incubation period of the parasite is achieved (10 days) are 11 and 9 ng/ml for formulations A and B if the blood meal is taken before the infectious one, and 15 and 13 ng/ml if it was taken after. Modeling showed that Ivermectin treatment of calves using BEPO® technology would reduce infectious vector populations, from at least 35% for most anthropophagic Anopheles in villages where cattle to human ratio is the lowest, to more than 75% if vectors were zoophagic and calves numbers superior to humans’.ConclusionOur study gives the proof of concept that a long-lasting formulation of Ivermectin administered to calves could help decrease field malaria vectors’ populations, which may, ultimately, have an impact at the epidemiological level.

Background African animal trypanosomosis (AAT), transmitted by tsetse flies, is arguably the main disease constraint to integrated crop-livestock agriculture in sub-Saharan Africa, and African heads of state and governments adopted a resolution to rid the continent of this scourge. In order to sustainably reduce or eliminate the burden of AAT, a progressive and evidence-based approach is needed, which must hinge on harmonized, spatially explicit information on the occurrence of AAT and its vectors. Methods A digital repository was assembled, containing tsetse and AAT data collected in Burkina Faso between 1990 and 2019. Data were collected either in the framework of control activities or for research purposes. Data were systematically verified, harmonized, georeferenced and integrated into a database (PostgreSQL). Entomological data on tsetse were mapped at the level of individual monitoring traps. When this was not possible, mapping was done at the level of site or location. Epidemiological data on AAT were mapped at the level of location or village. Results Entomological data showed the presence of four tsetse species in Burkina Faso. Glossina tachinoides, present from the eastern to the western part of the country, was the most widespread and abundant species (56.35% of the catches). Glossina palpalis gambiensis was the second most abundant species (35.56%), and it was mainly found in the west. Glossina morsitans submorsitans was found at lower densities (6.51%), with a patchy distribution in the southern parts of the country. A single cluster of G. medicorum was detected (less than 0.25%), located in the south-west. Unidentified tsetse flies accounted for 1.33%. For the AAT component, data for 54,948 animal blood samples were assembled from 218 geographic locations. The samples were tested with a variety of diagnostic methods. AAT was found in all surveyed departments, including the tsetse-free areas in the north. Trypanosoma vivax and T. congolense infections were the dominant ones, with a prevalence of 5.19 ± 18.97% and 6.11 ± 21.56%, respectively. Trypanosoma brucei infections were detected at a much lower rate (0.00 ± 0.10%). Conclusions The atlas provides a synoptic view of the available information on tsetse and AAT distribution in Burkina Faso. Data are very scanty for most of the tsetse-free areas in the northern part of the country. Despite this limitation, this study generated a robust tool for targeting future surveillance and control activities. The development of the atlas also strengthened the collaboration between the different institutions involved in tsetse and AAT research and control in Burkina Faso, which will be crucial for future updates and the sustainability of the initiative. Graphical Abstract

L’objectif de cette étude était d’évaluer les Connaissances, Attitudes et Pratiques (CAP) chez les sportifs face aux conduites dopantes dans la ville de Bobo-Dioulasso au Burkina Faso. Il s’est agi d’une étude transversale, de novembre 2020 à janvier 2021, portant sur 390 sportifs de trois disciplines sportives: football, basketball, et handball. Les données ont été collectées à partir de questionnaires anonymes administrés ou auto-administrés. Au total, 73.1% (285) des sportifs ont participé à l’étude. Le sexe masculin était majoritaire, soit un sex-ratio de 2.47 et l’âge moyen des sportifs était de 21.4±3.68 ans. De plus, 69.12% (197) des sportifs ont déclaré avoir des connaissances sur le dopage ou sur les conduites dopantes et que les canaux privilégiés étaient les mass médias (55.79%) et les amis (10.18%). A l’issue de l’enquête CAP, 76.84% (219) ont déclaré pratiqué les conduites dopantes (p