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International audience; In Madagascar, the high West Nile virus (WNV) antibody prevalence reported in horse populations suggests a high level of vector-horse contact. This study aims to characterize the mosquito species usually involved in WNV transmission in horse stables in Madagascar. Five horse stables were investigated in October and November 2016 in five distinct inland areas. Mosquitoes were collected using double net traps baited with human, poultry or horse as well as light traps. Blood meal identification from engorged females was performed using host-specific PCRs. A total of 2898 adult mosquitoes were collected with Culex (Culex) antennatus (Becker) (40.7%), and Cx. (Cux.) quinquefasciatus Say (14.9%), being the most abundant species. The mosquito abundance varied between horse stables (P < 10(-7)) and depending on the bait used in the double net traps (P < 0.003). Among the 190 tested blood meals, 119 consisted of single blood meals with 85 from horse, 17 from human, 16 from chicken, one from cattle and 71 consisted of mixed blood meals. The mosquito species collected during this study exhibited a generalist feeding behaviour allowing them to act as bridge vectors between different vertebrate hosts involved in WNV transmission cycle. Their vector status with regard to West Nile fever epidemiology is reviewed

International audience; The horizontal and vertical distribution of mosquito species was studied in Maromizaha rainforest, Madagascar. In November 2014, horizontal distribution was studied using light traps that were placed in four habitat types, ranging from degraded forest to primary rainforest. In November to December 2016, vertical distribution was studied using light traps placed near to the ground and elevated near the canopy. From the horizontal survey, 476 adults were collected: Uranotaenia (52.10%) and Culex (35.2%) were the most abundant genera. The highest numbers of mosquitoes were observed in the rainforest edge habitat, while the highest mosquito diversity was observed within primary rainforest. From the vertical survey, 276 adults were collected: Culex was the most abundant genus and represented 75.70% of adults caught. Mosquitoes were more abundant in traps placed near the ground than those near the canopy. The highest species diversity was observed near the canopy. The higher abundance of mosquitoes at the forest edge agrees with the role of this zone as an ecotone between intact rainforest and the nearest human habitation. Increased mosquito abundance in lower strata might heighten their contact with particular vertebrate hosts. The presence of vectors in different habitats and in varying elevations likely influences the risk of pathogen transmission between animals and humans in this rainforest.