Feeding behavior of Aedes (Aedimorphus) vexans arabiensis, a Rift valley fever virus vector in the Ferlo pastoral ecosystem of Senegal

Host-vector contact is a key factor in vectorial capacity assessment and thus the transmission of mosquito-borne viruses such as Rift Valley Fever (RVF), an emerging zoonotic disease of interest in West Africa. The knowledge of the host-feeding patterns of vector species constitutes a key element in the assessment of their epidemiological importance in a given environment. The aim of this work was to identify the blood meal origins of Aedes vexans arabiensis Patton (Diptera: Culicidae), the main vector of RVF virus in the Ferlo pastoral ecosystem of Senegal. Engorged female mosquitoes were collected in Younouféré in the pastoral ecosystem in the Ferlo region during the 2014 rainy season. CDC light CO2-baited traps were set at six sites for two consecutive nights every month from July to November. Domestic animals present around traps were identified and counted for each trapping session. Blood meal sources of engorged mosquitoes were identified using a vertebrate-specific multiplexed primer set based on cytochrome b. Blood meal sources were successfully identified for 319 out of 416 blood-fed females (76.68%), of which 163 (51.1%) were single meals, 146 (45.77%) mixed meals from two different hosts and 10 (3.13%) mixed meals from three different hosts. Aedes vexans arabiensis fed preferentially on mammals especially on horse compared to other hosts (P < 0.001). Proportions of single and mixed meals showed significant temporal (P < 0.001) and spatial variations (P < 0.001) according to hosts availability. Aedes vexans arabiensis shows an opportunistic feeding behavior depending on the host availability. Results were discussed in relation with the Rift valley fever virus transmission and vector involvement as well as its primary hosts.