Abstract

Mansonellosis is a vector-borne infection caused by different species of filarial nematodes of the genus Mansonella, including ozzardi, perstans, and streptocerca. The infection is mainly transmitted by bloodsucking midges of the genus Culicoides. All Mansonella species are known to induce little to no symptoms in humans. Due to the asymptomatic nature of the infection, epidemiological and immunological data are almost inexistent.  Here, we collected blood samples from 88 volunteers in 3 major departments of South Benin and analyzed using parasitological and molecular approaches, the presence of Mansonella infections in the region. Polymerase chain reaction (PCR) and entomological identification strategy were then used on 252 potential vectors collected in the same area to identify those hosting the parasite. While microscopic observations indicate a prevalence of 27.3% of Mansonella perstans infections, PCR analyses revealed a much higher burden (40.9%). Molecular analyses further showed that 2.27% of the tested individuals were positive for Mansonella streptocerca. Moreover, data from molecular identification of the parasites and morphological examination of the vectors revealed that out of 11 Culicoides species identified in the study region, milnei, imicola, and inornatipennis were positive for M. perstans. Our findings suggest PCR as a tool of choice to analyze the prevalence of Mansonellosis and demonstrate that M. perstans is the predominant Mansonella spp. in South Benin. Finally, the present study supports the hypothesis that a high transmission of M. perstans is maintained in the region of South Benin by three main Culicoides spp., including milnei, imicola, and inornatipennis.

Key words: Mansonella, M. perstans, vectors, Culicoides.