Diverse novel residentWolbachiastrains in Culicine mosquitoes from Madagascar

AbstractWolbachiaendosymbiotic bacteria are widespread throughout insect species andWolbachiatransinfected inAedesmosquito species has formed the basis for biocontrol programs asWolbachiastrains inhibit arboviral replication and can spread through populations. Resident strains in wild Culicine mosquito populations (the vectors of most arboviruses) requires further investigation given resident strains can also affect arboviral transmission. As Madagascar has a large diversity of both Culicine species and has had recent arboviral outbreaks, an entomology survey was undertaken, in five ecologically diverse sites, to determine theWolbachiaprevalence. We detected diverse novel residentWolbachiastrains within theAedeomyia, Culex, Ficalbia, MansoniaandUranotaeniagenera.Wolbachiaprevalence rates and strain characterisation through Sanger sequencing with multilocus sequence typing (MLST) and phylogenetic analysis revealed significant diversity and we detected co-infections with the environmentally acquired bacterial endosymbiontAsaia. Mosquitoes were screened for major arboviruses to investigate if any evidence could be provided for their potential role in transmission and we report the presence of Rift Valley fever virus in threeCulexspecies:Culex tritaeniorhynchus, Culex antennatusandCulex decens. The implications of the presence of residentWolbachiastrains are discussed and how the discovery of novel strains can be utilized for applications in the development of biocontrol strategies.