Novel Wolbachia strains in Anopheles malaria vectors from Sub-Saharan Africa

The Anopheles mosquito microbiome contains resident bacteria that can influence Plasmodium malaria parasite development. The endosymbiotic bacterium Wolbachia resides in ~40% of insect species but historically was considered absent from Anopheles species (with competing endosymbiotic bacteria such as Asaia postulated to prevent establishment). Recently, Wolbachia strains in wild An. gambiae populations was discovered, suggesting this endosymbiont may be more widespread in malaria vectors. In this study, Anopheles species from five malaria-endemic countries were analysed and Wolbachia strains were discovered in Anopheles coluzzii, Anopheles gambiae s.s., Anopheles moucheti and Anopheles species A. These novel Wolbachia strains are phylogenetically diverse, and high density infections in An. moucheti and Anopheles species A dominated the microbiota. We found no evidence of Wolbachia/Asaia co-infections, or for either of these two endosymbionts having any significant effect on malaria prevalence. We discuss the importance of novel Wolbachia strains in Anopheles species and potential implications for disease control.