Lack of robust evidence for aWolbachiainfection inAnopheles gambiaefrom Burkina Faso

Abstract

AbstractThe endosymbiontWolbachiacan have major effects on the reproductive fitness, and vectorial capacity of host insects and may provide new avenues to control mosquito borne pathogens.Anopheles gambiaes.l is the major vector of malaria in Africa but the use ofWolbachiain this species has been limited by challenges in establishing stable transinfected lines and uncertainty around native infections. High frequencies of infection ofWolbachiahave been previously reported inAn. gambiaecollected from the Valle du Kou region of Burkina Faso in 2011 and 2014. Here we re-evaluated the occurrence ofWolbachiain natural samples, collected from Valle du Kou over a 12-year time span, and in addition, expanded sampling to other sites in Burkina Faso. Our results showed that, in contrast to earlier reports,Wolbachiais present at an extremely low prevalence in natural population ofAn. gambiae. From 5,341 samples analysed only 29 were positive forWolbachiaby nested PCR representing 0.54% of prevalence. No positive samples were found with regular PCR. Phylogenetic analysis of 16S rRNA gene amplicons clustered across supergroup B, with some having similarity to sequences previously found inAnophelesfrom Burkina Faso. However, we cannot discount the possibility that the amplicon positive samples we detected were due to environmental contamination or were false positives. Regardless, the lack of a prominent native infection inAn. gambiaes.l. is encouraging for applications utilisingWolbachiatraninsfected mosquitoes for malaria control.