A Microsporidian can block Plasmodium falciparum transmission in Anopheles arabiensis mosquitoes

A possible novel malaria control approach involves the dissemination in mosquitoes of inherited symbiotic microbes to block Plasmodium transmission. However, in the Anopheles gambiae complex, the primary African vectors of malaria, there are limited reports of inherited symbionts with transmission-blocking capacity. We show that a vertically transmitted microsporidian symbiont (Microsporidia MB) in the An. gambiae complex can block Plasmodium transmission. Microsporidia MB is present at moderate prevalence in geographically dispersed populations of An. arabiensis in Kenya, localized to the mosquito midgut and ovaries, and is not associated with significant reductions in adult host fecundity or survival. Field-collected Microsporidia MB infected An. arabiensis are never found to harbor P. falciparum gametocytes and on experimental infection with P. falciparum no sporozoites are detected in Microsporidia MB infected mosquitoes. As a Plasmodium transmission-blocking microbe that is non-virulent and vertically transmitted, Microsporidia MB could be investigated as a strategy to limit malaria transmission. This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/