Asaia bacteria in sand flies and their impact on Leishmania transmission

Abstract

Midgut microbiome was demonstrated to affect the transmission of vector-borne pathogens. In sandflies, Asaia bacteria was found as a part diet and midgut microbiome. Here, we have investigated theeffect of two Asaia species on the development of Leishmania major in Phlebotomus duboscqi. Thesand flies were first infected with bacteria via sugar meal and then membrane-fed on bloodcontaining Leishmania promasgotes. Following this superinfecon, the development of Leishmaniainfecon was examined. Parcularly, we studied changes in localizaon and intensity of infecon andexamined Leishmania morphological forms on midgut smears. Both tested bacteria species, Asaiasiamensis, and Asaia krungthepensis, colonized the intesne of female Ph. Duboscqi for up to 8 daysaer infecon and were transmied vercally to the next generaon through contaminaon of theegg surface. The presence of Asaia within Ph. Duboscqi negavely affects the intensity of Leishmanialate-stage infecons. In addion to the wild type, we tested a strain of Asaia engineered for theexpression of a protein of Wolbachia (WSP). This strain of Asaia also readily survives in Ph.duboscqi midgut and experiments on its effect on Leishmania infecon are in progress.