A naturally isolated symbiotic bacterium suppresses flavivirus transmission by <i>Aedes</i> mosquitoes.

Abstract

The commensal microbiota of the mosquito gut plays a complex role in determining the vector competence for arboviruses. In this study, we identified a bacterium from the gut of field <i>Aedes albopictus</i> mosquitoes named <i>Rosenbergiella</i> sp. YN46 (<i>Rosenbergiella_</i>YN46) that rendered mosquitoes refractory to infection with dengue and Zika viruses. Inoculation of 1.6 × 10³ colony forming units (CFUs) of <i>Rosenbergiella_</i>YN46 into <i>A. albopictus</i> mosquitoes effectively prevents viral infection. Mechanistically, this bacterium secretes glucose dehydrogenase (<i>Ry</i>GDH), which acidifies the gut lumen of fed mosquitoes, causing irreversible conformational changes in the flavivirus envelope protein that prevent viral entry into cells. In semifield conditions, <i>Rosenbergiella_</i>YN46 exhibits effective transstadial transmission in field mosquitoes, which blocks transmission of dengue virus by newly emerged adult mosquitoes. The prevalence of <i>Rosenbergiella_</i>YN46 is greater in mosquitoes from low-dengue areas (52.9 to ~91.7%) than in those from dengue-endemic regions (0 to ~6.7%). <i>Rosenbergiella_</i>YN46 may offer an effective and safe lead for flavivirus biocontrol.