Wolbachia depletion blocks transmission of lymphatic filariasis by preventing chitinase-dependent parasite exsheathment

Abstract

Significance Lymphatic filariasis caused by Wuchereria bancrofti , Brugia malayi , and Brugia timori affects 51 million people, leading to severe physical and mental disabilities. A mutualistic symbiosis between these filarial nematodes and Wolbachia bacteria has been exploited as a new curative treatment. Epidemiological modeling of anti- Wolbachia treatment assumes that transmission persists due to the lag phase before microfilariae (mf) become removed from circulation. Here, we show that Wolbachia -depleted mf cannot develop within the mosquito vector—a phenotype associated with down-regulation of B. malayi mf-specific chitinase, an enzyme essential for exsheathment. Our findings add to the broad range of host biological processes dependent on Wolbachia and suggest that anti- Wolbachia treatment mediates a more accelerated impact on elimination of lymphatic filariasis than currently predicted.