An -associated fungus increases susceptibility to dengue virus by modulating gut trypsin activity.

Transmission of dengue virus (DENV) requires successful completion of the infection cycle in the vector, which is initiated in the midgut tissue after ingestion of an infectious blood meal. While certain midgut-associated bacteria influence virus infection, little is known about the midgut-associated fungi (mycobiota), and how its members might influence susceptibility to DENV infection. We show that a () fungus, isolated from field-caught render the mosquito more permissive to DENV infection. This modulation is attributed to a profound down-regulation of digestive enzyme genes and trypsin activity, upon exposure to -secreted factors. In conclusion, we show for the first time that a natural mosquito gut-associated fungus can alter physiology in a way that facilitates pathogen infection.