Control of mosquito vector populations is primarily intended to reduce the transmission of pathogens they transmit. Use of chemical controls, such as larvicides, can have unforeseen consequences on adult traits if not applied properly. The consequences of under application of larvicides are little studied, specifically the impacts on pathogen
infection and transmission by the vectors that survive exposure to larvicides. We compared vector susceptibility of Aedes aegypti (L.) for dengue virus, serotype 1 (DENV-1) previously exposed as larvae to an LC50 of different classes of
insecticides as formulated larvicides. Larval exposure to
insect growth regulators (
methoprene and
pyriproxyfen) significantly increased susceptibility to
infection of DENV-1 in Ae. aegypti adults but did not alter disseminated
infection or transmission. Larval exposure to
temephos,
spinosad, and Bti did not increase
infection, disseminated
infection, or transmission of DENV-1. Our findings describe a previously under observed phenomenon, the latent effects of select larvicides on mosquito vector susceptibility for arboviruses. These data suggest that there are unintended consequences of sublethal exposure to select larvicides that can influence susceptibility of Ae. aegypti to DENV
infection, and indicates the need for further investigation of sublethal effects of
insecticides on other aspects of mosquito biology, especially those parameters relevant to a mosquitoes ability to transmit arboviruses (life span, biting behavior, extrinsic incubation period).