281 - Sublethal effects of novel attractive toxic sugar baits reduce dengue virus vectorial capacity in insecticide resistant and insecticide susceptible Aedes aegypti

Abstract: Reliance on chemical insecticides in integrated mosquito management practices has driven the development of resistance in Aedes aegypti, a major arbovirus vector. Mosquitoes that survive insecticide exposure can exhibit alterations in fitness-related traits. Such insecticide-induced sublethal effects on fitness traits may, in turn, influence arbovirus transmission dynamics. To determine the propensity of novel attractive toxic sugar baits (ATSBs) to induce sublethal effects on fitness-related traits of insecticide resistant and insecticide susceptible Ae. aegypti, adult females ingested ATSBs (sugar, boric acid, dinotefuran, and Metarhizium robertsii) under laboratory conditions. Subacute survival, bloodfeeding, fecundity, and fertility were then measured. To determine ATSB effects on dengue virus infection and vectorial capacity, mosquitoes received an infectious dengue virus bloodmeal via an artificial membrane feeding system. Mosquito saliva was collected with honey-soaked cationic paper. Dissected bodies, legs, and collected saliva were analyzed by qRT-PCR. We found that ATSB ingestion reduced subacute survival and reproductive output in insecticide susceptible Ae. aegypti, decreased bloodfeeding rates, and diminished dengue virus vectorial capacity in both susceptible and resistant mosquitoes. Daily survival probability, biting rate, and vector competence had the greatest influence on Ae. aegypti vectorial capacity for DENV-1, with survival exerting the strongest impact under baseline conditions (local sensitivity index), while variation in biting rate and vector competence contributed most to large-scale uncertainty (global sensitivity analysis). These complementary insights highlight the value of our ATSB treatment effects in targeting multiple mosquito traits that collectively reduce Ae. aegypti vectorial capacity for DENV-1.