Simulated impacts on vectorial capacity from resistance and exposure to insecticides and repellents in Aedes aegypti

High levels of resistance to commonly used insecticides have been documented in many populations of Aedes aegypti, resulting in increased interest and use of alternative chemicals and spatial repellents.   Mosquitoes carrying resistance genes to insecticides or repellents may have other changes in their physiology, affecting fitness and vector competence for arboviruses.  Exposure to chemicals, whether sub-lethal doses of insecticides or spatial repellents, may also alter physiology.  Vectorial capacity, the entomological components of the basic reproduction number of a vector-borne arbovirus, is a useful way to integrate these varied effects to estimate impact on pathogen transmission.  Relatively little is known about the relationships between resistance and exposure and mosquito physiology traits (survival, biting rate) and virus interaction traits (infection and transmission rates, extrinsic incubation period).  Using an individual based model, we are integrating net effects on vectorial capacity under different assumptions about relationships between traits and resistance or exposure (e.g. increasing, decreasing and no effect).  Individual estimates are summed for population level vectorial capacity estimates.   We will compare population vectorial capacity across traits, relationships, resistance levels and exposure to assess which are most influential and where better estimates will have the strongest effect on prediction of outcomes. These results will inform mosquito control strategies in an environment of increasing resistance and use of alternative chemicals, and identify regions of parameter space where risk of transmission may increase with exposure.