Mechanistic evidence of widespread insecticide resistance among Illinois West Nile virus vectors (Culex pipiens and Culex restuans). Culex pipiens, Culex restuans

Mosquitoes are the vectors of many major diseases including malaria, dengue, yellow fever, zika, and West Nile virus. Insecticides are often used to control mosquitoes and the outbreaks they cause. However, evidence has shown that populations of different mosquito species worldwide have developed resistance to our most common insecticides. This study shows that West Nile virus vectors in Illinois, (Culex pipiens and Culex restuans) are no exception to this trend. Egg collections were made throughout the state during the 2018-2020 field seasons and the resulting adults were tested for resistance to two common insecticides using the CDC bottle bioassay protocol. The results indicate that rates of resistance vary throughout the state and population differences in resistance mechanisms are driving this variation.