Relevance study of vector competence and insecticide resistance in Aedes aegypti laboratory lines

The urban mosquito species Aedes aegypti is the main vector of arboviruses worldwide. Mosquito control with insecticides is the most prevalent method for preventing transmission in the absence of effective vaccines and available treatments; however, the extensive use of insecticides has led to the development of resistance in mosquito populations throughout the world, and the number of epidemics caused by arboviruses has increased. Three mosquito lines with different resistance profiles to deltamethrin were isolated in French Guiana, including one with the I1016 knock-down resistant allele. Significant differences were observed in the cumulative proportion of mosquitoes with a disseminated chikungunya virus infection over time. In addition, certain genes (CYP6BB2, CYP6N12, GST2, trypsin) were variably overexpressed in the midgut at 7 days after an infectious blood meal in these three lines. Therefore, detoxification enzymes and kdr mutations may contribute to an enhanced midgut barrier and reduced dissemination rate. Our work shows that vector competence for chikungunya virus varied between Ae. aegypti laboratory lines with different deltamethrin-resistance profiles. More accurate verification of the functional association between insecticide resistance and vector competence remains to be demonstrated. ### Competing Interest Statement The authors have declared no competing interest.