Spatial Distribution of Pyrethroid Resistance and kdr Mutations in Aedes aegypti from La Guajira, Colombia

Simple Summary Current strategies to suppress arbovirus outbreaks include insecticide use against larvae and adult mosquitoes. The control of Aedes aegypti by insecticides is challenging due to a rapid increase in resistance. In Colombia, pyrethroids have been one of the most widely used insecticides to control adult forms of Ae. aegypti because of its low impact on the environment, low toxicity to mammals, and greater effectiveness. We detected the frequency and intensity of resistance to permethrin, deltamethrin, lambda-cyhalothrin, and associated kdr mutations in Ae. aegypti from La Guajira, Colombia. Modeling the spatial distribution of pyrethroid resistance and the mechanisms (e.g., kdr mutations) provoking it could enhance current national and departmental vector control programs by classifying areas according to the insecticide resistance status of Ae. aegypti populations and orient strategies such as rotations in endangered areas. Thus, benefits such as susceptibility recovery might be obtained. Dengue, chikungunya, and Zika are of great concern to the public health of Colombia. One of the main control strategies for these diseases is the application of insecticides directed at the Aedes aegypti vector. However, insecticide resistance has been increasingly recorded in the country, making control measures difficult. Here, we evaluated the resistance profiles for pyrethroids in populations of Ae. aegypti from La Guajira, Colombia. The frequency (diagnostic dose, DD) and intensity (2x, 5x, and 10x DD) of resistance to permethrin, deltamethrin, and lambda-cyhalothrin were determined in 15 populations of Ae. aegypti from La Guajira, Colombia, using the bottle bioassay. The kdr mutations V1016I, F1534C, and V410L, were identified, and their allele and genotype frequencies were calculated. Finally, the mortality values for the analyzed pyrethroids were interpolated following the IDW method for predicting pyrethroid resistance. The populations of Ae. aegypti showed a high frequency of resistance to permethrin with a low to moderate intensity, which was associated with the triple-resistant haplotype LL410/II1016/CC1534. They remain susceptible to deltamethrin and, in some populations, expressed the risk of developing resistance to lambda-cyhalothrin.

Automated summary

Current strategies to suppress arbovirus outbreaks include the use of insecticides against larvae and adult mosquitoes. However, the control of Aedes aegypti by insecticides is challenging due to the rapid increase in resistance. In Colombia, pyrethroids have been widely used to control adult forms of Ae. aegypti, but resistance to these insecticides has been detected. Modeling the spatial distribution of resistance and identifying the mechanisms provoking it could enhance vector control programs by classifying areas according to the resistance status and implementing appropriate strategies.