Frequency of kdr alleles in Aedes aegypti populations from coastal and high jungle areas in Peru

The use of chemical insecticides for Aedes aegypti control has led to the development of resistance. Pyrethroid resistance has been associated with knockdown resistance (kdr) mutations (V1016I and F1534C). We characterized and quantified these mutations in Peruvian Ae. aegypti collected from coastal (Arequipa, Piura, Tumbes) and jungle (Amazonas, San Martin) regions. Mosquitoes were genotyped using standard melt curve analysis for 1016 and 1534 SNPs; susceptible (ORL 1952) and resistant (Puerto Rico) strains were included. Genotype frequencies were calculated.  Moderate levels of 1016II were found in Tumbes (31-74%) and Piura (20-39%) populations; low or no 1016II were found in Arequipa (17%), Amazonas (6%) and San Martin (0-8%). Amazonas, Piura and Tumbes populations were nearly fixed (≥ 95%) for 1534CC, unlike Arequipa and San Martin where 1534FF mosquitoes were found (50-100%).  Seven genotypes were observed (IICC, IIFC, VICC, VIFC, VVCC, VVFC, VVFF) with resistant genotypes (IICC, VICC), indicative of higher resistance (20X-60X) in Tumbes and Piura, and less resistant genotypes (VVCC, VVFC, VVFF) indicative of lower resistance (4X) in Arequipa, Amazonas and San Martin. Only the wildtype (VVFF) was found in one San Martin population. Results suggest that pyrethroid resistance genetic markers are widely present in Peruvian Ae. aegypti, yet resistance levels vary across regions with a higher frequency of kdr mutations in mosquitoes from Tumbes and Piura, high dengue transmission areas where pyrethroids are not effective. Further sampling and analysis will confirm these results. This study provides insights into pyrethroid resistance mechanisms and may guide mosquito control operations