Presence of Heterozygous V1016G kdr Mutation in Pyrethroid Insecticide Resistance in Aedes aegypti a Dengue vector from Southern India

Abstract

Aedes aegypti is a primary vector of Dengue, Chikungunya, and Zika viruses, and its control relies heavily on pyrethroid insecticides. However, the development of resistance in mosquito populations poses a major challenge to effective vector control. This study aimed to investigate the presence of the V1016G knockdown resistance (kdr) mutation in Aedes aegypti collected from Nagapattinam district, Tamil Nadu, India. Aedes immatures were collected from selected field sites and subjected to insecticide susceptibility testing using World Health Organization (WHO) guidelines. Genomic DNA was extracted, and allele-specific PCR was performed to detect the V1016G mutation in the voltage-gated sodium channel gene (vgsc). The analysis revealed the presence of the V1016G mutation in heterozygous form (VG) among the tested samples. No homozygous mutants (GG) were detected. The presence of heterozygous individuals indicates an early stage of resistance development, likely due to ongoing insecticide selection pressure. Bioassay results showed reduced susceptibility to pyrethroids in these populations, supporting the molecular findings. This study provides baseline data on the genetic mechanism of pyrethroid resistance in Aedes aegypti from Nagapattinam district. Regular monitoring of kdr mutations is essential to detect resistance early and guide insecticide use policies. Integrating molecular surveillance with conventional control measures will help delay the spread of resistance and improve the long-term success of vector management programs. The findings highlight the need for alternative control strategies and responsible insecticide use to maintain the effectiveness of current interventions.