Aedes aegypti is the primary vector of arboviruses, including the dengue virus. Insecticide-based vector control remains a key strategy for reducing mosquito populations and disrupting disease transmission; however, its effectiveness is increasingly challenged by resistance. Identifying resistance mechanisms is crucial for monitoring resistance trends and informing policy decisions for vector control and disease prevention. We aimed to investigate the voltage-gated sodium channel (vgsc) mutations in pyrethroid-resistant Ae. aegypti strains. In this study, we established a cypermethrin-resistant Ae. aegypti strain from field-collected mosquitoes in 2016 and performed whole-genome sequencing to identify resistance-associated vgsc mutations. Additionally, we genotyped field Ae. aegypti collected in 2024 to assess the variation and prevalence of resistance-related mutations. Our findings confirmed that R52H and N868D are associated with resistance, with R52H co-occurring with S989P+V1016G and N868D co-occurring with F1534C. The widespread presence of R52H and N868D, along with their co-circulation with other resistance-associated mutations in the field population, suggests that these mutations have been maintained under intense selection pressure. Furthermore, we identified 12 haplotypes and suggested a potential evolutionary trajectory based on co-occurrence patterns of mutation events. The emergence and persistence of novel vgsc mutations in field populations highlight the ongoing expansion of insecticide resistance in Taiwan and globally, which threatens the efforts for disease vector control. Understanding the functional impact of these mutations is essential for comprehensive monitoring and evaluating pyrethroid resistance dynamics. Systematic surveillance program is required to track resistance trends and guide evidence-based vector control strategies that ensure effective disease prevention and public health protection.
Chung et al. (Tue,) studied this question.