Development and application of a PCR-RFLP assay revealing widespread distribution of the pyrethroid resistance-associated VGSC V1016G mutation in Aedes albopictus from Guangyuan City, Sichuan Province of China.

BACKGROUND: Aedes albopictus is a primary vector of multiple arboviruses, including dengue, chikungunya, yellow fever, and Zika virus. Its control relies heavily on pyrethroid insecticides. The V1016G mutation in the voltage-gated sodium channel (VGSC) is a well-documented mechanism conferring pyrethroid resistance in Ae. albopictus, which directly challenges the efficacy of pyrethroid-based control. Understanding of the status of insecticide resistance will offer insights to inform evidence-based vector management. However, current phenotypic monitoring is laborious and time-consuming, highlighting the need for rapid and reliable genotyping tools.

METHODS: To detect the V1016G mutation, we developed a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. This assay was then applied to genotype 208 field-collected Ae. albopictus mosquitoes. These samples were collected in 2024 from seven counties/districts within Guangyuan City, a prefecture in northern Sichuan, China.

RESULTS: The PCR-RFLP assay demonstrated 100% concordance with Sanger sequencing results. Genotyping confirmed the widespread presence of the 1016G allele, with frequencies ranging from 3.13% to 14.06%. The resistance allele (1016G) was exclusively detected in heterozygotes, and all populations conformed to Hardy-Weinberg equilibrium (P > 0.05). Furthermore, no significant temporal changes in allele frequencies were detected between 2020 and 2024 across the populations (P > 0.05).

CONCLUSIONS: This study established a cost-effective and reliable PCR-RFLP assay for detecting the V1016G mutation in Ae. albopictus, and demonstrated the widespread distribution of this mutation across Guangyuan City, Sichuan Province of China.