Overview
- Field sampling and models show that a knockdown‑resistance mutation called F1534S was absent in 2016–17 and had become widespread by 2023, appearing in 84% of sampled residential areas and 39% of individual Aedes albopictus mosquitoes.
- Neighborhood analysis found higher resistance frequencies in wealthier blocks, a pattern researchers say is consistent with repeated, uncoordinated private spraying that creates strong local selection pressure.
- The F1534S change alters the mosquito voltage‑gated sodium channel and reduces sensitivity to pyrethroids, allowing carriers to survive treatments and spread the trait before obvious control failures appear.
- A separate July 2026 lab study on Aedes aegypti found a 97.91% mortality at the diagnostic dose of α‑cypermethrin and a more than 21‑fold rise in β‑esterase activity after exposure, signaling an early biochemical route to pyrethroid resistance and possible cross‑resistance.
- Researchers recommend integrated pest management, eliminating standing water, rotating or pairing insecticides with enzyme inhibitors, and coordinated action by homeowners, pest control firms, and public health agencies to slow further resistance.