Aedes albopictus shows growing resistance to pyrethroid insecticides in Spain

Researchers have documented a rapid increase in genetic mutations that make the Asian tiger mosquito (Aedes albopictus) resistant to pyrethroid insecticides in Spain. A longitudinal study carried out by the University of North Carolina from 2016 to 2024, and published in Frontiers in Tropical Diseases, found that the proportion of mosquitoes carrying resistance‑associated mutations rose from the first detections in 2018 to about 39 % of sampled individuals by 2024. The study focused on populations in the province of Cádiz, where the species has been established for years and is a prominent summer pest. The resistance is linked to the selection pressure from repeated use of the same chemical agents, mirroring patterns seen with antibiotic‑resistant bacteria. Experts warn that the diminishing efficacy of routine garden spraying and larger control campaigns could complicate efforts to curb mosquito numbers and limit disease transmission.