Prevalence of Knock-Down Resistance F1534S Mutations in Aedes albopictus(Skuse) (Diptera: Culicidae) in North Carolina

Knock-down resistance (kdr) mutations in the voltage-gated sodium channel gene of Aedesspecies mosquitoes are biomarkers for resistance to pyrethroid insecticides. In the United States, few studies have reported kdrmutations among Aedes albopictus(Skuse) (Diptera: Culicidae) populations. In this study, we sought to compare the presence of kdralleles among Ae. albopictusmosquitoes collected from Fort Bragg and Wake County, North Carolina. We collected 538 Ae. albopictusmosquitoes, including 156 from 4 sites at Fort Bragg, North Carolina and 382 from 15 sites in Wake County, North Carolina to compare the prevalence of kdrmutations. Of those successfully sequenced, we identified 12 (3.0%) mosquitoes with kdrmutations, all of which were attributed to variants at position 1534 within domain 3. All mutations were found in mosquitoes collected at Wake County sites; no mutations were identified in collections from Fort Bragg. There was a focus of mutations observed at the Wake County sites with approximately 92% (11 of 12) of the mosquitoes with the mutation coming from one site, where kdrmutations represented 24.4% (11 of 45) of all mosquitoes collected. We observed highly focal resistance in a suburban area of Raleigh, which may be attributable to peri-domestic mosquito control activities that involve area dispersal of pyrethroid insecticides. More robust surveillance is needed to monitor the emergence and spread of resistance.