Knockdown Resistance Mutations in Aedes aegypti (Diptera: Culicidae) From Puerto Rico

Abstract

Permethrin resistance is widespread in Aedes aegypti (L.), the main dengue, zika, and chikungunya virus vector in Latin America and the Caribbean. A common mechanism of resistance to pyrethroids-knockdown resistance (kdr)-is conferred through mutations in the insect's voltage-dependent sodium channel. In this mosquito, around 10 replacement substitutions in the voltage-gated sodium channel gene (vgsc) have been reported in pyrethroid-resistant strains. Two of these mutations, named Ile1,016 and Cys1,534, are widespread in mosquito populations from Latin America and the Caribbean. This study assessed the levels of permethrin resistance and the frequency of two kdr mutations in eight Ae. aegypti populations collected in Puerto Rico in 2013. Permethrin resistance factors ranged from 33-214-fold relative to the New Orleans reference strain. The frequency of kdr mutation Ile1,016 ranged from 0.65 to fixation (1.0), and for Cys1,534 frequencies varied from 0.8 to fixation. Alarmingly, two populations-Carolina and Caguas-reached fixation at both loci. Our results suggest that permethrin effectiveness for Ae. aegypti control is compromised in these collections from Puerto Rico.

Reduced effectiveness of repellents in a pyrethroid‐resistant strain of Aedes aegypti (Diptera: culicidae) and its correlation with olfactory sensitivity

“…1(a)). The overall curve fit of the EC 50 for metofluthrin decreased from 0.29 (0.13-0.66) to 0.26 (0.12-0.55) μg cm -2 against the OR strain and from 17 (10-30) to 12 (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) against the PR strain ( Fig. 1(a)).…”

“…For example, Ae. aegypti from Puerto Rico showed up to 214‐fold resistance to permethrin, and 650‐fold resistance to deltamethrin compared to the susceptible Orlando strain . The resistance mechanisms in this strain include knockdown resistance due to two kdr mutations, V1016I and F1534C, present at 0.97 and 1.00 frequencies, respectively, in the voltage‐dependent sodium channel gene, as well as upregulated cytochrome P450s and glutathione‐ S ‐transferases …”

Quantification of permethrin resistance andkdralleles in Florida strains ofAedes aegypti(L.) andAedes albopictus(Skuse)

“…Pyrethroid resistance and kdr alleles have been well documented in Ae. aegypti strains from Central America, South America and the Caribbean [7-11]. Recent testing as part of the Zika emergency response in Puerto Rico has shown that isolated, early reports of resistance were indicative of widespread resistance on the island [11-14].…”

“…aegypti strains from Central America, South America and the Caribbean [7-11]. Recent testing as part of the Zika emergency response in Puerto Rico has shown that isolated, early reports of resistance were indicative of widespread resistance on the island [11-14]. Studies have also shown the pyrethroid resistance is not specific to a particular chemical but is generally class-wide to type I, type II, and non-ester pyrethroids [11, 15, 16].…”

Rapid Screening of Aedes aegypti Mosquitoes for Susceptibility to Insecticides as Part of Zika Emergency Response, Puerto Rico

“…The heavy reliance on permethrin-based products raised concerns, given recent reports that Ae. aegypti populations in 8 municipalities were already highly resistant to it ( 7 ). …”