A Single Crossing-Over Event in Voltage-Sensitive Na+ Channel Genes May Cause Critical Failure of Dengue Mosquito Control by Insecticides

Abstract

The voltage-sensitive sodium (Na+) channel (Vssc) is the target site of pyrethroid insecticides. Pest insects develop resistance to this class of insecticide by acquisition of one or multiple amino acid substitution(s) in this channel. In Southeast Asia, two major Vssc types confer pyrethroid resistance in the dengue mosquito vector Aedes aegypti, namely, S989P+V1016G and F1534C. We expressed several types of Vssc in Xenopus oocytes and examined the effect of amino acid substitutions in Vssc on pyrethroid susceptibilities. S989P+V1016G and F1534C haplotypes reduced the channel sensitivity to permethrin by 100- and 25-fold, respectively, while S989P+V1016G+F1534C triple mutations reduced the channel sensitivity to permethrin by 1100-fold. S989P+V1016G and F1534C haplotypes reduced the channel sensitivity to deltamethrin by 10- and 1-fold (no reduction), respectively, but S989P+V1016G+F1534C triple mutations reduced the channel sensitivity to deltamethrin by 90-fold. These results imply that pyrethroid insecticides are highly likely to lose their effectiveness against A. aegypti if such a Vssc haplotype emerges as the result of a single crossing-over event; thus, this may cause failure to control this key mosquito vector. Here, we strongly emphasize the importance of monitoring the occurrence of triple mutations in Vssc in the field population of A. aegypti.

Characterization of metabolic detoxifying enzymes in an insecticide resistant strain of <i>Aedes aegypti</i> harboring homozygous S989P and V1016G <i>kdr</i> mutations

“…aegypti populations in Thailand, the S989P mutation was absent from Ae. aegypti populations in Malaysia, and hence they lacked the additive resistant effect conferred by the V1016G mutation (Hirata et al, 2014;Plernsub et al, 2016b). Among Brazilian Ae.…”

“…Interestingly, the V1016G mutation is often found with a serine to proline mutation (S989P) in domain II (Stenhouse et al, 2013;Kawada et al, 2014). Although S989P itself does not reduce the sensitivity to pyrethroids, its combination with V1016G mutation in homozygous forms largely increases resistance to pyrethroids (Hirata et al, 2014). Recent studies in Thailand revealed three genotypes of kdr mutations in Ae.…”

Evaluation of larvicidal activity of a nanoemulsion of Rosmarinus officinalis essential oil

“…Many substances have been tested to control the vector Aedes aegypti. Several substances have been tested to control de vector Aedes aegypti (Hirata et al, 2014). However, many of them are synthetic chemicals, including the organophosphate temephos and the pyrethroid deltamethrin, which may lead resistance in the mosquitoes and even negative impacts to the environment (Marcombe et al, 2009).…”

Mutations of two acidic residues at the cytoplasmic end of segment IIIS6 of an insect sodium channel have distinct effects on pyrethroid resistance

“…High levels of pyrethroid resistance could be conferred by the apparently additive effects of double or triple mutations (Hirata et al, 2014; Vais et al, 2003). In some cases, though, where multiple mutations are involved, it was found that there are primary and secondary mutations.…”