Frequency of the Val1016Ile mutation on the kdr gene in Aedes aegypti (Diptera: Culicidae) in south Brazil

Abstract

Recently, the number of Aedes aegypti foci has increased in west of Santa Catarina, south Brazil, which has increased concern regarding mosquito-borne disease outbreaks such as dengue fever, Zika virus, and chikungunya. Therefore, it is important to monitor genetic resistance to insecticides through "knockdown resistance". Homozygosity (Ile/Ile) at position 1016 in the coding region of a voltage-dependent sodium channel gene (Na) may induce resistance to pyrethroid insecticides. We evaluated the frequency of these alleles in A. aegypti in west Santa Catarina. In total, 349 specimens were obtained from the microregions of Joaçaba (31), Concórdia (35), Chapecó (154), and São Miguel do Oeste (129). We found that 109 individuals (31.0%) were homozygous for Val/Val, 102 (29.0%) were heterozygous for Val/Ile, and 138 (40.0%) were homozygous for Ile/Ile. The allele frequencies were similar for Val (0.455) and Ile (0.545). Joaçaba and Concórdia had the highest mutant allele frequencies (0.825 and 0.685, respectively). Therefore, these populations should be monitored for increases in pyrethroid resistance. The São Miguel do Oeste and Chapecó populations had similar frequencies of Val and Ile and were not in Hardy-Weinberg equilibrium, suggesting that a selection pressure or other evolutionary force has occurred. In conclusion, the observed frequency of Ile/Ile homozygous individuals in the region studied requires attention, because the implementation of controls using pyrethroid may increase the frequency of the mutant allele through the selection of resistant populations.

A Point Mutation V419L in the Sodium Channel Gene from Natural Populations of Aedes aegypti Is Involved in Resistance to λ-Cyhalothrin in Colombia

“…aegypti from China, Indonesia, and Thailand [ 11 ]. In America, the mutation V1016I was discovered to coexist with F1534C in Venezuela [ 14 ] and Brazil [ 19 , 20 , 21 ]. Interestingly, Vera-Maloof et al, in 2015, proposed that the F1534C mutation was selected first and confers a low level of pyrethroid resistance, and that the V1016I haplotype cannot be selected in the absence of F1534C [ 22 ].…”

Spatial Distribution of Pyrethroid Resistance and kdr Mutations in Aedes aegypti from La Guajira, Colombia

“…In this species, the kdr mutations G923V, L982W, I1011M, V1016G, I1011V, V1016I, F1534C, S989P, D1763Y, T1520I, and V410L have been identified worldwide with differences in allele and genotype frequencies between Ae. aegypti populations reported [ 30 , 31 , 44 , 45 , 46 , 47 , 48 ].…”

Insecticide resistance status and mechanisms in Aedes aegypti and Aedes albopictus from different dengue endemic regions of Panama

“…In addition, the F1534C was discovered recently in Brazil [16], Venezuela [17] and Colombia [18]. In the Americas, the Val1016Ile mutation was found to coexist with F1534C in Venezuela [17] and Brazil [19].…”