Pyrethroid-resistance and presence of two knockdown resistance (kdr) mutations, F1534C and a novel mutation T1520I, in Indian Aedes aegypti
Autor(es): Kushwah, Raja Babu S.; Dykes, Cherry L.; Kapoor, Neera; Adak, Tridibes; Singh, Om P.
Resumo: Background: Control of Aedes aegypti, the mosquito vector of dengue, chikungunya and yellow fever, is a challenging task. Pyrethroid insecticides have emerged as a preferred choice for vector control but are threatened by the emergence of resistance. The present study reports a focus of pyrethroid resistance and presence of two kdr mutations-F1534C and a novel mutation T1520I, in Ae. aegypti from Delhi, India.Methodology/Principal Findings: Insecticide susceptibility status of adult-female Ae. aegypti against DDT (4%), deltamethrin (0.05%) and permethrin (0.75%) was determined using WHO's standard insecticide susceptibility kit, which revealed resistance to DDT, deltamethrin and permethrin with corrected mortalities of 35%, 72% and 76% respectively. Mosquitoes were screened for the presence of kdr mutations including those reported earlier (I1011V/M, V1016G/I, F1534C, D1794Y and S989P), which revealed the presence of F1534C and a novel mutation T1520I. Highly specific PCR-RFLP assays were developed for genotyping of these two mutations. Genotyping using allele specific PCR and new PCR-RFLP assays revealed a high frequency of F1534C (0.41-0.79) and low frequency of novel mutation T1520I (0.13). The latter was observed to be tightly linked with F1534C and possibly serve as a compensatory mutation. A positive association of F1534C mutation with DDT and deltamethrin resistance in Ae. aegypti was established. However, F1534C-kdr did not show significant protection against permethrin.Conclusions/Significance: The Aedes aegypti population of Delhi is resistant to DDT, deltamethrin and permethrin. Two kdr mutations, F1534C and a novel mutation T1520I, were identified in this population. This is the first report of kdr mutations being present in the Indian Ae. aegypti population. Highly specific PCR-RFLP assays were developed for discrimination of alleles at both kdr loci. A positive association of F1534C mutation with DDT and deltamethrin resistance was confirmed.
Palavras-Chave: Sodium-channel gene; High-throughput assays; Insecticide resistance; Dengue vectors; Deltamethrin resistance; Susceptibility status; Diptera-culicidae; Populations; Thailand; Chikungunya
Imprenta: Plos Neglected Tropical Diseases, v. 9, n. 1, 2015
Identificador do objeto digital: 10.1371/journal.pntd.0003332
Descritores: Aedes aegypti - Molecular screening ; Aedes aegypti - Chikungunya Fever
Data de publicação: 2015
