First report on kdr mutations in wild populations of Aedes aegypti from Argentina determined by a novel multiplex high resolution melting PCR method

Abstract

Abstract Background: Aedes aegypti is an urban mosquito vector of dengue and other arboviruses. During epidemic periods, pyrethroid insecticides are used for the control of adult mosquitoes; the worldwide distributed resistance to these insecticides is a cause of failures in vector control campaigns. The primary target of pyrethroids is the voltage-gated sodium channel; point mutations on this channel, called kdr mutations, are associated with pyrethroid resistance. Two kdr mutations, called V1016I and F1534C, augmented in frequency in natural populations of Ae. aegypti from the Americas in the last decade; their association with pyrethroid resistance has been largely demonstrated in field populations throughout the country, and in in vitro assays. The diagnostic of kdr polymorphisms allows an early detection of insecticide resistance spreading, which is critical for timely decisions on vector management. Given the relevance of resistance management, high-throughput methods for kdr genotyping are valuable tools for resistance monitoring programs. These methods should also be cost-effective, to allow regional-scale surveys. Despite the extended presence of Ae. aegypti and the incidence of dengue in Argentina, the presence, abundance and distribution of kdr mutations were not reported in this country up to date. Methods: Aedes aegypti samples were collected from Metropolitan Area of Buenos Aires, and northern localities of Tartagal (Salta province) and Calilegua (Jujuy province). A high resolution melting assay was developed for the simultaneous detection of V1016I and F1534C kdr mutations. Results: We demonstrate the presence of kdrmutations in Argentina in regions under different selection pressure with pyrethroids. We also report a multiplex high-throughput assay based in high resolution melting PCR for the simultaneous genotyping of V1016I and F1534C kdr mutations. Conclusions: We report for the first time the presence of kdr mutations in distant populations from Argentina, with different epidemiological situations and different history of mosquito control efforts. We have developed a high-throughput method for the genotyping of kdr mutations in Ae. aegypti from the American continent. Given its convenient cost and running time, this method can be incorporated in control campaigns for monitoring the presence and spreading of kdr alleles.