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Análisis molecular de la mutación “knock down resistance” (kdr) y distribución de los genotipos kdren una población salvaje de Culex quinquefasciatus de la India
Author(s) -
Sarkar Manas,
Borkotoki Aparajita,
Baruah Indra,
Bhattacharyya Indra Kumar,
Srivastava Ravi Bihari
Publication year - 2009
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1111/j.1365-3156.2009.02323.x
Subject(s) - genotype , culex quinquefasciatus , biology , population , genetics , mutation , medicine , gene , botany , environmental health , aedes aegypti , larva
Summary Objective To investigate the presence of knock down resistance ( kdr ) mutation, its frequency distribution in the principal vector of bancroftian filariasis, Culex quinquefasciatus from northeastern India, and to relate kdr genotypes with susceptibility and/or resistance to DDT and deltamethrin in this vectors. Methods Adult female mosquitoes were collected by aspiration from human dwellings in two villages, Benganajuli and Rikamari, and two military establishments, Field Units I and II. Insecticide susceptibility tests were performed following WHO methods with 4% DDT and 0.05% deltamethrin. Molecular identification of kdr mutation and genotyping of kdr locus was performed by allele‐specific PCR (AS‐PCR) and direct sequencing in a subset of samples. Results Mosquitoes were resistant to DDT and showed 11.9–41.2% mortality, whereas the knock down bioassay for deltamethrin suggests complete susceptibility to this insecticide in all study sites except Benganajuli. The result of AS‐PCR confirmed the presence of three genotypes: susceptible (SS), resistant (RR) and heterozygous (SR) in the population. Genotype frequencies at kdr locus for DDT‐resistant individuals conformed with the Hardy–Weinberg proportion, whereas DDT and deltamethrin susceptible individuals differed significantly ( P < 0.05). The efficacy of AS‐PCR in detecting the correct genotype was not encouraging. Conclusions This is the first report from India on kdr genotyping in C. quinquefasciatus , and it confirms the occurrence of kdr allele in this vector in northeastern India. This finding has serious implications for the filariasis control programmes in India.