Anopheles gambiae s.l. is the primary vector of human malaria in West Africa. Insecticide resistance among species within this vector complex is a serious threat to the management and control of malaria. Resistance to pyrethroids and DDT appears to be expanding among populations of An. gambiae s.s. Resistance to these insecticides may be derived from selection for metabolic resistance (esterases, GSTs or monooxygenases) or from single point mutations in the sodium channel gene that confers knockdown resistance (kdr) to both pyrethroids and DDT or from a combination of both metabolic and mutation mechanisms. Anopheles gambiae were collected from three sites, one with high insecticide exposure, one with medium levels of exposure and one with low levels of exposure. Each mosquito collected was evaluated by the WHO bioassay for insecticide resistance. Molecular diagnostics were used to identify the An. gambiae, differentiate between the molecular M and S forms and screen for kdr alleles. Homozygous and heterozygous kdr genotypes were correlated with site and bioassay results. These comparisons did not result in 100% congruence, but kdr alleles are present at high rates in some populations of An. gambiae s.s. in Mali. In addition, 10 microsatellites on chromosome 3 were used to evaluate the genetic structure of each population. The three populations sampled were genetically distinct with variable levels of internal population structure.
Species 1: Diptera Culicidae Anopheles gambiae (malaria mosquito)
Keywords: malaria
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