| 18402142 |
Reimer L, Fondjo E, Patchoke S, Diallo B, Lee Y, Ng A, Ndjemai HM, Atangana J, Traore SF, Lanzaro G, Cornel AJ: Relationship between kdr mutation and resistance to pyrethroid and DDT insecticides in natural populations of Anopheles gambiae. J Med Entomol. 2008 Mar;45(2):260-6.
The spread of insecticide resistance genes in Anopheles gambiae Giles sensu stricto threatens to compromise vector-based malaria control programs. Two mutations at the same locus in the voltage-gated sodium channel gene are known to confer knockdown resistance (kdr) to pyrethroids and DDT. Kdr-e involves a leucine-serine substitution, and it was until recently thought to be restricted to East Africa, whereas kdr-w, which involves a leucine-phenylalanine substitution, is associated with resistance in West Africa. In this study, we analyze the frequency and relationship between the kdr genotypes and resistance to type I and type II pyrethroids and DDT by using WHO test kits in both the Forest-M and S molecular forms of An. gambiae in Cameroon. Both kdr-w and kdr-e polymorphisms were found in sympatric An. gambiae, and in many cases in the same mosquito. Kdr-e and kdr-w were detected in both forms, but they were predominant in the S form. Both kdr-e and kdr-w were closely associated with resistance to DDT and weakly associated with resistance to type II pyrethroids. Kdr-w conferred greater resistance to permethrin than kdr-e. We also describe a modified diagnostic designed to detect both resistant alleles simultaneously. |
1(0,0,0,1) |