Etude des insecticides utilisés contre les anophèles vecteurs du paludisme en République Démocratique du Congo : identification et impact sur la sélection des mutants résistants

Abstract

Malaria endemic disease in DR Congo kills about almost 150 000 to 250 000 children per year. It has as a vector the Anopheles gambiaess, one of seven members belonging to the Anopheles gambiaecomplex, mosquito endophilic and endophagous. To fight against this disease, WHO has recommended the widespread use of bed nets impregnated with pyrethroids as a vector control strategy. In addition to pyrethroids; DDT, dichlovos and piperonylbutoxide were also found in the specialties used in household insecticides in the DR Congo. These insecticides are involved in genetic mutations L1014F, L1014S and G119S which led to the selection of resistance genes kdr and ace1R in the Anopheles larvae which were collected in four different breeding sites in the DR Congo (Katana, Kimpese, Kingasani and Bolenge). The bioassay showed the resisitance of the vector to DDT in all the four sites. Pyrethroid resistance was also found in all sites except Kingasani. For molecular testing, only the mutation involving the kdr gene was present in 53% of cases for the resistant genotype (RR) and 22.4% in intermediate heterozygous (RS). No single case of positive mutation ace 1Rwas detected. Moreover, permethrin has been studied by means of mass spectrometry. The mass spectrum of this compound is characterized in particular by the presence of a peak at m / z = 183, which identify the presence of this molecule in a mixture. The most advantaged fragmentations of this ion was also explained based on tandem mass spectrometry.