Malaria vectors resistance to commonly used insecticides in the control of malaria in Bichi, northern Nigeria

Abstract

This study was carried out in 2015 to assess the level of resistance of sibling species of Anopheles gambiae complex the principal malaria vector from Bichi in Kano state to three classes of insecticides; (DDT, Permethrin and Bendiocarb) approved by World Health Organization (WHO) for vector control with the aim of obtaining baseline susceptibility and resistance data by evaluating the potency of brands of insecticides used against the mosquito vector in the area where the disease is prevalent. An. gambiae larvae collected from ecologically contrasting breeding sites were reared to adults in the laboratory. Adults from the F1 progeny were assayed for resistance using the WHO adult insecticide susceptibility bioassay protocol. The mosquitoes were exposed to DDT, permethrin and bendiocarb belonging to 3 classes of insecticides. The individual sibling species were identified molecularly and the molecular resistance mechanisms characterized by SINE and kdr PCR methods respectively. The An. gambiae populations tested revealed high level of resistance to DDT and permethrin but less resistant to bendiocarb. Analysis of the genetic composition of the vector population revealed predominance of An. coluzzii (> 77%). L1014F and L1014S kdr mutations correlated to insecticide resistance phenotype expression. This study indicates differential distribution of the resistant genotype of Anopheles malaria vector between ecologically different habitats in the area. This insecticide resistance represents a threat to vector control tool and should be monitored. The information obtained could be useful in decision and planning making for vector control programs in the region.

Keywords: Anopheles coluzzii, Anopheles gambiae, Insecticides, Malaria control, resistance, Susceptibility