Susceptibility pattern of Anopheles mosquito to different classes of insecticides in selected communities in Ila-Orangun, Southwest Nigeria

Abstract

Malaria remains a public health issue and it is endemic throughout Nigeria, where it accounts for about one million episodes annually. In recent times, distribution of long lasting insecticide nets (LLINs) was scaled up in Nigeria to curb the menace of the disease. Successful implementation of this strategy depends on the susceptibility of the local anopheline mosquitoes to the insecticides used in treating the LLINs. In the present study, we investigated the susceptibility status and knock-down data of local Anopheles mosquito species using World Health Organization Pesticide Scheme (WHOPES) recommended insecticides. Anopheles species larvae were collected in naturally infested water bodies using the standard (350ml dipper) dipping method from four communities in Ila-Orangun. The unfed 2-3 days old adult females were subjected to susceptibility test following WHO recommended protocol against six insecticides (0.05% Lambdacyhalothrin, 0.75% Permethrin, 0.05% Deltamethrin, 4% Dichloro-Diphenyl-Trichloroethane (DDT), 1% Fenitrothion and 0.1% Bendiocarb) using diagnostic kits. Anopheles gambiae were found to be resistant to Lambdacyhalothrin, Permethrin and Deltamethrin, and DDT but susceptible to Fenitrothion and Bendiocarb. The susceptibility pattern observed could be attributed to the types of pesticides/insecticides used for agricultural activities and public health programmes in the study area. The implication of this study to the success of vector control programmes is discussed.