Insecticide susceptibility status of Aedes aegypti in umudike, Ikwuano lga Abia State, Nigeria

Abstract

This study was conducted in order to evaluate the insecticide susceptibility status of Aedes aegypti in Umudike, Abia State, Nigeria. Larval and pupal stages of the mosquitoes were collected from different points within Umudike, and reared to adulthood in the laboratory. The adults that emerged were tested on 4 % DDT (organochlorines), 0.1 % bendiocarb (carbamates), 0.25 % primiphos-methyl (organophosphates) and 0.05 % deltamethrin (pyrethroids) procured from National Arbovirus and Vector Research Institute, Enugu. Twenty sugar fed female Aedes aegypti mosquitoes aged 3 – 5 days were used for the bioassay which was replicated four times with two control. Knockdown was recorded at five minutes, and then 10 minutes interval for 1 hour and the maintained for 24 hours post-exposure on 7 % sugar solution, after which a final mortality was recorded. The Knockdown times (KDT50 and KDT90) were determined by Probit analysis. Aedes aegypti was susceptible to all the insecticides but DDT, with 24- hour post exposure percentage mortalities of 62.85, 100, 97.50 and 93.75 in DDT, bendiocarb, primiphos-methyl and deltamethrin, respectively. It is necessary that the mechanism behind this resistance displayed by Ae. aegypti mosquitoes in Umudike to DDT be investigated. Routine surveillance of insecticide susceptibility/resistance in wild mosquito population is also advocated in line with integrated vector control strategy in Umudike.

Keywords: Aedes aegypti, Insecticide, DDT, Bendiocarb, Primiphos-methyl, Deltamethrin, Knockdown times, Susceptibility, Umudike