Insecticide resistance and KDR mutations in malaria vector from different transmission sites in Uganda

Abstract

Background: Despite the development of various interventions aimed at the control of the malaria vector the African Region continues to carry a disproportionately high share of the global malaria burden. This has been attributed to the increased resistance to the chemicals that have been employed in the various vector control interventions. The aim of this study was to pinpoint the susceptibility patterns to these chemicals and determine the frequencies of the major genes responsible for the development of insecticide resistance in Jinja, Tororo, and Kanungu districts. Methods: Mosquito larval collected in April and May 2013 the first annual rainy season in three settings. The larvae were allowed to undergo metamorphosis to 2-week adults before subjecting them to discriminate insecticide concentrations to determine susceptibility patterns. The same batches were further subjected to SNP analysis using real-time PCR to determine the frequency of occurrence of KDR resistance gene mutations. Results: In the population (n=705) 51%, 35%, and 36% female Anopheles mosquitoes from the three sites were susceptible to DDT, deltamethrin, and permethrin respectively awhile for KDR –east 261 (47.4%) resistant mutant were detected with the highest frequencies observed in Tororo 147 (75.4%) followed by Kanungu with 112 (53.6%) sites with An.gambiea as the dominant vector, Jinja had lowest (1.7%) frequencies of KDR- east mutations across the three sites. Conclusion: There was confirmed phenotypic resistance to Pyrethroids (Deltamethrin, Permethrin) across the three sites, and the frequency of KDR-east gene circulation in Tororo was higher (75%) than any other site in this study.