Assessment of Insecticide Resistance in Culex quinquefasciatus Populations from Urban Areas of Lagos State, South West Nigeria

Culex quinquefasciatus is the principal vector of lymphatic filariasis in urban Nigeria and causes significant nuisance biting across densely populated cities. Lagos State, with the highest urban density in sub-Saharan Africa, relies heavily on synthetic insecticides for mosquito control, raising concerns about resistance development. This study assesses the susceptibility status of Culex quinquefasciatus populations from four urban zones of Lagos to four classes of insecticides commonly used in vector control programs. Adult mosquitoes reared from field-collected larvae will be exposed to WHO standard discriminating doses of deltamethrin, permethrin, malathion, and bendiocarb using WHO tube bioassay protocols. Mortality rates will be recorded at 24 hours post-exposure and resistance status classified according to WHO thresholds. Samples exhibiting resistance will be tested for the presence of the kdr mutation and mixed function oxidase activity. Urban mosquito population data from areas with varying insecticide exposure histories will be compared. This study addresses a timely need to characterize insecticide resistance in a major coastal metropolis, as this information directly informs larviciding and adulticiding strategies for the Lagos State Ministry of Health. Keywords: Culex quinquefasciatus, insecticide resistance, Lagos State, lymphatic filariasis, WHO bioassay