The development of insecticide resistance in different species of mosquitoes to
Pyrethroids is a major challenge for
vector-borne diseases transmitted by mosquitoes. Failure of
Pyrethroids in control of mosquitoes would impact negatively on the gains recorded in control of
mosquito-borne diseases in previous years. In anticipation of a country-wide deployment of
Pyrethroid-treated nets for control of
mosquito-borne diseases in Nigeria, this study assessed susceptibility of Culex quinquefasciatus Say. (Diptera: Culicidae) to
Pyrethroids in Owhelogbo, Ejeme and Oria-Abraka communities in Delta State, Niger-Delta, Nigeria. Three to five day old Cx. quinquefasciatus were exposed to
Deltamethrin (0.05%),
Permethrin (0.75%), and
Alphacypermethrin (0.05%) using World Health Organization bioassay method. Polymerase chain reaction (PCR) was employed in characterization of species and knockdown mutation. Results revealed that Cx. quinquefasciatus were generally susceptible (98-100%) to
Deltamethrin,
Permethrin, and
Alphacypermethrin in the three communities with the exception of Owhelogbo where resistance to
Deltamethrin (97%) was suspected. Knockdown time to
Deltamethrin (11.51, 11.23, and 12.68 min),
Permethrin (28.75, 13.26, and 14.49 min), and
Alphacypermethrin (15.07, 12.50, and 13.03 min) were considerably low for Owhelogbo, Ejeme, and Oria-Abraka Cx. quinquefasciatus populations, respectively. Species identification result showed that all amplified samples were Cx. quinquefasciatus; however, no kdr allele was found in the three populations. Deployment of
pyrethroid-treated nets for control of
mosquito-borne diseases in Niger-Delta region of Nigeria is capable of reducing burden of diseases transmitted by Cx. quinquefasciatus as well as addressing nuisance value of the vector; however, caution must be entertained so as not to increase selection pressure thereby aiding resistance development.