Pyrethroid Susceptibility inCulex quinquefasciatusSay. (Diptera: Culicidae) Populations from Delta State, Niger-Delta Region, Nigeria

Abstract

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.

High pyrethroid-resistance intensity in Culex quinquefasciatus (Say) (Diptera: Culicidae) populations from Jigawa, North-West, Nigeria

“…pipiens has been recorded in the work of Rabi'u and Ahmed [30] in the Northern region of Nigeria, prevalence of Cx. quinquefasciatus is well reported in several other studies in Nigeria [22,31].…”

“…Absence of "Kdr-west" in Cx. quinquefasciatus from Nigeria had earlier been reported in the work of Ojianwuna et al, [22]. This suggests the possible involvement of other resistance mechanisms in resistance development in the Cx.…”

“…Report of resistance in Cx. quinquefasciatus to alphacypermethrin is a major development because alphacypermethrin is the pyrethroid insecticide employed in the treatment of new nets proposed for the country in 2022 [22]. Similarly, resistance to permethrin may be easily attributed to an increase in the selection pressure due to increase in volume of permethrin in the environment occasioned by current use of permethrin-treated nets in the country.…”

“…Notably, IR in Culex species could also impact malaria elimination programmes if communities perceive reduced efficacy of IRS and ITN/LLINs due to IR in Culex spp. and the usage rate of these tools decline [22]. Therefore, it is imminent to monitor the resistance status of Culex spp.…”

Investigating the Potency of Camphor Combined With Kerosene on the Emergence of Anopheles Gambiae

“…3 This has necessitated the need for research on improving existing formulations of insecticides or developing newer insecticides especially of plant and other viable origin. With insecticide resistance thriving in almost all WHO regions, several innovations in VCIs included the combination of recommended insecticide classes, 4 synergizing insecticides, 5 genetic transplant, 6 application of insecticidal microbes; Wolbachia, 7 techniques applying male mosquitoes exposed to irradiations 8 and introduction of predacious fish species in mosquito breeding site. 9,10 In insecticide resistant species, 2 primary mechanisms have been implicated; up regulating insecticidedetoxifying enzymes and altering the insecticide target site to decrease the affinity between the agent and the binding site.…”