Prevalence and insecticide resistance in Anopheles coluzzii in Ado-Ota, Nigeria

Full text loading... Abstract The increasing resistance to pyrethroids poses a significant challenge to effective vector control in Africa. This study assessed mosquito species composition and resistance level to pyrethroids in selected towns in Ado Odo Ota Local Govt, Ogun; a 6-month longitudinal entomological survey was carried out using light trap and larval sampling. Mosquitoes were collected, and Anopheles species were identified through morphological examination using Coetzee’s taxonomic keys and molecular analyses. Sporozoite detection using ELISA was conducted. The susceptibility status of Anopheles gambiae sensu lato to permethrin (0.75%) and deltamethrin (0.05%) was assessed using the World Health Organization insecticide susceptibility test. The identified species were also screened for knockdown (kdr) target site resistance alleles. Five hundred seventy-nine (579) adult mosquitoes were collected and morphologically identified. Two-thirds (376/579) of the mosquitoes were identified as Culex spp., constituting the most abundant species in the selected towns. Molecular identification using intentional mismatch primers confirmed Anopheles coluzzii's presence as the communities' main species. Thirty per cent 30% (22.5 – 37.5) of the Anopheles gambiae mosquitoes were susceptible to permethrin after 24 hours, while 98% (95.7 -100) of the vectors were susceptible to deltamethrin. Sporozoite detection showed none (0/40) of the tested blood-fed female Anopheles gambiae were positive for sporozoites, and the West African and East African knockdown resistance genes were detected in very high frequencies among the sampled population (L1014F – 64% [0.36 – 0.83], L1014S – 60% [0.30 – 0.77]). This study revealed that Anopheles coluzzii (99%) is the predominant species in the study area, and Deltamethrin is still effective in the tested communities; however, the high knockdown resistance of both the east and west alleles calls for urgent implementation of integrated vector control. - Received: - Version Posted: Funding - Covenant Applied Informatics and Communication Africa Centre of Excellence - Principal Award Recipient: Daniel Oluwatobiloba Balogun