Molecular Xenomonitoring of Mosquito Vectors Post-Mass Drug Administration: Detection of Wuchereria bancrofti DNA in Akwanga LGA, Nasarawa State, Nigeria

Abstract

Background: Molecular xenomonitoring is an effective technique for evaluating the success of Mass Drug Administration (MDA) programs in eliminating lymphatic filariasis. Therefore, This study investigated mosquito vectors and the presence of Wuchereria bancrofti in mosquito vectors collected from two post-MDA communities in Akwanga Local Government Area, Nasarawa State, Nigeria. Methods: An entomological survey was conducted in the communities of Angwan Zaria and Angwan Habu using the Pyrethrum Spray Catch (PSC) technique to capture adult mosquitoes and perform subsequent morphological identification. The female mosquitoes were further tested for physiological status and parity, and the 10 mosquito pools were tested for Wuchereria bancrofti DNA using polymerase chain reaction (PCR) in the Molecular Epidemiology and Vector Biology Laboratory of the Department of Animal and Environmental Biology, Osun State University, Osogbo, Nigeria. Results: A total of 201 mosquitoes were captured that belong to two mosquito groups and spread across three species in which Culex quinquefasciatus was the predominant mosquito species149 (88.2%) followed by An. funestus 17 (8.50%) then An. gambiae 15 (7.50%) and the differences was significant (χ2 = 232.955, df = 2, P = 0.001). No significant variation (χ2 = 2.6318, df = 1, P = 0.105) was observed in the abundance of mosquitoes between the communities sampled. However, the abundance of mosquitoes sex-wise differed significantly (χ2 = 104.602, df = 1, P = 0.001) in favour of 173 females (86.10%). Physiologically, majority of the females were freshly fed 93 (53.80%). Greater number of females 148 (85.55%) were nulliparous mosquitoes, while only 25 (14.45%) were parous. Molecular xenomonitoring of the ten mosquito pools revealed a 10% prevalence of Wuchereria bancrofti infection. Conclusion: Molecular xenomonitoring has shown to be effective in detecting Wuchereria bancrofti DNA in Culex quinquefasciatus vectors. Continuous entomological and molecular surveillance along with high treatment coverage and vector control is recommended to ensure interruption of transmission and elimination of lymphatic filariasis.