Vector Competence and Molecular Xenomonitoring of Wuchereria bancrofti in Culex quinquefasciatus Mosquitoes from LF-Endemic States in Nigeria

Vector competence assessment and molecular xenomonitoring of Wuchereria bancrofti in Culex quinquefasciatus mosquitoes provide critical entomological transmission indicators that complement human parasitological surveys for monitoring progress toward lymphatic filariasis elimination in Nigeria. This doctoral research characterises vector competence parameters and applies molecular xenomonitoring of W. bancrofti in C. quinquefasciatus populations from six LF-endemic states across Nigeria's geopolitical zones. Mosquito collections were conducted using CDC light traps and oviposition traps across endemic communities in Oyo, Niger, Kano, Ebonyi, Akwa Ibom, and Gombe States. Blood-fed and gravid C. quinquefasciatus were dissected to assess natural filarial larval infection rates at L1, L2, and infective L3 stages. Molecular xenomonitoring pools of 200 mosquitoes were tested by quantitative PCR targeting the W. bancrofti-specific repeat sequence Bm14, with pool-screen analysis estimating infection prevalence. Vector competence parameters including infection, development, and infective rates were characterised in field-derived colonies maintained under controlled laboratory conditions. Seasonal variation in infective rates was correlated with temperature, humidity, and host microfilaraemia density in co-resident populations. Evidence from 2020 to 2024 establishes molecular xenomonitoring as a sensitive and scalable tool for post-MDA transmission surveillance in West African settings. This study develops standardised xenomonitoring protocols validated for Nigerian C. quinquefasciatus populations and produces an entomological transmission index for each study state. Keywords: Wuchereria bancrofti, Culex quinquefasciatus, vector competence, molecular xenomonitoring, lymphatic filariasis.