Molecular xenomonitoring of lymphatic filariasis transmission in Okobo, Akwa Ibom State, Nigeria
Keywords:
PCR, Lymphatic filariasis, Molecular xenomonitoring, Mosquitoes, Wuchereria bancrofti, Ssp IAbstract
Lymphatic filariasis (LF) is still a significant public health disease of great burden in endemic regions. Molecular xenomonitoring (MX) is crucial to evaluate elimination efforts during mass drug administration (MDA) and post-MDA settings. This study investigated Wuchereria bancrofti prevalence in mosquitoes using molecular techniques in Okobo LGA, an endemic area that has undergone rounds of MDA. Entomological survey involved capturing mosquitoes using CDC light traps during wet (May-July, 2024) and dry (November 2024 - January 2025) seasons. A total of 518 female mosquitoes were captured and morphologically identified comprising of Culex spp. (95.95%, 497) and Anopheles spp. (4.05%, 21). PCR was used to detect W. bancrofti DNA in ≤ 30 mosquito pools. This protocol amplified a segment of the Ssp I repeat found in all larva stages of W. bancrofti enabling detection of parasite’s DNA. Results showed 82.22% pool positivity. PoolTestR was used to estimate prevalence of W. bancrofti in mosquitoes throughout the LGA using Maximum Likelihood Estimates (MLE). The overall estimated prevalence (MLE) of W. bancrofti DNA in Culex spp. mosquitoes was 9.99% (95% CI: 6.49%-14.69%) while Anopheles spp., was 63.91% (95% CI: 39.59%–84.67%). The high infection rate revealed by this study begs the need for continued MDA in Okobo as high estimated prevalence is suggestive of ongoing human infection. These findings provide a baseline data for LF monitoring and elimination strategies and emphasizes the importance of molecular surveillance in transmission assessment surveys in endemic LGAs.
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