Molecular Xenomonitoring of Lymphatic Filariasis Transmission in Okobo LGA, Akwa Ibom State, Nigeria

Abstract

Endemic regions require constant monitoring to prevent reemergence of neglected tropical diseases as lymphatic filariasis (LF), which is still a major public health concern. Molecular xenomonitoring (MX) has been proven to be a useful tool to detect residual transmission and evaluate elimination efforts during mass drug administration (MDA) and post-MDA settings, therefore serving as an early warning system to prevent potential resurgence This study investigated Wuchereria bancrofti prevalence in mosquitoes using molecular techniques for the first time in Okobo, an endemic area that has undergone rounds of MDA. Female mosquitoes (518) were caught using CDC light traps (Culex spp: 95.95%, 497 and Anopheles spp: 4.05%, 21) across wet and dry seasons Mosquito pools were screened using PCR, targeting the Ssp I repeat. PoolTestR was used to estimate prevalence of Wuchereria 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 alarming high infection rate revealed by this study begs the need for continued MDA in Okobo as high estimated prevalence is suggestive of high risk of ongoing human infection and LF reemergence. 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.