Evaluating Wuchereria bancrofti Microfilaraemia Trends Following Annual Mass Drug Administration in Ogun State, South West Nigeria

Evaluating trends in Wuchereria bancrofti microfilaraemia following successive rounds of annual mass drug administration with ivermectin plus albendazole is essential for determining whether lymphatic filariasis programmes are making sufficient progress toward elimination thresholds in endemic communities. This study evaluates W. bancrofti microfilaraemia trends following annual mass drug administration in Ogun State, South West Nigeria. A longitudinal repeated cross-sectional design was used, with parasitological surveys conducted in 15 sentinel communities in Ifo, Sagamu, and Odeda Local Government Areas before the 2021 MDA round and annually for three subsequent years. Nocturnal blood samples were collected from 50 adults per community per survey round and examined by thick blood film for microfilariae counting. Immunochromatographic card testing for W. bancrofti circulating filarial antigen was performed concurrently. Coverage data from MDA registers were obtained to correlate treatment coverage with microfilaraemia decline rates. Evidence from 2020 to 2024 confirms that communities achieving above 65 percent therapeutic coverage consistently show microfilaraemia reductions exceeding 30 percent per round in West African programme evaluations. This study provides empirical trend data for Ogun State, identifying communities that may require additional MDA rounds or targeted intensification before transmission assessment surveys. Findings will be submitted to the Ogun State NTD Programme and the WHO collaborating centre for LF elimination. Keywords: Wuchereria bancrofti, microfilaraemia trends, mass drug administration, lymphatic filariasis elimination, Ogun State.