Microplanning for entomological surveys to sustain the onchocerciasis elimination effort in West Africa

Abstract

BACKGROUND: Former OCP countries like Senegal have made important progress towards eliminating onchocerciasis. Senegal has engaged in post-MDA activities, mainly entomological surveillance, but the country initially struggled to collect the recommended number of blackflies in all the country' transmission zones. Here we implemented a simple approach in the entomological surveillance protocol to increase the number of S. damnosum collected. METHODS: The study was conducted over two consecutive years, 2022 and 2023, in the main S. damnosum capture points located along the Gambie and the Faleme river basins. We reviewed environmental data, analysed and interpreted previous blackflies capture data, and processed field visits to identify optimal periods of blackfly capture in each capture point. RESULTS: After the implementation of our approach, the number of blackflies captured increased by approximately 42% in 2023 when compared to 2022 captures. The numbers of blackflies captured increased from 71 999 and 23 666 respectively in Gambia and Falemé in 2022, to 101 276 and 34 780 in 2023. CONCLUSION: Our results revealed that simple and effective microplanning of blackfly capture periods can support onchocerciasis post-MDA surveillance activities by increasing the number of blackflies captured.