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

BACKGROUND

Former Onchocerciasis Control Programme countries like Senegal have made important progress towards eliminating onchocerciasis. Senegal has engaged in post-mass drug administration (MDA) activities, mainly entomological surveillance, but the country initially struggled to collect the recommended number of blackflies in all the country's transmission zones. Here, we implemented a simple approach in the entomological surveillance protocol to increase the number of Simulium 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 Falémé 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 compared with 2022 captures. The numbers of blackflies captured increased from 71 999 and 23 666, respectively, in Gambia and Falémé in 2022, to 101 276 and 34 780 in 2023.

CONCLUSION

Our results reveal that simple and effective microplanning of blackfly capture periods can support onchocerciasis post-MDA surveillance activities by increasing the number of blackflies captured.