Baseline onchocerciasis prevalence, community perceptions and attitudes around the Singrobo-Ahouaty hydroelectric dam before impoundment, South-Central Côte d’ivoire

Hydroelectric dams are one of the major development projects designed to meet the requirements of sustainable development and improve living conditions and living standards. While contributing to socio-economic development, these dams profoundly alter ecosystems, leading to the proliferation of several vectors of water-linked diseases, including onchocerciasis transmitted by black fly bites. This study aims to assess baseline onchocerciasis prevalence, as well as community perceptions and attitudes in the Singrobo-Ahouaty dam area during its construction. A cross-sectional survey was conducted in six villages between February and March 2021. Consenting participants, selected from households, were aged five years and older. They underwent a clinical examination and skin scrapings were obtained to assess symptoms and detect microfilariae. A semi-structured questionnaire targeting heads of households was used to assess their perception, knowledge, and attitudes regarding onchocerciasis transmission. Data were double-entered into an Excel sheet, cross-checked, and analysed using STATA software 14.2. A total of 522 participants were included, of whom 274 were men (52.49%), yielding a sex ratio of 1.10. Farming was the most common occupation among the population, with 32.75%. Symptoms of onchocerciasis were observed in 30 (5.75%) participants. The most frequently reported symptoms were blindness (23.68%) and itching (16.62%). Among the participants included, 0.77% were carriers of microfilariae, and all were male farmers. The community microfilarial load (CMFL) obtained was 0.05 microfilariae/ skin snip. Out of 307 people interviewed, 48.86% were aware of onchocerciasis as a disease that causes blindness, and 36.48% were aware it was transmitted by black fly bites. 66.28% of those interviewed irregularly participated in the Community-Directed Treatment with Ivermectin, and 33.72% had stopped taking ivermectin. The results show a very low prevalence of onchocerciasis and CMFL, associated with low community awareness of the disease. However, the water filling of the Singrobo-Ahouaty dam could promote a resurgence of transmission by creating environmental conditions conducive to black flies and increasing human-vector contact. It would therefore be necessary to strengthen and maintain epidemiological surveillance and implement vector control and awareness-raising measures. Not applicable.