Background <p>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.</p> Methods <p>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.</p> Results <p>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.</p> Conclusions <p>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.</p> Clinical trial number <p>Not applicable.</p>