Innovative approaches to reduce the burden of disease caused by onchocerciasis

Principal Investigator: Dr. Gasim Abd-Elfarag

Research Snapshot: Reducing epilepsy deaths in South Sudan

Building on a prior project to trial effective interventions, this implementation science study explored impacts of an intensified community awareness programme on onchocerciasis and epilepsy, which has increased community directed treatment with ivermectin (CDTi) coverage in Maridi, resulting in a reduction in incidence of onchocerciasis-associated epilepsy (OAE).

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What did the study set out to achieve?

Onchocerciasis, known as ‘river blindness’, and linked with blackfly bites, is a debilitating eye and skin disease that causes discomfort and can lead to permanent blindness. In the absence of effective elimination programs, onchocerciasis is linked to high rates of epilepsy, including ‘Nodding Syndrome’/ OAE, leading to severe disabilities and increased mortality.

This study combined formative research, a quasi-experimental pre–post intervention evaluation, cohort studies, and cross-sectional surveys. It evaluated efforts to reduce the impacts of OAE through ivermectin treatment, (including targeting post-partum women and school age children), vector control, and enhancing epilepsy care in onchocerciasis endemic districts of South Sudan. Disease burden assessment and cost-effectiveness analysis was also completed.

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What were the key findings?

Boosting coverage of ivermectin treatment and improving care programmes has a significant impact in communities affected by onchocerciasis-associated epilepsy (OAE).

• Ivermectin coverage significantly improved in Maridi district in 2023 after biennial treatment (70.3%). The intervention targeting post-partum women increased coverage by 2%. The school intervention could not be assessed.
• There was only limited reduction in blackfly biting rates after one round of ‘slash and clear’ in Mundri and Mvolo.
• In 2024, deaths among people with epilepsy in Maridi dropped 4-fold compared with baseline in 2018. The biggest improvement was among 11–20-year-olds. However, in 2024, epilepsy mortality was nearly 2x the general rate.
• Areas with ongoing transmission of onchocerciasis is still spreading, like Wulu in Lakes State, still have high rates of epilepsy, with a high proportion also having nodding seizures.
• Direct costs for the school-based approach targeting children were USD0.14 per child and for slash and clear was 1380$. There were no additional costs associated with the programme targeting postpartum women.

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