High epilepsy prevalence and excess mortality in onchocerciasis-endemic counties of South Sudan: A call for integrated interventions
Epilepsy is a major health concern in onchocerciasis-endemic regions with intense transmission, where the infection is associated with a high epilepsy burden. This study investigated epilepsy prevalence and mortality in five onchocerciasis-endemic counties of South Sudan, and the association between onchocerciasis transmission and epilepsy, including probable nodding syndrome (pNS).
House-to-house cross-sectional surveys (2021–2024) identified persons with suspected epilepsy (sPWE) and retrospectively documented deaths among sPWE and individuals without epilepsy (IWE). Ongoing onchocerciasis transmission was assessed using anti-Ov16 seroprevalence in children aged 3–9 years.
Among 34,019 individuals screened, 166 deaths occurred in 3,101 person-years for sPWE versus 466 deaths in 63,420 person-years for IWE. Epilepsy prevalence was 4.1% (range: 2.3–7.1%), and pNS prevalence was 1.5% (range: 0.6–2.2%). Anti-Ov16 seroprevalence among children was 23.3% (range: 1.4–44.1%). Onchocerciasis is linked to high rates of epilepsy, and this study found that higher rates of onchocerciasis transmission were associated with higher epilepsy and probable nodding syndrome (pNS) prevalence across the five counties. Median age at death was lower for sPWE (20 years) than IWE (38 years). Standardised mortality rates per 1,000 person-years were significantly higher in sPWE (67.6) than in IWE (9.0); the overall standardised mortality ratio was 6.9, indicating sPWE were seven times more likely to die than IWE.
The high epilepsy burden in onchocerciasis-endemic areas is driven by elevated epilepsy prevalence and mortality. Integrated onchocerciasis and epilepsy programmes must be strengthened to decrease epilepsy incidence and ensure uninterrupted access to antiseizure medication.
This publication relates to R2HC funded study: Innovative approaches to reduce the burden of disease caused by onchocerciasis