Recognising the neurological burden of onchocerciasis: the need to include onchocerciasis-associated epilepsy in onchocerciasis global health metrics.

Abstract

Background: Historically, onchocerciasis has been recognised for its dermatological and ophthalmological manifestations, such as blindness. However, growing epidemiological evidence indicates that onchocerciasis is also associated with neurological complications, particularly onchocerciasis-associated epilepsy (OAE). These complications are not currently reflected in disease burden estimates and associated disability-adjusted life years (DALYs) for onchocerciasis.

Main text: The most recent global burden of disease estimates for onchocerciasis in 2019 reported 1.23 million DALYs without accounting for OAE. Yet, a preliminary study suggested that 128,000 years of life lost to disability (YLD, a key component of DALYs) may be attributable to epilepsy in onchocerciasis-endemic areas of East and Central Africa. This figure, which would represent over 13% of the total onchocerciasis morbidity burden and 10% of the global epilepsy morbidity burden, is likely still an underestimation. Current disability weights for epilepsy YLD estimation may not fully capture the spectrum of OAE, which often involves nodding syndrome, developmental delays, motor disabilities, cognitive impairments and stigma. In regions where access to antiseizure medication treatment is sparse, poorly controlled seizures can exacerbate disability and lead to premature mortality. Targeted integrated strategies-combining onchocerciasis control measures with improved epilepsy care-could help address these critical gaps.

Conclusions: Recognising OAE as part of the disease burden associated with onchocerciasis may encourage global health stakeholders to allocate resources for targeted interventions, thereby refining disease burden estimates, reducing disability, averting premature deaths and improving overall health outcomes.