The effect of bi-annual community-directed treatment with ivermectin on the incidence of epilepsy in onchocerciasis endemic villages in South Sudan: a study protocol

Abstract

BackgroundNodding syndrome (NS) is a devastating epileptic illness of unknown aetiology mainly affecting children 5–15 years of age. Head nodding distinguishes NS from other forms of epilepsy. Other manifestations of the illness include mental and physical growth retardation. Many children die as a result of falling in fires or drowning. Recently, it was shown that NS is only one of the phenotypic presentations of onchocerciasis associated epilepsy (OAE). Despite the strong epidemiological association between epilepsy and onchocerciasis, the causal mechanism is unknown. After implementation of bi-annual community directed treatment with ivermectin (CDTi) and larviciding of rivers in northern Uganda, new cases of NS have ceased, while new cases continue to emerge in South Sudanese onchocerciasis-endemic areas with an interrupted CDTi programme. This study is designed to evaluate the potential effects of bi-annual CDTi on reducing the incidence of NS/OAE in onchocerciasis-endemic areas in South Sudan.MethodsA pre-intervention door-to-door population-based household survey will be conducted in selected onchocerciasis-endemic villages in Mundri and Maridi Counties, which have a high prevalence of epilepsy. Using a validated questionnaire, the entire village will be screened by community research assistants for suspected epilepsy cases. Suspected cases will be interviewed and examined by a trained clinical officer or medical doctor who will confirm or reject the diagnosis of epilepsy. Bi-annual CDTi will be implemented in the villages and a surveillance system for epilepsy set up. By implementing an epilepsy onchocerciasis awareness campaign we expect to obtain > 90% CDTi coverage of eligible individuals. The door-to-door survey will be repeated two years after the baseline survey. The incidence of NS/OAE will be compared before and after bi-annual CDTi.DiscussionOur study is the first population-based study to evaluate the effect of bi-annual CDTi to reduce the incidence of NS/OAE. If the study demonstrates such a reduction, these findings are expected to motivate communities in onchocerciasis-endemic regions to participate in CDTi, and will encourage policy makers, funders and other stakeholders to increase their efforts to eliminate onchocerciasis.Electronic supplementary materialThe online version of this article (10.1186/s40249-018-0496-2) contains supplementary material, which is available to authorized users.

Onchocerca volvulus and epilepsy: A comprehensive review using the Bradford Hill criteria for causation

“…volvulus- infected individuals treated or not treated with ivermectin. However, a prospective study is planned in South Sudan to demonstrate whether implementation of ivermectin twice yearly (biannual CDTI) will decrease the incidence of OAE in a highly endemic area [ 107 ].…”

High prevalence of onchocerciasis-associated epilepsy in villages in Maridi County, Republic of South Sudan: A community-based survey

“…The study was conducted in May 2018 prior to starting the biannual mass distribution of ivermectin programme. The study protocol to evaluate the effect of a biannual CDTi programme to decrease the incidence of NS and other forms of epilepsy has been published previously [21]. To obtain baseline information, all individuals in selected villages close to Maridi town and the Maridi River were included in a door-to-door survey.…”

Clinical characteristics of onchocerciasis-associated epilepsy in villages in Maridi County, Republic of South Sudan

“…The study protocol has been previously published [8]. In brief, all individuals in selected villages in the area around Maridi town were included in a door-to-door survey in May 2018.…”