Effect of Onchocerciasis Elimination Measures on the Incidence of Epilepsy in Maridi, South Sudan

For the first time using a prospective design, a study confirms the results of previous retrospective studies, which found that strengthening onchocerciasis elimination efforts decreases the incidence of epilepsy, including nodding syndrome. Therefore, this study confirms the solid epidemiological link between onchocerciasis and epilepsy.

This study also shows that a community-based "Slash and Clear" vector control method can effectively decrease blackfly biting rates and potentially decrease onchocerciasis transmission.

Moreover, this study shows that epilepsy is a major cause of death in onchocerciasis endemic areas with high ongoing transmission.

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Key information

Conditions

Onchocerciasis Brain Diseases Central Nervous System Diseases Epilepsy Filariasis Helminthiasis Infections Nematode Infections Nervous System Diseases Parasitic Diseases Secernentea Infections Skin Diseases Skin Diseases, Infectious Skin Diseases, Parasitic Skin and Connective Tissue Diseases Spirurida Infections

Sex eligibility

All sexes

Study type

Observational

Primary location

Amref Health Africa

Juba, Central, 140, South Sudan

About this study

Background High onchocerciasis transmission predisposes communities in endemic areas to a high epilepsy burden. The 4·4% (95%CI:4·1-4·7%) epilepsy prevalence documented in 2018 in Maridi, South Sudan, motivated the strengthening of onchocerciasis elimination measures. We evaluated the effect of these interventions on the incidence of epilepsy, including nodding syndrome (NS).

Methods Annual community-directed treatment with ivermectin (CDTi) was implemented in 2019, temporarily interrupted in 2020 and reimplemented biannually in 2021. Additionally, a community-based "Slash and Clear" vector control method was initiated in 2019 at the Maridi dam. A two-stage house-to-house survey was conducted before (2018) and after (2022) implementing the interventions, consisting of initial screening by community workers to detect suspected cases of epilepsy, followed by confirmation of the diagnosis by a trained clinician.

Finding Overall, 17,652 and 14,402 individuals participated in the pre- and post-intervention surveys, respectively. The epilepsy incidence decreased from 313·0 (95% confidence intervals (CI):273·7-357·7) to 34·7 (95%CI:17·6-66·1) per 100,000 person-years. Similarly, the incidence of NS decreased from 120·4 (95%CI:96·7-149·6) to 10·4 (95%CI:2·7-33·2) per 100,000 person-years. Despite biannual CDTi, only 56·6% of the population took ivermectin in 2021. Mortality of persons with epilepsy accounted for 17·1% (95%CI:14·0-20·7%) of the overall number of deaths in the population.

Interpretation In onchocerciasis-endemic areas with high prevalence of epilepsy, strengthening onchocerciasis elimination interventions can decrease the incidence of epilepsy, including NS. Additional efforts are needed in Maridi, where epilepsy is a major cause of mortality, to increase CDTi coverage and sustain blackfly control.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

entire population of selected villages in Maridi County

Exclusion criteria

Treatment and study plan

bi-annual CDTI

Drug

bi-annual community directed treatment with ivermectin (CDTI) and community-based "slash and clear" vector control intervention

Other names: "slash and clear" vector control intervention

Primary outcomes

epilepsy incidence

Time frame: 4 years

Incidence of epilepsy including nodding syndrome

Sponsors and collaborators

Lead sponsor

Universiteit Antwerpen

Other

Collaborators

Amref Health Africa

Registry information

Official study title

Effect of Onchocerciasis Elimination Measures on the Incidence of Epilepsy in Maridi, South Sudan, a Three-year Prospective Study

Acronym: OAEMaridi

Important dates

Study start: 2018
Primary completion: 2023
Study completion: 2023
First posted: Mar 1, 2023
Registry last updated: Nov 30, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed