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

Completed

• Conditions: Onchocerciasis; Epilepsy
• Interventions: Drug: bi-annual CDTI

• Registration Number: NCT05750043
• Lead Sponsor: Universiteit Antwerpen

Brief Summary

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.

Detailed Description

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.

Study Timeline

• Study Start: 2018-03-01
• Primary Completion: 2023-01-31
• Study Completion: 2023-02-19
• Study First Submitted: 2023-02-19
• Study First Submitted QC: 2023-02-19
• Study First Posted: 2023-03-01
• Status Verified: 2023-11
• Last Update Submitted: 2023-11-27
• Last Update Posted: 2023-11-30

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 17000

Inclusion Criteria

• entire population of selected villages in Maridi County

Exclusion Criteria

• No

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Population of selected villages in Maridi county	bi-annual CDTI	A total of 2,511 households containing 17,652 individuals were visited in 2018, and 2,254 households containing 14,402 individuals in 2022.

Primary Outcome Measures

Name	Time	Method
epilepsy incidence	4 years	Incidence of epilepsy including nodding syndrome

Trial Locations

Locations (1)

Amref Health Africa; 🇸🇸 Juba, Central, South Sudan