Onchocerciasis-Associated Epilepsy, an Explorative Case-control Study

Study Overview
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Brief Summary
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This is an exploratory case control study with the aim to compare the Onchocerca volvulus virome between persons with onchocerciasis-associated epilepsy (OAE) and persons with onchocerciasis but without epilepsy. The main question we want to address is: Is there a virus contained in the O. volulus worm that may have a pathogenic role in causing OAE. In Maridi County, South Sudan, 20 persons with OAE with onchocerciasis nodules, and 20 age- and village-matched controls without OAE will be enrolled in a nodulectomy study.The adult O. volvulus worms will be extracted from the nodules and a viral metagenomic study of the worms. The O. volvulus virome of persons with and without OAE will be compared.

Detailed Description
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A high prevalence of onchocerciasis-associated epilepsy (OAE) has been observed in onchocerciasis-endemic areas with high ongoing Onchocerca volvulus transmission. However, the pathogenesis of OAE remains to be elucidated. We hypothesise that the O. volvulus virome could be involved in inducing epilepsy. With this study, we aim to describe the O. volvulus virome and identify possible viruses linked to OAE. In Maridi County, South Sudan, 20 persons with OAE with onchocerciasis nodules, and 20 age- and village-matched controls without OAE will be enrolled in the study. For each study participant, two skin snips at the iliac crest will be obtained to collect O. volvulus microfilaria, and one nodulectomy will be performed to obtain adult worms. A viral metagenomic study will be conducted on microfilariae and adult worms, and the O. volvulus virome of persons with and without OAE will be compared. Moreover, the prevalence, numbers and localisation of onchocerciasis nodules in persons with and without OAE in villages with a high prevalence of epilepsy in Maridi will be described.

Official Title
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Onchocerciasis-Associated Epilepsy, an Explorative Case-control Study With Viral Metagenomic Analysis of Onchocerca Volvulus.

Conditions
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Onchocercal Subcutaneous Nodule, Epilepsy, Virus

Intervention / Treatment
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* Procedure: nodulectomy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Onchocerciasis nodules Age 12-35 years old informed consent signed Living in Maridi County, Western Equatorial State, South Sudan Exclusion Criteria: below the age of 12

Ages Eligible for Study
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Minimum Age: 12 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Persons with onchocerciasis nodules with OAE and without epilepsy<br>nodulectomy to extract adult worms | Procedure: nodulectomy<br>* incision in an onchocerciasis nodule to extract adult worms<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The O. volvulus virome of persons with onchocerciasis-associated epilepsy (OAE) and of persons with onchocerciasis but without epilepsy | The type of virusses present in the O. volvulus worm present in the nodules of persons with OAE and in nodules of persons without epilepsy | 1 day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Onchocerciasis, Epilepsy, metagenomics, South Sudan, Pathogenesis