ASSOCIATION OF ONCHOCERCIASIS NODULE PREVALENCE IN MOTHERS AND THE DEVELOPMENT OF EPILEPSY IN THEIR CHILDREN IN MAHENGE, AN ONCHOCERCIASIS-ENDEMIC AREA OF TANZANIA: A CASE-CONTROL STUDY

Abstract

Intro: A child born from an Onchocerca volvulus infected mother is at increased risk of developing a high microfilarial load. High microfilarial loads are associated with a higher risk of developing onchocerciasis-associated epilepsy (OAE). Onchocerciasis is targeted for elimination through mass drug administration with ivermectin, which excludes pregnant women because of the potential teratogenic effect of ivermectin. Therefore, many pregnant women are O. volvulus infected during pregnancy in onchocerciasis-endemic areas. The consequence of such an infection on the risk of their children developing epilepsy has never been investigated. Methods: A case-control study was conducted in eight rural villages in Mahenge, Tanzania, an onchocerciasis endemic area with a high prevalence of epilepsy. Participants were enrolled in September 2021 and March 2022. Cases were persons with epilepsy, with a mean age of 26.3 (SD 9.0) years. Of these, 48.6% reported a history of nodding seizures. Controls were age-matched healthy individuals. Available mothers of participants were examined for palpable onchocerciasis nodules and tested with Ov16 ELISA. Findings: Seventy mothers of epilepsy cases and 49 of controls agreed to participate. Of these, 30 (42.8%) of mothers of cases and 19 (38.7%) of mothers of controls had palpable nodules (p-value = 0.80); 83.7%, 14.3% and 2% had one, two or three nodules, respectively. Ov16 positivity of the mothers of cases was 72.0% and of controls 75.8%. Using a logistic regression controlled for village and mothers’ age, mothers of persons with epilepsy were more likely to present palpable nodules (OR = 2.65, 95% CI 1.06-7.11). Discussion: Conclusion: Persons with OAE generally live in households close to blackfly breeding sites. Their mothers are likely to have similar high exposures to blackflies, explaining the high prevalence of nodules. Whether an O. volvulus infection in pregnant women may lead to an increased risk of OAE needs further investigation.