A Second Population-Based Cohort Study in Cameroon Confirms the Temporal Relationship Between Onchocerciasis and Epilepsy

Cédric B Chesnais; Charlotte Bizet; Jérémy T Campillo; Wepnyu Y Njamnshi; Jean Bopda; Philippe Nwane; Sébastien D Pion; Alfred K Njamnshi; Michel Boussinesq

doi:10.1093/ofid/ofaa206

A Second Population-Based Cohort Study in Cameroon Confirms the Temporal Relationship Between Onchocerciasis and Epilepsy

Open Forum Infect Dis. 2020 Jun 2;7(6):ofaa206. doi: 10.1093/ofid/ofaa206. eCollection 2020 Jun.

Authors

Affiliations

¹ UMI 233, Institut de Recherche pour le Développement (IRD), Université Montpellier, INSERM Unité 1175, Montpellier, France.
² Centre for Research on Filariasis and other Tropical Diseases (CRFilMT), Yaoundé, Cameroon.
³ Neurology Department, Central Hospital/Faculty of Medicine & Biomedical Sciences, The University of Yaoundé I, (FMBS-UYI), Yaoundé, Cameroon.
⁴ Brain Research Africa Initiative, BRAIN, Geneva, Switzerland/Yaoundé, Cameroon.

Abstract

To confirm our earlier evidence of a temporal and dose-response relationship between onchocerciasis and epilepsy, we conducted another cohort study in a different setting in Cameroon. Individuals whose Onchocerca volvulus microfilarial density (Ov-MFD) was measured in 1992-1994 when they were children were revisited in 2019 to determine if they acquired epilepsy. With reference to individuals with no microfilariae in 1992-1994, the relative risks of acquiring epilepsy were 0.96, 2.76, 3.67, and 11.87 in subjects with initial Ov-MFD of 1-7, 8-70, 71-200, and > 200 microfilariae per skin snip, respectively. This study further demonstrates reproducibility using the Bradford Hill's criteria for causality.

Keywords: Africa; causal relationship; cohort; epilepsy; onchocerciasis.