Global Health Institute, University of Antwerp, Antwerp, Belgium.
Neurology Department, Yaoundé Central Hospital, Yaoundé, Cameroon.
PLoS Negl Trop Dis. 2021 Jan 7;15(1):e0008965. doi: 10.1371/journal.pntd.0008965. eCollection 2021 Jan.
The possibility that onchocerciasis may cause epilepsy has been suggested for a long time, but thus far, an etiological link has not been universally accepted. The objective of this review is to critically appraise the relationship between Onchocerca volvulus and epilepsy and subsequently apply the Bradford Hill criteria to further evaluate the likelihood of a causal association.
PubMed and gray literature published until September 15, 2020, were searched and findings from original research were synthesized. Adherence to the 9 Bradford Hill criteria in the context of onchocerciasis and epilepsy was determined to assess whether the criteria are met to strengthen the evidence base for a causal link between infection with O. volvulus and epilepsy, including the nodding syndrome.
Onchocerciasis as a risk factor for epilepsy meets the following Bradford Hill criteria for causality: strength of the association, consistency, temporality, and biological gradient. There is weaker evidence supporting causality based on the specificity, plausibility, coherence, and analogy criteria. There is little experimental evidence. Considering the Bradford Hill criteria, available data suggest that under certain conditions (high microfilarial load, timing of infection, and perhaps genetic predisposition), onchocerciasis is likely to cause epilepsy including nodding and Nakalanga syndromes.
Applying the Bradford Hill criteria suggests consistent epidemiological evidence that O. volvulus infection is a trigger of epilepsy. However, the pathophysiological mechanisms responsible for seizure induction still need to be elucidated.
盘尾丝虫病可能导致癫痫的可能性由来已久，但迄今为止，其病因学联系尚未被普遍接受。本综述的目的是批判性地评估旋盘尾丝虫与癫痫之间的关系，并随后应用布拉德福·希尔标准来进一步评估因果关联的可能性。
检索了截至 2020 年 9 月 15 日在 PubMed 和灰色文献中发表的研究，并综合了原始研究的结果。在盘尾丝虫病和癫痫的背景下，确定了对 9 项布拉德福·希尔标准的遵循情况，以评估是否符合这些标准，从而加强感染旋盘尾丝虫与癫痫（包括点头综合征）之间因果关联的证据基础。
盘尾丝虫病作为癫痫的危险因素符合因果关系的以下布拉德福·希尔标准：关联性强度、一致性、时间性和生物学梯度。基于特异性、合理性、连贯性和类比标准，有更弱的证据支持因果关系。几乎没有实验证据。考虑到布拉德福·希尔标准，现有数据表明，在某些条件下（高微丝蚴载量、感染时间以及可能的遗传易感性），盘尾丝虫病很可能导致癫痫，包括点头和纳卡兰加综合征。
应用布拉德福·希尔标准表明，有一致的流行病学证据表明旋盘尾丝虫感染是癫痫的触发因素。然而，引起癫痫发作的病理生理机制仍需阐明。
