ReviewPLoS neglected tropical diseases2021
Onchocerca volvulus and epilepsy: A comprehensive review using the Bradford Hill criteria for causation.
Review in PLoS neglected tropical diseases, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 55 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
55 citing papers in PubMed, 98 citations in OpenAlex.
- Declining Onchocerca volvulus transmission despite limited ivermectin delivery in the Kakoi-Koda focus, Ituri, Democratic Republic of the Congo: An epidemiological, entomological and landscape evidence synthesis.PLoS neglected tropical diseases · 2026Article
- Nodding Syndrome: Shifting the Focus from Cause to Treatment.The American journal of tropical medicine and hygiene · 2026Review
- Nodding Syndrome: The Need to Strengthen Epilepsy Care in Onchocerciasis-Endemic Areas and to Investigate the Pathogenesis of Onchocerciasis-Associated Epilepsy.The American journal of tropical medicine and hygiene · 2026Article
- Article
- Is polycystic ovary syndrome associated with uterine malformations? A systematic review using Bradford Hill's causality framework.Human reproduction open · 2026Review
- Investigating HLA haplotypes as a potential risk factor for nodding syndrome: A case-control study in the Mahenge area, Tanzania.PLoS neglected tropical diseases · 2025Article
- Community-directed treatment with ivermectin in Maridi, South Sudan: Impact of an onchocerciasis awareness campaign and bi-annual treatment on therapeutic coverage.PLoS neglected tropical diseases · 2025Article
- High epilepsy prevalence and excess mortality in onchocerciasis-endemic counties of South Sudan: A call for integrated interventions.PLoS neglected tropical diseases · 2025Article
- Community-based epilepsy care in an onchocerciasis-endemic area: A 3-year cohort study in Mahenge, Tanzania.Epilepsia · 2025Article
- Causal inference from observational data in neurosurgical studies: a mini-review and tutorial.Acta neurochirurgica · 2025Review
- Cameroonian blackflies (Diptera: Simuliidae) harbour a plethora of RNA viruses.Virus evolution · 2025Article
- Epidemiology of epilepsy in Wulu County, an onchocerciasis-endemic area in South Sudan.Heliyon · 2024Article
- Attitudes and perceptions towards epilepsy in an onchocerciasis-endemic region of Tanzania: a mixed approach to determine the magnitude and driving factors.BMC public health · 2024Article
- Prevalence of onchocerciasis and epilepsy in a Tanzanian region after a prolonged community-directed treatment with ivermectin.PLoS neglected tropical diseases · 2024Article
- Modelling onchocerciasis-associated epilepsy and the impact of ivermectin treatment on its prevalence and incidence.Nature communications · 2024Article
- Dementia Prevalence andPathogens (Basel, Switzerland) · 2024Article
- Community Perceptions of Blackfly Nuisance and Acceptability of the "Slash and Clear" Vector Control Approach in the Ntui Health District of Cameroon: A Qualitative Study.International journal of environmental research and public health · 2024Article
- Article
- PMHeliyon · 2024Article
- Review of epilepsy care in the Democratic Republic of the Congo.Epilepsia open · 2024Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
9 authors at 5 institutions in 5 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundThe 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.
methodsPubMed 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.
resultsOnchocerciasis 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.
conclusionApplying 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.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.