Design: systematic review and Bayesian meta-analysis, PROSPERO registered, 20 databases
Population: 77 studies of people presenting with epileptic seizures in endemic regions; 35 with clear case definitions pooled
Primary outcome: proportion with neurocysticercosis by neuroimaging, biopsy or autopsy
Effect: 25.2% (95% Bayesian credible interval 19.5-32.2), high heterogeneity, declining after 2008

A Bayesian meta-analysis screened 16,202 records across twenty databases to estimate how often neurocysticercosis underlies epileptic seizures in Taenia solium endemic regions between 1990 and 2023. Seventy-seven studies met inclusion; the headline estimate rests on the 35 that used explicit case definitions for both the infection and the seizures and diagnosed by neuroimaging, biopsy or autopsy.

Among those, the pooled proportion was 25.2% (95% Bayesian credible interval 19.5 to 32.2). It did not vary by sex or age. Studies with loose definitions reported considerably lower figures, which the authors interpret as misclassification rather than as a different population. The proportion fell between the 1990-2008 and 2008-2023 periods across Africa, the Americas and southeast Asia.

For Indian neurology this quantifies the working assumption behind imaging every first unprovoked seizure. It also sets the prior for interpreting a solitary ring-enhancing lesion: in an endemic setting, cysticercosis is the single likeliest identifiable cause, not an incidental finding to be watched. The reported decline is the weaker part of the paper - the authors are explicit that better imaging, changed definitions and different study populations could all produce an apparent fall without any change in transmission.

Image every first unprovoked seizure in a patient from or living in an endemic area
Stage the lesion before deciding on antiparasitic treatment - viable, degenerating and calcified behave differently
Examine the fundus before starting albendazole, and consider corticosteroid cover
Ask about household pork exposure and consider screening close contacts for taeniasis
Do not read the reported decline as evidence that transmission has fallen

Why it matters

It replaces an impression with a defensible number for the commonest identifiable cause of adult-onset seizures in endemic practice.

The statistics, in plain English

The credible interval of 19.5 to 32.2% is wide because the studies genuinely disagreed - between-study heterogeneity was high, and the authors say the pooled figure should not be read as universally generalisable. Use it as a prior for an endemic district rather than as your clinic's rate. The comparison between loosely and clearly defined studies is the more useful methodological point: it shows that most of the variation in the published literature is definitional, not biological.