Toxocariasis and Epilepsy: Systematic Review and Meta-Analysis

Objective: human toxocariasis is a zoonotic infection caused by the larval stages of toxocara canis (t. canis) and less frequently toxocara cati (t. cati). a relationship between toxocariasis and epilepsy has been hypothesized. we conducted a systematic review and a meta-analysis of available data to evaluate the strength of association between epilepsy and toxocara spp. seropositivity and to propose some guidelines for future surveys. data sources: electronic databases,the database from the institute of neuroepidemiology and tropical neurology of the university of limoges (http://www-ient.unilim.fr/) and the reference lists of all relevant papers and books were screened up to october 2011. methods: we performed a systematic review of literature on toxocariasis (the exposure) and epilepsy (the outcome). two authors independently assessed eligibility and study quality and extracted data. a common odds ratio (or) was estimated using a random-effects meta-analysis model of aggregated published data. results: seven case-control studies met the inclusion criteria,for a total of 1867 participants (850 cases and 1017 controls). the percentage of seropositivity (presence of anti-toxocara spp. antibodies) was higher among people with epilepsy (pwe) in all the included studies even if the association between epilepsy and toxocara spp. seropositivity was statistically significant in only 4 studies,with crude ors ranging 2.04-2.85. another study bordered statistical significance,while in 2 of the included studies no significant association was found. a significant (p<0.001) common or of 1.92 [95% confidence interval (ci) 1.50-2.44] was estimated. similar results were found when meta-analysis was restricted to the studies considering an exclusively juvenile population and to surveys using western blot as confirmatory or diagnostic serological assay. conclusion: our results support the existence of a positive association between toxocara spp. seropositivity and epilepsy. further studies,possibly including incident cases,should be performed to better investigate the relationship between toxocariasis and epilepsy. © 2012 quattrocchi et al.