A systematic review and meta-analysis of the relationship between toxoplasmosis and epilepsy

Epilepsy is the third most common neurological disorder after stroke and Alzheimer's disease. Genetic factors, infectious diseases, brain trauma / stroke, inflammation and febrile seizure during childhood are among the factors that cause epilepsy. However, the underlying cause of epilepsy is not known in 60% of patients, which is called cryptogenic epilepsy. Toxoplasmosis is an important parasitic infection with a worldwide spread caused by Toxoplasma gondii. Chronic infection does not have symptoms in people with an effective immune system. Nevertheless, recent studies have shown that this infection is probably a risk factor for some of the neurological abnormalities, including epilepsy. The aim of this study was to review published articles to estimate the risk of epilepsy due to Toxoplasmosis.

We directed a systematic literature search on the history of toxoplasmosis and epilepsy from different databases without any date limitation, to identify studies published in Persian or English. Search was conducted in a series of keywords in both Persian and English. The odds ratio was used to calculate the risk factor of Toxoplasma gondii for epilepsy. In all experiments, p < 0.05 was considered statistically significant.

Ten studies were found until 2017. 3925 cases were studied, of which 2023 cases (627 Toxoplasma-positive) were epileptic and 1902 cases were not (572 Toxoplasma-positive). The total odds ratio was 1.16 (1.01-1.32), p = 0.034.

Despite few studies, toxoplasmosis might be considered as a risk factor for acquisition of epilepsy. To further clarify the effect of this parasite on acquisition of epilepsy, more comprehensive studies with enough number of different types of epilepsy and appropriate controls are required.