Approved research

Role of toxoplasmosis in epilepsy

Lay summary

Some people regularly have seizures. While medicine can control seizures, often people with recurrent seizures have a hard time keeping jobs, require brain surgery, and even die prematurely. It is unclear why most people have seizures. One theory is that a common parasite that has infected about 1/3 of the human population could contribute to the risk of seizures in a subset of people. This parasite, called Toxoplasma gondii (toxoplasma) does cause seizures in animals. Past work by the UKbiobank suggests that a toxoplasma infection alters the human brain. The link to human seizures, though, remains controversial. This study will use pre-existing data in the UKbiobank to determine if there is a connection between human seizures and exposure to Toxoplasma. If we find a link, we will identify characteristics that differ between patients with seizures who test positive and negative for the parasite. It is likely that Toxoplasma is linked to only a subset of seizures, and identifying these differences will help us better understand these groups. We expect this project to last three years.

If we confirm a link to seizures and Toxoplasma this will set up three important goals for future research that could transform the diagnosis and treatment of seizures in humans. First, currently we can not distinguish between a distant, smoldering Toxoplasma exposure, and a recent heavy exposure that is more likely to cause seizures. This study would likely allow us to achieve that goal, again if our results are consistent with past studies. Second, suppose we find that some seizures are unrelated to Toxoplasma and others are related. In that case, we can test in both laboratory experiments and humans whether certain seizure medications work better for Toxoplasma-related seizures than others. Currently, seizure medications are given on a trial-and-error basis; it is difficult to match the best seizure medication for specific patients quickly. Lastly, an early toxoplasmosis infection can be treated with current antibiotics. Yet no current antibiotic exists that can cure the chronic late stage of Toxoplasmosis. There is plenty of evidence though that late-stage toxoplasmosis could be cured, if a clear and common need to treat this infection was evidence-based. Our research may dramatically increase the rationale for developing medication that eliminates chronic toxoplasma. Overall, this research should reduce the controversy about whether or not Toxoplasmosis causes human seizures, and if so, aid in diagnosing and treating that condition.