Neurocognitive and neuropsychiatric effects of toxocariasis.

Caused by the neuroinvasive nematodes Toxocara canis and Toxocara cati, human toxocariasis has a worldwide distribution with seroprevalence in humans associated with low socioeconomic status and low educational attainment. Third-stage Toxocara larvae can invade human tissues, including the brain and spine, where they can result in encephalitis, meningitis, and inflammation. Toxocara infection in animal models has been associated with cognitive and behavioural changes. In humans, preliminary cross-sectional research suggests that Toxocara seropositivity is associated with worse cognitive function in children and adults. Additional preliminary cross-sectional findings suggest associations between Toxocara seropositivity and neuropsychiatric function, including schizophrenia and neurologic conditions such as epilepsy. Given the widespread distribution of human toxocariasis and early evidence suggesting that it can be associated with cognitive and neuropsychiatric function in humans, additional research regarding the effects of toxocariasis on the human brain is required.