[Dog]

A research group from the University of Leeds has shown that infection by the brain parasite Toxoplasma gondii, found in 10-20 percent of the UK's population, directly affects the production of dopamine, a key chemical messenger in the brain.

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[RobynC]

Toxoplasmosis has long since been suspected as causing or playing a role in schizophrenia. Considering toxoplasmosis affects 10-20% of the public in the UK and about 1% have schizophrenia, it would seem that certain people are more prone to getting schizophrenia when affected by this disease than others.