Infection by the brain parasite Toxoplasma gondii, found in 10-20 per cent of the UK’s population, directly affects the production of dopamine, a key chemical messenger in the brain, a research group from the University of Leeds has found.

Dopamine controls the brain’s reward and pleasure centers and regulates emotional responses such as fear. The presence of a certain kind of dopamine receptor is also associated with sensation-seeking, and dopamine deficiency in humans results in Parkinson’s disease.

The findings could ultimately shed new light on treating human neurological disorders that are dopamine-related, such as schizophrenia, attention deficit hyperactivity disorder, and Parkinson’s disease.