"That cat poop can pose a health risk to humans no longer surprises us. Some cats carry a parasite called Toxoplasma gondii. Infected cats shed embryonic T. gondii, called oocysts, in their feces."
These oocysts are easily transmitted to humans, and researchers have explored their possible link to various mental health problems, including schizophrenia. More recently, studies of school-age children show a correlation between testing positive for T. gondii and having difficulty in school.
The parasites can cause more acute health problems in newborns and people with weak immune systems, as the Centers for Disease Control and Prevention points out."
Anna Haensch reports for NPR's Shots blog July 9, 2013.