Toxoplasma gondii is a single celled organism that lives in the guts of cats and is spread to humans through contact with cat crap. About a third of the human population is infected with it. It resides in the brain and muscles, and doesn't always cause symptoms. But a new study at the University of Iowa and Florida International University has linked Toxoplasma gondii to reading and memory difficulties in children. The study also suggests that vitamin E can reduce the effects.
Infected rats are already known to lose their fear of cats, making it more likely that they will be killed and eaten. This is advantageous to the parasite, since it reproduces inside the intestines of cats. The organism's egg-like oocysts are shed in cat faeces which may then contaminate food or infect other animals. Some studies have suggested that Toxoplasma gondii can alter the behaviour of humans too, making men more aggressive and even causing women to cheat on their husbands. Other research has pointed to a strong link between the parasite and schizophrenia.