Regardless of whether you have a cat or not, there's a good chance that you've heard horror stories about toxoplasmosis, an infection caused by the toxoplasma gondii parasite, and its links to cat feces and undercooked meats. While the infection itself is often nothing serious, beyond a person experiencing flu-like symptoms that soon pass, medical studies have linked the parasite to instances of Intermittent Explosive Disorder (IED), a behavioral disorder characterized by outbursts of rage and violence.
A recent study conducted by researchers from the University of Chicago has once again linked IED to toxoplasmosis, noting a "consistent link" between suicidal thoughts and aggression and blood test results that showed positive indications of toxoplasma gondii.
Let's have a look at the study. In addition to examinations and blood tests, the 358 test subjects were also queried extensively about their prior medical history, enabling clinicians to determine the other factors that might be causing changes to their personalities. Some 15.9% of the subjects returned positive toxoplasma gondii test results. The researchers were able to determine that the parasite was a "strong predictor of aggressive behavior" in patients with IED, and that toxoplasma gondii tended to be more common among those that already showed signs of mental health conditions.
However, the study at no point examined the test subjects' relationships with cats, or even asked if they shared their home with one. In fact, the researchers were happy to note that there are various contributing factors that could cause toxoplasmosis, and thus IED, including congenital infection, and handling or consuming undercooked meat or contaminated water. Cat feces can carry the parasite, but toxoplasma gondii can remain dormant for as long as 18 months and lie quite happily in the soil until it is picked up by an animal.
The short of it is that you must always wash your hands after handling cat feces, but you must also be wary of undercooked meats; pretty standard advice, we'd say.