Researchers Discover How Cat Parasite Alters Human Behavior

It's no secret that cats and a certain parasite called Toxoplasma gondii are associated with each other. Pregnant women, for example, are advised to stay away from cats during their pregnancy due to the risk of contracting the parasite, which causes a disease called toxoplasmosis. Toxoplasmosis was long thought to (usually) have no symptoms in healthy adults, but researchers have increasingly found evidence of so-called brain 'hijacking.'

Toxoplasma, in addition to being transmitted by cats, is also found in raw meat. The number of people infected by the parasite is thought to be fairly high — about 30-percent of the population. Past research has found that toxoplasma may alter the host's behaviors, a topic recently again looked into by researchers from the Walter and Eliza Hall Institute.

Toxoplasma, in the most serious cases, can cause birth defects, miscarriages, and serious issues in individuals with compromised immune systems. In healthy adults, researchers have found the parasite can remain dormant for long periods of time — perhaps decades — subsisting off its own stockpile of food.

Said Dr. Chris Tonkin, one of the researchers who worked on the projects:

Toxoplasma infection leads to massive changes in the host cell to prevent immune attack and enable it to acquire a steady nutrient supply. The parasite achieves this by sending proteins into the host cell that manipulate the host's own cellular pathways, enabling it to grow and reproduce.

Those proteins could result in the behavioral changes observed in some infected individuals. Schizophrenia and bipolar disease are two psychiatric illnesses that have a "fascinating association" with Toxoplasma, according to one researcher. The parasite is likely to exit 'hibernation' if one's immune system becomes compromised, otherwise it can remain in a dormant state for its' host's full life.

During their study, the researchers found pathways through which the parasite causes infections, and with that discovery comes the possibility of a vaccine that could prevent such parasitic infections and drugs that could clear up already existing conditions.

SOURCE: EurekAlert