If you or anyone you know has ever been pregnant with kitties living in the house, you’ve probably heard of Toxoplasma gondii, or T. gondii for short. Though the single-celled parasite is very nearly harmless to every species it has been found in – which is about all of the warm blooded ones – it can wreak havoc on a fetus if the mother is exposed for the first time during pregnancy.
Because T. gondii can procreate sexually only in felines, that’s the only animal’s shit that you have to worry about. By sexually reproducing, its eggs wind up in a cat’s digestive tract, and thus eventually in its feces.
However, the little bugger has another way to procreate.
Outside the intestines of a cat – or inside of most any other warm-blooded animal – T. gondii also reproduces asexually. It finds itself a nice little host cells, gets inside of it, forms a small cyst around itself and slowly begins reproducing while waving a giant middle finger in the general vicinity of the body’s immune system. Once the cell is full of more T. gondii, it bursts, sending forth its spawn throughout the body.
Luckily, once outside the cell and in the blood stream, the body’s natural defenses wipes the floor with most all of them. Yet some of them inevitable get away to invade a new cell. In this manner, the infection remains in an animal throughout its entire life, but never gets out of hand. Thus, most all animals who contract the parasite – even cats – never show any symptoms.
Or do they?
According to recent research co-led by Michigan State University Associate Professor of Experimental Psychiatry Lena Brundin, those infected with the parasite may be showing symptoms after all. Inevitably, some of those cells reach the brain and begin forming cysts and reproducing. This causes the brain to swell slightly. And slightly swollen brains are commonly found inside the skulls of the victims of suicide.
Assuming said brain and skull are still intact afterward.
This was the starting point of the study. The resulting question asked whether or not T. gondii could be causing an increase in depression and suicide attempts.
To figure this out, Brundin and her coauthors administered a test to assess the likeliness of suicide to people infected with the parasite, including some who had attempted suicide. The results showed that those with the infection scored much higher on the scale and are seven times more likely to attempt suicide.
Now, roughly 10-20 percent of people in the United States have T. gondii. But you can bet that not 10-20 percent of Americans will attempt suicide. There is an estimated number of about 750,000 suicide attempts each year. And if each was unique to an individual, which it’s not, that would still not come close to the bottom edge of 10 percent of the population.
What I’m saying is not to worry. Seven times a small chance is still a small chance. But if there is some causal link between the two, as this study concludes, it could lead to a new way of treating suicidal thoughts.
Big Ten Science 