There is a parasite out there that can infect virtually any warm-blooded creature on Earth. It’s found just about everywhere, and approximately 33% of humans are infected. It’s mysteriously linked to people committing suicide and brain cancer, and it’s most commonly found in cats.
Known as Toxoplasma gondii, the parasite can cause a disease aptly called toxoplasmosis in virtually any warm-blooded creature it infects. Luckily for us, toxoplasmosis is rarely, if ever, fatal in any species.
That said, it is still a very major concern to the scientific and medical community. As noted in a work sheet released by Stanford University, toxoplasmosis has a very high mortality rate when people with a weaker immune system, such as patients suffering from HIV/AIDS, are infected with it. The disease is also noted as being very dangerous to infants and other, otherwise immunocompromised patients.
So how do you catch it? Well, there are several well documented and universally agreed upon ways in which an ordinary person can come into contact with the parasite, and hence the disease.
• Raw, undercooked meat.
• Unpasteurized milk.
• Raw/unwashed vegetables.
The link between eating uncooked meat and the parasite was conclusively proven when scientists in Paris fed orphans nearly raw beef, horse and lamb meat to test the hypothesis that the parasite could be transmitted in this way. If you’re hoping that this happened hundreds of years ago, it took place in 1965.
In regards to cats, they are noted as being the “definitive host” of the Toxoplasma gondii parasite. In fact, it can only sexually reproduce when it is inside of a cat. However, it can asexually reproduce and live “indefinitely” inside the body of virtually any warm-blooded host, like a human. Since Toxoplasma gondii parasites can’t complete their life-cycle inside of us though, we are defined as being “intermediate hosts”.
About 40% of people in the U.S. have been exposed to the parasite at some point, often in unwashed vegetables or undercooked meat, and about 15% of people in the U.S. have the telltale cysts in their heart, nervous system tissues, and skeletal muscle, with each cyst containing many thousands of the parasite.
The symptoms of toxoplasmosis in ordinary, healthy people are usually mild. If any symptoms do show up, it generally only happens when you first acquire the parasite, and these are simply mild flu-like symptoms that last a couple weeks.
Despite the fact that a third of the world is infected with this parasite, unless you have a crippling disease that’s ravaging your immune system, are getting an organ transplant, or are a tiny baby, it will probably never bother or affect you in definitive way.
Again, we say “probably” because there is a growing, but as yet unproven concern that the parasite can cause a number of mental health problems. For example, research conducted by the Maryland School of Medicine found that women infected with the parasite were “1.5 times more likely to attempt suicide”. Other studies have linked the parasite to even more alarming health issues such as schizophrenia and even brain cancer.
By far the most fascinating thing about the parasite, however, is its apparent ability to control the mind, or at least the behavior of certain of its hosts. Specifically, rats infected with the parasite will become unusually attracted to the scent of cat urine, a scent they’d usually avoid like the plague. Terrifyingly, the parasite seems to accomplish this by completely and permanently overriding the rat’s natural fear of cats and their distinctive odor. Instead, the rat becomes intensely sexually attracted to it instead. Needless to say, this makes it much more likely that the rat will be eaten by a cat, which allows the Toxoplasma gondii to get inside its preferred host.
In the end, our own immune system keeps the majority of symptoms at bay. When it doesn’t, for example in immune deficient people, the subsequent disease often results in death, with initial complications including encephalitis and pneumonia.