Toxoplasmosis is a
fascinating disease. It’s caused by a single celled parasite called
Toxoplasma gondii that looks like a cool space alien, and is even more likely to be contracted from contaminated meat as cat poop. It’s the number one cause of death from food borne illness in the US.
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See? Cool space alien
The only species that it can complete its life cycle in is felines, everything else it just forms muscle cysts, little fibrous capsules in your body, pretty much anywhere since it can’t complete its reproduction. The parasite breeds within these cats and is released just as you mentioned. Cats are such good groomers that it is rarely found in their fur, and people then become infected via litter or by ingesting the eggs. These eggs are shed in the soil, and picked up by mice, where they form the muscle cysts to then be consumed by cats and infect them.
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Here's the CDC life cycle -- complete with suspicious looking cat with forward facing eyes like a primate. Nobody said scientists are good at drawing!
This article from the Scientific American is much better written than I could share, and goes into a lot of the history and background, but to answer your “heightened risk taking” question – it’s based on the fact that in mice, the parasite finds its way to their brain and modulates their behavior, removing their species aversion to cat urine and places cats frequent – scientists call this “fatal cat attraction!” It is speculated that this could occur in humans as well, and several studies seem to point to some sort of behavioral modification in folks infected with it. Granted, those sample sizes are small, and toxoplasmosis has no reason to evolve to affect other mammalian brains than rodent ones – primate brains like ours have a lot of differences. Still, the research is still out as to what exactly happens with toxoplasma infections in human nervous tissue. If anything, the most common thing it does in humans is make benign cysts in the muscle.
It absolutely is a very successful worldwide parasite -- Europe and the US and everywhere else. But if you're a immunocompetant you will be totally fine, won't even get symptoms, and not need treatment. Some people get flu like symptoms, and it's especially dangerous for immunocomprimised folks, pregnant people (because of the risk to the fetus) and if you're older (when your immune system is naturally decreased in effectiveness).