If you're a regular reader of the Loom, you're no doubt familiar with the parasite Toxoplasma gondii. If you're not, now is the perfect time to meet this sinister creature which may very well be residing in your brain. It seems like every year or two, it gets more remarkable, and today it's taken another step into awesomeness.
Here's a quick Toxoplasma primer. It's a single-celled protozoan that reproduces inside the digestive tract of cats. The cats poop out egg-like Toxoplasma cells into kitty litter and dirt. Other animals take up the parasite, which makes its way into their tissues, especially the brain. There it forms cysts that can linger for years or decades. Only if that animal gets eaten by a cat can Toxoplasma complete its life cycle.
This life cycle opens up opportunities for Toxoplasma to evolve. For example, natural selection should favor mildness in the parasite in ...
