Next time I go to the doctor, I think I'll get him to give me a test for Toxoplasma. Fifty million Americans have the parasite, so I wouldn't be the first. And if I was carrying it around in my head, that might explain why it's so fascinating to me. I first encountered the strange ways of this single-celled creature while working on my book Parasite Rex, and since then I've tried to keep up with new research on what makes it so successful. In January I wrote on the Loom about a potential link between Toxoplasma and schizophrenia. In Tuesday's New York Times I have an article that surveys some of the newest work on this bug--how, for example, it turns our immune cells into Trojan horses to get into our brains, and how it can precisely manipulate its hosts to hurtle to their doom. If you prefer your parasites podcasted, I'm chatting about Toxoplasma on the June 20 podcast for the Science Times. You can access it through the Times web site here, or through Itunes. Get infected by ear or eye--your choice.