Imagine that pesky tabby cat has been pooing in your backyard again. Unbeknown to you, it has transferred some of the parasite spores it was carrying onto your herb garden. Unintentionally, while preparing a tasty salad, you forget to wash your hands and infect yourself with the Toxoplasma gondii spores. For months you display no symptoms, then after six months you are driving your car more aggressively, taking chances in road junctions and generally filled with more road rage as you angrily gesticulate with fellow drivers. Could all this be linked to that tasty salad?
T. gondii is a fascinating protozoan parasite which, like many similar organisms, needs to move between several different host species in order to fully develop and reproduce. As such, it appears to have evolved clever methods to make transmission between hosts more likely. For example, studies have found that once rats—intermediate hosts—are infected they display less caution towards cats—the final stage hosts—and so the parasite is more likely to be passed on.