You Are Probably Infected With Toxoplasma
And scientists are just beginning to figure out what that means. This is, plain and simple, a fantastic story and somebody should win a prize for it.
This parasite is everywhere, it is mostly benign but can cause serious brain damage, produces little egg-like things called oocysts that can live for a year in the ground and contaminate drinking water and get this: It may be the reason people like cats.
As if that’s not enough (and it is), the story has this incredibly beautiful image:
Scientists added a firefly gene to the parasites so that they produced a glow. When they injected the parasites into mice, a little of the light escaped from the animals. By putting the mice in a darkened box, Barragan and his colleagues could track the parasites as they spread.