https://en.wikipedia.org/wiki/Toxoplasmosis https://en.wikipedia.org/wiki/Toxoplasmosis maybe? "Up to half of the world's population is infected by toxoplasmos

https://en.wikipedia.org/wiki/Toxoplasmosis https://en.wikipedia.org/wiki/Toxoplasmosis maybe? "Up to half of the world's population is infected by toxoplasmosis, but have no symptoms." (No symptoms that we/they know of but read about how it affects mice. Makes them crazy reckless and wanna go get eaten by a cat.)