Human brains are the slightest bit more complicated than ant or fish brains, though. Any complex behavioural alteration that doesn't already exist would take too long to evolve, and we'd be able to deal with it easily.
Tell that to Toxoplasmosa gondii. Nothing as dramatic as what it does to rats (it makes them run
toward cat sounds and smells), but it does have an impact on human behavior (and, even better, 20-80% of all humans are already infected!)