http://www.economist.com/node/16271339
A game of cat and mouse:
There is tantalising evidence that a common parasite may affect human behaviour
“If an alien bug invaded the brains of half the population, hijacked their neurochemistry, altered the way they acted and drove some of them crazy, then you might expect a few excitable headlines to appear in the press. Yet something disturbingly like this may actually be happening without the world noticing.”
Citizens Against Toxoplasmosis 