Invasion Of The Mind-Controlling Zombie Parasites
A few months back, something terrible happened to millions of flies around Washington, D.C. They were attacked by a fungus that basically made them zombies, unable to control their behavior. and flies are far from the only vulnerable creatures out there.
Source: http://www.npr.org/2011/10/30/141832947/invasion-of-the-mind-controlling-parasites?ft=1&f=1007