Between the rumored Mayan apocalypse on December 21, 2012 and the new season of The Walking Dead, many people have the zombie apocalypse on the brain. Even the Department of Homeland Security and the Centers for Disease Control and Prevention released a preparedness manual helping people best ready themselves for the zombie apocalypse (and also plain old natural disasters). However, did you know that the zombie apocalypse could be jumpstarted by regular old parasites?

Parasites can highjack hosts' nervous systems, making them into walking zombies. These parasites are able to completely change hosts' behavior, making them into more bold creatures. Less kind parasites can take away animals' ability to move, allowing the parasite to remote control the host. These parasites will simply use the host to retrieve food for the parasite and its young.

"The fact that parasites can so efficiently alter host behaviour is fascinating," Michael Dickinson, from the University of Washington, said in a statement. "There is something horrifying and wondrous about a tiny 'implant' being able to control such a large animal machine'. What is more, it appears that these minute manipulators can have a significant, and often under-appreciated, impact on ecology, physiology and evolution, orchestrating the behaviour of vertebrates and invertebrates alike. Neuroparasitology is a science where science meets science fiction."

Much of these parasites operate on smaller organisms, like insects, but do not make the mistake of thinking that humans are exempt from this zombie behavior. The toxoplasma gondii has been known to infect rodents, cats, and even making the leap to humans. Though the parasite is not known as a household name, perhaps it should be. Researchers have linked the parasite with schizophrenia, the severe mental illness that is most characterized by an inability to tell the difference between what is real and what is not. While research on the matter is in its formative stages, it is still frightening - all the more so because there is no cure for the condition.

Research has been published in the Journal of Experimental Biology in a series of reviews.