- Zombie Rats - Toxoplasma gondii. This was a very interesting article written by the author of Parasite Rex, Carl Zimmer, and is well worth the read. Toxoplasma gondii is a parasite that is passed through cat urine and feces to infect the rat with the desire to get eaten. You heard it. Rats infected with the parasite show no fear at the smell of cat urine or even an approaching cat, because the parasite affects the brain. It is estimated that about half the population (3 billion people) is infected, but no one yet knows what the effects on humans are.
The article mentions another parasite, Euhaplorchis californiensis, which "causes infected fish to shimmy and jump, greatly increasing the chance that wading birds will grab them," and thus be infected.
- Zombie Snails - Leucochloridium Paradoxum. A flatworm that infects snails' brains and causes to, instead of hide in their shell or underneath things, be right out there in the open for birds to eat. The worm, spread through bird droppings, causes the smail's body to swell so that it cannot get back into its shell.
And look what it does to its eyes:
I was nice and spared you from the pulsating image. You're welcome. No, that's not normal. They pulsate and swell to look like maggots (yummy to birds), so birds swoop down and eat just the eyes of the snail! The snail stays alive and grows its eyes back, only to have the same thing happen again. (See above link for more info.)
- Zombie Grasshoppers - Spinochordodes tellinii. A parasitic hairworm that affects the grasshopper's central nervous system, leading it to jump into water and die. The worms then reproduce in water.
- Zombie Humans - Outbreak of zombism in Cambodia and London. It didn't actually happen. But it was funny, because BBC posted the Cambodia one on April 1, 2005 and the London one on April 1, 2009. The link is to the Snopes article saying that they were both April Fools jokes.
Also, read Cracked.com's article: 5 Scientific Reasons A Zombie Apocalypse Could Actually Happen. Additionally, here is a similar blog post I found when I was almost done writing this one.
Happy human hunting, zombies!
NOTE: This information is just for fun. It might not all be correct. There are especially questions surrounding the first article. Just be aware.