It's basically the virus that makes you a zombie... I found a link but I'm not sure if the facts in it is true, mainly because of the website and the pictures in it, heh.

http://zombie.wikia.com/wiki/Necro_Mortosis

Feedback please!

I don't want to be the guy that points out the obvious but if you scroll down to the very bottom of the page you'll see a reference link to the virus "Solanum" a.k.a. the disease from "The Zombie Survival Guide". While the site looks very informative and all of that I highly doubt the credibility of it all. In fact considering that their possible outbreaks include Voodoo and a by product of chemical/bacterial warfare, I'm going to go ahead and say this is false.

Weeeeeeeee this is fun.

Wait just a minute...This isnt real? DAMNIT!

"this article uses in-universe perspective"

And man, their Latin sucks like Electrolux.

No it is real. Just inactive. Well it is mostly found in Haiti. Not here. I looked it up. It is a real but not that much understood virus.

I thought that was a good thing.