I've always felt that a zombie 'disease' wouldn't be that effective at wiping out humanity. Wouldn't something of this nature burn itself out so rapidly that it wouldn't be able to spread? Zombies, being mindless and all, wouldn't be able to survive that long, nor would they be able to travel to the corners of the Earth to spread their condition to the isolated groups of humans. But big cities, I imagine, would be in for a Hell of a time. 
it all depends on how many vectors there were, how long the contagin lies dormant before manifesting, whether they can track and hunt and how long they can go without meals. Its these kinds of questions that make a lot of academic studies that critics like to mock worth while. Once you have built the model, fill in any bio-agent and it still works. Zombies today, ebola tommorow.
FQ13 who would prefer zombies to ebola, if only for the sake of humor and being able to say I warned you, before dying an ugly death