Not Supernatural

The biggest hurtle a zombie hunter has to leap when explaining the zombie menace to the uninformed, is making the uninitiated understand that the zombie threat is an actual, plausible threat. I believe this has to do with the misconception that zombies are a supernatural entity.

This belief probably coincides with the association of zombies with Voodoo. As Wade Davis pointed out in The Serpent and the Rainbow, this "supernatural" phenomenon has a pharmacological explanation. Similarly, real zombies are caused by the zombie virus, not some manifestation of evil spirit (despite what Evil Dead would have you believe). This virus merely has the ability to reanimate human flesh. Since reanimation which has been replicated under controlled conditions many times (see references below); this virus is anything but farfetched. Of course, the conditions under which the virus operates make no effort to preserve the brain, so the resurrected human is nothing like its former self. However, the rudimentary need to feed is still very much present, in part because of the virus' poor ability to sustain its host, it will need to continue to infect in order not to be extinguished.
Having never come face-to-face with a zombie, I have to admit, that they are difficult to believe in. However, believing in the possibility of the threat, is no problem. Like I've said many times, it's not a question of "if", it's a question of "when".

Reanimation references:
"Zombie Dog"- though everyone should clearly recognize that this is not actually a zombie.
Soviet Research into Reanimation- this video is profoundly disturbing. I couldn't watch all of it because I was too disgusted. You've been warned.
Wired Article- about the future (and past) of head transplants.
...and there's lots more out there