I think if a virus ever comes about to turn people to zombies its going to be a form of rabies. Its aggressive, and scientifically proven to mutate. Ive said this before I also don't think the zombies it creates are going to be dead, or able to live without function internal organs like the heart. I think their going to be more like the zombies from 28 days later, living just rabbid. I don't think, or hope if something like that occured that they'll be able to run. I think the virus will much like it does in animals alter their coordination and balance. Making them stumbly, clumsy, and slow. I do believe they will move much like the zombies in the walking dead, because of the lack of coordination. Lets hope that that is the issue, because otherwise that possible future could be a lot scarier.
Exactly, everyone is love with the idea of zombies being actually "dead" truth of the matter is there is no way they will be actually dead. Its just not possible from a medical stand point.