The only Zombie movie plot I ever found plausible was “28 Days Later” with the rage virus. A disease like that could actually have the advertised effect.
I kind of wonder if that’s what WWZ will be based on, as opposed to the (implausible) reanimated dead.
According to Max Brooks (The author of WWZ and The Zombie Survival Guide), the zombies were the result of a virus called Solanum. He gets into extreme detail in TZSG. This movie could follow that plotline.