Human-zombie coexistence is impossible... Since all eigenvalues of the doomsday equilibrium are negative, it is asymptotically stable. It follows that, in a short outbreak, zombies will likely infect everyone.Gosh, Dr. Science, how come?
So there you have it. Scientifically proved.
According to Smith, a major factor restraining normal plagues from utterly devastating humanity is that they tend to kill their victims, after which the sufferers can no longer move about and infect others. This is one reason the frightful Ebola virus has never spread, for instance: it knocks people down and then kills them so fast that they have only a limited chance to pass it on.Not so with zombification. Once someone has died of Z-plague, they remain a mobile carrier. The factors which have prevented humanity being rendered extinct by the Black Death, smallpox, cholera etc don't apply.
So learn and survive, people. Sure, it's all a truckload of yucks now, but when all those Canadian Zombies come pouring south across the border, you'll be trying to sort out which end of an 870 is which.