I found this paper (When Zombies Attack!: Mathematical Modelling of an Outbreak of Zombie Infection) very funny and informative. It's a real mathematical modelling of how a zombie outbreak might occur by viewing it through infectious disease models.
The main points:
An outbreak of zombies infecting humans is likely to be disastrous, unless extremely aggressive tactics are employed against the undead. While aggressive quarantine may eradicate the infection, this is unlikely to happen in practice. A cure would only result in some humans surviving the outbreak, although they will still coexist with zombies. Only sufﬁciently frequent attacks, with increasing force, will result in eradication, assuming the available resources can be mustered in time.
In summary, a zombie outbreak is likely to lead to the collapse of civilisation, unless it is dealt with quickly. While aggressive quarantine may contain the epidemic, or a cure may lead to coexistence of humans and zombies, the most effective way to contain the rise of the undead is to hit hard and hit often. As seen in the movies, it is imperative that zombies are dealt with quickly, or else we are all in a great deal of trouble.