Only coordinated attacks against the zombies would save humanity, the model shows.
Epidemiology and 'WWZ' Models of disease outbreaks, like the one Smith developed, play a prominent role in real-life epidemiology, Smith said.
"Unlike most popular monsters, zombies are inherently biological in nature," said Mat Mogk, founder of the Zombie Research Society. "They don't fly or live forever, so you can apply real-world biological models to them."
Zombies are walking representations of a contagion, because they depict flesh-devouring monsters who spread their affliction by gnawing on the healthy. Some recent zombie flicks, notably "28 Days Later" and "Zombieland," even explicitly portray zombieism as a virus.
"A zombie is a bit like giving a virus legs and teeth," said Ian MacKay, a virologist at the Australian Infectious Diseases Research Centre, University of Queensland, who blogged about "World War Z." "This is basically a virus taking over a host, and spreading very quickly and efficiently. ... It's an extreme virus-transmission event, if you like."