The upcoming Walking Dead spin-off, Fear The Walking Dead, promises to show exactly how the world became one big undead flash party, finally revealing what the early stages of the zombie apocalypse were like.
By the time Rick wakes up in the hospital in The Walking Dead, the country has gone completely to pot. The police have vanished, the military are isolated and uncoordinated and there isn't a decent coffee place open anywhere. It's a nightmare.
However, how quickly could a zombie virus spread across the country, and could humans actually ever win against the zombie hordes? Well, that's what Professor Robert J. Smith and his students attempted to find out in their book, Mathematical Modeling of Zombies. Eventually, through the application of real world mathematics and epidemiological methods, the University of Ottawa team came up with an equation that solves everything: (bN)(S/N)Z = bSZ.
But what does this actually mean? Well, the equation breaks as follows:
- N = the total population
- S = the number of susceptible people
- Z = the number of zombies
- b = the likelihood of transmission
Basically, this equation states that the zombie virus would spread extremely quickly, especially if the likelihood of transmission is very high. Smith's studies concluded that once Patient Zero bit their first victim, the ball would begin rolling uncontrollably, eventually leading to zombies taking over the world. He also concluded there is no chance of a "stable equilibrium" between humans and zombies. It's all or nothing.
The only way to save humanity would be early, coordinated attacks against the zombies. However, this would require communications, command and control elements to still be in place. This could be unlikely.
Epidemiology and Zombies
There is, of course, a serious side to all this. The model used to show the rise of the zombie apocalypse is essentially the same as any other model used in modern epidemiology. In fact, there isn't much difference between a zombie and a virus. Ian MacKay, a virologist with the Australian Infectious Diseases Research Center claimed:
A zombie is a bit like giving a virus legs and teeth... 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.
However, there are clearly some differences between zombie-ism and other viruses. As Smith explains, usually the dead people in an epidemic are not a 'dynamic variable.' Basically, usually the dead don't try to eat the living.
In a bad epidemic situation, the number of those infected will usually increase, plateau and then eventually decrease. The decrease will be due to various factors including the human response, but another more morbid reason is that people with the infection will start dying off. The zombie virus doesn't work in this way. It can only naturally increases. The only way to reduce it is with human intervention.
This human intervention is another important variable. Usually, the uninfected are not actively trying to kill those who are infected. All told, this adds two complex nonlinear factors to the zombie model which makes the entire equation sensitive to small fluctuations. Indeed, it is almost unheard of in mathematic modeling, so much so Smith had to utilize a relatively new mathematical technique known as "impulsive differential equations." This technique, developed in the 1990s, is designed to show how sudden shock can affect systems - both economic and societal.
He concludes that the most important variable in the equation is disease transmission - i.e. the amount of time it takes those infected to show symptoms and become contagious. This varies greatly depending on which zombie story you're looking at, although almost all show the infection taking over the body extremely quickly - sometimes mere seconds after transmission.
If this is the case, the zombie apocalypse will be nearly unstoppable, as one zombie could very quickly take over a densely populated area. As mentioned above, only frequent, and increasingly effective strikes against the undead should stop the tide.
Where's The Safest Place To Be?
So where would the safest places be in a zombie apocalypse? Well, LiveScience created an infographic which included the 10 safest countries to be in during a zombie outbreak. Using variables such as geographic location, topography, population density, armed populace and military preparedness, they compiled the following list:
- 1. Australia
- 2. Canada
- 3. United States
- 4. Russia
- 5. Kazakhstan
- 6. Bolivia
- 7. Norway
- 8. Finland
- 9. Argentina
- 10. Sweden