Planning for a zombie apocalypse might sound like the trivial pursuit of an amateur survivalist, but two epidemiologists claim the task raises important questions about the nature of infectious diseases.
Writing in the Conversation, Manchester Metropolitan University’s Joanna Verran and Matthew Crossley have revealed a scientific approach to combatting an outbreak of flesh-eating humans.
First things first, establish the threat level. According to the scientists, zombieism isn’t especially infectious because it requires saliva to be transferred through bites. But the fact that it makes infected individuals paranoid and agitated makes it more dangerous.
The epidemiologists then suggested we should calculate a basic reproduction ratio. It’s based on the number of additional cases the average infected person will generate. If the number is lower than 1, it will soon expire. But an outbreak with a ratio higher than 1 is likely to spread rapidly through the population.
The figure will be determined by population density, the ease with which zombies can be killed and how quickly they can move.
Responses can be organised into four categories, the scientists say:
1. Quarantine the infected and develop a vaccine. Quarantines are difficult to maintain and vaccines take time develop.
2. Hide the uninfected. A great plan if you’re outnumbered, until the zombies breach your zone and find what the scientists says is a “perfect environment” for the disease to spread.
3. A selective cull. Effective if precisely orchestrated, but nearly impossible to achieve given that early cases may not show obvious symptoms.
4. Eradicate the infected area. It’s guaranteed to end the outbreak, but moral issues remain given the “heavy losses of uninfected individuals”.
In short, there’s no easy option. Verran and Crossley conclude: “Real diseases are rarely as powerful as those in zombie films, which usually have a 100% transmission rate and come with a near complete lack of immunity, recovery or treatment.
“But exploring fictitious zombie-like pandemics also offers an exciting way to discuss infectious disease transmission, prevention and treatment.”