Could a zombie apocalypse really happen? Are there viruses in the plant and animal kingdom that mimic the symptoms of zombies in popular culture?
The Center for Disease Control and Prevention, the main national public health institute in the United States, has a zombie preparedness guide. When I first heard this, I was more than a little concerned. I always thought zombies were just a fun and wildly popular horror movie genre. But could a zombie apocalypse really happen?
Does a Zombie Virus Really Exist?
The concept of zombies, or bodies reanimated after death, originated with Haitian slaves in the 1600s and 1700s who felt trapped in their own bodies and without the free will to decide their own movements. Stories of the undead eventually worked their way into the Haitian Voodoo religion which suggested sorcerers could use them to carry out their dirty work.
From the undead Haitian slaves of 400 years ago to the present day zombies popular in television and film, zombies usually share a few common traits. They have no sense of right and wrong, no ability to plan, and no impulse control, all of which indicate a lack of a functioning frontal lobe of the brain. They do, however, still have basic motor control and are driven primarily by hunger.
While there are no viruses that can cause neurons to fire in an already deceased brain and thus reanimate a corpse, there are infectious diseases that mimic some of the standard zombie characteristics while a patient is still alive. In particular, a genre of viruses called neurotropic viruses attack our brains and can make us act strange or aggressive.
For example, rabies is spread by a bite (which will sound familiar to zombie movie lovers) and, once contracted, strictly affects the brain leaving its victim aggressive and looking to bite others.
Another neurobehavioral disorder, Kluver-Bucy syndrome, has symptoms that include hyperorality (the urge to put inappropriate things in your mouth), an inability to recognize normal objects, dementia, and a tendency toward a confused, catatonic state while being prone to violent outbursts. Encephalitis lethargica, also called "sleeping sickness," causes hallucinations and puts its sufferers into a catatonic state while making them prone to violent outbursts if roused.
And while a real zombie virus does not currently exist, viruses do evolve. It is feasible that one could evolve, for example, if two viruses infect the same cell, to cut off higher brain function and induce starvation. Infectious diseases can also have mutations just as our regular genetics can which can give the disease an advantage. But a virus evolving into something that can affect even a dead body remains science fiction.
Would We Survive a Zombie Virus?
Whenever a new virus is introduced into a population where there is no immunity—think of the measles and smallpox brought to the Americas in the late 1400s from Europe—the virus is incredibly efficient at claiming its victims. The good news is that since, at least according to lore, a zombie virus would not be transmitted through the air, there is a higher chance of containing it.