World War Z: The Science of Zombification

By Syed Mohammad Raza Hamdani 

The Science of Zombification

If you were to ask an accountant or someone in your family if a zombie apocalypse can ever occur they would probably say no or laugh at the question, but a bio-physicist might have a different response. In this technological age, zombie apocalyptic movies and video games are around every corner. If you, like me, have ever wondered if a zombie apocalypse can ever become a reality then you’re at the right place: today we’ll scientifically analyze how realistic the portrayal of a zombie apocalypse is in the Brad Pitt blockbuster hit, World War Z.

In general, let’s start with what we know about the zombies in the movie: apparently, the ‘Zekes’ don’t need to consume food or water as they don’t eat their prey, they rather just bite them and move on. Moreover, the zombie bite victim loses control of their bodies and mind in a minimum of 12 seconds, the zombies rely on sound as their biggest trigger yet their host's other senses are active too such as vision and the pathogen through which the zombie infection spreads is un-identified: it could be bacterial, viral or something else entirely. Lastly, the zombies can detect terminal diseases in their hosts and as a response ignore such potential hosts along with displaying self-destructive behavior.

What went wrong?

Firstly, let's analyze the actual biological probability of such an event occurring: The zombie bite, for example, apparently converts its human host to a zombie in 12 seconds and the zombification process is immediate and complete (meaning humans turn into zombies suddenly and totally). When the host becomes a zombie, we see excessive twitching which shows that the nervous system is affected and that the immune system is responding to the zombie infection and by the twelfth second- brain function is lost to the pathogen. This is less than likely, considering that it takes at least a minute or so, on average, for blood to circulate throughout the body, moreover, the way in which the infection elicits a response from the human’s immune system isn’t something that happens rapidly, rather gradually over time, and so we would rate the biological practicality on the spread of the virus to be low, however, since we know the pathogen is of an unknown kind so perhaps it may add an explanation for the rapid and complete onset of the infection as it may act differently than viruses and bacteria that we know off, still in terms of biological realistically it doesn’t give an accurate portrayal.

Secondly, let's look at the behavior of the zombies we see throughout the movie- they just bite their prey and move on. Meaning the zombie’s goal is to spread the pathogen rather than survival. I mean we see the zombies literally running around and attacking whole cities in response to cues such as loud noises or visually seeing a potential host, a healthy human, and of course they want to spread their pathogen, hence, one might figure that don’t the zombies need some sort of food or water to survive? I mean they use so much energy during this running around and attacking, moreover, when there are no cues to respond to; the zombies just stand in one place, dormant. This, too, is biologically unrealistic as most parasites or viruses actually require nutrients from their host to survive like that's kind of the point of finding a healthy host: so you can feed off of them. An alternative cure that I came up with while watching the movie was that the humans should just hide and wait for the zombies to starve to death.

Lastly, let's look at the apparent cure provided for the virus: injecting individuals with meningitis as camouflage from the zombies. While this is a basic survival technique used by animals too, such as playing dead in front of prey or releasing foul odors to seem undesirable by prey such as skunks do. Biologically speaking, the zombies are seen to respond to cues such as loud sounds and visually looking at their prey, so that shows that their senses, such as eyesight, smell, and sound are functional. However, to assume that the zombies can detect terminal illnesses in hosts is a bit far fetched. One plausible theory is that the infection dials up the human sense of smell in the zombies or Zekes, and thus this allows them to smell terminally ill diseases off of humans from afar as experiments have shown that dogs can smell certain types of cancers in humans in controlled environments. Thus, it may be a possibility that zombies can detect diseases from afar but it still isn’t the most biologically accurate explanation, hence, once again it gets a lower rating in terms of practicality and plausibility.

So, can it actually happen?

At the same time, neurotropic viruses and parasites do exist that attack our brains and can cause aggressive or bizarre behavior. One such example could be hairworms, who need to get to aquatic bodies in order to reproduce, thus a hairworm enters a cricket and produces chemicals that incline crickets to go towards light sources which usually results in the cricket going towards a moon’s reflection on a water body and ultimately committing suicide by drowning as the hairworm then emerges to reproduce.

Thus, an actual possibility of zombies, according to biophysicist, is perhaps a combination of two of such neurotropic parasites or viruses or perhaps an emergence of a new such virus which has capabilities to affect the human brain. What we see of the zombies or Zekes in world war Z is far from realistic, as we previously established, however, the self-destructive behavior of the zombies such as jumping off a roof of a building while chasing its prey taking off in a helicopter does portray the self-destructive tendencies of such viruses to its host accurately.

Sources:

1. “A Biophysicist Fact-Checks World War Z's Swarming, Sniffing, Tireless Zombies.” Vulture, 25 June 2013, vulture.com/2013/06/biophysicist-assesses-world-war-z.html (Links to an external site.).
2.  Bates, Mary. “Meet 5 ‘Zombie’ Parasites That Mind-Control Their Hosts.” "Zombie" Parasites That Mind-Control Their Hosts, 7 June 2020, nationalgeographic.com/news/2018/10/141031-zombies-parasites-animals-science-halloween/ (Links to an external site.).
3.  Dell'Amore, Christine. “World War Z: Could a Zombie Virus Happen?” National Geographic Society Newsroom, 15 Nov. 2017, blog.nationalgeographic.org/2013/06/25/world-war-z-could-a-zombie-virus-happen/.

 Additional info: 

1. https://www.youtube.com/watch?v=vijGdWn5-h8 (Links to an external site.)
2. https://on.natgeo.com/2IFsAEU