I was not able to contain zombies to one part and they spread to a second part. This time, I am tackling the more classical zombie apocalypse, the one where zombies are not created on purpose… a pandemic of some sort if you will.
To start of, let us dive into one type of pandemic that you might have heard of: zoonoses. A zoonosis is a disease that is transmitted from a non-human animal to the human species. Why am I referring to it here? It is a possible explanation for a zombie apocalypse, as in 28 days later, Zombieland… One thing they miss in my opinion, is the reason for the outbreak of zoonoses. In 28 days later, it is suggested that the disease comes from a lab animal. Truth be told, it is unlikely considering the safety protocols, and moreover it has been proven that intensification of agriculture is responsible of the zoonoses problem, at least partly.
In other cases, the origin of the virus or bacteria causing the zombie “illness” may be unknown. This is the case in I am Legend. Technically, it is more about vampires than zombies, but its structure is so akin to one of a zombie novel. The world is completely overwhelmed with undead creatures and there is a lone survivor amidst the chaos of it all: Robert Neville. Robert tries to find a cure, he tries again and again, loses hope more than once. One would have told me this book was a lablit book, I would have believed him.
Slowly, Robert tries to uncover what happened around him. Vampires do not exist: that much he knows. Why are they around him then? The scientific adventure is great, breathtaking. At first, Robert thinks the mosquitoes could have transmitted the disease from blood to blood. A fair assumption, after all, chikungunya is a good example of mosquitoes transmitting a disease. They could do it with vampirism, right? Or maybe not, since the spread of the disease was so fast. How then did this vampire apocalypse happened? The “sand” storms! Robert discovers that vampirism is caused by a bacteria able to sporulate. When the body of a vampire is destroyed, it sends spores from the bacteria flying around, and there you have it! The spores fly with the wind, causing a spore storm (not sand, spore), until they find a new host… Simple. Efficient. Deadly.
There are many discoveries that I could spoil, but I think it is better to leave some mysteries around Robert Neville and his search for a cure… Just know that R. Matheson found a plausible scientific explanation for everything (and I do mean everything), and that is something I admire. Before I leave his work behind, I will just cite this part of his book:
“No, I should think it over carefully, he thought, I should collect all the questions before I try to answer them. Things should be done the right way, the scientific way.“
One thing I found while hunting for bacterias that could have a link with the Bacillus Vampiris from I am Legend is this. An article about blood seeking behaviour in ticks and how bacteria can affect it. Actually, it is much more common than one could think! Bacteria, fungi, parasites… there are many examples of small organisms that alter the behaviour of their hosts. One of the most known is Toxoplasma Gondii, a single cell organism able to modify rodent behaviour so that they feel less fear. Hence they stay longer in front of a cat and the cat eats them, which is important for Toxoplasma Gondii as it can only reproduce in cat intestines.
So why am I telling you all of this about parasites and how they may affect an animal’s behaviour? Well, because this comes to one of the most unique interpretation of what a zombie is: The Last of Us.
The Last of Us is a game in which zombies are the result of a fungi infection. The fungi is heavily inspired by the so-called “zombie-ant fungus”: Ophiocordyceps Unilateralis. This fungus is able to modify the behaviour of some ants. I will not go into all the details about this fungi, but it forces ants to climb trees and die as far up as they can, clenching their teeth onto tree bark. It seems as if O. Unilateralis takes full control of them! So now, imagine this fungi, but with humans… You now have clickers.
Apart from this specific interpretation of the zombie, The Last of Us is great to comment on the development of a cure and how the devil is in the details. I now have to warn that heavy spoilers are ahead.
Someone in this game is immune to the Cordyceps. They cannot become a zombie. Of course, studying their immunity is a great way to find a vaccine. A cure would be nicer, turning infected back to humans, however it is impossible as the fungi develops around the brain and breaks the skull of the infected person open at some point. A vaccine will have to do.
Now, hear me out. That immune person has a mutated cordyceps attached to their brain, this is the reason they are immune. They arrive in a hospital and first thing (not even a day has passed) the doctor ask is to kill them to extract the cordyceps! But moments ago, the exact same doctor said on a tape recorder that they verified the mutation thanks to cell culture, and actually it is possible to cultivate fungi from the cordyceps family. Why not investigate longer the fungi culture then? After all, it has the mutation! Killing the immune person is also killing the only immune person. This choice, from a scientific perspective, is pointless and not justified as a mutated fungi culture represents years and years of experiments, far from the mere duration of a single day.
I love this plot point as a narrative tool… but I cannot accept it, as my scientific mind rages against it.
What can we take away from all of this? That a bit of scientific truth (or extrapolation) behind your zombies can sometimes create creatures that are more believable and more original at the same time. Where does your infectious agent come from? How does it reproduce? Spores? Feasting on a rotting corpse? Science is full of options and writing fiction within its frame both lead to creative thinking and educational stories.