This is the final part of our exploration of the culture, science and mythology of zombies. Find Part 1 and Part 2 here.

While the majority of people have long believed that zombies are nothing more than myths and sci-fi, it’s time to look at the possibility that a zombie apocalypse is actually scientifically plausible.

By Katerina Flynn: @katerinaflynn1 | Image by Nathan Wright on Unsplash

When they think of zombies, most people imagine flesh-eating, mind-controlled corpses raised from the dead. But behind the supernatural zombies of pop culture, there are viruses which cause symptoms closer to our idea of zombies than you might think. And with the relentless pace of scientific development, progress is even being made in  experimenting with reanimating corpses. So how do “zombie” viruses affect us, and are we standing on the precipice of one of humankind’s longest held dreams – bringing the dead back to life?

The Viruses that Control Minds

Zombies of fiction often spread the infection through a nasty bite, and the Carpenter ants of the Amazon or Thai rainforests fix themselves to fungus of the genus Ophiocordyceps in a similar way. Sometimes, they grip on with their jaws in a deathlock. They then die with that horrifying clench intact.

Once infected, the zombified ant will mindlessly crawl to a specific type of location determined by the species of fungus to which it has fallen victim. Perhaps the most famous fungus, Ophiocordyceps unilateralis, prompts its hosts to end their days perched under a leaf. Those that have succumbed to Ophiocordyceps australis, meanwhile, will die in the forest litter below. It is also known that, once “zombified”, muscular tissue in the ants gradually breaks down.

These real-life zombies now influence the zombies in stories. As they have become better known, cordyceps fungi have inspired modern tales about the undead. For instance, in M R Carey’s novel, The Girl With All the Gifts, and in the video game The Last of Us, human victims fall victim to a fungal parasite, not a zombie virus.

If a zombie is an organism whose behaviour has been drastically modified in order to benefit its parasite, then another bizarre example can be found in the Japanese tree frogs of South Korea.

The amphibians may essentially have been turned into “sex zombies”

Batrachochytrium dendrobatidis is a fungus that is a well-known threat to many frog species, but Japanese tree frogs in Asia do not seem to be dying off so suddenly when a population is infected. When researchers listened to the mating calls of 42 male tree frogs, they realised that the nine that were infected with Batrachochytrium dendrobatidis had calls that were faster and longer – making them more attractive to potential mates.

The amphibians may essentially have been turned into “sex zombies”

Fortunately for us, there isn’t going to be a zombie outbreak from any of these infections. Now that we’ve looked at some of the ‘’zombie like’’ diseases that infect animals, what about the equally dangerous viruses and diseases that infect humans. ‘’It is fortunate that none of these diseases can cross the species barrier or we’d be in trouble,’’ says infectious disease specialist Tara Smith, a researcher at Kent State University’s Emerging Infections Laboratory.

However, some diseases that are known to infect humans could lead to zombie-like effects. Rabies is a rare but very serious infection of the brain and nerves. It’s usually caught from the bite or scratch of an infected animal, most often a dog. Rabies is found throughout the world, particularly in Asia, Africa, and Central and South America. It’s not found in the UK except in a small number of wild bats. It’s almost always fatal once symptoms appear, but treatment before this is very effective. There’s also a vaccine for people at risk of being infected.

The symptoms of rabies usually develop after 3 to 12 weeks. The first symptoms can include: a high temperature of 38C or above, a headache, feeling anxious and discomfort at the site of the bite. Other symptoms appear a few days later, such as: confusion or aggressive behaviour seeing or hearing things. Producing lots of saliva or frothing at the mouth, muscle spasms, difficulty swallowing and breathing inability to move.

Once the second set of symptoms have appeared, death is almost always certain as the vaccine can only be given during the first stages of symptoms.

Of all the diseases out there that resemble a ‘zombie virus’, rabies is considered the one to  be the most dangerous, simply because if it mutated it could be passed from human to human. The aggression in this virus is more frightening than that in Trypanosoma Brucei and certainly the appearance of those infected with rabies is far more terrifying.

Fortunately, Smith believes that ‘’it is very unlikely that rabies would mutate, but you can never completely rule it out.’’

But what if it wasn’t a disease, but a condition which turned us into the walking dead? Necrosis, or premature cell death, has a lot of different possible causes, including cancer, poison, injury, and infection.If we’re being literal about what the walking dead really are, then a patient with necrotic tissue is the closest equivalent. After all, a patient suffering from necrosis technically is partially dead, albeit still very much alive in all the important areas (the brain, the heart, and the rest of the vital organs) that we generally associate with the living.

Necrosis triggers a series of event that can lead to even greater negative effects outside the affected area. The dead tissue stops sending signals to the nervous system, and necrotic cells can release dangerous chemicals that hurt nearby, still healthy cells.

This chain reaction can cause the necrosis to spread and can ultimately be fatal. The only way to cure the condition is through a process known as debridement. If the dead area is too large, this may require amputation. If there is any sort of bright side to all this – it’s that at least necrosis isn’t contagious, meaning it’s not the sort of thing that could spur a zombie outbreak. Of course, a sudden wave of hyper-aggressive, necrosis-spreading spiders or snakes? That might be another matter entirely.

Bringing The Dead Back To Life

Infectious disease only tells one part of the zombie story. Another key part of the folklore is the idea of raising the dead. And it may come as a surprise that there are life science companies out there who are attempting to do precisely that.

Bioquark, Inc. is a life sciences company developing proprietary combinatorial biologic products for both the regeneration and repair of human organs and tissues, as well as the reversion of a range of chronic degenerative diseases.

‘’Bioquark admits that it has never actually tested the regimen, even in animals.’’

In July 2019 they are planning to take 20 clinically brain dead and attempt to bring them back to life. Their idea is to reanimate parts of the upper spinal cord, where the lower brain stem is located, to potentially energize vital body functions like breathing and heartbeats.

Anyone who knows anything about modern zombie flicks would know that this is how they all start, with scientists messing with life and death, essentially playing God.

Trial participants will have been declared dead and kept alive solely through life support machines. “This represents the first trial of its kind and another step towards the eventual reversal of death in our lifetime,” said CEO of Bioquark Inc., Ira Pastor.

Whether the treatment will work is an entirely different matter. Bioquark admits that it has never actually tested the regimen, even in animals, and the various component treatments have never themselves been applied to brain death. They’ve shown some promise in cases like stroke, brain damage and comas but never actually Lazarus-ing a corpse.

“I think [someone reviving] would technically be a miracle,” Dr. Charles Cox, a pediatric surgeon at the University of Texas Health Science Center at Houston, told Stat News. “I think the pope would technically call that a miracle.”

Many are wary of the consequences of this procedure, and it seems like Bioquark haven’t really considered the risks. Looking at their website it’s evident that they haven’t looked at what the potential side effects this ‘’cure’’ could have.

Part of their research for this experiment is combining the DNA of animals that have the ability to regenerate serious injuries with that of humans. Assuming that they are successful and they can reverse brain death, what would the future hold for someone has animal DNA mixed in with their own? Could they live a normal life, would they be able to reproduce, what issues would their children have?

A modern zombie is defined as a person whose brain stem is alive but the rest of their brain, the parts with logic and emotion – the parts that make them human – isn’t. Have they thought about what would happen if their experiment only reanimates the base brain and not the rest?

There are too many worrying questions and given that their experiment is due to start in less than two months, will they be able to answer these questions before it’s too late?