A zombie apocalypse could never actually happen...could it?

For some reason, the idea of the living dead has fascinated humanity and we love to imagine bizarre scenarios where zombies take over the world.

In the past few decades, with the creation of popular TV shows such as 'The Walking Dead' or films like '28 Days Later' or 'Zombieland,' zombies have gained in popularity.

However, perhaps we enjoy the idea of zombies so much because deep down, we know that there is no such thing as zombies...or is there? Could a zombie apocalypse actually happen?

But before we delve into whether or not zombies are real or not let's take a look at the history of the undead.

According to History.com, the first civilization to be worried about the living dead may have been the Ancient Greeks.

Archaeologists discovered Ancient Greek graves containing human skeletons weighed down with heavy objects and rocks in what some believe was an attempt to keep the dead underground.

Later, in Haiti's 17th and 18th centuries, according to History.com, the concept of zombies really began to take its modern shape.

When hundreds of enslaved people were taken by the French from Africa to Saint-Domingue, present-day Haiti, deaths among the enslaved were extremely high.

The horrendous conditions led to the belief among slaves that once they died, they would return back to life and live free in Africa once again.

However, over time this concept changed, and the legends evolved into the practice of voodoo. Many believed that a voodoo practitioner known as a bokor could raise the dead and even bewitch the undead to perform evil tasks. In fact, the modern word for zombie originates from the Kongo word nzambi, which means "spirit of a dead person."

Generally, stories about the living dead were mainly found in Haiti. However, after the first film on the subject 'White Zombie' in 1932 and then the cult classic 'Night of the Living Dead,' the idea of zombies found an important place in pop culture around the world.

Suppose you are a fan of the zombie genre, surely more than once, you've thought about the zombie apocalypse and if such a scenario could actually happen.

Could a person shuffle around in a catatonic state solely focused on food? Well, believe it or not, yes! But certainly, not a person who had passed away, but several diseases exist that leave patients with zombie-like traits.

Neuropathologist at Boston University Peter Cummings is also an advisor to the Zombie Research Society. Cummings says that Klüver-Bucy syndrome is one of the diseases out there, that if the average person saw someone afflicted with it, they would think the zombie apocalypse is about to start.

In an interview with Global News, Cummings spoke about the syndrome saying, "That has a whole bunch of weird stuff, there's hyperorality [the desire to put inappropriate objects in your mouth], the inability to recognize objects, distractibility and dementia … in their catatonic state, they can become quite violent."

Cummings also spoke of another infrequent condition that causes patients to act like zombies: encephalitis lethargica. According to Global News, Cummings said an outbreak of this condition occurred in 1918 in connection with the Spanish Flu epidemic. Patients suffering from the disease had hallucinations, entered into a stupor, and eventually became catatonic.

However, Cummings said if the patients were stimulated, for example, some tapped them on the shoulder, those with encephalitis lethargica would snap out of their catatonic state and go "berserk."

Add in the shuffling gait and motor defects the patients suffered, and the symptoms made the patients seem like how we imagined the undead would act. Cummings told Global News, "There are real things out there that affect the brain to alter behavior where you do socially unacceptable things," he said.

Some experts out there believe that it will be viruses that could turn humans into zombies. Dr. Ben Neuman, a professor of virology at the University of Reading, is one of them. Dr. Neuman told Yahoo, "There are parasites out there that get close to making actual walking around zombies."

Dr. Neuman continued, "But the real weirdoes locked up in Mother Nature's basement are the viruses. There are more viruses out there than we will probably ever discover, and I bet that somewhere out there in nature, something like this is happening."

Dr. Neuman then went on to say that rabies is a good example of a common disease that causes zombie-like behavior, saying, "If you look at rabies, it completely changes the way a dog behaves. It's transmitted by bites, it leads to madness, convulsions, and so it's not really that far-fetched."

Another cause of zombie behavior is toxins. According to Harvard Health Publishing, ethnobotanist Wade Davis of Harvard University discovered a medical explanation for "zombie-like living deaths" in the country of Haiti in the 1980s.

Davis found that a neurotoxin found in pufferfish and other animals "created the appearance of death," but the effect was only temporary. Pictured: Two Haitian "zombies." Clairvius Narcisse and Francina aka Ti Femme both were declared dead and buried but then returned home again several year later, alive and well.

An article in Harvard Health Publishing states that "to launch any type of (zombie) apocalyptic scenario, there must be an infective agent and an efficient route of transmission." So toxins alone and the diseases discussed here are not contagious enough to cause a zombie apocalypse.

However, Harvard Health Publishing stated that there is one agent that could cause something close to zombieism: prions. The article states, "Prions are oddly shaped proteins that cause abnormal folding of proteins in the brain. Essentially, they turn the brain's centers of higher thought into spongy mush."

Photo: By Tulemo - Wikimedia Commons

Prions cause the disease known as kuru, which became famous when a cannibalistic tribe known as the Fore People in New Guinea became infected with it. The members of the tribe contracted the disease because they were eating human brains.

The symptoms of kuru include: poor coordination, personality changes, loss of speech, and open sores. All of which sounds an awful lot like a zombie. However, if a zombie apocalypse of this nature were to occur, humans would have to develop a taste for brains BEFORE becoming infected with kuru.

Actual human zombies most likely don't exist unless they are holed up in some hidden corner of the Earth yet to be discovered. However, scientists and doctors cannot entirely rule out a pandemic that causes those infected to display zombie-like symptoms.

Dr. Steven Schlozman, a zombie enthusiast and professor of psychiatry at Harvard Medical School, told Harvard Health Publishing that "a real-life zombie apocalypse shouldn't be high up on our list of worries." Dr. Schlozman continued, "What I always say is we're humans, so we have plenty of ways to do ourselves in without zombies."