In movies and TV, pandemics are pretty scary
things. That’s because, they are. The only
way to make them scarier... 
Zombies.
Now The Walking Dead is arguably the most
popular zombie story of our generation. Most
of the story is centered around infection
and how people get bit by zombies so I thought
it’d be fun if we figured out…
How the virus works.
First let’s start with what we know.
Well, from the end of Season 1 when they all
venture to the CDC, the Centers for Disease
Control and Prevention in Atlanta, we know
that Rick and the gang figured out that Zombie
Virus is indeed a virus and everybody has
it. No matter how you die, you come back.
Unless your brain is destroyed.
Now is there anything in the real-world that
even comes close to this? Well there are a
number of parasites, that after infecting
their hosts they effectively mind-control
them. In the popular video game The Last of
Us, there’s a genus of fungus called cordyceps
which infects ants, mind controls them and
bursts forth from the backs of their heads
to infect more unfortunate hosts.
There’s even another parasite called toxoplasma
gondii that affects an estimated
one third of the human population.
To complete its life cycle, it gets into the
bodies of rats, mind controls them so that they’re
no longer fearful of the smell of cat urine,
which makes them get eaten more often by cats.
The parasite then reproduces in the bodies
of cats and eventually infects us. Now, is
that a form of mind control? I think it is.
But knowing what we do from the real world,
The Walking Dead virus doesn’t exactly control
a living host, and the chief concern is getting
bit by a zombie and getting infected. Now
in reality, dying from a virus that you already
have doesn’t really make sense. When you
already have a virus but it’s not affecting
you, that’s called a reservoir.
For example, we think that bats are a reservoir
for the deadly Ebola virus. That means that
Ebola is definitely coursing through their
veins, but they don’t die from it. Similarly,
it’d be odd if getting bit by a zombie that
has the zombie virus would kill you with that
virus if everyone already had it.
So if all of humanity is already a reservoir
for the virus in The Walking Dead, it has
to be something else that makes the bite so
deadly. I think it has something to do with
the bacteria in their mouths.
In a world where nothing works, it would be
nearly impossible to get anything like proper
medical care--bandages, antibiotics, medications--even if you had your own octogenarian veterinarian
on hand. So what in real life kills with a
dirty mouth?
Well, famously, the giant lizard called komodo
dragons have enough bacteria in their—wait,
wait a second, that’s not quite right. New
research has actually come out showing that
komodo dragons do kill with venom found in
the glands of their mouth. So we’re gonna
have to think of something a little bit different
for that. How about, natural disaster victims?
Unfortunately we know when we pick up dead
bodies from natural disasters that they can
harbor sometimes deadly bacteria and viruses
like tuberculosis and even Ebola. If we consider
a dead and decaying body to have some of that
bacteria and virus in their mouth, it stands
to reason that if you got chomped on in the
arm or the neck and it went straight to your
bloodstream that would almost be a death sentence.
Sorry about that leg, Hershel.
So, what do we know? Well although there are
real world parasites that zombify their hosts,
this isn’t quite what The Walking Dead had
in mind when it created its own zombie virus.
That’s not quite how viruses work. However,
we can guess at what really kills you in The
Walking Dead: and it seems to be a dead, diseased,
decaying mouth chomping down on you, and not
having access to the right medical care or
supplies to treat it. Why? Because Science.
Eughhh brains agghhh!
