Some of the forever asked and never answered questions in the Walking Dead universe are: How did this happen?  Where did the Walker virus come from? (and) What is it, exactly?  Because these questions remain unanswered there’s plenty of opportunity to speculate by fans and it seems every other person out there has a theory.  As a fan I am no different…what probably is different is my theory.  My own personal theory about the Walker virus has to do with herpes.

Yes, herpes.  Not the STD or coldsore-causing herpes most immediately think of, but the herpesvirus family as a whole.  There are many different species within that family and certain ones in particular share surprising similarities to what is already known about the Walker virus.  The one that seems to share the most – and most important – connections is the Varicella-Zoster virus; comparisons can be made in both viruses’ overall communicability, latency, and reactivation.

Overall communicability

The first part of the name Varicella-Zoster refers to the first disease that the virus causes, which is better known as chickenpox.  You know, the (typically) kid’s disease with the itchy rash that can cover the whole body and drive a person nuts?  The disease that can spread like wildfire throughout classrooms and neighborhoods of the unvaccinated before the first kid even has those infamous bumps?  Yeah, that chickenpox.  Now there are likely three reasons it’s transmitted so easily: first, it is airborne through the mouth and virus-filled bumps (vesicles) of the rash, second, it can last a few hours or even a day or two outside a host, and third, a person remains contagious from 1-2 days before the rash appears until all those vesicles are scabbed over.

Given how quickly the Walker virus seemed to spread to the point that everyone had it, it’s not a stretch to consider this virus being airborne as well.  In fact, it’s really the only option that makes sense.  One cough from one infected person could easily infect hundreds and from those hundreds, thousands could be infected, and so on.  Generally speaking, if it’s airborne a virus can also be spread via skin contact, sexual contact, and any other exchange of fluids including/especially any containing said virus.  With all these modes of transmission going on and no one knowing the Walker virus even exists in the beginning a fast-spreading pandemic is practically a foregone conclusion.

Most viruses don’t last long outside a host body, yet the Varicella-Zoster virus can last up to two days; this spells trouble for the unvaccinated.  Picking up the toy of an infected child a day later could mean picking up the virus without ever having seen the risk coming.  If the Walker virus lasted the same amount of time it’d be just as contagious; if it lasted longer, if the virus could survive without a host for days or weeks, then it’d become exponentially contagious.  It would also explain why even those living out on a farm mainly removed from the rest of society (like the Greene family) might have it…all they’d need to do is grab a feedbag previously touched by an infected and they’d pick up the virus to spread to the rest of the farm.

As mentioned a person infected with chickenpox is contagious before their rash even appears, which makes spotting (and then avoiding) them more difficult.  If the Walker virus is initially without obvious signs and/or symptoms as well then, again, the communicability is heightened.  How can you avoid infected people if they don’t even know they are infected?  That being said there should be some indication that a virus has entered the body eventually, even with the Walker virus, so…what might be the first signs and symptoms of it?  It’d be easy to say turning into a Walker is the first sign/symptom, but I honestly doubt that that is the initial (and thus only) indication.  It makes far more sense that the virus is dismissed as some other illness because the signs and symptoms are too common and fleeting to disrupt and cause worry for the infected individual.  (“I think I caught a cold, no biggie.”  “I knew I should’ve gotten my flu shot.”  “I think we need to switch detergents, this one’s giving me a rash.” … “Never mind, I guess it resolved itself.”)

Now you have a highly contagious Walker virus with initial signs and/or symptoms that potentially go unnoticed or disregarded…but why all that time between initial infection and when Walkers appear?


Herpes comes from the Greek word herpein, meaning “to creep”, which refers to the latent, recurring, diseases the members of this virus family are known to cause.  The length and number of latency periods varies depending on species, but again I feel the Varicella-Zoster virus is most comparable to what’s possibly occurring with the Walker virus.

In the time after the Varicella (chickenpox) aspect and before the Zoster (shingles, to be discussed later) aspect of the Varicella-Zoster virus there is a period of dormancy.  The virus is still in the body, but now inactive as it gathers in the nerves cells based somewhere along the Central Nervous System.  During the latency period there are no signs or symptoms, the virus is not contagious, and is often forgotten about by even those infected with it.  Forgotten because the latency period is often decades long.  Frequently the virus remains dormant for 50+ years, which in some people can be almost their entire lifetime.  Long enough to forget the virus remains inside your body, long enough to not make the connection between the chickenpox you had at seven and the shingles now appearing at sixty.

It would be easy to not see the Walkers coming (so to speak) if the virus causing it had a latency period as long as the Varicella-Zoster virus.  Looking at things closely and speaking more accurately though, it’s most likely that the Walker virus has a latency period that’s actually longer.  Longer than that of the Varicella-Zoster virus and longer than a lifetime.  Considering no one is ever shown turning into a Walker pre-death it is logical to presume that it is a person’s actual death that triggers the virus’s reactivation.  With that long of a latency period it’d certainly be understandable if no one was able to make the connection to whatever happens when the Walker virus first enters the body and someone turning into a Walker at the end of their life.

But what, if any, similarities do the Walker virus and Varicella-Zoster virus have when reactivated?


How the Varicella-Zoster virus is reactivated is still something of a mystery; there are any of a number of triggers for reactivation, and sometimes none at all.  Known reasons all seem to involve a compromised immune system due to things like: old age, other illnesses (from colds to cancers), immunosuppressive therapy, and/or stress.  Whatever the trigger is the disease that appears as a result is always Herpes Zoster, better known as shingles.

Shingles is a different disease from chickenpox even though they are caused by the same virus.  Chickenpox involves a rash of incredibly itchy, virus-filled, bumps that are spread throughout the body.  Shingles involves a rash of incredibly painful, virus-filled, bumps that are focused in a horizontal strip on only one side based from the center of the body outwards.  Varicella is spread throughout the cells of the body; Zoster is concentrated in sensory nerve cells gathered in a bundle whose base is at the spine or brain.  Two very different diseases with two distinct presentations both coming from the same exact virus.

The Walker virus might similarly be a virus that causes one disease to start and then a completely different one post-reactivation.  This would further explain why no one’s figured out where the Walkers or the virus itself came from.  It’d be rather difficult to make a proper connection with a virus that enters someone’s body early in their life causing a minor illness and a disease that reanimates their corpse after their death.  With two separate presentations of the same virus it’d be somewhat logical to dismiss a possible connection at the beginning of the outbreak and, by the time the zombie apocalypse is in full swing, it’s too late to properly study a connection at all.

Of course there is also something else that the Walker and reactivated Varicella-Zoster virus have in common and that’s where the infection occurs.  The Herpes Zoster rash occurs where it does because the virus has housed itself in nerve cells attached somewhere along the Central Nervous System.  After the initial chickenpox infection the virus goes dormant, hiding out along nerves, where it will cause painful inflammation when reactivated.  Likewise the Walker virus is shown to focus on the Central Nervous System – specifically the brain stem or “lizard brain” – and causes inflammation the CDC’s Dr Jenner from The Walking Dead episode “TS-19” says is comparable to meningitis (something certain herpes viruses, including Varicella-Zoster, can cause).

There is, of course, no virus that is precisely like the Walker virus.  Perhaps it’s a virus that evolved naturally from one in the herpesvirus family (viruses are known to evolve over time just like any other organism) or a mixture of a number of various virus families created in some lab that was released?  Something tells me that the writers of the shows and comics will never fully explain the mysteries surrounding the virus, but that’s part of what makes the Walking Dead verse fun.  People can develop their own theories about the Walker virus, what it is, and where it came from.  One can find connections to the real world or even other fandoms.  They can imagine a mixture and/or evolution of known viruses, or some recently uncovered giant virus that (unlike past ones) is dangerously infectious to humans, or some totally new virus forming or being made, or they can imagine something else entirely.  The possibilities are as endless as the theories and all of them might have merit.

Do you have a theory on the Walker virus?  What is it?