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I'm wondering where the infection causing peoples to turn into zombies start from?

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I'm assuming that you are talking about the TV Show, but to be clear, you should probably formally state if you are asking about the TV Show or comics. The show is based on the comics, but has diverged greatly already. – spong Feb 17 '12 at 18:30
@sunpech does this retag do the job? – DavRob60 Feb 17 '12 at 18:33
Yup, looks good. :) – spong Feb 17 '12 at 18:35
Must be a Sumatran Rat Monkey. – Jeff Feb 17 '12 at 20:29
In the TV series there hasn't been an explanation so far. This is easily found by, you know, actually watching the series ;) (painful, I know, what with all the soap opera drama) – Andres F. Feb 17 '12 at 20:39
up vote 11 down vote accepted

The cause of the outbreak is not known. It has been made fairly clear that the initial source of the virus is not currently something that either the comic or the show are planned to address, as this quote from an interview with show producer Glen Mazzara indicates:

Will determining the cause of the outbreak be something that the group, now that they know they're all infected, spends time on?

Mazzara: Robert has not been interested in addressing in the comic book, and I'm not interested in addressing in the show. That being said, if it leads to new story -- if there's something that's important that we get out of it -- I'll be the first one to write it. But right now the cause of the zombie outbreak seems irrelevant. I always want the show to play like a horror movie every week. If you define what caused the outbreak, that puts us in a world of science fiction, and this isn't science fiction to me, it's horror. In my mind that's two different genres, so that is an important distinction to me.

All we really know about the virus is:

  • Everyone has it

  • It remains dormant in the brain

  • Sometime (anywhere from a few minutes to several hours) after the moment of death, the virus activates, and reanimates the body

We can also speculate that humans are likely the only animals that the virus infects.

All we can really infer from this is that the virus is likely airborne, due to how widespread the infection is.

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"Not science fiction"? I guess we have to close this question for being off-topic now. – Rogue Jedi Apr 18 at 1:16

"No explanation is offered for this behavior -- indeed, what explanation would suffice?" -- Roger Ebert

Logically there must have been a start to it, a Patient Zero, but that start wasn't revealed to us. The characters don't know how it started. Even Dr. Jenner of the CDC, who watched the progression of the contagion from the first reports, and had every possible research tool at his disposal, had no idea what it was and didn't seem to know where it really began.

This follows the real-life pattern of diseases like AIDS and Ebola. We can study them right down to their molecules, we can trace them back to a few square miles in Africa, but that might be as far as we ever get.

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Actually, there is no need for a patient zero in the usual sense. Since the virus manifests itself only upon death, If the virus was produced by mutation in a very young person, and that person lived another 90 years spreading the virus, the first zombie could be observed in a person infected long after the original virus developed and started to spread.. – WhatRoughBeast Apr 18 at 0:53
@WhatRoughBeast: I wrote my Answer before seeing the Reveal that everyone has the condition (and is asymptomatic). So now for all we know it might not even be a contagion at all. – Beta Apr 18 at 1:31

Not sure if it helps, the io9 article Everything you need to know about The Walking Dead explain why it has never been revealed.

What causes the zombie uprising in The Walking Dead?

In the comic, it's not entirely clear, and it's kind of a moot point anyway. Kirkman's said that he'll never reveal the origins of the undead uprising. Furthermore, it's just not the series' foremost concern. The main characters aren't super-sexy undead researchers. They're average schmos with average lives, and — barring one or two seemingly unkillable characters — they die extremely easily. The series is about staying alive (i.e. finding food, ammunition, and shelter; not going insane). We have yet to see whether the TV show will address the zombies' origins.

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In the webisodes a terrorist attack was mentioned. At the end of series 2 it was revealed that everyone is infected and they will reanimate after death. There would have been a further explanation to the outbreak in a planned webisode. Remember, in series 1 when Rick jumps in the tank and there is a walker in there? Well this was to be the ending of the planned webisode. The walker was a US Army Ranger in Atlanta trying to evacuate the population during the outbreak but the city was overrun. This webisode was shelved due to budgeting issues. It is a shame because it would have given us a picture of what happened prior to Rick waking from his coma at the hospital.

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In the comics, and I am just assuming the show, it is an infection. It is not believed to be air-born but basically everyone has it. You fall down stairs and break your neck, you're a zombie.

Quote from Robert Kirkman:

The rule is: WHATEVER it is that causes the zombies, is something everyone already has. If you stub your toe, get an infection and die, you turn into a zombie, UNLESS your brain is damaged. If someone shoots you in the head and you die, you're dead. A zombie bite kills you because of infection, or blood loss, not because of the zombie "virus."

He has also said he won't reveal the cause in the comics so we will have to wait to see on the TV show but I wouldn't hold your breath. I guess it is up to the viewers own imagination.

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The OP isn't asking how people turn into zombies (which your reply explains), but how the infection started. – Andres F. Apr 5 '13 at 17:18
Well then this is basically an unanswerable question since Robert Kirkman has said he won't reveal it in the comics so I take it they won't reveal it in the show. – c8irish Apr 5 '13 at 17:22
I agree with you: it's unanswerable. So that must be the "answer" to this question, with a quote from Kirkman :) (I've reverted my downvote after your last edit, btw) – Andres F. Apr 5 '13 at 17:22

There can be many explanations for the outbreak of the infection:

  • It broke out as a common virus and became a global epidemic in the few months that Rick was in coma for. As in the first season The CDC was working on it, this shows maybe that it started as a virus.

  • It started off as a terrorist attack as in the Comics.

  • It started off like in "Resident Evil" i.e. by mistake maybe, there is no proof for this, but it is just a possibility.

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Nothing in the comics suggests that the outbreak began with a terrorist attack. We know nothing about how it began in the comics, and on the show, we only know a tiny bit more than we do in the comics – Wad Cheber May 12 '15 at 21:22

You have the simplest answer in the previous responses - basically, "We don't know how it started". As to that specific point, I can only add a little: This summer, a new spinoff series will begin airing on AMC - "Fear the Walking Dead"; it will cover the early days of the outbreak, and will be set in southern California (specifically L.A., if I'm not mistaken). This series will be consistent with the theme of the main show and the comic books, but will cover new ground not addressed by any other The Walking Dead media. I doubt you'll get a straight answer as to what caused the outbreak (Jenner at the CDC didn't know how it started, so chances are, no one in "Fear.." will know either.

But my main reason for answering your question is that no one addressed WHY Robert Kirkman (creator of the comic book series and Executive Producer of the show) and the show's writers and producers don't tell us about the origins of the outbreak. Kirkman wants TWD to feel authentic to the audience. In his view - and mine - if the events of TWD happened in real life, and the world fell apart within a matter of weeks, ordinary people like the members of Rick's group would have no way of knowing how or why the outbreak began, and frankly, it wouldn't matter much anyway.

They Wouldn't Know

There are no newspapers anymore. No TV. No internet. No telephones. No radios. Information can only travel by word of mouth in the post-apocalyptic world. The people best suited to discover how and why the outbreak began - doctors and epidemiologists - were among the first to die. When the outbreak began, people who had been bitten went to the hospitals; then they died, turned, and quickly overran the hospitals. Doctors and nurses were in the greatest danger, and few survived the initial stages of the epidemic. Epidemiologists like Jenner were safer than hospital staff, but some were bitten, some lost hope and killed themselves ("they... opted out", in Jenner's words), and as the world outside fell apart, many went home to be with their families. Soon, even those who kept working were unable to continue, because the infrastructure began to fail - they lost contact with the outside world, the water stopped running, and eventually, the power went out for good. As Jenner said, the scientists just didn't have enough time to figure out what was causing the problem, let alone how to fix it. And even what little they did know was impossible to share with anyone outside their own facilities, because the means of communication were breaking down

It Wouldn't Matter Anyway

How would knowing how and why the outbreak began help people like Rick's group? It wouldn't. All they need to know is that the world has ended, strangers can't be trusted, walking corpses are everywhere trying to eat people, and you can kill them by destroying the brain. That would be true whether the outbreak was caused by a virus, or bacteria, or a fungus, or radiation, or magic, or aliens, or an act of god. They might wonder about it in their rare moments of peace and safety, but having the answer wouldn't change anything. They are desperate people fighting to survive a living hell. Knowing how the outbreak happened would be as useless to them as a man whose ship just sank in the middle of the ocean knowing that the life preserver keeping him afloat was made in Philadelphia.

If You Were In Their Shoes, You Wouldn't Know Or Care Either

Kirkman wants TWD to feel real. The closest the TV show came to explaining the outbreak was the last episode of season 1, when the group went to the CDC and got a tiny bit of information. This actually never happened in the comics, and this is one of many cases where the comics beat the show. The CDC episode seems unrealistic and artificial, because the odds of a random group of people getting there, being allowed in, and finding the last man standing is ridiculously small. In the comics, we know even less than we do on the show, and we know almost nothing on the show.

Picture yourself in the group's situation - you hear weird stories about people biting each other. Then you see it happen. Someone says the biters are actually dead p̤eople, which is too stupid to believe. Then someone you know is bitten, dies, and attacks you. The government tells you to stay home. Two days have passed. The next day, you phone goes dead. The government tells you to get to a big city. You try, but you're sitting in traffic when the government broadcasts stop; you see planes dropping napalm on the city ahead. You go back home. A week has gone by. The power gets shut off. No news of any kind is available now. Someone starts pounding on your door. You hear gunfire nearby. The shooting stops. You hear moans, then screaming, then more moaning. You look out the window - three zombies are eating your neighbor. You bolt out the door, hop in your car, and head for the countryside. The few radio stations that are still broadcasting are all playing a looped message telling people to lock their doors and wait for military assistance. Every town you pass through looks worse than the last - burning buildings, corpses in the streets, roads blocked by abandoned and crashed vehicles, looters, zombies, fire, blood, death - the world is falling apart before your eyes. You reach a campsite with people who seem to be decent enough, and fight off frequent zombie attacks together. No one knows more than you do - there are different variations of the same rumors about safe places far away, but deep down, you know they are all wishful thinking - nowhere is safe anymore.

So, now that you've imagined all of this, what part of the story makes you think you'd know how, why, and where the outbreak began? What part of the story makes you think you'd even care, when you're so busy worrying about when the next attack will happen, how you're going to get food and water, when a herd too big to fight off is going to show up, how long it will take for the people in your group to turn on each other, and when armed raiders will storm your camp, rape and murder everyone in it, and steal everything in sight?

This was Kirkman's reasoning when he decided that we shouldn't learn anything specific about the origins of the outbreak. I actually read an interview where he said so (in a much more condensed form than my rambling account, of course). I'll try to find the article and post a link here, but it was 5 years ago and I doubt I'll be able to find it.

Edit: I didn't find the article, but I found something close on the TWD wiki.

Cause of the Zombie outbreak and government collapse

Kirkman said that going back to explain how the government originally collapsed, "...doesn't interest me, for the time being...I may change my mind eventually." As to the cause of the zombie outbreak, Kirkman wrote, "I have ideas [about the cause of the zombie plague]...but it's nothing set in stone because I never plan on writing it. So yes...I do know...kind of."

In response to a question:

"I think you should elaborate more on how people can turn into zombies without one biting you, or how this whole mess started in the first place. Was it like a plague or a rapture kind of thing?"

Kirkman responded:

"...That starts to get into the origin of all this stuff, and I think that's unimportant to the series itself. There will be smaller answers as things progress...but never will we see the whole picture."

There have been instances throughout the series where the characters theorize about the origins and cause of the undead or converse about their observations of them over time. The characters have acknowledged and discussed the lack of undead mobility and presence during the Winter months, and Eugene has specifically discussed the physical deterioration of a zombie clawing at Rosita. Most recently, Heath encountered an undead with blackened skin and a weaker will to attack.

Fear The Walking Dead will be a prequel to the television series, taking place during the start of the zombie apocalypse and showing attempts to control it. The origins of it will be explored in the series.

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In the TV series, they differ greatly from the comic book series, in the TV series the infection is more closely and probably intentionally styled after the Solanum Virus from "The Zombie Survival Guide" and "World War Z". The difference being is that with the Solanum Virus or with the Walking Dead, everyone is already infected. But bites cause a lethal infection that kills you, and then you are reanimated. How this started is a little sketchy, I imagine the virus that everyone was already infected with mutated and when someone died they came back.. this is probably why infections started out in multiple locations and there is no true "patient zero"

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If everyone had the virus before it mutated, then not everyone would have the virus causing the reanimation. – phantom42 Jul 16 '12 at 20:18
They are one in the same virus, Phantom42. The virus causing reanimation was already present in nature, and had to have mutated somehow. This is why people start coming back from the dead. This is also why people are coming back even though they have not been injured by one of the walkers. The zombie bite doesn't actually cause the spread of the virus, it just causes a lethal infection that kills. This is why in the comics and such it can be stopped by amputating the affected limb quickly after it has been bitten. – Aron Jul 17 '12 at 22:58
The virus causing the reanimation may have already existed, but the mutation had to have occurred BEFORE everyone was infected. Once it is present in everyone, a newly mutated virus in one organism is not going to suddenly propagate the changes to all other existing copies of it within other organisms. That said, the virus could have existed with some sort of dormant mutation which was triggered/activated by some sort of catalyst (think of comic mutant powers first exhibiting due to adrenaline). – phantom42 Jul 18 '12 at 12:39
Can you give an example of someone in "The Walking Dead" (TV) being reanimated without having been in contact with a walker? – Beta Aug 2 '12 at 14:15
@AndresF.: you have the advantage of me; I've seen only season 1 so far. – Beta Sep 17 '12 at 19:26

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