- Dr. Tara Smith rates the realism of
viruses inzombie movies, how they spread and infect characters, and their cures. - Smith is an infectious disease epidemiologist at Kent State University College of Public Health.
- She looks at the realism of virus outbreaks in "Resident Evil" (2002), "World War Z" (2013), "Quarantine" (2008), "28 Days Later" (2002), "Z Nation" (2014-2018), "The Walking Dead" (2010-), "Zombieland" (2009) and more.
Following is a transcript of the
Tara Smith: In some cases, people do infect themselves.
Hi, I'm Tara Smith. I'm a professor of epidemiology at Kent State University in Ohio. I study infectious diseases and have long been interested in zombie infections. So, today, we'll be talking about zombies in movies and rating them for realism.
"The Walking Dead" (2010-)
Edwin: It invades the brain like meningitis. The adrenal glands hemorrhage. The brain goes into shutdown. Two hours, one minute.
Smith: So, this one is mixed. So, it does have an incubation period. It usually takes several days between the time that one is exposed to a virus and one develops symptoms.
Lori: It restarts the brain?
Edwin: No, just the brain stem.
Smith: Viruses can get into the brain. He mentions meningitis, which is actually about kind of the outside covering of the brain, and then you would say encephalitis when it actually goes into the deeper parts of the brain. So that can happen. There are viruses that cause those type of illnesses. But, you know, once you're dead, you're dead. And even if this reanimated the brain stem, that still wouldn't quite make sense because you wouldn't be able to walk. You could breathe, your heart would beat, but you wouldn't be actively going out, you know, shambling around. But that anyone who died would also become a zombie, even if they died in other mechanisms. So, that's a little less realistic. I mean, yellow fever is one that people can get very ill, be close to death, and then sometimes they come back and feel fine and then are dead the next day.
So it has what we call a biphasic illness. It has different phases. And, of course, back in the day, before people had stethoscopes and things like that, if you had somebody who, again, was very ill with some infection, you listen for a heartbeat or try to feel for a pulse. It might be very weak. It might not be detectable to the average person. And so there are lots of stories from outbreaks of the bubonic plague, outbreaks of cholera, and even also yellow fever and other types of infections where people have been taken out of their homes, put in the dead cart, going off to be hauled to the graveyard, and they wake up in the cart. You know, the human body decomposes rather quickly. So it starts out really from the inside that you have all these bacteria in your gut, in your mouth, on your skin, that, once you die, you become a big food source for them. So they're the ones that do a lot of the initial decomposing. And there's nothing about this particular virus that would stop that. They have these shamblers that have taken years and years that are still walking around after the outbreak, and they would all just be bones by that time. Something would have eaten them, whether it would be the bacteria that they carry or other rats or scavengers or something like that. Yeah, again, it gets a bump for the incubation period, but downgraded for the reanimation, so maybe a five.
Rating: 5/10
"Resident Evil" (2002)
I mean, as a lab scientist, [laughs] it makes me cringe. But you could see that the virus is liquid on the floor, and it would not be aerosolized like that. So, there would be maybe a little bit of a splash in the immediate vicinity, but there's nothing that is making that liquid become airborne.
But he's in the blue suit with the helmets and everything, so obviously this is a lab that studies things that are dangerous. You wouldn't have ventilation go into the rest of the building. What you would have would be filters in the ventilation system that have very small pores so they can trap even viruses from getting out of the building. And then that ventilation usually goes out to fresh air, so to outside rather than inside the building. So even if there was a few viral particles that made it out, they would be diluted when they made it outside to the fresh air and not a danger to anyone. That also would completely not happen, even in my laboratory. No food, no drink in the laboratory, anything at all.
[dog sniffing]
[dog barking]
There are some animals that have been trained to detect certain pathogens. So, not necessarily like how they are in, how they would be in the room air here, but sometimes dogs, or sometimes they've used pouched rats that can be trained to diagnose people who are infected, like, with tuberculosis, for example. So they're using more of the chemicals that humans put off when they're infected, rather than directly smelling, like, the tuberculosis bacterium. Yeah, this is about a one.
Rating: 1/10
"World War Z" (2013)
[laughs]
Doctor: He's gonna inject himself.
Segen: We have no idea which one's gonna work.
[zombie moaning]
[teeth chattering]
Smith: So, they had noticed previously in the movie that people who are sick are avoided by zombies. So Pitt is trying to inject himself with something to basically make the zombies ignore him and believe that he is sick so they don't want to bite him. Of course, we're not trying to hide from predators like this when we're ill, but there are examples where we can use microbes to kind of fight off each other. Back before antibiotics were common for treatment of infections, they actually used injection with malaria, a parasite that causes high fevers, as an attempt to treat syphilis, a bacterial infection, and that actually won a Nobel Prize in 1927. Today, we don't use it anymore because we do have antibiotics.
So, what we do use sometimes are viruses called bacteriophage that can actually kill bacteria that may be resistant to the drugs we have, but not quite in the way it's described in "World War Z." In some cases, people do infect themselves. Probably the most famous of those was Dr. Barry Marshall. He was an Australian scientist who won the Nobel Prize, again, for discovering that a bacterium called Helicobacter pylori causes, first, gastric ulcers. People didn't necessarily believe him, so he ended up swallowing a mixture of Helicobacter pylori himself and then treated himself with antibiotics.
Maybe about a three. [laughs] I think the book was much better as far as realism, but the movie took the concept and I think twisted it a little bit.
Rating: 3/10
"28 Days Later" (2002)
Scientist: The chimps are infected!
Activist: Infected with what?
Scientist: Rage.
[chimpanzees hollering]
[men screaming]
[chimps screaming]
[blood splatters]
Activist: [screams] Oh, my God!
[woman gagging]
[man screaming]
Smith: The incubation period is basically instantaneous. When blood goes all over, that is how some blood-borne diseases can be transmitted. For example, Ebola is a disease that is transmitted by exposure to blood and other body fluids. In this case, potentially even if people aren't bitten, if that blood goes into their eyes or other mucus membranes, they could be infected that way as well. So that part could happen. But, again, the incubation period would take days for this. In animals, at least, rabies does cause a lot of aggression. In humans, a little bit less. It does cause depression. It does cause active biting, because in rabies it's transmitted through saliva, as well. So, not too surprising that a virus called rage could have those similar kind of aggressive, biting.
[man screaming]
[dramatic music]
Smith: Yeah, so some viruses do cause eye infections, so basically a form of conjunctivitis. In this case, it's infecting usually a different place of the eye that you don't typically see with viruses. Again, we see that with Ebola. We've seen that a little bit with the current coronavirus also, that some people do seem to have eye infections from that as well. So, there are carrier states for various types of organisms. You don't see it as often in viruses, but you do have things like HIV that people can have chronic infection and be infected for a long time and transmit the virus to others. So, we actually do see that occasionally with blood-borne pathogens, like not only HIV, but hepatitis B virus and hepatitis C virus. And they do try to incorporate some of those aspects of the biology of the virus. So I'd say this one's maybe a six or a seven.
Rating: 7/10
Columbus: It's been two months since patient zero took a bite of a contaminated burger at a Gas N' Gulp. Just two months, and I might be the last non-cannibal freak in the country.
Smith: This is another one that is not a viral infection. When we're talking about mad cow disease, that's actually caused by what, we call it prion, so an infectious protein. One of the things about those is they often are ingested. That's why the big scare in the UK many years ago, some cows infected with this may have gotten into the food chain, people may have eaten it, and potentially could develop disease that way. But that two-month time frame would not be realistic at all. This is a condition that takes many years to develop, 'cause what happens is that you ingest the prion and it ends up in your brain eventually. And what it does is that all of the proteins in your body have to be folded a certain way, OK? So they have, you know, a long amino acid sequence, but that's just the first part. Those amino acids have to not only come together one after another in the right way, but also they have to have what we call a tertiary structure, so a three-dimensional structure that has to be a certain way in order for the protein to function correctly. And so what this prion does is that not only is it folded incorrectly, but as it gets into your brain, it basically acts as a template for other proteins in your brain and causes them to misfold. And so as those proteins increasingly are misfolded in your brain, it causes little sections of your brain to die. So it causes what's called a spongiform encephalopathy. So that's the official name for mad cow disease, is bovine spongiform encephalopathy, and it basically leads your brain to become Swiss cheese over time.
It can take decades, so the timeframe is pretty off here. Coming back from the dead is, as well.
[Columbus screaming]
[zombies growling]
It can definitely cause behavioral changes, you know, aggression or things like that. Although to the level of chasing people and trying to eat them, I don't think that's ever been established with any kind of prion disease. I would give this one also maybe a five.
Rating: 5/10
"Quarantine" (2008)
Firefighter: We can't help you. We can't help you unless you calm down. An ambulance is on its way right now, all right?
Woman: No!
[screams]
[medic screaming]
[blood squelching]
Smith: Yeah, so this is kind of similar to, again, that rabies aspect of it. Rabies is probably the only other virus that we know that is basically 100% fatal. There have been a couple of people who were infected. You can get what's called postexposure prophylaxis. So if you have not gotten the rabies vaccine before and you've been exposed, you've had a bite from a rabid dog or a wild animal or exposed to a bat, you can get the rabies vaccine shortly after your exposure. That can basically stop the virus from replicating in your body, so that will protect you from infection. But rabies has a very long incubation period, you know, weeks to sometimes months or more. So once you have symptoms of rabies, basically it is completely 100% fatal.
Police: You need to remain in the building!
Smith: I mean, you would have to get public health involved really quickly, 'cause they're the ones really with the authority to shut anything down. So, presumably somebody would call 911, call police, call an ambulance, and it would go from the hospital first responders to the public-health department, who would say, "OK, we have some kind of an outbreak here." We would quarantine everyone. So that would be a pretty rapid response. Yeah, I would give this, again, maybe, like, a three.
Rating: 3/10
"The Girl with All the Gifts" (2016)
[stroller wheels creaking]
[zombie growls]
[gun bangs]
[zombie grunts]
There are some fungal infections that can affect the brain, but they don't seem to cause the type of behavioral changes like this.
Dr. Caroline: The next stage in the fungus' life cycle, the mature sexual stage. This is a sporangium, a seed pod. If they were to open...
Sgt. Eddie: What?
Dr. Caroline: The end of the world.
Smith: You know, this is modeled on insect pathogens, where the fungus infects the insect, and it does change its behavior. They basically force the insects to go as high as they can up a tree, and eventually, the fungus causes the insect to just basically be a host for kind of that next phase of evolution. They talk about it in there. But basically you have this fruiting body that will replicate in the insect and then kind of pop out somewhere of their body, from their head or elsewhere. And then that is what sporulates. And so, when it sporulates, it releases all of the new fungi, and then they kind of rain down over the colony of insects and can infect all of those. So that's how it ends up amplifying. We have had fungal infections that have gone around the world or around a country. So, I live in an area in northeast Ohio that used to be covered by chestnuts, but then they all got a fungal disease and they basically all died. This can happen. Those can be transported very easily through the air. So that's kind of the premise of this, that if something was adapted to humans that was like this cordyceps that infects insects, that this could be the result. I believe in The Last of Us they have a lot of different kind of phenotypes or different types of zombies that kind of evolve over the course of infection. Yeah, I would say, I would give this a six.
Rating: 6/10
"Z Nation" (2014-2018)
Prisoner: No! Guard: They don't look like volunteers to me.
Scientist: Millions of people are dying for no reason. These men are gonna die to help us find a vaccine.
Smith: So, I love this show. I think "Z Nation" is completely underrated as far as zombie shows go. So, some things that are at least somewhat accurate here is that we do have a long history, one, of doing experiments on prisoners. For many years, if you needed something done, you went to prisons and you went to orphanages, because they were places where you could get consent rather easily. Whether this is being done legally or not, it would be actually very difficult to do these experiments on prisoners right now because there's so many issues of consent. So that is actually kind of accurate, although hopefully not anymore. So, you have Murphy, who was injected with this serum. Of course, he gets bitten and doesn't turn. So, throughout the show, he's kind of not only resistant to the virus but able to control other zombies, which, again, may not be very realistic. But you do have people with perhaps kind of partial immunity to some of these infections.
Murphy: Eight times I was bitten, and did not turn! Eight times I was infected by their bloody saliva!
Smith: Sometimes, vaccine protection is complete. Sometimes it's incomplete. That's actually what we are expecting for the coronavirus vaccine, that we don't expect it will be 100% effective. But this is kind of what we see for the influenza vaccine, that it protects people from infection, but not all of the time. But even for people who are vaccinated, get influenza, you tend to have more mild symptoms, so kind of what Murphy is seeing here. Yeah, probably about a two. It's pretty unrealistic, especially some of the scenarios they get into later on.
Rating: 2/10
"The Crazies" (2010)
[dramatic music]
[water splashing]
[man yells]
David: It was a big plane, Russ.
Russ: Why's that?
David: 'Cause we're right on top of it.
Smith: If you're transporting a very deadly bioweapon, it would likely be in very tight storage, multiple layers probably, and you'd also have dry ice or something to keep it cold. So exactly how it was released during this plane crash is not very clear, I think. That water supply, the virus would be diluted, and even further so as it got spread out to all the people of the town. So you'd have to have a really small infectious dose for this, like one virus for people to get infected. And then, most likely the virus would be killed off in the water, because rabies is a virus that needs a host to amplify. It's not typically a waterborne virus. So it's unclear exactly how that would happen, how it would survive in that water in order to infect those. If you don't have that knowledge that a government plane went down carrying a bioweapon there and you're just doing this based on the symptoms, it would take a lot to kind of tie those together. Usually when we see outbreaks of waterborne disease, we respond to them, because you have upticks in people reporting to their doctors with gastrointestinal symptoms, with diarrhea and vomiting. One of the biggest-ever outbreaks of waterborne disease in the United States in modern times was in Milwaukee in 1993. They had an outbreak of a parasite called cryptosporidium. And one of the early indicators for that was that all of the Imodium was gone from stores. People weren't necessarily reporting to their doctor that they had diarrhea, but they were going out for anti-diarrheal medicine. I'll put this down at about a two.
Rating: 2/10
"Cargo" (2017)
[laughs]
[Kay screaming]
Andy: Oh, no.
[grumbling]
[Andy groaning]
[bite squelching]
[Andy screams]
Smith: While he's in that incubation period, know that he is going to turn eventually. And so this idea of bringing back pathogens from history as you're digging into the ground, as the permafrost thaws, can some of these pathogens that have been locked in ice cores for millennia or longer, could those come back? Yes, some of them definitely can. Anthrax has caused outbreaks in some areas of Siberia. One thing is that anthrax is a really hearty bacterium. It forms spores, so it's really stable in the environment. But again, we don't know how long those would last. If it's decades or centuries or longer, we're not sure.
But I do want to kind of put a flip side to this, is that when scientists were trying to study the 1918 flu virus, so the one that caused the last big global pandemic, they found some samples from this that were frozen in permafrost, so one in Alaska and one in northern Europe. In Alaska in the 1950s, scientists went up there, dug up some of the people who had died and who were, again, preserved in permafrost for many years, took samples of their lungs, tried to grow them in the laboratory, completely unsuccessful. There was no live virus there. Did the same thing with some of the samples from, again, northern Europe, just about 15 years ago or so. So we were able to get viral RNA from those, and that's actually one of the reasons we know so much about the sequence of the 1918 flu virus, but could not grow it at all. And so most viruses are more fragile than, like, bacteria, so a viral outbreak would probably be less likely from something that has been long put in the ground.
[fire crackling]
[crickets chirping]
Cleverman: They're poisoning this land, you know? This country's changing. Sick, we all get sick.
Smith: Interrupting nature, that's a big problem. In West Africa, we had the Ebola outbreak a couple years ago, the really big one, and part of that may have been from the more frequent introductions of the virus into the human population across parts of Africa where they're being deforested. Now the bats are all in close contact and they're in closer contact with other animals in the forest because there's only this little part of it left. So there's more potential for transmission for that virus to other animals. People eat those other animals. People come in contact with that through butchering them or other types of things. And so it can jump into humans. So we see that cycle on and on. So maybe at a four.
Rating: 4/10
I like "28 Days Later" just 'cause it really scares me. I can suspend disbelief for all of the science that's maybe exaggerated or kind of mistold in there, but the story just really freaks me out.