Here's the story about rabies in three sentences. You get bitten by a rabbit animal, you lose control of your mind, and then you die. So it is not surprising that Raby's terrified humanity for thousands of years. Why do you write a book about Raby's, gosh?
I have always thought Rabi's was so interesting in terms of its biology, the way it hijacks the brain to ensure that it'll continue its own spread, the way it affects the relationship between people and animals, which, since I'm a veterinarian, is pretty central to my life.
Monica Murphy is a veterinarian and the co author with Bill Wasick of Rabbit, a Cultural History of the world's most diabolical virus. I should mention that Monica also happens to be my neighbor and a friend of mine.
I think the stories that my rabbit Google alert turns up every week, you know, Bobcat's like coming into a bar and like assaulting someone at a pool table, or raccoons attacking people's trucks. All that stuff is just really interesting and scary and the stuff of nightmares. But I love that science has an answer for all of that in the.
Developed world, almost nobody gets rabies anymore. In the United States, it's fewer than ten people a year. Even our dogs are safe from the disease for the most part. And the reason for this, the reason we don't have to worry that every barking dog we see might bite us and kill us, goes back to one of the most important scientists in the history of both viruses and vaccines, Louis Pasteur. I'm Jacob Goldstein, and this is Incubation, a
show about viruses. We're delighted to be launching season two today. We have lots more viruses to talk about this season, and we're starting with rabies. In the first half of the show, we'll be talking to Monica about rabies and the work of Louis Pasteur. Second after the show, we'll talk to a scientist who's fighting rabies in wildlife in a really surprising way. So let's talk about rabies. What is rabies?
So rabies is an RNA virus. It is special because it is transmitted through bites, primarily unlike the sort of transmission pattern we see with other viruses. In rabies, at the site of the bite, the virus is looking to interact with a nerve, and once it has engaged the nerve, it kind of ratchets its way up the central nervous system from the bite site through peripheral nerves up into the spine, and from the spine up into the brain. It takes a while. It's a slow, slow process.
It's like a centimeter a day or There is a.
Real sort of relationship between how far away the is from the brain and how long it takes to develop rabies, although it's not strict, and it does mean that if you're bitten on the face, you are likely to come down with rabies faster than if you're bitten on the toe, and not every bite from a rabbit animal will result in transmission something like twenty percent to your round number. And once the virus does make it into the brain,
you're going to develop symptoms of rabies. They're horrible, and then you're going to die. It's practically speaking, one hundred percent fatal, like wo really rotten. And the way it works, too, which is pretty horrifying if you think about it, is it's hijacking the brain to ensure that it's going to be spread to another individual.
And you say, what do you mean so in especially in.
The species it's adapted to, let's say, dog rabies. In the dog, it is going to stimulate parts of the brain that kind of rev up that dog's sort of social emotional state, make it much more prone to violence and biting incidents with other dogs. So that meanwhile it's being secreted in the saliva. It's really increasing the likelihood that it's going to make it into another dog and continuous life cycle, which is.
Kind of amazing, right, Like it's just a virus, yeah, and it's essentially evolved to like change the behavior of this complex mammal to make it bite other mammals so that the virus will spread. Like that is a wild feet of evolution.
Yeah. Yeah, it's really really scary. In places where humans are frequently in contact with rabbit animals, the sort of behavioral changes that occur in the human Rebe's victim are also really messy. You know, a human with Rabe's might not actively try to bite you, unless they're a little kid. They might punch you in the nose or just scream curses at you.
In general, people become more hostile.
More violent, yeah, or sext up uh huh.
So just like more id. Yeah, terrifying. You're being attacked by your own brain, right, somehow, You're like your own thoughts are attacking you.
Yeah.
Yeah, I mean so you talk with respect to that in the book about kind of rabies and mythology, right, rabies and were wolves, rabies and vampires, Like, tell me about that.
There's at least a deep resonance between these stories of a sort of contagious you know, contagious zombieism or werewolf ism or vampirism where the bite the bite. Yeah, and there's the association with bats and vampires and.
Both and both bats and wolves are historical vectors of rabies, just to be clear. So this is kind of rabies. It's this ancient disease. It is terrifying where crazed animals bite people and turn people into crazed animals who then die. It's basically the state of play rabis forever. And then onto the stage of history walks our hero, Louis Pasteur. That's right, tell me about Pasteur.
Most folks know at least a little bit about Louis Pastor because he had a long scientific career. He was trained as a physicist and chemist, and he grew into more of a microbiological concentration in his work. Along the way, he established germ theory.
Yes, that people thought was like a crazy idea, And this is like a mid to late eighteen hundreds, right, and the world already had the smallpox vaccine at this point. But I do feel like it's worth remembering here that that was sort of this lucky break, right, where like there just happened to be this mild disease, cowpox, that made people immune to this terrible disease, to smallpox. And Pasteur, as you write in the book, he decides that he's
going to apply this germ theory to vaccines. Right, He's actually going to use science to create a vaccine, So tell us about that.
What Louis Prestor sought to do and succeeded in doing for the first time ever is manipulating microbes to sort of move them away from their wild state into an attenuated a week in state and induce immunity using.
Those right, So okay, So Pasteur he develops a few animal vaccines in this way, and then he decides that the first human vaccine he's going to make is going to be a rabies vaccine, you know, a vaccine for this terrifying disease. So what does he actually have to do?
So, because there's no way to grow rabies inside of a test tube, he had to maintain a population of rabbit animals in his lab.
Terrifying.
Yeah awful, I mean really gruesome and scary for the people he worked with. They would harvest the saliva and introduce it into more dogs or into rabbits.
How do you harvest the saliva from a rabid dog really carefully? Right, I walked into that.
But yeah, involving like a high pet Oh my god.
Yeah, in the mouth of a rabbit dog. Yeah, yeah, I'm gonna die. Yeah, I'm afraid. So so you've got step one, find the nasty disease. Step two, seemingly the harder part, turn that nasty disease into a thing that will induce some immunity without causing disease.
Right, they can't see the microbe. They know it's in the nervous tissue, So they start dissecting out nervous tissue from animals with rabies, specifically rabbits, and they aged it. They age the tissue in a sort of desiccating tray. And determined that with sufficient aging, it weakens it.
Just leave it sitting on the shell for a while.
Yeah, except they ultimately arrived at a method that was a lot more complex. They had a sort of well whole sort of assembly line of tissues at various stages of aging. So you know, you've got your your rabbit spinal quarter over here that's aged fourteen days, and here's a thirteen day one, and okay, et cetera. The ones that are oldest are least virulent. The ones that are newest are most virulent and too dangerous to put right
into a person right out of the gate. So they start with an injection of the longest aged nervous tissue, the weakest the weakest one, and then over they think of a ten days the initial protocol. They inject thirteen injections with progressively stronger that is, newer tissue.
And so is the basic idea, like the weakest one induces some immune response so that you can then tolerate a slightly stronger one, and you're kind of going up a staircase of immunity.
That's how he developed it, And of course today we just have a single strength. Rayby's vaccine in use. So his method wasn't the only way to induce immunity, but it's you know, they were dealing with a one hundred percent fatal disease, I think understandably nervous about introducing it into people. And they realized both that they can They can do pre exposure vaccination so that the dog can't get infected with Rabi's. Uh huh, hold that thought. That's
not put into use right away. But then they also can start a series of vaccine after the dog has been exposed to Raby's and prevent him from coming down with the disease.
So they figure this out, and then we have this moment when it's time to try it on a person for the first time. What is that moment?
So a case was brought to Louis Pester's attention that seemed sufficiently concerning to take a chance on this vaccine and involved a young boy who was bitten by the grocer's dog who had had undergone a suspicious behavior change and was marauding the neighborhood. The bites were extensive, and so that's another potential risk factor for development of Rabi's.
We talked about, meaning he got lots of places, you know, lots of places really deeply, so, lots of places where the virus could have encountered a nerve, making it likely that he was going to come down with rabies at some point. They were very pessimistic about the boy's chances, and so they sent him to Paris, to.
Louis Pestor's lab, where he had this vaccine that he had not yet tested on a human being.
Yeah, he had been thinking about testing it on himself.
Uh huh, a kind of tradition in science.
Yes, But before he had a chance to test on himself, he was persuaded by the physicians caring for this boy that this kid might very likely to die if he doesn't get the vaccine, and so Pastor went ahead with his process.
So the boy gets this experimental vaccine, and now Pastor has to just wait right wait to see what happened. So what's going on with Pastor while he's, you know, waiting to see whether the boy survives.
Well, Pastor was sleepless. He was just in a state of agonized waiting and was having health problems related to that. He traveled a little bit for his health. Well, he sort of ticked down the days.
What happens with the boy?
The boy does great. He remains healthy during the ten day process where he could see inoculations, and once a few months had passed, at the point at which you know, I was believed he would have come down with rabies by now, if not because of the because of the bytes, perhaps because the vaccine was dangerous, he continued to thrive.
Okay, so the vaccine works. What like, how does it play?
People were excited around the world. I mean, the vanquishing of rabies was big news, just as Pistar had calculated, not immediately embraced by everyone. There were physicians everywhere who had been following the science and sort of got it and were eager to put it to use.
And in the in the sort of long run, in the you know, one hundred year arc. What what does pastors work mean? Both for rabies and for you know, disease research and treatment more.
Generally, His lab is often credited with developing the science of immunology and furthermore lead the foundations just with the basic idea that like, you can take infectious agents and you can figure out a way to make them weaker. That is the basis on which all modern vaccine science works.
So let's let's talk about rabies today. What is the status of rabi's today.
So rabies is still a problem in many parts of the world who have not yet eliminated dog rabies. But we're really lucky here that the use of the pre exposure vaccine and dogs eliminated dog rabies. We no longer have to like look as scance at our pet dogs and worry that contact with them could kill us. The parts of the world where that is not true, where dog brabies is still endemic, places like India and parts of Africa, there are still a lot of human rabies deaths.
I think the who uses the number sixty thousand rabies deaths are still happening every year around the world. That numbers is really contested. It's been a real challenge getting the vaccines and the other products that fight brabies to the people who need them most. But those products are prohibitively expensive. So rabies is considered a neglected disease by the international health authorities, but people are still dying of rabies.
And then in parts of the world like Europe and the United States where dog rabies is not the issue, we do still have wildlife rabies, So.
Like in the US, what wild animals have rabies?
There's rabies adapted to foxes, skunks, raccoons, and a whole lot of bats in the United States.
Right, I read that, like, if you wake up and there's a bat in your room, you should probably get a rabies shot because bats can bite you and you don't even know us.
Yes, there's an argument for getting Raby's vaccine if you wake up in a room with a bat, although you know you should consult your local health guard.
Did writing the book change the way you think about the relationship between humans and animals?
I do think that there is a way in which our relationship with dogs and cats, especially, you know, the sort of pure sweetness of it that a lot of us experience now, like it had a darker side in the pre vaccine era.
Your dog could turn into a monster and kill you or your child. Yes, that was like a real thing that could definitely have It was a.
Real thing, and that was that made it really hard to like love and baby our dogs in quite the same way as we do today.
So like this modern phenomenon of the dog being to what is arguably a weird extent a part of the family, and I include my own family as you know, in that that like, you couldn't really have that without pasteur without the rabies vaccine.
It certainly doesn't reach its sort of completion without that. I mean, it's wonderful for those of us who love dogs.
Thank you, Monica. That was delightful.
Yeah. Thanks.
Monica Murphy is the co author with Bill Wassick, of Rabbit, a Cultural History of the world's most diabolical virus. Their most recent book is Our Kindred Creatures, How Americans came to feel the way they do about animals. We'll be back in a minute to talk about the surprising way that wildlife bilegious are fighting rabies in America right now.
By the early part of the twenty first century, the rabies vaccine had almost entirely eliminated rabies from people and dogs in the United States, but the disease has persisted in wild animals. I talked about this with Kathy Nelson years ago.
When I was in Vermont. We used to operate a rabies hotline in the state. It would get calls in from the public and we would sometimes go out to investigate them, and we had a skunk that was trying to bite the gas cap off of a lawnmower, and they'll just bite anything that's in sight, because that's one of the fascinating parts about the virus is that it's designed to tell the brain to bite things.
Kathy is the wildlife biologist and the operations supervisor for the National Rabies Management Program with the US Department of Agriculture. For the past twenty six years, she's been part of a federal program that has been fighting rabies in a way that that I have to say, I found delightful. So tell me about the first time you went up in the air, too, fleeing rabies vaccines at the ground.
Yeah, I still remember. It was so exciting. You you know, you help load all these baits onto a plane. You walk up the little steps of the small plane, you get in it, someone closes the hatch on you. You know,
the engines start, you take off. You're flying over beautiful terrain and landscape, just beautiful agricultural forested land, and you know, the person up front says, okay, machine on and you know, baits are going down this little belt and I'm just moving them around looking out the window, seeing moose, deer, you know, all kinds of wildlife. I could literally could not believe that I was getting paid to do a job like this.
What kind of plans were you going up?
Then they have a single wing, two engines.
How many seats? It's like, how small is it?
If there were seats in them, there probably would be. There would probably be about a dozen seats.
You're basically fly that cargo van. Yeah, so these baits are falling from the sky. Maybe this is a dumb question, but like, is there ever any word they're going to hit somebody on the head.
Yeah, No, not a dumb question at all. Yeah, So the navigator in the front seat, not the pilot, but the other person who is a USDA wild Life Services employee. They have an on off switch, So anytime we're approaching a house or a road or a major body of water, that switch goes off so that baits aren't distributed. You know, over the course of a twenty five year program, we've
hit a roof for two. But fortunately, you know, once folks learn about our program, they're generally really really accepting of it, and you know, they're not too mad.
Is it happening like literally today is it happening this, you know, we're talking in August of twenty twenty four. Is there a plane in the air today?
There is? Literally I got a text this morning saying all five aircraft are taxing for run ups and take off in Watertown. That's Watertown, New York.
Tell me about the baits, like, what's one of them look like? Taste like?
So we use different vaccine types. One of them looks like kind of like a little ketchup packet with a slight oil on the outside and attached to that oil or tiny little fish.
Mail crumbs fishmeal sounds delicious to a raccoon, I'm sure, yeah, Okay.
So the other company they make a sweet bait, and it's a sugary, sweet, like marshmallow kind of sweet vanilla based bait.
Presumably you can't just like fling these things out of an airplane over a city, right, So how do you do it? In you know, urban areas.
Primarily we drive around in trucks. You know, someone's driving another person has the window down in the passenger seat. They're tossing a couple baits down. We record the location of all of these baits with a GPS unit, so that we know where we've baited. Our biggest struggle right now is because there's so many other food sources, you know, trying to pull them away from a dumpster full of pizza to eat one of our baits is a real challenge.
I have literally feed a raccoon in Prospect Park in Brooklyn eating a whole slice of It's. Yeah.
They I mean, they're omnivores, so they're going to eat anything you know around. But we have done a ton of research in urban areas looking at movement patterns, home range sizes, because you have to get them right in the right spot for them to even find them.
So let's talk about the scope of the project now, Like what is the range of where you where you do this.
We have a band of vaccine distribution zone that goes from Maine kind of across the Canada border down to Ohio and then pretty much straight down from Ohio to Alabama, and that's designed to stop the westward spread of raccoon Raby's and the northward spread into Canada.
Oh interesting, it's like a line of defense.
Yep, exactly.
Was that the notion when you started was the issue like, oh, rabies is spreading let's defend against the spread of rabies.
Yes, So the story of raccoon rabies is a really interesting one. Raccoon rabies was first sort of documented in the late nineteen forties in Florida. But then there were some raccoon hunters from West Virginia, Virginia area who wanted
to replenish their raccoon supply. They went down It was real commonplace back then to move raccoons around for raccoon hunting, so they went down south, got some raccoons, released them into an area on the Virginia West Virginia line and inevitably released some rabid raccoons without knowing it, and then raccoon rabies exploded from there. It reached most Northeastern states by the early nineties.
And is there risk of raccoons passing rabies to humans?
Yeah? Absolutely. Over the years there have been humans that have contracted raccoon rabies. Certainly, human health and safety is always paramount. Also animal health and safety. You know, every year there's there's about three hundred cats in the US that die from rabies. There's about fifty dogs that die
from rabis. It's a cost benefit sort of program where what it costs us to manage our program is significantly less than what it costs the American public to live with rabies every year, just in terms of healthcare costs, you know, public education, post exposure, prophylaxis, all of that adds up really fast.
So the program started in the nineties to stop the spread of raccoon rabies. Has it worked? Did it stop the spread of raccoon rabies?
It did.
After we distribute baits, about a month after, we go back into an area and we use live traps to catch raccoons, We take a blood sam pull from a pull a tooth, wigh them, sects them, takes some general notes on you know, their condition, and that blood sample get sent off to the lab and that tells us ultimately whether or not they have antibodies against rabies. And the tooth gives us their age and also tells us whether or not they ate the bait because the bait
has a biomarker that stains their tooth. So that whole process, that's our monitoring program, along with all the surveillance we do where we do pick up dead raccoons off the road and test them for rabies. The centers for Disease Control. CDC has documented a seventy seven percent decline in raccoons with raccoon variants since our program began in nineteen ninety seven,
so we know it's working. We've made significant progress in being able to move that zone to the east toward the ocean, which is what you know, our ultimate goal is that bait zone of containment, and then just keep marching it toward the ocean till, you know, till you've eliminated the variant.
Right when you get to the sea, you're done. You're like marching to the sea.
Yep, you're done.
So so you've been doing this a long time. You are a wildlife biologist by training. I'm curious if your career has changed the way you feel about wildlife, about the relationship between humans and wildlife.
Yeah. I mean I love all wildlife, you know. When I was in college getting my degree, you know, like any wildlife professional, I think you dream of, you know, working with polar bears or mountain lions or you know, some some big charismatic megafauna and you know, and I landed on raccoons, But I wouldn't change it for anything.
That they're so smart, they have not made a trash can yet that they can't get into, or they're just you know, if you have ever seen one up close or I you know, I would encourage any listeners if they have the opportunity and they see one dead on the road. It sounds crazy, but just stop and look at it. They're fascinating animals. They have little hands, just like we do. They have an opposable thumb. Genetically, they're closer in origin to bears than they are to like
cats and dogs and those kind of things. So they're just really smart animals. They think about what they're doing. We have a National Wildlife Research Center and they did a side study where they would put a marshmallow in the tub of water and the raccoons would learn that all they had to do was keep putting more rocks in the water till that marshmallow rose to the top
and they could reach in and eat it. So that's just one example of how smart they are and how if they're given enough time, they'll figure something out.
Thank you so much for your time. It was great to speak with you.
Yeah you too, thanks for having me.
Kathy Nelson is a wildlife biologist with the US Department of Agriculture. Thanks to both my guests today, Kathy Nelson and Monica Murphy. Next week on Incubation, I'm met on my mind that I have to go do it, but at a same time, I was going to deal with the beasts, which means I may not come back home alive. Incubation is a co production of Pushkin Industries and Ruby Studio at iHeartMedia. It's produced by Kate Ferby and Brittany Cronin. The show is edited by Lacy Roberts. It's mastered by
Sarah Bruguier, fact checking by Joseph friedman Or. Executive producers are Lacey Roberts and Matt Romano. I'm Jacob Goldstein. Thanks for listening.