Happy Saturday, everybody. Today we have one of our most unintentionally terrifying episodes of all time. It is on encephalitis lethargica, and it originally came out We did not ever intend for this to be a Halloween episode, but it originally came out in October and we heard from a lot of listeners that it scared them more than anything else we have ever done. So this story of a frightening and mysterious illness is also a good segue into a new show on our network. It's The End of the World with Josh Clark, and Josh, one of the hosts of the other podcast Stuff You Should Know, is hosting a ten part series that explores all of the various ways that humanity could abruptly end. So stay tuned at the end of today's episode for the trailer to the End of the World with Josh Clark. Enjoy. Welcome to Stuff You Missed in History Class from how Stuff Works dot Com. Hello, and welcome to the podcast. I'm Tracy B. Wilson and I'm probably so. I did not intend for today to be a Halloween episode. Is scary? Yeah, due to some quirks in our publishing schedule. It happens to be coming out right before Halloween. It is a listener request from listener Ellen or perhaps Ellen, And in researching it, I realized it was the most frightening thing I had ever learned about. So, so buckle up. History has scared Tracy. History has scared me. So. From nineteen sixteen to about nine seven, this really bizarre epidemic spread around the world. It came to be known as sleepy sickness, and it is not to be confused with sleeping sickness, which is a tropical disease found in sub Saharan Africa. This is another name for a disease called encephalitis lethargica, and it caused this really weird variety of symptoms, from drastic behavior changes to unusual eye movements. Especially in the beginning years of it. Uh, the really common element was this deep, prolonged sleep that went on and on from days two months, and people just couldn't wake up. Between twenty and of the people who got this disease died, and of the ones who survived, only about a third really fully recovered. The rest developed what came to be known as post and syphilitic Parkinson ism, and some of these patients persisted in a semi comatose state for decades. It's extra terrifying. The next part is even more terrifying. Yeah, as if all of this were not enough to scare the pants off of you. While in this extremely deep sleep that was part of many of the cases, people appeared to be unconscious, but in reality they were actually alert. They were completely aware of what was going on, but they were unable to overspeaks, so it was a sort of paralysis. Really. Yeah, So people today may have heard about this whole disease from the movie Awakenings starring Robin Williams, or maybe from the first pages of Neil Gaiman's amazing comic book series Sandman, which starts off when a ritual that was meant to capture death instead captures dream and causes people to sleep endlessly. Otherwise, it's pretty far in the background of medical history most of the time. It's not something that people remember all that well today. But from its onset until about ten years after it faded away, there were more than nine thousand papers and books published on it, so at the time it was a big deal. Even though people don't necessarily come up with it immediately when thinking about huge epidemics today. Yeah, and I wonder why that is, um talk about some of that. Yeah, Prolonged sleep as an illness has been reported really really way back into history. There are written records as early as Hippocrates of this kind of incident happening. And then there are also, of course, in our cultural consciousness tales like sleeping beauty and these stories like rip van Winkle uh, and some people along the line have theorized that these were actually rooted to some degree in some kind of sleeping illness. In the real world, there had also been an outbreak of a similar condition in Italy in eighteen eighty nine and eighteen ninety, which came to be known as Landona, and it was thought at the time to be a complication of the flu. And around the world, other outbreaks of encephalitis had also followed behind other epidemics, particularly the flu. This particular one started just a couple of years before the nineteen eighteen Spanish flu epidemic, which killed between twenty and forty million people, and when it came to the encephalitis lethargica epidemic, the first reports came at about the same time in two different places, which were France in Austria. In nineteen six, in France, a doctor named Genre nee Cruche started to see six soldiers with this weird assortment of seemingly unrelated neurological symptoms, and the one common element was that the patients just slept, apparently peacefully and deeply, and that they could not be woken up, and he started to wonder whether there was some kind of new chemical weapon at work. At about the same time, a British doctor named A. J. Hall also reported similar symptoms, and other troops who were stationed in France. In Vienna, it came to the attention of Romanian Austrian psychiatrists Constantine von Economo after a sleepy, disoriented civilian wandered into the Wagner Jarre clinic where he worked. The doctors there had mostly been treating soldiers who were wounded in the war, so they really weren't prepared for this apparently uninjured civilian with nothing physically wrong that they could really point to. And then more and more patients with similar symptoms arrived at the clinic and there you know, they had the similar part of this uncontrollable sleepiness and sleep. But the rest of their symptoms were so strange and diverse that the doctors were really at a loss to figure out a cause or a treatment. These patients had fevers, malaise, double vision, they became lethargic. Sometimes they had sore throats. Their eye muscles would start working and their eyes would dart around or roll back in their heads. Some of them developed very strange eye and tongue movement movements, and this variety of other neurological and psychiatric symptoms. A few of them even had uncontrollable hiccups, and one died of that. How does that work? Well, if you can't stop hiccuping, you can't really eat or sleep, and then it can cause all kinds of other interesting Yeah. Once again, throughout all of this, the common element was this strange deep sleep from which they could not be woken. Vanni Conomos saw this common element and said, we're dealing with a sleeping sickness. Yeah. He was really the one that just laid that out there, and he's a character on his own. He was also a pilot who had been serving in the war, but he came back home to Vienna after his brother was killed and he really wanted to be flying, but reluctantly transferred to doing medical work instead to try to keep himself more out of danger and spare his family from further grief. On top of all that, he was also a baron, having been born to a family of Greek aristocrats and then married the daughter of an Austrian prince. As the patient started to die from sleep, Vonni Konomos started an intense research effort to find a cause and a cure. He studied autopsies of patients who had died of the disease, and he found common areas of damage to their brains, specifically in the hypothalamus, and he suspected that the differences and how much people slept was related to just how their hypothalamus was damaged. He also found that brain tissue could transmit the disease to monkeys, so he concluded that they were looking at something that was contagious. He publicly announced his conclusion that they were dealing with a new disease, probably a virus, before the Psychiatric Society in Vienna, on April seventeenth of nineteen seventeen. Uh Consequently, sometimes the disease has been referred to as von Economo's disease. His announcement was not at all well received. At the time. The prevailing view was that mental illnesses were all products of things like trauma and buried memories. Freud was really at the forefront of psychology at this point, so a lot of people just scoffed at the idea that there could be a virus or other disease process causing the kinds of behavior changes and psychological problems that some of the patients were exhibiting. The ongoing debate and this mystery of the whole thing kept much progress from being made in terms of treatment and prevention. But then, uh, the illness mostly disappeared from continental Europe. It really just fell off suddenly, and Spanish flew on the rise, took its place, and it became a much more pressing priority. Not long after that, though, the disease appeared in London and it followed much the same pattern as it had on the continent. There were, you know, all these patients who were suddenly having the strange collective collection of symptoms and sleeping constantly. The government in Britain quickly made it a reportable disease. The Ministry of Health had to be notified of all new cases and its appearance and spread UH in London was much like it had been in France and Austria. Strange symptoms and unending sleep uh you know, baffling the doctors. But in England the symptoms became even more alarming, with patients who could never sleep, or who couldn't stop laughing, or had other strange physical or emotional present sians It also seemed like fewer and fewer people were truly recovering. In Austria and France, there had been people that had gotten better, but as it's spread around England, a lot of people were becoming comatose or developing. As we mentioned at the beginning, what later it came to be known as post and syphilitic parkinson is um or PEP. Sometimes the onset of parkinson Is m happened years after people recovered, after they had apparently been healthy all that time. During the epidemic, the average age for the onset of Parkinson's dropped to thirty six years old. Today, while there are people who have early onset, the average age for people to start exhibiting Parkinson's is sixty. So this was really a significant and strange happening. Uh. Following the epidemic, two thirds of Parkinson's patients had previously had encephalitis, so it clearly was causing it. Right, this, this disease is was causing a drastic shift in who developed Parkinson's and when. And we're going to pause before we start talking about how then the rest of the world gets to be terrified. So to return to the story of encephalitis lethargica from England, the disease spread all over the globe, and the same story just played out over and over and over. People would start showing up with these strange symptoms that prevent that presented themselves in such different ways that it would take a while for doctors to realize what was happening. It really didn't help that the epidemic had started just at the end of World War One and just before the start of the nineteen eighteen Spanish flu epidemic, and so resources were just scarce and there were definitely bigger priorities going on. And this crazy, although terrifying disease, and as it spread, it started to prompt a variety of different sleep disorders. So while some patients would sleep for months at a time, others couldn't sleep at all, and they would actually die of exhaustion. The disease came to be known in some places as epidemic encephalitis rather than encephalitis lethargica, since not everyone could really be called lethargic anymore. As its spread, it also started to affect more and more children and young people. Children who contracted the disease developed impulse control issues that led to them having violent behavior in their adolescence. Some of them injured themselves or other people. One even removed her own eyes and several of her own teeth okay after unclenched. After that um, this behavior often would continue for the rest of these patients lives after they progress out of childhood, unless post and cephalitic parkinson is M made them physically unable to continue. For children with the disease, outbursts were so severe that many had to be institutionalized. Hospitals and asylums that were accustomed to providing care for adults suddenly had to develop new practices to care for children because there were so many suddenly having to move into institutions. Researchers theorized that the reason this encephalitis was causing behavior changes like this and young people was because their brains hadn't yet developed the capacity for self control that adults typically had by the time they were infected, and this tendency towards violent behavior and other erratic behavior even led to encephalitis lethargica being blamed for gangster behavior and lawlessness during the nineteen twenties. Once this disease spread to the United States, neurologist Frederick Tilney, who was known as Fred and had also been Helen Keller's neurologist, became the country's foremost authority on sleepy sickness. One of his most famous encephalitis patients was Jesse Morgan, who was the wife of Jack p Morgan, who himself was the son of banker and full anthropist John Pierpoint Morgan. She got the disease in After Jesse's death, Jack donated two hundred thousand dollars to the Neurological Institute to fund research into this disease. The Neurological Institute was behind most of the research into encephalitis lethargica that came from that point. Later on, William Matheson, who was the wealthy founder of a chemical company and an encephalitis patient started the Matheson Commission to fund research at the Neurological Institute, with Dr Josephine B. Neil, who was an encephalitis expert, helming the project and the commission's aim was to study the disease and eventually find a vaccine. Since nobody knew exactly what was causing the disease, they worked on three theories simultaneously. One was that it was being caused by an unknown virus, the next was that it was being caused by bacteria, possibly strapped UH, and the third was that it was being caused by herpes. This was a long shot to begin with because no causative agent had been found for this disease. They were basically operating in the dark based on best guesses. On top of that, there was a ton of infighting among the researchers. A lot of them were extremely prominent neurologists and scientists. Each of them really wanted to be the one to crack this case and figure out what's going on. Um that they were not working together very well. They were each trying to get the glory for themselves. And then there was another huge setback when Matheson himself died in nineteen thirty. That was in the middle of the Great Depression, and he had been providing the funding, so after his death there wasn't really other funding to be had, so the Matheson Commission ceased operations in ninety two and so no workable vaccine had been developed, and one of the things that doctors tried to treat post encephalitist patients of was lobotomies, which also did not work. There was a lot of ending that did not work. There were a few outlying successes during this time that would kind of give people false hope that maybe they were on the right track, but nothing led to an actual treatment or cure. Most of the medical care that the patients were receiving was really about just caring for their bodies and keeping them alive. The thirty or so percent who developed parkinson Is um generally wound up in long term care for the rest of their lives, and many of them were completely unable to move or take care of themselves. In the nineteen sixties, after the drug leve Adopa, or el dopa as it was called, was introduced for treating Parkinson's, New York doctor Oliver Sacks, who are some of our listeners may have heard of, administered it to some encephalitis lethargica patients who were in long term care. Some patients actually showed a limited recovery from their post and sephalitis lethargica parkinson symptoms. This is the story that's actually told in the movie Awakenings, which is why people may have heard of Olliver sex. But they all apparently developed a tolerance until the dosage was really just too much for the human body to handle, and then they would return to their semi comatose state in the end. This epidemic went on from nineteen sixteen to nineteen twenty seven, reaching its peak in nineteen twenty four, after which the number of cases started to drop off. The total numbers of people affected are really unclear. There are sources who say that a million people were killed, while others say that only half a million were affected in one way or another. Regardless, though the mortality rate was pretty serious in England, almost half of the cases in nineteen nineteen and nineteen twenty died. Although it was roughly concurrent with the Spanish flu pandemic, and flu came up frequently when looking at possible causes. Many doctors at the time didn't really think the disease was actually flu related. Only a small percentage of the patients had also had Spanish flu. In nineteen eighty two, however, doctors from the Centers for Disease Control published this list of connections between the two diseases. So for a little while. In more recent years, flu became a prime suspect for causing encephalitis lethargica. Uh there is, you know, especially since there have been other incidents of encephalitis that have followed outbreaks of the flu. Today, the idea that the flu was the culprit has pretty much been ruled out. Thanks to modern testing methods. They haven't turned up any sign of the flu virus in tissue samples from patients who died from encephalitis. Although it's never reached that same epidemic state again, isolated cases of encephalitis lethargica have continued to crop up even in recent years. Most recently in a twenty three year old named Becky Powell was diagnosed with the disease and it took her two years to recover. Several similar ass followed. In two thousand three, a team of doctors published a paper in the journal Brain that put forth a pretty good case that the cause of encephalitis lethargica is actually a massive autoimmune reaction to an unidentified pathogen. A strain of strep comes up in the discussion, but it's ultimately dismissed as unlikely. And their research was done on twenty different patients who developed the disease between two thousand two, and those patients had a much lower mortality rate than during the epidemic. Only one died, but five of them did have to be placed on a ventilator. Had those five patients lived in the ninety twenties, they probably would not have made it, but almost none of them had fully recovered a year or so later when the paper was published. They continued to have neurological and psychiatric symptoms. Yeah. If if there had been if today's ventilation technology had existed in the nineteen twenties, the mortality rate would have been sign Yeah, because people would get into this just deep uninterrupted sleep and their respiratory functions would fail, and there wasn't really anything that people could do about it. But now that we have ventilators, uh, that there are actual there's a treatment for that part of it that didn't exist back then. In a paper in the journal BMC Infectious Diseases reported that a team of researchers had found virus like particles in the brains of both epidemic encephalitis patients and modern patients, so people who had died either recently or during the epidemic. This supports the idea that the cause of encephalitis lethargica is an interarovirus, but exactly what interarovirus we still do you not know. So encephalitis lethargica has a some you know, a legacy today, even though a lot of people have not really heard of it as tragic and frightening as the disease was and is really. In the end, it helped doctors understand more about the brain. Von economos conclusion about the hypothalamus and its role in the patient's sleep, for example, was hugely unpopular at the time, but many years later it was proved to be true after we developed sorts of imaging technologies that we can use to look directly at the brain as it's working today. Neurologist Bernard Sacks also wrote that the epidemic of encephalitis quote revolutionized the practice of neurology, So it really changed the way that, uh, these things were examined from the get go. Yeah, it helped solidifying neurology as an actual field. In the early days, there was sort of this hodgepodge of neurology ideas and psychology ideas and all these things that were kind of together in one big pot. And in part because of encephalitis being spread the way that it was, a group of doctors branched off to study just neurology and it celf lightest lethargica was also one of the conditions that made it clear that disease processes can lead to mental illnesses. Uh, it's solidified the idea that mental illnesses were not solely in the realm of emotions or traumatic experiences. It's not always buried memories. Sometimes there can actually be a physical happening that causes mental illness. There are a couple of books that are out about this epidemic. The one that I read researching this podcast was called Asleep, The Forgotten Epidemic That Remains one of Medicine's Greatest Mysteries by Molly Caldwell Crosby and her grandmother survived sleepy sickness. It starts with sort of a case study of her grandmother. That's terrifying because it's about her grandmother being asleep for so long but also being aware of what was happening around her, which to me is just terrifying. The one caveat about this book is that it was written before the very most recent research about what might have caused this particular epidemic, which is going to be the case with just about every book now since the latest research is just from very new Yeah. Last year, as we were recording, I have read several papers that you know, and when the bird flu epidemic was was everybody was very frightened about bird flu. There were several articles that that came up where doctors were like, actually, what you really should be afraid of is a resurgence of this still unidentified encephalitis that sometimes that sometimes follows outbreaks of other diseases. I yeah, it's basically my worst nightmare. I mean, I have not a good relationship with sleep anyway. If I didn't have to do it, I wouldn't. So the idea of not having any control over the situation and just being asleep but not really because you're conscious of things happening. Is my worst nightmare. Yeah, not play on sleep jokes, but well, it's terrifying and the there are many things about this whole the epidemic and the illness itself that are are frightening to me, and one of them is that people would seem to recover and they would be fine for a long time, and then the developed fine developed parkinson symptoms um and once it had been established that that was a pattern, I can imagine like the people who had gotten better really being like I'm never going to be which I know that's the case with a lot of diseases that people have now, Like there are many cancer patients who never feel like they are in the clear because you can be in remission. So yeah, it's a scary thing to live with that kind of over you. Thank you so much for joining us on this Saturday. If you have heard an email address or a Facebook you are l or something similar over the course of today's episode, since it is from the archive that might be out of date now, you can email us at History Podcast at how Stuff Works dot com, and you can find us all over social media at missed in history, and you can subscribe to our show on Apple Podcasts, Google podcast, the I Heart Radio app, and wherever else you listen to podcasts. For more on this and thousands of other topics, visit how Stuff Works dot com. I'm Stuff you Should Know as Josh Clark, I'm launching a ten part podcast series about all the ways humanity might accidentally wipe ourselves right out of existence. It covers everything from whether we're alone in the universe to the evolution of life on Earth, from artificial intelligence to what goes on inside a particle collider. It is in a mensely interesting deep dive into the world of existential risks, and I hope that you enjoy listening to it as much as I have making it. I want to share a preview of the series with you. This clip comes from episode four and it features economist Robin Hansen, creator of the Great Filter hypothesis, which is something we may have to contend with in the near future. When we settled down, our cities, developed agriculture can support more people than hunting and gathering, and the more people there are, the more brilliant ideas there are. Two so our civilization began to advance by leaps and bounds in the last nine or ten thousand years. Ideas spread more quickly among those people who lived together in those new cities, so innovations were able to develop over the span of a handful of years rather than millennia. Almost everything we have in the world today can be traced back to our collective decision to settle down and raise crops. It was, to say the least, a sweeping change for us humans. With our next great leap spreading out into space, we are effectively doing the opposite of when we settled down into cities. Rather than contracting, we will be expanding. From that huge coming together, we will spread out. Over time, humans will begin to colonize other planets, and generations of little human babies will be borne on planets other than Earth. They will be shaped by forces and experiences that no earthbound human will have ever encountered, and they will learn to adapt to their home planet just like we did. We are quite capable of becoming all the things that it's possible to become. Life that starts from us and radiates out cannot only spread to different places that can create different styles and techniques and cultures and approaches. All of the life that you see on Earth started out from a much smaller amount of variation, but with time it could explore lots of different niches and ways of living. And that's probably what would happen to us too. If we're the only life around it, we can survive, we will radiate. We will become diverse and different and fill thousand million billion different niches of different ways of being. Over time, perhaps their physical connection to humans on Earth will become distant enough that new species of humans will form, and the universe will be home to more than one species of human again, just as it was fifty years ago. We will become the aliens we seek, and later on they might be surprised to learn that they came from something that was simple and not as very It's odd to think of, but humans are in an evolutionary bottleneck of our own. Right now. There's only one species of us, and with the exception of maybe half a dozen astronauts on the International Space Station at any given time, we are all stranded on this island Earth. Those astronauts aboard the I s S showed just the faintous beginnings of our future. If we become a space faring species, all of humanities eggs will no longer be in just the one basket of Earth. Should some catastrophe befall those of us here on Earth, there will be other humans living elsewhere to carry on. We will begin to trickle from our bottleneck and spread throughout the universe, and when we do, we will have made it through the great Filter. Colonizing beyond Earth is something we should begin working on as soon as we can, because Earth is vulnerable to a wide variety of catastrophes that are pretty hostile to life, things like exploding stars, the death of our son, even Earth's own systems going haywire. Please join me for the End of the World with Josh Clark. Listen and subscribe at Apple Podcasts or on the I Heart Radio app, or listen wherever you get your podcasts.

Happy Saturday, everybody. Today we have one of our most unintentionally terrifying episodes of all time. It is on encephalitis lethargica, and it originally came out We did not ever intend for this to be a Halloween episode, but it originally came out in October and we heard from a lot of listeners that it scared them more than anything else we have ever done. So this story of a frightening and mysterious illness is also a good segue into a new show on our network. It's The End of the World with Josh Clark, and Josh, one of the hosts of the other podcast Stuff You Should Know, is hosting a ten part series that explores all of the various ways that humanity could abruptly end. So stay tuned at the end of today's episode for the trailer to the End of the World with Josh Clark. Enjoy. Welcome to Stuff You Missed in History Class from how Stuff Works dot Com. Hello, and welcome to the podcast. I'm Tracy B. Wilson and I'm probably so. I did not intend for today to be a Halloween episode. Is scary? Yeah, due to some quirks in our publishing schedule. It happens to be coming out right before Halloween. It is a listener request from listener Ellen or perhaps Ellen, And in researching it, I realized it was the most frightening thing I had ever learned about. So, so buckle up. History has scared Tracy. History has scared me. So. From nineteen sixteen to about nine seven, this really bizarre epidemic spread around the world. It came to be known as sleepy sickness, and it is not to be confused with sleeping sickness, which is a tropical disease found in sub Saharan Africa. This is another name for a disease called encephalitis lethargica, and it caused this really weird variety of symptoms, from drastic behavior changes to unusual eye movements. Especially in the beginning years of it. Uh, the really common element was this deep, prolonged sleep that went on and on from days two months, and people just couldn't wake up. Between twenty and of the people who got this disease died, and of the ones who survived, only about a third really fully recovered. The rest developed what came to be known as post and syphilitic Parkinson ism, and some of these patients persisted in a semi comatose state for decades. It's extra terrifying. The next part is even more terrifying. Yeah, as if all of this were not enough to scare the pants off of you. While in this extremely deep sleep that was part of many of the cases, people appeared to be unconscious, but in reality they were actually alert. They were completely aware of what was going on, but they were unable to overspeaks, so it was a sort of paralysis. Really. Yeah, So people today may have heard about this whole disease from the movie Awakenings starring Robin Williams, or maybe from the first pages of Neil Gaiman's amazing comic book series Sandman, which starts off when a ritual that was meant to capture death instead captures dream and causes people to sleep endlessly. Otherwise, it's pretty far in the background of medical history most of the time. It's not something that people remember all that well today. But from its onset until about ten years after it faded away, there were more than nine thousand papers and books published on it, so at the time it was a big deal. Even though people don't necessarily come up with it immediately when thinking about huge epidemics today. Yeah, and I wonder why that is, um talk about some of that. Yeah, Prolonged sleep as an illness has been reported really really way back into history. There are written records as early as Hippocrates of this kind of incident happening. And then there are also, of course, in our cultural consciousness tales like sleeping beauty and these stories like rip van Winkle uh, and some people along the line have theorized that these were actually rooted to some degree in some kind of sleeping illness. In the real world, there had also been an outbreak of a similar condition in Italy in eighteen eighty nine and eighteen ninety, which came to be known as Landona, and it was thought at the time to be a complication of the flu. And around the world, other outbreaks of encephalitis had also followed behind other epidemics, particularly the flu. This particular one started just a couple of years before the nineteen eighteen Spanish flu epidemic, which killed between twenty and forty million people, and when it came to the encephalitis lethargica epidemic, the first reports came at about the same time in two different places, which were France in Austria. In nineteen six, in France, a doctor named Genre nee Cruche started to see six soldiers with this weird assortment of seemingly unrelated neurological symptoms, and the one common element was that the patients just slept, apparently peacefully and deeply, and that they could not be woken up, and he started to wonder whether there was some kind of new chemical weapon at work. At about the same time, a British doctor named A. J. Hall also reported similar symptoms, and other troops who were stationed in France. In Vienna, it came to the attention of Romanian Austrian psychiatrists Constantine von Economo after a sleepy, disoriented civilian wandered into the Wagner Jarre clinic where he worked. The doctors there had mostly been treating soldiers who were wounded in the war, so they really weren't prepared for this apparently uninjured civilian with nothing physically wrong that they could really point to. And then more and more patients with similar symptoms arrived at the clinic and there you know, they had the similar part of this uncontrollable sleepiness and sleep. But the rest of their symptoms were so strange and diverse that the doctors were really at a loss to figure out a cause or a treatment. These patients had fevers, malaise, double vision, they became lethargic. Sometimes they had sore throats. Their eye muscles would start working and their eyes would dart around or roll back in their heads. Some of them developed very strange eye and tongue movement movements, and this variety of other neurological and psychiatric symptoms. A few of them even had uncontrollable hiccups, and one died of that. How does that work? Well, if you can't stop hiccuping, you can't really eat or sleep, and then it can cause all kinds of other interesting Yeah. Once again, throughout all of this, the common element was this strange deep sleep from which they could not be woken. Vanni Conomos saw this common element and said, we're dealing with a sleeping sickness. Yeah. He was really the one that just laid that out there, and he's a character on his own. He was also a pilot who had been serving in the war, but he came back home to Vienna after his brother was killed and he really wanted to be flying, but reluctantly transferred to doing medical work instead to try to keep himself more out of danger and spare his family from further grief. On top of all that, he was also a baron, having been born to a family of Greek aristocrats and then married the daughter of an Austrian prince. As the patient started to die from sleep, Vonni Konomos started an intense research effort to find a cause and a cure. He studied autopsies of patients who had died of the disease, and he found common areas of damage to their brains, specifically in the hypothalamus, and he suspected that the differences and how much people slept was related to just how their hypothalamus was damaged. He also found that brain tissue could transmit the disease to monkeys, so he concluded that they were looking at something that was contagious. He publicly announced his conclusion that they were dealing with a new disease, probably a virus, before the Psychiatric Society in Vienna, on April seventeenth of nineteen seventeen. Uh Consequently, sometimes the disease has been referred to as von Economo's disease. His announcement was not at all well received. At the time. The prevailing view was that mental illnesses were all products of things like trauma and buried memories. Freud was really at the forefront of psychology at this point, so a lot of people just scoffed at the idea that there could be a virus or other disease process causing the kinds of behavior changes and psychological problems that some of the patients were exhibiting. The ongoing debate and this mystery of the whole thing kept much progress from being made in terms of treatment and prevention. But then, uh, the illness mostly disappeared from continental Europe. It really just fell off suddenly, and Spanish flew on the rise, took its place, and it became a much more pressing priority. Not long after that, though, the disease appeared in London and it followed much the same pattern as it had on the continent. There were, you know, all these patients who were suddenly having the strange collective collection of symptoms and sleeping constantly. The government in Britain quickly made it a reportable disease. The Ministry of Health had to be notified of all new cases and its appearance and spread UH in London was much like it had been in France and Austria. Strange symptoms and unending sleep uh you know, baffling the doctors. But in England the symptoms became even more alarming, with patients who could never sleep, or who couldn't stop laughing, or had other strange physical or emotional present sians It also seemed like fewer and fewer people were truly recovering. In Austria and France, there had been people that had gotten better, but as it's spread around England, a lot of people were becoming comatose or developing. As we mentioned at the beginning, what later it came to be known as post and syphilitic parkinson is um or PEP. Sometimes the onset of parkinson Is m happened years after people recovered, after they had apparently been healthy all that time. During the epidemic, the average age for the onset of Parkinson's dropped to thirty six years old. Today, while there are people who have early onset, the average age for people to start exhibiting Parkinson's is sixty. So this was really a significant and strange happening. Uh. Following the epidemic, two thirds of Parkinson's patients had previously had encephalitis, so it clearly was causing it. Right, this, this disease is was causing a drastic shift in who developed Parkinson's and when. And we're going to pause before we start talking about how then the rest of the world gets to be terrified. So to return to the story of encephalitis lethargica from England, the disease spread all over the globe, and the same story just played out over and over and over. People would start showing up with these strange symptoms that prevent that presented themselves in such different ways that it would take a while for doctors to realize what was happening. It really didn't help that the epidemic had started just at the end of World War One and just before the start of the nineteen eighteen Spanish flu epidemic, and so resources were just scarce and there were definitely bigger priorities going on. And this crazy, although terrifying disease, and as it spread, it started to prompt a variety of different sleep disorders. So while some patients would sleep for months at a time, others couldn't sleep at all, and they would actually die of exhaustion. The disease came to be known in some places as epidemic encephalitis rather than encephalitis lethargica, since not everyone could really be called lethargic anymore. As its spread, it also started to affect more and more children and young people. Children who contracted the disease developed impulse control issues that led to them having violent behavior in their adolescence. Some of them injured themselves or other people. One even removed her own eyes and several of her own teeth okay after unclenched. After that um, this behavior often would continue for the rest of these patients lives after they progress out of childhood, unless post and cephalitic parkinson is M made them physically unable to continue. For children with the disease, outbursts were so severe that many had to be institutionalized. Hospitals and asylums that were accustomed to providing care for adults suddenly had to develop new practices to care for children because there were so many suddenly having to move into institutions. Researchers theorized that the reason this encephalitis was causing behavior changes like this and young people was because their brains hadn't yet developed the capacity for self control that adults typically had by the time they were infected, and this tendency towards violent behavior and other erratic behavior even led to encephalitis lethargica being blamed for gangster behavior and lawlessness during the nineteen twenties. Once this disease spread to the United States, neurologist Frederick Tilney, who was known as Fred and had also been Helen Keller's neurologist, became the country's foremost authority on sleepy sickness. One of his most famous encephalitis patients was Jesse Morgan, who was the wife of Jack p Morgan, who himself was the son of banker and full anthropist John Pierpoint Morgan. She got the disease in After Jesse's death, Jack donated two hundred thousand dollars to the Neurological Institute to fund research into this disease. The Neurological Institute was behind most of the research into encephalitis lethargica that came from that point. Later on, William Matheson, who was the wealthy founder of a chemical company and an encephalitis patient started the Matheson Commission to fund research at the Neurological Institute, with Dr Josephine B. Neil, who was an encephalitis expert, helming the project and the commission's aim was to study the disease and eventually find a vaccine. Since nobody knew exactly what was causing the disease, they worked on three theories simultaneously. One was that it was being caused by an unknown virus, the next was that it was being caused by bacteria, possibly strapped UH, and the third was that it was being caused by herpes. This was a long shot to begin with because no causative agent had been found for this disease. They were basically operating in the dark based on best guesses. On top of that, there was a ton of infighting among the researchers. A lot of them were extremely prominent neurologists and scientists. Each of them really wanted to be the one to crack this case and figure out what's going on. Um that they were not working together very well. They were each trying to get the glory for themselves. And then there was another huge setback when Matheson himself died in nineteen thirty. That was in the middle of the Great Depression, and he had been providing the funding, so after his death there wasn't really other funding to be had, so the Matheson Commission ceased operations in ninety two and so no workable vaccine had been developed, and one of the things that doctors tried to treat post encephalitist patients of was lobotomies, which also did not work. There was a lot of ending that did not work. There were a few outlying successes during this time that would kind of give people false hope that maybe they were on the right track, but nothing led to an actual treatment or cure. Most of the medical care that the patients were receiving was really about just caring for their bodies and keeping them alive. The thirty or so percent who developed parkinson Is um generally wound up in long term care for the rest of their lives, and many of them were completely unable to move or take care of themselves. In the nineteen sixties, after the drug leve Adopa, or el dopa as it was called, was introduced for treating Parkinson's, New York doctor Oliver Sacks, who are some of our listeners may have heard of, administered it to some encephalitis lethargica patients who were in long term care. Some patients actually showed a limited recovery from their post and sephalitis lethargica parkinson symptoms. This is the story that's actually told in the movie Awakenings, which is why people may have heard of Olliver sex. But they all apparently developed a tolerance until the dosage was really just too much for the human body to handle, and then they would return to their semi comatose state in the end. This epidemic went on from nineteen sixteen to nineteen twenty seven, reaching its peak in nineteen twenty four, after which the number of cases started to drop off. The total numbers of people affected are really unclear. There are sources who say that a million people were killed, while others say that only half a million were affected in one way or another. Regardless, though the mortality rate was pretty serious in England, almost half of the cases in nineteen nineteen and nineteen twenty died. Although it was roughly concurrent with the Spanish flu pandemic, and flu came up frequently when looking at possible causes. Many doctors at the time didn't really think the disease was actually flu related. Only a small percentage of the patients had also had Spanish flu. In nineteen eighty two, however, doctors from the Centers for Disease Control published this list of connections between the two diseases. So for a little while. In more recent years, flu became a prime suspect for causing encephalitis lethargica. Uh there is, you know, especially since there have been other incidents of encephalitis that have followed outbreaks of the flu. Today, the idea that the flu was the culprit has pretty much been ruled out. Thanks to modern testing methods. They haven't turned up any sign of the flu virus in tissue samples from patients who died from encephalitis. Although it's never reached that same epidemic state again, isolated cases of encephalitis lethargica have continued to crop up even in recent years. Most recently in a twenty three year old named Becky Powell was diagnosed with the disease and it took her two years to recover. Several similar ass followed. In two thousand three, a team of doctors published a paper in the journal Brain that put forth a pretty good case that the cause of encephalitis lethargica is actually a massive autoimmune reaction to an unidentified pathogen. A strain of strep comes up in the discussion, but it's ultimately dismissed as unlikely. And their research was done on twenty different patients who developed the disease between two thousand two, and those patients had a much lower mortality rate than during the epidemic. Only one died, but five of them did have to be placed on a ventilator. Had those five patients lived in the ninety twenties, they probably would not have made it, but almost none of them had fully recovered a year or so later when the paper was published. They continued to have neurological and psychiatric symptoms. Yeah. If if there had been if today's ventilation technology had existed in the nineteen twenties, the mortality rate would have been sign Yeah, because people would get into this just deep uninterrupted sleep and their respiratory functions would fail, and there wasn't really anything that people could do about it. But now that we have ventilators, uh, that there are actual there's a treatment for that part of it that didn't exist back then. In a paper in the journal BMC Infectious Diseases reported that a team of researchers had found virus like particles in the brains of both epidemic encephalitis patients and modern patients, so people who had died either recently or during the epidemic. This supports the idea that the cause of encephalitis lethargica is an interarovirus, but exactly what interarovirus we still do you not know. So encephalitis lethargica has a some you know, a legacy today, even though a lot of people have not really heard of it as tragic and frightening as the disease was and is really. In the end, it helped doctors understand more about the brain. Von economos conclusion about the hypothalamus and its role in the patient's sleep, for example, was hugely unpopular at the time, but many years later it was proved to be true after we developed sorts of imaging technologies that we can use to look directly at the brain as it's working today. Neurologist Bernard Sacks also wrote that the epidemic of encephalitis quote revolutionized the practice of neurology, So it really changed the way that, uh, these things were examined from the get go. Yeah, it helped solidifying neurology as an actual field. In the early days, there was sort of this hodgepodge of neurology ideas and psychology ideas and all these things that were kind of together in one big pot. And in part because of encephalitis being spread the way that it was, a group of doctors branched off to study just neurology and it celf lightest lethargica was also one of the conditions that made it clear that disease processes can lead to mental illnesses. Uh, it's solidified the idea that mental illnesses were not solely in the realm of emotions or traumatic experiences. It's not always buried memories. Sometimes there can actually be a physical happening that causes mental illness. There are a couple of books that are out about this epidemic. The one that I read researching this podcast was called Asleep, The Forgotten Epidemic That Remains one of Medicine's Greatest Mysteries by Molly Caldwell Crosby and her grandmother survived sleepy sickness. It starts with sort of a case study of her grandmother. That's terrifying because it's about her grandmother being asleep for so long but also being aware of what was happening around her, which to me is just terrifying. The one caveat about this book is that it was written before the very most recent research about what might have caused this particular epidemic, which is going to be the case with just about every book now since the latest research is just from very new Yeah. Last year, as we were recording, I have read several papers that you know, and when the bird flu epidemic was was everybody was very frightened about bird flu. There were several articles that that came up where doctors were like, actually, what you really should be afraid of is a resurgence of this still unidentified encephalitis that sometimes that sometimes follows outbreaks of other diseases. I yeah, it's basically my worst nightmare. I mean, I have not a good relationship with sleep anyway. If I didn't have to do it, I wouldn't. So the idea of not having any control over the situation and just being asleep but not really because you're conscious of things happening. Is my worst nightmare. Yeah, not play on sleep jokes, but well, it's terrifying and the there are many things about this whole the epidemic and the illness itself that are are frightening to me, and one of them is that people would seem to recover and they would be fine for a long time, and then the developed fine developed parkinson symptoms um and once it had been established that that was a pattern, I can imagine like the people who had gotten better really being like I'm never going to be which I know that's the case with a lot of diseases that people have now, Like there are many cancer patients who never feel like they are in the clear because you can be in remission. So yeah, it's a scary thing to live with that kind of over you. Thank you so much for joining us on this Saturday. If you have heard an email address or a Facebook you are l or something similar over the course of today's episode, since it is from the archive that might be out of date now, you can email us at History Podcast at how Stuff Works dot com, and you can find us all over social media at missed in history, and you can subscribe to our show on Apple Podcasts, Google podcast, the I Heart Radio app, and wherever else you listen to podcasts. For more on this and thousands of other topics, visit how Stuff Works dot com. I'm Stuff you Should Know as Josh Clark, I'm launching a ten part podcast series about all the ways humanity might accidentally wipe ourselves right out of existence. It covers everything from whether we're alone in the universe to the evolution of life on Earth, from artificial intelligence to what goes on inside a particle collider. It is in a mensely interesting deep dive into the world of existential risks, and I hope that you enjoy listening to it as much as I have making it. I want to share a preview of the series with you. This clip comes from episode four and it features economist Robin Hansen, creator of the Great Filter hypothesis, which is something we may have to contend with in the near future. When we settled down, our cities, developed agriculture can support more people than hunting and gathering, and the more people there are, the more brilliant ideas there are. Two so our civilization began to advance by leaps and bounds in the last nine or ten thousand years. Ideas spread more quickly among those people who lived together in those new cities, so innovations were able to develop over the span of a handful of years rather than millennia. Almost everything we have in the world today can be traced back to our collective decision to settle down and raise crops. It was, to say the least, a sweeping change for us humans. With our next great leap spreading out into space, we are effectively doing the opposite of when we settled down into cities. Rather than contracting, we will be expanding. From that huge coming together, we will spread out. Over time, humans will begin to colonize other planets, and generations of little human babies will be borne on planets other than Earth. They will be shaped by forces and experiences that no earthbound human will have ever encountered, and they will learn to adapt to their home planet just like we did. We are quite capable of becoming all the things that it's possible to become. Life that starts from us and radiates out cannot only spread to different places that can create different styles and techniques and cultures and approaches. All of the life that you see on Earth started out from a much smaller amount of variation, but with time it could explore lots of different niches and ways of living. And that's probably what would happen to us too. If we're the only life around it, we can survive, we will radiate. We will become diverse and different and fill thousand million billion different niches of different ways of being. Over time, perhaps their physical connection to humans on Earth will become distant enough that new species of humans will form, and the universe will be home to more than one species of human again, just as it was fifty years ago. We will become the aliens we seek, and later on they might be surprised to learn that they came from something that was simple and not as very It's odd to think of, but humans are in an evolutionary bottleneck of our own. Right now. There's only one species of us, and with the exception of maybe half a dozen astronauts on the International Space Station at any given time, we are all stranded on this island Earth. Those astronauts aboard the I s S showed just the faintous beginnings of our future. If we become a space faring species, all of humanities eggs will no longer be in just the one basket of Earth. Should some catastrophe befall those of us here on Earth, there will be other humans living elsewhere to carry on. We will begin to trickle from our bottleneck and spread throughout the universe, and when we do, we will have made it through the great Filter. Colonizing beyond Earth is something we should begin working on as soon as we can, because Earth is vulnerable to a wide variety of catastrophes that are pretty hostile to life, things like exploding stars, the death of our son, even Earth's own systems going haywire. Please join me for the End of the World with Josh Clark. Listen and subscribe at Apple Podcasts or on the I Heart Radio app, or listen wherever you get your podcasts.