[00:00:08] Speaker In Florence, the cleansing of the city from many impurities, the refusal of entrance to all sick folk, and the adoption of many precautions for the preservation of health, also supplication addressed to God and often repeated in public procession, otherwise by the devout. Towards the beginning of the spring of the same year, the doleful effects of the pestilence began to be horribly apparent by symptoms that showed as if miraculous. Not such were they as in the East, where an issue of blood from the nose was a manifest sign of inevitable death. But in men and women alike, it first betrayed itself by the emergence of certain tumors in the groin or the armpits. From the two said parts of the body, this deadly lump soon began to spread itself in all directions, after which the forms of the malady began to change, black spots or purple? Making their appearance, in many cases, on the arm or the thigh. And as the lump had been, infallible token of approaching death, such also were these spots on whosoever they showed themselves.
[00:01:40] Narrator The quote above was written by Giovanni Boccaccio in the Decameron, circa 1350, about what is commonly called the Black Death, a wave of plague that occurred in Europe from 1346 to 1353, one of the most fatal pandemics in human history, killing up to an estimated 50 percent of the population. Welcome to Countermeasures. This season, we are looking back at historic public health outbreaks and bioterrorism events. From the Black Plague to the 2001 anthrax attacks, we are looking across the span of time to uncover how we have responded to health threats, what we’ve learned, and what we still have to do. Being over 650 years ago, the Black Death has loomed large in the public imagination ever since. This cataclysmic event reshaped European and global history in a multitude of ways, some of which we’ll explore in today’s episode. Plague was not a new disease to humanity in the 14th century. Waves of it had already hit Asia and Europe long before. So what makes the Black Death in particular resonate today? And what can we learn about public health response from an event that happened over six centuries ago? Philip Slavin is Professor of Medieval and Environmental History at the University of Stirling. Alongside three colleagues, he leads the Plague Synergy Project, a highly multidisciplinary project that expands our understanding of plague. He explains exactly how what we now call the Black Death got its start.
[00:03:20] Philip Slavin The Black Death was the first wave of what we know as the Second Plague Pandemic, just the first wave. So, how did it all start? In the 1330s, there was some really, really bizarre evolutionary event whereby several new biological branches of a Yersinia pestis bacteria, which is responsible for plague outbreaks, emerged. And one of these branches, known as Branch 1, emerged somewhere in Central Asia. This is something which led to the beginning of this really tragic and very massive mortality that starts in Central Asia in the 1330s. In the course of the 1340s it spread all the way to the Caspian Sea. From there it spread to Crimea. We know that it arrived in Crimea in 1346 and from there it continued spreading all over the world. It penetrated the Mediterranean region in 1347. It covered most of Southern Europe in 1348, then it moved on northwards to central Northern Europe in 1349, 1350. And it completed its vicious circle in the boreal forest of what is today Russia and Ukraine in 1352, 1353. So to make very important distinction, the Black Death is just the first wave of the second plague pandemic. The second plague pandemic was a continuum of dozens, if not hundreds of different waves of plague that covered all of Eurasia and parts of Africa between the 14th and the 19th century.
[00:04:43] Narrator When most of us think of the plague today, we picture rats and fleas, but there were many modes of transmission.
[00:04:50] Philip Slavin There were lots of different mechanisms. Obviously, one of the most important mechanism is commercial routes. So, you know, trade has always been playing very, very important role. I mean, if you think about Central Asia, I mean the only way for a plague, for the initial wave of the Black Death to arrive all the way from Central Asia into Mediterranean and beyond was to go through this network of commercial hubs, so-called Silk Road. It took several years, I mean it was really remarkable speed. So between 1338 and 1345 it really covered several thousands of kilometers. We know from both archeological and textual sources that trade was playing a very important role here. Now I mean once it gets into regions with a little bit better, I mean one problem about Central Asia is that we don’t have that much textual evidence there, but once it get to the Mediterranean region where we have really abundance of written sources. We know that not only trade played a very important role, but also raise human migration, because people never seen anything like that before. Plague was a new emerging disease, and it really created widespread panic all over the place there. People were really running for their lives from the city to the countryside, from the countryside to different cities, right? And by doing that, they willing nearly were spreading this awful pathogen that nobody had any idea what was all about. So you have human migration, you have trade links and I mean, if you also add to that military campaigns that were happening around the same time, you have several wars that were going on in different parts of Eurasia. I mean you end up with a perfect storm which facilitates the spread of plague. And we can say the same thing about the subsequent waves as well. I mean that’s that’s something which I call the unholy trinity. You have the wars, you have migration and you have trade.
[00:06:28] Narrator Sharon DeWitt is a professor of the Department of Anthropology and the Institute of Behavioral Science at the University of Colorado Boulder. She is a biological anthropologist specializing in bioarchaeology, reconstructing life in the past using data collected from human skeletal remains. Her research focuses on mortality crises in the medieval period, with an emphasis on the Black Death.
[00:06:54] Sharon DeWitt So when studying skeletons, when we’re interested in diseases, there are some diseases that do leave pretty diagnostic markers on the bones, but a disease that’s very rapidly killing like plague, which was what caused the Black Death in the 14th century, people either recover without any skeletal signs of the disease or they die before any skeletal signs might have formed. And so in order for us to actually try to study anything about the Black Death using human skeletal remains, we also have to rely on documentary evidence that gives us some information that a particular burial ground might contain people who died during the Black Death. So what we have in contexts like Medieval England is, which is where I do most of my research, we do have exclusive Black Death cemeteries where we know everybody buried in those cemetries died during the course of the Black Death and therefore that most of the people were victims of the Black Death itself and we also have contemporary written records that confirm the presence of plague and the creation of burial grounds to deal with mortality during the Black Death and so what we’re able to do by studying the skeletal remains of people who died during the Black Death is tell us a richer story about experiences at the time that includes many more people than are often included in written records from those past periods. So in England, for example, where I do most of my work, there are very rich documentary sources, but they primarily describe the experiences of land holding males above the age of 12, which is a portion of the total population that lived at the time. So we’re missing a lot of information about the lives and experiences and health and demography of women in general, of impoverished people, of children. But those individuals are included in the cemeteries that we have the privilege of studying. So what we can get from data from human skeletal remains is information about the health histories of those individuals who died during the Black Death. And what I mean by that is what are their experiences of exposures to stressors? We can get some idea about nutritional status and other factors, and we can get that information for a broad representation of the once living population. And what that allows us to do is go beyond sort of biomedical studies of plague in the past and actually consider how social context, social relationships, shaped health and shaped experiences and outcomes during the Black Death.
[00:09:36] Narrator There’s a lot of researchers like Sharon can tell from skeletal remains.
[00:09:41] Sharon DeWitt Yeah, I think a lot of people are surprised to find out how much our skeletons and our teeth reveal about our lives. So I’m going to start with just basic building a basic demographic profile. Almost all of the individuals that I study, and this is true for a lot of bioarchaeological research, there’s no independent identifying information for those individuals that means that we have to estimate everything we are interested in from features of the skeleton. So we estimate age at death in children. We can estimate age based on the fusion of bones. We can also look at the growth and eruption of teeth into the mouth. And then once somebody is fully mature, the way that we estimate age at death is by basically looking at degeneration of the skeleton over time, and using information that we know from people living people of known age and what their skeletons look like. And then in terms of health, there’s so much that the skeleton records about our health conditions. There are some markers or lesions on the skeleton that are indicative of early life stressors that temporarily halted the formation of enamel. And then for individuals who survived that stressor, the enamel resumes in a normal fashion. And what it leaves is a lasting record throughout the rest of that person’s life, as long as the teeth remain in the mouth of stressors that they experienced in infancy, in childhood, in early adolescence.
[00:11:11] Narrator As with many outbreaks today, disease and illness do not affect everyone equally. Medieval written sources tend to focus on the experiences of elites, so skeletal evidence helps researchers understand how ordinary people were affected.
[00:11:25] Sharon DeWitt In terms of using the skeletons to assess how social status affects life and health, very often we have to rely on contextual information to understand the social status of any one particular individual. So for example, there’s a cemetery that I have studied in my research from medieval, England, in which the location of burial indicates the status of the individual. So individuals who were wealthy, who were important religious personnel, they were buried within or very close to the church buildings. And then the general population, lower status people, they were buried in a separate cemetery that’s farther away from the church buildings. So that burial location tells us something about relative social standing in that particular population. In some cases, we have entire cemeteries that were only used for higher status or wealthier individuals and separate cemeteries used for lower status impoverished individuals. So very often we were using external information to determine social status and then comparing people of different social statuses and seeing how their the health that’s been recorded, the signs of health in their skeletons might differ and how that might tell us something about the protective or dangerous aspects of living in poverty or having wealth and high status.
[00:12:50] Narrator Understanding of illness in the 14th century was worlds away from our own, and it varied dramatically depending on where you were, and often was influenced by region.
[00:13:01] Philip Slavin Here we have to make a very important distinction between the theological explanation and the quasi-scientific. I’m a little bit hesitant to say scientific, so let’s just call it quasi-scientific. So theologically speaking, all three Abrahamic religions thought about this as the punishment from God for human sins. Judaism and Christianity and Islam, people were talking about in very, very similar terms about divine punishment for human sins. When it comes to more, if you want, quasi-scientific explanations, so the predominant view was that there was something called miasma. Now, miasmas were bad airs that originated somewhere inside the crust of the earth. And then, you know, when you have some natural disasters like the earthquakes, they would release those bad vapors into the air and they would be spread in pathogens. I mean, that was the classical Galenian view which perpetuated for over millennia. I mean all the way from the Roman antiquity up until the 19th century. I mean it was not until the 18th century when people started getting the idea of bacterial or viral nature of pathogens. And then, of course, you can also add to that more popular view of how diseases are being transmitted. For example, the popular view within Islamic communities was the idea of the jinn. You have some bizarre spirits that are bad spirits that live in somewhere and they’re responsible for transmit for doing all bad things. It’s a little bit like fake news and conspiracy theory of that time. So, if you encounter some intellectual, say, in Cairo, the same person will tell you that it was, on the one hand, divine punishment, but it was also the act of miasma. But if you step outside of Cairo for example, in 1348 and go to a local village, the chances are that a local inhabitant of that village will tell you, oh, it’s all about the jinn.
[00:14:48] Narrator Some communities did take effective measures. It wasn’t public health as we’d recognize it today. But in many ways, these were the first steps toward communities coming together to prevent illness.
[00:15:01] Philip Slavin They had no idea how to contain the pathogen. I mean, the only exception, if you will, was the communal response in Pistoia. That’s a city in the region of Tuscany, in Italy, that attempted to do something. So it realized that the plague was already disseminating quite widely in nearby Lucca and the Florence, the two major Tuscan cities. And they realized lots of people were dying there. So they were really trying to contain as much as possible. For example, they forbade anyone to move in and out. They also forbade any imports and exports of clothes because they realized that trade also meant the spread of pathogen. To no avail, didn’t really help much because plague did come anyways to Pistoia and kill a large proportion of local population. I mean, you really have to wait several outbreaks after that. It was not really until 1377 that you have the first Lazaretto that was established in Dubrovnik, Ragusa, which was a Venetian colony by itself. So, I mean, Venetians authorities, I mean I think they really deserve special praise because they were quite progressive for their own age in how they were addressing the challenges of plague. Then of course you have the establishment of a local Lazaretto for plague victims in Venice as well in 1423. And it was not until the 15th century that other major European cities were catching up after Venice using the Venetian model. So first other Italian cities, then Catalan cities, then South French cities, then slowly but surely it’s also this idea of plague control also disseminated to the Northern Europe, to Germany, to England towards the end of the 15th century. So you really see a change for better in the course of the 16th century when you have more and more efficient control of plague but also of other infectious diseases addressed by local authorities. It always takes two to tango, so on the one hand you have the authorities, but on the other hand you also have very clear evidence in the course of the 15th century all over Europe of this environmental conscious, you know this environmental conscious among local communities. And it was then that they were taking initiative to make sure that their communities are clean, they’re looked after, that all the garbage has been taken away, that streets are being mopped and their the all the pathogens are kept at bay. The idea was that in 1423, you have the establishment of so-called the old Lazzaretto, Lazzareto Vecchio in Venice. And the idea was, that once you have an outbreak, people had to come there and kind of turn themselves in, either by themselves or by the relatives. And they were kept there for a certain period of time, sometimes 40 days. And that’s why we have this term, quarantine comes from the word literally. This is one idea, by the way, another major and you can say revolutionary thing that the authority did, they established the first historical health board. In 1486 it was called Provviditori alla Sanità, you know, providers of health or health board, I mean, that’s the way I prefer to translate it. And this health board consisted of officers that were responsible for maintaining high standards of health and cleanliness in the city. When there was an outbreak in the city, the responsibility was not only to make sure that all the sick people are isolated within their own communities and they’re not allowed to intermingle with the healthier streets, but they also were responsible for making sure that whoever arrives in the Venetian port are forced to go into quarantine for 40 days. And once the quarantine was over, not only that, they were interviewed in a very meticulous way and we have wonderful records in the venetian state archives of those interviews whereby local ship captains were actually telling where they came from, how many people were on board.
[00:18:47] Narrator The Black Death reshaped European society forever.
[00:18:51] Philip Slavin We can really generalize here, I think we can distinguish between several regional cases, I mean some regions really profited from that, quite paradoxically some other places actually were doomed to very long decline and stagnation, if you look into places like England for example, so comes the Black Death and kills about 50, possibly 60 percent of England’s population, right? And it’s really changed the ratio between land and labor quite drastically, right? All of a sudden you have all this surplus land. So, and the local lords were actually in trouble because they were really struggling to find tenants in order to occupy their land. And they, you know, if you don’t have local tenants, who on earth will plow your land and harvest your crops, right? So they had to actually negotiate much better terms to attract new tenants, and the tenants actually for the first time in many centuries had an upper hand in commanding their own terms and conditions of land occupation. As a result, this first form of serfdom was abolished in the course of the 14th and 15th century, and in some regions it was abolish right after the Black Death. So, by the mid-14th century, you also have the emergence of new rural classes. You have, first of all, you have the emergence of gentry, that was a, you know, new rural capitalist class. You also have emergence of a barrow of tenants, which were supplementary to the gentry. And if you’re looking for the roots of agrarian capitalism. And indeed the industrial revolution later on, that’s your roots here. So simply, you know, you add more land and much more favorable conditions and you all of a sudden you have the emergence of the new rural class with a very, very progressive capitalist mentality which was very, you now, different from the previous señorial mentality.
[00:20:34] Narrator There’s a lot about the Black Death that we think we know, but a surprising amount of the common knowledge doesn’t actually come from evidence of the period itself.
[00:20:43] Sharon DeWitt One of the things that I think that people get wrong is a lot of what we think we know about plague in the medieval period, in the post-medieval period, is not actually known based on evidence from those time periods. And instead, a lot of what think we think about the Black Death, the Great Plague of London in the 1600s, other outbreaks of plague in the past. A lot of what we think we know about those is simply limited information from more recent outbreaks of plague that has been unquestioningly applied to outbreaks in the past. And that includes this common perception of the dynamics of plague and always involving rats and fleas and then humans as victims. Absolutely rats and fleas are involved in plague spread and plague dynamics, but there are over 200 non-human animal reservoirs of plague that are the natural hosts of the disease and the disease is maintained within those populations. And there are lots of ectoparasites other than fleas that can transmit plague from one animal to another. But when we read about the Black Death in the Medieval period, very often you hear rats and fleas, rats and fleas. But we don’t actually know that rats and fleas are the primary vectors overall or in any particular location that was affected by the Black Death. We don’t know the extent to which the Black Death might have been spread directly person to person. There is a form of plague, a clinical form called pneumonic plague, and pneumonic plague is a disease of the lungs, and it is possible for people to spread the pneumonic form directly to other people. So it could be that there are more people suffered from pneumonic plague during the Black Death than has been observed in more recent outbreaks. There’s just a lot about the epidemiology of the Black Death that we don’t know about. But because of that sort of background information about rats and fleas. It is reproduced in the literature about the Black Death. It sort of limits people from thinking about the possibility of actually examining those epidemiological trends in the past. So I think it’s important for people to understand that not everything that’s reported about the Black Death is actually known using evidence from the medieval period. And there’s still a lot more to disentangle about what was happening at the time of the Black Death. And the more that we know about the emergence and the spread of the Black Death in the 14th century, the better we are in terms of understanding emerging diseases more generally. So what are the risks of diseases coming into populations from, into human populations from our interactions with animals, how climate might affect the spread of disease, how human activities affect the spreading of disease. If we just rely on patterns that we observe in the 20th and 21st century to understand the past, we’re gonna have an incomplete understanding. And that might actually be harmful in terms of our attempts to control diseases going forward.
[00:23:55] Narrator Phil sees similar pattern of misconception, including one that came up when a very different pandemic hit in 2020.
[00:24:01] Philip Slavin I will confine myself to two or three examples, right? So the first example, and when the COVID started, I got like a flurry of emails from all sorts of journalists and other people asking me, well, so how can we use our knowledge about plague in order to address COVID? COVID and plague have nothing to do together. COVID is a viral disease. Plague is a bacterial disease. Plague has been around for many, many years. COVID is an emerging new disease that we at that point knew nothing about. So there’s absolutely no connection. You cannot really extrapolate any experiences and knowledge of plague and assume that you can say, you can use the same knowledge in order to improve the situation with COVID.
[00:24:42] Narrator Sharon stresses that there are still lessons to be learned from the Black Death, even today.
[00:24:47] Sharon DeWitt One of the things that can cause these markers of early life stress in the skeleton is malnutrition during childhood. We know how important nutrition is for the performance of our immune systems, our immune competence, and health more generally. And what we know from the huge body of literature in it that looks at the effect of early-life stress on later health outcomes And that’s basically, there’s now an entire field called developmental origins of health and disease. We refer to it as DOHaD. From studies of living people, recent historic populations, and now using bioecological approaches to look at these phenomena in much, much older populations, when an individual is growing and developing and they experience malnutrition, that can cause dysregulation of physiological systems throughout the rest of their life. So if they’re not receiving enough nutrition while they’re growing and developing, there can be these trade-offs in growth and development that ensure the short-term survival of the individual, but it might hamper the development of the immune system. It might lead to issues with insulin sensitivity, a lot of things that can ultimately lead to poor health outcomes decades later. So we know from many, many studies that nutritional status has immediate effects on health and longer-term effects on health. And we also know that in living populations, in historical populations, social status very often is intimately linked with nutritional status. And so we have these combination of factors that can very strongly shape health immediately and over the long term. And what we see from evidence at the time of the Black Death is that it’s possible that that earlier nutritional status or nutritional status at the times of the Black Death shaped risks of mortality and we know that social status is the context that can affect nutritional status and this is not unique to the Black Death. We see this repeatedly. This is a factor that is at some level external to the human body. And that means that there is the theoretical possibility that there are interventions that can be made. So I think this repeated evidence across time, across multiple disease outbreaks, epidemics, pandemics of nutritional status, tied to social status, tied to health outcomes, and the fact that some of these are exogenous external to the human body, we should be really attentive to ways in which we can intervene because we know this is gonna continue to be a factor in future disease outbreaks. It’s just a fundamental mechanism that we know about, that we’ve know there are ways to address it. We just need the will and the resources to actually do something about it.
[00:27:45] Narrator What emerges from Phil Slavin’s and Sharon DeWitt’s work is how much the Black Death still has to teach us, not just about the 14th century, but about how societies respond to disease outbreaks today. The instinct to blame outside forces, the gap between what we assume we know and what the evidence actually shows, and the way social status and health are connected. 650 years later, plague still exists in the wild reservoirs around the world. It hasn’t gone anywhere. And as this history shows, the real lesson of the Black Death isn’t a history lesson at all. It’s a warning about how quickly we forget what we’ve learned, and how much is still riding on whether we choose to remember it. Thank you for listening to Countermeasures. If you enjoy the show, please consider leaving us a rating or review. Thank you to our guests for taking the time to share their insights. If you found this episode insightful, please share it with colleagues and friends. And don’t forget to subscribe! So you don’t miss future conversations.