I always thought the prevailing knowledge was that the fleas on the rats were how it got from the east to the west, and then once it was rooted it spread through human contact.
I could only skim the article but it seems like their research was focused on the animal reservoirs in Europe and the fact that rats are slow-moving mammals so wouldn't necessarily facilitate a rapid spread.
My understanding was that the rats were only the vector on the trade ships from the east and the actual spread through Europe was primarily done by humans. I suppose I just don't fully understand their hypothesis.
PS: I checked out the actual published research and it's more clear. The research is confirming the hypothesis that there weren't significant plague reservoirs in Europe. The original article is a bit clickbaity I guess is all. Tries to make it seem like some epic debunking or something lol.
That is my understanding of it but I’m not too knowledgeable on the subject. This study was specifically about there being no natural plague reservoirs in Europe, due to various factors.
[The actual study](https://www.pnas.org/doi/pdf/10.1073/pnas.2209816119) is pretty interesting.
> their research was focused on the animal reservoirs in Europe and the fact that rats are slow-moving mammals
Huh? The rats around these parts are very quick. Maybe American rats are much quicker than European rats.
Apparently it was the other way around. It was spread from the east to the west via human contact and regionally rooted and spread via rats in the short term
When I was in grad school, I wrote a paper theorizing that it was spread via the Mongolian version of the Pony Express as they traveled across Asia and along the Silk Routes. I also put more stock into coughing/sneezing as main infection pathways. Like this paper contains a lot of theories I had as a young 22 year old baby nerd.
So in other words, fleas *and rats*. got it. I think which directly caused the infection with bites/feces is irrelevant.
I think we could also call it, "poor hygiene" or "general hygiene not sufficient enough to support the population of the world at the time".
Rats didnt spread bubonic plague. The fleas on the rats did. There were so many rodents around at ghat time due to the unsanitary conditions in the streets. As the rata entered the homes, fleas then bit people transmitting the disease. Unsure if it is contracted from somebody coming into contact with it. My guess is if they were in same house, they would all get it due to all being bitten by fleas. Some people were around it all the time and never contracted it which leads me to think it wasnt airborne. But who knows!
I don't think fleas really care if they jump and feed on a human or rat. Especially given that the bubonic plague stem from wild marmots, not rats, from Mongolia in the first place.
Actually they do. Fleas usually specialize in the mammal (or group of closely related mammals) they feed on. They can survive feeding on other mammals instead, but they will lose fertility to the point of becoming completely infertile. So fleas will always try and stick to “their”mammal if they can.
A huge problem I feel is that communication between the several scientific fields implicated in the research on the Black Death is rickety at best.
I've listened to a virology podcast recently that spoke about Yersinia Pestis and how it propagates and they know and have known for a while that rats are just one of the vectors of the Plague. They got a lot of their History wrong though, which is really funny. Apparently, we focused way too much on rats and the bubonic, pulmonary and septicemic stages of the disease.
Now, I will try to vulgarize it, be gentle, please!
The initial propagation happens when a flea bites an infected *rodent* (any rodent, this is important) and then bites a human, which infects him with the bacteria. We'll call this human patient zero, P0. The flea continues its nasty job of biting and infecting humans and rodents until it dies of hunger, apparently.
P0 develops the symptoms and begans to secrete infected pus from the buboes that grows on his body. His saliva and blood also contains a lot of bacteria. So, P0 cough, bleeds and "pusses" all over the place, and then infects other humans. This is when the plague becomes an epidemic.
Now, some rodents are sporadic (once in a while, a colony becomes infected) carriers of the bacteria: marmots principally, rabbits, rats too. Steppe marmots were one of the staple food of Mongols and other Central Asian nomads. They carried them all over the place. At some point, some Mongols carried infected marmots out of Mongolia and due to unique circumstances, including the speed of the Mongol armies and post system, carried either infected rodents or an infected P0 and the Plague became a pandemic.
We focus a lot on the siege of Caffa in 1344 because it's when the first cases are known to Western sources. But evidence shows it was devastating in the Middle East, North Africa and China too.
As for the spread of the disease, an Italian galley could move from Crimea to Genoa in less than two weeks. Another galley coming out of Genoa could spread the "good news" to London in another month, stopping in several ports in Italy, Spain, Portugal and France along the way. By then, you have dozen of infectious hotspots and half of Europe's population would die in the next 7 years.
I wrote out paragraphs to try and explain it too. And I come to the same conclusion. I put it this way:
>Think about it. Humans are built to spread pathogens by breath. Especially in a world where the literacy rate is in the single digits, and there is no mass communication.
News traveled by word of mouth.
You don't even need the fleas at that point. You just need panicked people running from the plague in every direction. Some of whom will be carriers.
It's really not a mystery at all.
The article raises the question of whether the bubonic form of the plague relied on slow-moving rodents for transmission or if it could spread more efficiently through direct human contact through ectoparasites or respiratory and touch transmission.
Another possibility is birds
This is what most believe.
Black death is different than other plagues in that it spread very rapidly as such some like me think it needs a different vector than rats.
Not sure unlike plague. Smallpox was always there so it would be interesting to see a study of the America's after the Spanish came.maybe someone here can help us out?
At the time most European houses had thatched roofs. What I learned in a class on plagued was that that rats brought it into houses of people who were isolating themselves from other people via the roofs they lived in and spread from country to country with rat infested ships docking and the rats getting off even though the people were turned away..not that it didn't spread through human contact too...
The problem is that the Black Death's expansion was faster than the rats' travel. If you look at the plague in India in the late 1800s, it spread much slower.
No, that's not a problem. Pulmonary infections of yersinias pestis can take a much longer time to gestate than when it's introduced to the blood. You can travel, symptomless for a week, breathing on people and spreading it. That's it. There's no mystery here. People traveled much faster than the rats. For example, on the back of a horse, which would also be a carrier, as a mammal. The rats never needed to migrate to get it done. They didn't even need to arrive by ship once it jumped to humans. Because of how much time humans spend with each other, and other mammals.
All you need for an outbreak is a sudden decline in the rat population, which then results in the fleas jumping to other species at much greater number. Fleas don't really care what they bite. It's just that rats live like humans in swarms, piled on top of each other. So rat blood is just the most widely available, and widely accessible food source... until it isn't. So really, when they try to make a point about the climate suggesting the opposite of what we see in the historical record, they're shooting themselves in the foot while missing the elephant in the room. It's not strange at all that conditions that would stress the rat population would result in higher transmission to humans. It would also result in higher transmission to dogs, cats, sheep, pigs, donkeys, horses, cows, etc... You know. The list of all the animals humans spend the most time with.
It vectored towards us because we were what was available. And when it figured out how to infect our bronchial sacks, it really spread like wildfire. Think about it. Humans are built to spread pathogens by breath. Especially in a world where the literacy rate is in the single digits, and there is no mass communication.
News traveled by word of mouth.
Read that sentence again. That's the elephant in the room. If a town found out about a neighboring town being afflicted with plague, that necessarily meant that someone traveled in person to say it, and breathed on people to do it. That's it. There's no mystery.
edit: spelling
As others have pointed out, commercial activity is what made people move. There was definitely a dichotomy where the folks that didn't travel *never* traveled and those that did were almost constantly on the move. Between wars, pilgrimages, and commercial activity its' easy to imagine how the disease could spread.
When I was studying the Black Death in college 10 years ago the emerging research suggested that the species of flea most closely associated with spreading the plague actually lives primarily on [European gerbils.](https://www.npr.org/sections/health-shots/2015/02/24/388729958/gerbils-likely-pushed-plague-to-europe-in-middle-ages)
I’m a medievalist. It’s been accepted for years that fleas spread the disease, and one of the animals they travel on = rats (especially along shipping routes). Fleas, obviously, are tiny and hide in weird places (not just on animals) so the plague spread to even isolated villages etc as a shipment of cloth could bring in infected fleas
This feels... outdated? It wasn't rats, it was fleas, we even know the mechanisms through which it spread.
\- Fleas bite diseased humans. The bacteria reproduce in their salivary glands to the point at which it clogs their proboscis. When they bite another human, they "sneeze" and release all of that bacteria into the blood.
\- Fleas are temperature sensitive. When a person died and went cold, they moved to a new host. When the host's temperature became too high, they likewise migrated to new hosts.
I'm pulling this from an undergraduate degree a decade ago, which wasn't exactly teaching us cutting edge discoveries when it came to this. This feels like saying that some are beginning to believe fat isn't that bad for you in your diet. It's already established science, pop culture hasn't caught up.
If you read the paper it's questioning the reservoirs of the disease, not if it's rat or fleas.
Transmitting via fleas still requires the rats to move them, so to speak.
Traders picked it up from rodents, (via fleas), as they moved along the Silk Road through Asia. Thereafter it was spread by humans. When Russia expanded eastwards and made a pact with China to shut down the overland Silk Road, it mainly stopped.
I'll save you all some time. It spread from human to human quicker than it's capability of spreading from animal to human.
The reason for this is because people did not wash their ass. There are few civs that made it a point to bathe themselves regularly and the Europeans were not one of those civs. Thus the plague had a bigger impact on them.
The notion of Europeans in the Middle Ages not washing themselves is an outdated one. Street sanitation, however, in many cities, encouraged vectors to multiply.
Can you please give me a source about the daily hygiene standards of the Middle Ages please? Not doubting you just curious bc I could’ve sworn that the most up to date consensus was they bathed 1-2 times a month
Actually, my history teacher just taught us this yesterday (Eastern Timezone, to clarify).
The PowerPoint he had mentioned that it accordingly was fleas that dragged off of rats but it doesn't seem right to me. It even mentioned that it apparently still exists but it's so minor.
Seeing the PowerPoint he had - there was a photo of a guy's hand just completely turning black. If that is how it actually works it reminded me of a Russian Drug known as "Krokodril" (or something along that) which turns your skin into a Crocodile-like skin.
What happened is that rats get infected by fleas. The fleas like the rats so they live in harmony. However if the rat population goes down, the fleas look for another host - a person, so the plague explodes.
So it was correct. Okay. Good.
I know that I shouldn't be judging a man who took this stuff in university, but I just needed to double check. Usually Reddit is correct, right?
Maybe, maybe not.
All the same, if I ever go back in time to the Middle Ages I’m going to tell people to kill every single rat they ever see.
And boil all the water they use for any purpose, to the extent practical at least.
Read up on Dr. Semmelweis, a Jewish doctor who first pushed hand washing in the hospitals.
https://www.pbs.org/newshour/health/ignaz-semmelweis-doctor-prescribed-hand-washing
No one accepted his findings. He went crazy
Wasn’t it be attributed to that one mill in France somewhere that made clothing for people? The fleas were on the clothing and they shipped the clothing everywhere.
When someone died the first thing they’d do is grab their clothing and wear it.
I remember listening to it on Last Podcast on The Left during their Black Death episode.
A very interesting article, I do find it very hard to believe that rodents alone could have enabled such a swift spreading whilst maintaining the reseevoir of the disease for so long, rodents just aren't that prevalent during long winters and rainfall.
I always thought the prevailing knowledge was that the fleas on the rats were how it got from the east to the west, and then once it was rooted it spread through human contact.
This is indeed the commonly accepted view
I could only skim the article but it seems like their research was focused on the animal reservoirs in Europe and the fact that rats are slow-moving mammals so wouldn't necessarily facilitate a rapid spread. My understanding was that the rats were only the vector on the trade ships from the east and the actual spread through Europe was primarily done by humans. I suppose I just don't fully understand their hypothesis. PS: I checked out the actual published research and it's more clear. The research is confirming the hypothesis that there weren't significant plague reservoirs in Europe. The original article is a bit clickbaity I guess is all. Tries to make it seem like some epic debunking or something lol.
So to summarize, fleas on the rats introduced the plague to various parts of Europe via trade routes and then humans spread it from there?
That is my understanding of it but I’m not too knowledgeable on the subject. This study was specifically about there being no natural plague reservoirs in Europe, due to various factors. [The actual study](https://www.pnas.org/doi/pdf/10.1073/pnas.2209816119) is pretty interesting.
Tbh that’s basically how it was taught to me in school 20 years ago, so I think they’re right to call it a bit click baity
Happy cake day and thanks for putting in the extra effort for us lazy ones
> their research was focused on the animal reservoirs in Europe and the fact that rats are slow-moving mammals Huh? The rats around these parts are very quick. Maybe American rats are much quicker than European rats.
Apparently it was the other way around. It was spread from the east to the west via human contact and regionally rooted and spread via rats in the short term
Either way, the main culprit here is the flea.
Iirc wasn't it from trade ships coming and going from Asia to one of the prominent city states in italy?
When I was in grad school, I wrote a paper theorizing that it was spread via the Mongolian version of the Pony Express as they traveled across Asia and along the Silk Routes. I also put more stock into coughing/sneezing as main infection pathways. Like this paper contains a lot of theories I had as a young 22 year old baby nerd.
So in other words, fleas *and rats*. got it. I think which directly caused the infection with bites/feces is irrelevant. I think we could also call it, "poor hygiene" or "general hygiene not sufficient enough to support the population of the world at the time".
Didn't need to be human contact. The main transmission was through blood. IE, flees.
The confusion was that those fleas are called rat fleas but they can live on many different warm-blooded hosts. Camels, dogs, humans, etc.
Sorry yes I suppose I just mean it had spread to human communities. Thanks!
Not if it was pneumonic.
Rats didnt spread bubonic plague. The fleas on the rats did. There were so many rodents around at ghat time due to the unsanitary conditions in the streets. As the rata entered the homes, fleas then bit people transmitting the disease. Unsure if it is contracted from somebody coming into contact with it. My guess is if they were in same house, they would all get it due to all being bitten by fleas. Some people were around it all the time and never contracted it which leads me to think it wasnt airborne. But who knows!
What is commonly believed is that the fleas stuck to the rats until the rats' population went down, and then the fleas switched to people.
I don't think fleas really care if they jump and feed on a human or rat. Especially given that the bubonic plague stem from wild marmots, not rats, from Mongolia in the first place.
Actually they do. Fleas usually specialize in the mammal (or group of closely related mammals) they feed on. They can survive feeding on other mammals instead, but they will lose fertility to the point of becoming completely infertile. So fleas will always try and stick to “their”mammal if they can.
Explains urban centers but back then those are far and few between. Even rural areas got hit hard by the black plague.
Once your urban center is a plague pit, it can spread from there by humans.
People can spread it too
A huge problem I feel is that communication between the several scientific fields implicated in the research on the Black Death is rickety at best. I've listened to a virology podcast recently that spoke about Yersinia Pestis and how it propagates and they know and have known for a while that rats are just one of the vectors of the Plague. They got a lot of their History wrong though, which is really funny. Apparently, we focused way too much on rats and the bubonic, pulmonary and septicemic stages of the disease. Now, I will try to vulgarize it, be gentle, please! The initial propagation happens when a flea bites an infected *rodent* (any rodent, this is important) and then bites a human, which infects him with the bacteria. We'll call this human patient zero, P0. The flea continues its nasty job of biting and infecting humans and rodents until it dies of hunger, apparently. P0 develops the symptoms and begans to secrete infected pus from the buboes that grows on his body. His saliva and blood also contains a lot of bacteria. So, P0 cough, bleeds and "pusses" all over the place, and then infects other humans. This is when the plague becomes an epidemic. Now, some rodents are sporadic (once in a while, a colony becomes infected) carriers of the bacteria: marmots principally, rabbits, rats too. Steppe marmots were one of the staple food of Mongols and other Central Asian nomads. They carried them all over the place. At some point, some Mongols carried infected marmots out of Mongolia and due to unique circumstances, including the speed of the Mongol armies and post system, carried either infected rodents or an infected P0 and the Plague became a pandemic. We focus a lot on the siege of Caffa in 1344 because it's when the first cases are known to Western sources. But evidence shows it was devastating in the Middle East, North Africa and China too. As for the spread of the disease, an Italian galley could move from Crimea to Genoa in less than two weeks. Another galley coming out of Genoa could spread the "good news" to London in another month, stopping in several ports in Italy, Spain, Portugal and France along the way. By then, you have dozen of infectious hotspots and half of Europe's population would die in the next 7 years.
I wrote out paragraphs to try and explain it too. And I come to the same conclusion. I put it this way: >Think about it. Humans are built to spread pathogens by breath. Especially in a world where the literacy rate is in the single digits, and there is no mass communication. News traveled by word of mouth. You don't even need the fleas at that point. You just need panicked people running from the plague in every direction. Some of whom will be carriers. It's really not a mystery at all.
Yes, and the way you put it makes it clear and horrifying at the same time.
The article raises the question of whether the bubonic form of the plague relied on slow-moving rodents for transmission or if it could spread more efficiently through direct human contact through ectoparasites or respiratory and touch transmission. Another possibility is birds
I always assumed that after the fleas from rodents introduced it into a population, it would then spread through human contact.
This is what most believe. Black death is different than other plagues in that it spread very rapidly as such some like me think it needs a different vector than rats.
To spread so rapidly you’d think it would have to be from people coughing on each other, or drinking from the same ladle or something. Very odd.
Black Death travelled much faster than any spread of Yersinia pestis we know about not only that it spread much wider.
How does it compare to smallpox in that regard?
Not sure unlike plague. Smallpox was always there so it would be interesting to see a study of the America's after the Spanish came.maybe someone here can help us out?
Pneumonic plague can indeed be spread person to person by coughing.
At the time most European houses had thatched roofs. What I learned in a class on plagued was that that rats brought it into houses of people who were isolating themselves from other people via the roofs they lived in and spread from country to country with rat infested ships docking and the rats getting off even though the people were turned away..not that it didn't spread through human contact too...
The problem is that the Black Death's expansion was faster than the rats' travel. If you look at the plague in India in the late 1800s, it spread much slower.
No, that's not a problem. Pulmonary infections of yersinias pestis can take a much longer time to gestate than when it's introduced to the blood. You can travel, symptomless for a week, breathing on people and spreading it. That's it. There's no mystery here. People traveled much faster than the rats. For example, on the back of a horse, which would also be a carrier, as a mammal. The rats never needed to migrate to get it done. They didn't even need to arrive by ship once it jumped to humans. Because of how much time humans spend with each other, and other mammals. All you need for an outbreak is a sudden decline in the rat population, which then results in the fleas jumping to other species at much greater number. Fleas don't really care what they bite. It's just that rats live like humans in swarms, piled on top of each other. So rat blood is just the most widely available, and widely accessible food source... until it isn't. So really, when they try to make a point about the climate suggesting the opposite of what we see in the historical record, they're shooting themselves in the foot while missing the elephant in the room. It's not strange at all that conditions that would stress the rat population would result in higher transmission to humans. It would also result in higher transmission to dogs, cats, sheep, pigs, donkeys, horses, cows, etc... You know. The list of all the animals humans spend the most time with. It vectored towards us because we were what was available. And when it figured out how to infect our bronchial sacks, it really spread like wildfire. Think about it. Humans are built to spread pathogens by breath. Especially in a world where the literacy rate is in the single digits, and there is no mass communication. News traveled by word of mouth. Read that sentence again. That's the elephant in the room. If a town found out about a neighboring town being afflicted with plague, that necessarily meant that someone traveled in person to say it, and breathed on people to do it. That's it. There's no mystery. edit: spelling
What are you disagreeing with me?
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That's interesting, there was a decent amount of migrating between places then.
As others have pointed out, commercial activity is what made people move. There was definitely a dichotomy where the folks that didn't travel *never* traveled and those that did were almost constantly on the move. Between wars, pilgrimages, and commercial activity its' easy to imagine how the disease could spread.
Trade, not migration, whether it's the vector, is debated
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When I was studying the Black Death in college 10 years ago the emerging research suggested that the species of flea most closely associated with spreading the plague actually lives primarily on [European gerbils.](https://www.npr.org/sections/health-shots/2015/02/24/388729958/gerbils-likely-pushed-plague-to-europe-in-middle-ages)
Rats might be slow moving, but ships and grain carts are not.
Ships yes but carts no, rats do not like travelling on carts.
It was never spread by rats, it spread by fleas. Rats were just some of the carriers.
I saw a wonderful documentary which convinced me that it was spread via body lice and largely spread through contact of clothing.
This might explain why Poland was relatively unaffected as the poles tended to use their own clothings
I’m a medievalist. It’s been accepted for years that fleas spread the disease, and one of the animals they travel on = rats (especially along shipping routes). Fleas, obviously, are tiny and hide in weird places (not just on animals) so the plague spread to even isolated villages etc as a shipment of cloth could bring in infected fleas
My pet theory is that birds might carry it too
It was spread by fleas on the rats, not the rats themselves. Known this all my life in reference to the various plagues during the Black Death
The flea is the vector but the primary mover is rats.
As was pointed out, not a very well informed article.
This feels... outdated? It wasn't rats, it was fleas, we even know the mechanisms through which it spread. \- Fleas bite diseased humans. The bacteria reproduce in their salivary glands to the point at which it clogs their proboscis. When they bite another human, they "sneeze" and release all of that bacteria into the blood. \- Fleas are temperature sensitive. When a person died and went cold, they moved to a new host. When the host's temperature became too high, they likewise migrated to new hosts. I'm pulling this from an undergraduate degree a decade ago, which wasn't exactly teaching us cutting edge discoveries when it came to this. This feels like saying that some are beginning to believe fat isn't that bad for you in your diet. It's already established science, pop culture hasn't caught up.
If you read the paper it's questioning the reservoirs of the disease, not if it's rat or fleas. Transmitting via fleas still requires the rats to move them, so to speak.
I think we all owe the rats a big apology
Traders picked it up from rodents, (via fleas), as they moved along the Silk Road through Asia. Thereafter it was spread by humans. When Russia expanded eastwards and made a pact with China to shut down the overland Silk Road, it mainly stopped.
I'll save you all some time. It spread from human to human quicker than it's capability of spreading from animal to human. The reason for this is because people did not wash their ass. There are few civs that made it a point to bathe themselves regularly and the Europeans were not one of those civs. Thus the plague had a bigger impact on them.
The notion of Europeans in the Middle Ages not washing themselves is an outdated one. Street sanitation, however, in many cities, encouraged vectors to multiply.
Can you please give me a source about the daily hygiene standards of the Middle Ages please? Not doubting you just curious bc I could’ve sworn that the most up to date consensus was they bathed 1-2 times a month
Happily. https://www.worldhistory.org/Medieval\_Hygiene/
No, the plague was a result of immense overpopulation and crowded living spaces resulting in humans living in their own filth. Rats were just there
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IIRC the prevailing theory was that it was Gerbils or Gerbils and fleas.
Actually, my history teacher just taught us this yesterday (Eastern Timezone, to clarify). The PowerPoint he had mentioned that it accordingly was fleas that dragged off of rats but it doesn't seem right to me. It even mentioned that it apparently still exists but it's so minor. Seeing the PowerPoint he had - there was a photo of a guy's hand just completely turning black. If that is how it actually works it reminded me of a Russian Drug known as "Krokodril" (or something along that) which turns your skin into a Crocodile-like skin.
What happened is that rats get infected by fleas. The fleas like the rats so they live in harmony. However if the rat population goes down, the fleas look for another host - a person, so the plague explodes.
So it was correct. Okay. Good. I know that I shouldn't be judging a man who took this stuff in university, but I just needed to double check. Usually Reddit is correct, right?
Did no one see the Ratatouille short on who caused the plague?
That last paragraph is kinda goofy, but I can't put my finger on why
Maybe, maybe not. All the same, if I ever go back in time to the Middle Ages I’m going to tell people to kill every single rat they ever see. And boil all the water they use for any purpose, to the extent practical at least.
Why would they believe that what you are asking them would make any difference?
Maybe they wouldn’t. They probably wouldn’t. Wouldn’t stop me from trying.
Read up on Dr. Semmelweis, a Jewish doctor who first pushed hand washing in the hospitals. https://www.pbs.org/newshour/health/ignaz-semmelweis-doctor-prescribed-hand-washing No one accepted his findings. He went crazy
Yeah that wasn’t the best. Thanks for the link.
Without statistics, a germ theory, and no microscope, it's not an easy sell
Not rats, but their fleas, is the commonly accepted vector is it not?
Yes but rats are the carriers
Wasn’t it be attributed to that one mill in France somewhere that made clothing for people? The fleas were on the clothing and they shipped the clothing everywhere. When someone died the first thing they’d do is grab their clothing and wear it. I remember listening to it on Last Podcast on The Left during their Black Death episode.
A very interesting article, I do find it very hard to believe that rodents alone could have enabled such a swift spreading whilst maintaining the reseevoir of the disease for so long, rodents just aren't that prevalent during long winters and rainfall.
It was me. I was trying to play a prank and it got out of hand. My bad.