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Medicine Science

New Study Claims That the 'Black Death' Was Spread By Humans, Not Rats (bbc.com) 97

dryriver shares a report from BBC: Rats were not to blame for the spread of plague during the Black Death, according to a study. The rodents and their fleas were thought to have spread a series of outbreaks in 14th-19th Century Europe. But a team from the universities of Oslo and Ferrara now says the first, the Black Death, can be "largely ascribed to human fleas and body lice." The study, in the Proceedings of the National Academy of Science, uses records of its pattern and scale. The Black Death claimed an estimated 25 million lives, more than a third of Europe's population, between 1347 and 1351. "We have good mortality data from outbreaks in nine cities in Europe," Prof Nils Stenseth, from the University of Oslo, told BBC News. "So we could construct models of the disease dynamics [there]." He and his colleagues then simulated disease outbreaks in each of these cities, creating three models where the disease was spread by: rats, airborne transmission, and fleas and lice that live on humans and their clothes. In seven out of the nine cities studied, the "human parasite model" was a much better match for the pattern of the outbreak. It mirrored how quickly it spread and how many people it affected. "The conclusion was very clear," said Prof Stenseth. "The lice model fits best. It would be unlikely to spread as fast as it did if it was transmitted by rats. It would have to go through this extra loop of the rats, rather than being spread from person to person." Plague is still endemic in some countries of Asia, Africa and the Americas, where it persists in "reservoirs" of infected rodents. According to the World Health Organization, from 2010 to 2015 there were 3,248 cases reported worldwide, including 584 deaths. And, in 2001, a study that decoded the plague genome used a bacterium that had come from a vet in the U.S. who had died in 1992 after a plague-infested cat sneezed on him as he had been trying to rescue it from underneath a house.
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New Study Claims That the 'Black Death' Was Spread By Humans, Not Rats

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  • by Kenja ( 541830 ) on Tuesday January 16, 2018 @09:46PM (#55943165)
    Humans are disgusting! Shooting DNA at each other, like savages. I FIND IT OFFENSIVE!
  • by AHuxley ( 892839 ) on Tuesday January 16, 2018 @09:53PM (#55943205) Journal
    Stop the infect people from wondering around globally and such issues stay more local.
    • by arth1 ( 260657 )

      Stop the infect people from wondering around globally and such issues stay more local.

      Fighting human nature is difficult. People fleeing the black death is one of the reasons it spread so quickly. Similar with Ebola, with scared people already infected trying to escape affected areas.

      The horror scenario is a highly infectious disease in affluent areas with a high amount of air traffic. Because humans will attempt to flee, and don't care one bit how many millions may die because of it, if they think it increases their own survival chances.

      • by rmdingler ( 1955220 ) on Tuesday January 16, 2018 @10:30PM (#55943369) Journal
        Much of the quarantine attempts actually failed in Africa, as many carriers preferred the state of denial versus being outed as sickened.
        • The quarantine in Africa regarding the last Ebola outbreaks worked actually quite good.
          What did not work was keeping the relatives away from the deceased and burning the corpses instead of letting them be washed and buried by surviving, not yet infected, relatives.

          • The traditional cleaning of the dead was an initial source of disease proliferation, but as efforts to educate the afflicted tribes gained traction, traditional burial rites were altered somewhat successfully.

            One of the biggest impediments to stifling the spread of ebola was the native distrust of well-meaning healthcare workers who would appear dressed like spacemen and remove villagers who were often never seen again. This caused a number of the infected to hide their disease and continue its spread.

            • One of the biggest impediments to stifling the spread of ebola was the native distrust of well-meaning healthcare workers who would appear dressed like spacemen and remove villagers who were often never seen again. This caused a number of the infected to hide their disease and continue its spread.
              Of course, and they don't belivee into that infection/bacteria hocus pockus at all.

        • So, do we realize that the people inside the quarantine area are expected to die? Because that's what a quarantine area is. This is why quarantines are always enforced at gunpoint. It can't be any other way.
          • Not all of them. Some will have natural immunity and the rest will have easier access to treatment than elsewhere. In some cases, it's feasible to vaccinate everyone in a quarantine area, but not everyone in a country, so the survival rate for uninfected people in the quarantine area may be higher than if the disease escaped into the general population.
      • Re: (Score:2, Insightful)

        by AHuxley ( 892839 )
        How to stop airlines from moving the infected people out of infected nations.
        Make a person from an infected nation get a visa and then apply for full private health insurance in the nation they want to visit.
        The visa can be blocked until the health issue in their nation is over.
        Private health insurance can be set to reflect the true cost to cover of any treatments before travel.
        The infected just don't get to fly out around the world expecting free treatment in other nations.
        If the infected person arriv
        • Most countries have health insurance that covers world wide.
          Regardless of "private" or "government" / "mandatory health insurance".

          If the infected person arrives with forged, fake or borrowed documents, make the airline pay in full for all their private sector medical care.
          This makes no sense at all. How should the airline know one is infected?

          • by AHuxley ( 892839 )
            The profit incentive for an airline to service a nation and then to fly sick infected people out of that nation is reduced.
            Sick people no longer have the ability to spread their inception globally thanks to an airline.
    • by mjwx ( 966435 )

      Stop the infect people from wondering around globally and such issues stay more local.

      You're assuming you're dealing with rational actors. You aren't. People will deny their sick just to get away from a quarantine area.

      Also quarantines need to be enforced by people, you cans ask soldiers to shoot civilians because they might carry a communicable disease.

      However it's not necessary with the Bubonic plague. Modern isolation and sanitation techniques are enough. It was nowhere near as infectious or deadly as Ebola, the main issue was that we didn't know about pathogens in the 14th century,

  • by Anonymous Coward on Tuesday January 16, 2018 @09:54PM (#55943211)

    It wasn't the rats, it was from the fleas carried by the rats. A rat bite is a rare thing, comparatively to a flea bite.

    • by Jarik C-Bol ( 894741 ) on Tuesday January 16, 2018 @10:18PM (#55943305)
      I think their point is that it was mainly human hosted parasites, not animal hosted ones. Fleas and lice moving from infected humans to healthy humans in crowded conditions, shared beds, etc. Rather than fleas moving from (infected) humans, down to rats, then rats transmitting to other rats, to fleas, then back somehow to healthy humans.
      It is shortening the transmission cycle by 2-3 hosts, which is borne out by the speed at which the disease spread. Besides, humans are not generally happy with co-habbiting with rats, and endeavor to prevent/reduce their presence, as such, the window for human/rat flea transfer is probably minimal at best. Human to Human flea/lice transfer on the other hand, is pretty freaking easy.
      • by WRX Gav ( 867999 )
        But they're saying that it still persists in rodent parasites now? Seems to somewhat contradict the assertion of the article?
        • by Memnos ( 937795 ) on Tuesday January 16, 2018 @11:15PM (#55943517) Journal

          No, they're saying that human-human flea transmission was likely the most direct way for Y. pestis to spread. It could still be harbored in rodents, just that means of transmission is less efficient and would not predominate.

        • by gl4ss ( 559668 )

          once it got in, it probably spread by human-human parasite infections.. however, such a contamination would die off quickly, while a rat population would get it out of quarantine. I'd imagine.

          it's just a model they made up anyways. could be just that the humans in one place got infected from the same rats and the rats travelled with the humans(likely). because that would shorten the loop, it wouldnt have to be human->rat->human, just rat->human. what they are suggesting is that their model shows th

          • I once read a "theory" that first the plague killed the rats, at least enough rats so that many "surplus flea" were searching for new hosts.
            Partly the rats died due to the plague partly they got hunted because they were to many in the streets.
            Anyway, the "surplus" flea then searched for replacement hosts, which would be anything but particularly humans.
            So the "initial outbreak" according to that (old) theory would be by flea coming from rats but the further spreading according to this article would be from

            • For pneumonic infection; you're not going to get bubonic from another human.
              • As soon as the pustules rupture, every plague bearer can infect other people.
                To sad that the english/american wikipedia article is unclear/wrong abut that :D

                • Sure! I don't think you get buboes from that, though. If I recall, you'd just get a dermal infection.
    • From the article summary: "The rodents and their fleas."

      If you can't even read the 1st line of the summary,
      1) Why are you posting?
      2) Why are you moderating?

    • It likely wasn't from rats or their fleas. Fleas and even more so lice are largely species specific. There are actually two types of human inhabiting lice, our head lice and the pubes lice. It's interesting to know the difference.

      • While flea have preferences for certain species, they jump on others if needed. E.g. so called dog flea or cat flea have no problem to jump on me. Even if there is no particular reason, as: they could stay on the original host.
        I minimum had 10 times in my life a dog or cat flea ... supper annoying. A single beast like that makes life already hellish.

  • by crunchygranola ( 1954152 ) on Tuesday January 16, 2018 @10:39PM (#55943409)

    Our knowledge of plague pandemics is largely drawn from observations made since the germ theory of disease gained ascendancy in the 1880s, which coincided with the world-wide Third Plague Pandemic. There are multiple potential routes of plague bacillus transmission, so the processes observed during the recent pandemic (1855 to 1959) were used to interpret the records we had from the Second Plague Pandemic (the Black Death, from the 1340s to the late 1700s).

    We have not seen a plague pandemic like the one that affected Late Medieval Europe, the conditions of living are radically different from the time and so this provides a model that matches the historical data we have.

    In other recent historical plague news, population genetic analysis of modern day plague survivals, have recently provided confirming evidence that the Plague of Justinian (541–542), which was possibly even more catastrophic than the Black Death, was also due to the plague bacillus Yersinia pestis. The world-wide distribution of genetic variations is best explained by two gigantic events of adaptive radiation -- about 700 years ago and 1500 years ago.

    • by Anonymous Coward

      I am puzzled by the lack of plague samples until 1992. When I was in the US Army in the late 60's, I received a Plague inoculation.

      • by AHuxley ( 892839 )
        Changes to medical research.
        https://en.wikipedia.org/wiki/... [wikipedia.org]
        AC The DoD protected its troops and US military "advisers" in Vietnam from the plague in country.
        Very, very few US troops get yersinia pestis in Vietnam due to good medical care, the vaccine and pesticide use.
        Cholera was another problem.
        The US mil also changed its supply of who made its plague inoculation over the decades but that is another story.
  • by Michael Woodhams ( 112247 ) on Tuesday January 16, 2018 @11:13PM (#55943511) Journal

    Some time ago (a decade?) I saw a TV documentary calling into question whether the Black Death was caused by the Y. pestis bacterium.

    Y. pestis was shown to be the cause of a plague outbreak in 1894. Because that plague outbreak was very similar to the symptoms of the Black Death, it was believed to be the same disease.

    Eventually (around 2000?) this was questioned. Arguments against that I remember include that, where available, records of who caught the disease when in a given village were more consistent with human-to-human spread; that the 1894 plague was accompanied by very many dead rats, but medieval descriptions do not mention this; and that the required rat species wasn't actually around in most of the European places hit by the plague.

    Shortly thereafter, ancient DNA evidence conclusively showed that Y. pestis was indeed the cause of the Black Death. However this research fits nicely with the objections from above.

    This is a fine example of science questioning old assumptions/results, and gaining better understanding by doing so, even though a false conclusion (that BD was not caused by Y. pestis) was reached along the way by some scientists.

    • Update: here [thelancet.com] is a paper discussing the black death/Y pestis link. It is behind a paywall, so I only have the abstract:

      Recent correspondence on the cause of Black Death1–3 includes incorrect citation of unpublished results obtained by one of us (MBP).2 The origin of this correspondence was a report4 of a conference presentation by James Wood suggesting, on the basis of epidemiological data, that Yersinia pestis was not the cause of the Black Death. Two recent books come to similar conclusions with diff

  • It was WITCHES that had cats, that killed rats, that had lice, that had plague. But the Witches were killed off, for being - Witches.... and now the X-spurts want to blame people? C'mon - it was Witches that caused the 'cleansing' that got rid of cats that allowed lice to breed on rats..... what myth are you trying to kill, and WHY? Conspiracy Rewels.
  • So... humans are the REAL rats?!

  • You dirty brother, you killed my rat!

  • From their abstract:

    Our results support that human ectoparasites were primary vectors for plague [...]ultimately challenging the assumption that plague in Europe was predominantly spread by rats.

    Basically, once there is an outbreak the speed of the outbreak can best be explained by a human-human parasite transfer. Human to rat to human would be too slow for the disease to have spread that quickly.

    - But that's only half the story and the rats still play an important role:
    They are the slow transfer and form the reservoir for the disease. Without a second, much slower transfer method, the plaque wouldn't have been able to cross oceans and jump from continent to continent.


  • There are written records of Mongol Empire (and their successor kingdoms) delivering plague infested corpses to the cities being under siege. Obviously they did not know about the bacteria, nor they had microscope, but they knew about contagious and lethal nature of the disease. Source: Wheelis M. (2002), "Biological warfare at the 1346 siege of Caffa." There are written records and there are many undocumented instances of humans transmitting disease, intentionally or unintentionally.
  • You can't quarantine a rat flea -- no, the rat flea doesn't care.
    If your quarantine's successful, then the virus spreads by air.
    If the Black Death were bubonic, then the quarantines would fail,
    And the fact that they succeeded tells a very different tale.

    The Black Death hit hard in Iceland, and there's something you should know:
    That there are no rats in Iceland, 'cause the temperature's too low,
    And without rats, there's no rat fleas to infect you with a bite,
    So the Black Death had to spread by means beyond their appetite!

    In this case the song is arguing that it's droplet based transmission rather than fleas on humans, but they both agree that rats as a vector is problematical.

    Source [seananmcguire.com]

  • In the fourteenth century, the rats were considerably cleaner than the humans.
  • We know that the citizens back then thought it was the cats. Cats were thought evil so they killed off the cats. Since cats were the predators of the rats, rats began to thrive. They got into everything. They were everywhere. We know that people would dump their chamber pots in the streets and that would flow into the rivers, streams and lakes. We know that personal hygiene was terrible as there were few facilities for running water. Using precious water on bathing was considered bad. So yes, we kno

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