Catch up on stories from the past week (and beyond) at the Slashdot story archive

 



Forgot your password?
typodupeerror
×
Medicine

Researchers: Rats Didn't Spread Black Death, Humans Did 135

concertina226 (2447056) writes "Scientists studying the human remains of plague victims found during excavations for London's new Crossrail train line have concluded that humans spread the Black Death rather than rats, a fact that could rewrite history books. University of Keele scientists, working together with Crossrail's lead archaeologist Jay Carver and osteologists from the Museum of London, analyzed the bones and teeth of 25 skeletons dug up by Crossrail. They found DNA of Yersinia pestis, which is responsible for the Black Death, on the teeth of some of the victims."
This discussion has been archived. No new comments can be posted.

Researchers: Rats Didn't Spread Black Death, Humans Did

Comments Filter:
  • by Anonymous Coward

    Obviously.

    • Or maybe they were just eating rat?

      • "Or maybe they were just eating rat?"

        People were keeping coins in the mouth, harder for pickpockets to get at, so at every transaction, you got the pest for free.

        • "Or maybe they were just eating rat?"

          People were keeping coins in the mouth, harder for pickpockets to get at, so at every transaction, you got the pest for free.

          Wasn't that ancient Greece? I mean, really. Or did they keep coins in their mouths in the middle ages too?

      • Or maybe they were just eating rat?

        Well, it's got some rat in it. And get rid of that damn dead bishop on the landing, I've got three of 'em down by the bin, and the dustmen won't touch 'em.

      • by Wolfrider ( 856 )

        --Yah, srsly - these geniuses never watched "Demolition Man"?

        / ratburger FTW

    • "The presence of the virus on the victims' teeth supports Brooks' claim."

      Coincidentally, the author of The Zombie Survival Guide shares the same surname... or not so coincidental?

      Talk about a historical cover-up!

  • by Garybaldy ( 1233166 ) on Sunday March 30, 2014 @08:29AM (#46614445)

    That black death was actually zombies. The teeth says it all.

  • Old News (Score:5, Informative)

    by wisnoskij ( 1206448 ) on Sunday March 30, 2014 @08:31AM (#46614459) Homepage

    Scientists discovered this at least 6 years ago when I watched a documentary about it, and most likely quite a bit before that.

    • by Anonymous Coward

      it's not binary.

      the fact that some transmission was not by rats does NOT imply
      that no transmission was done by rats.

      • Re:Old News (Score:5, Informative)

        by Concerned Onlooker ( 473481 ) on Sunday March 30, 2014 @10:28AM (#46614951) Homepage Journal

        "the fact that some transmission was not by rats does NOT imply
        that no transmission was done by rats."

        What it DOES imply is that no matter who does the research or what the conclusion there is going to be disagreement from armchair scientists and contrarians on Slashdot.

      • The real interesting thing was that i was told it wasn't the rats but the fleas on the rats which is why employing cats and terriers (dogs) didn't help much.

        I don't remember where i picked that up but think it was in highschool. I asked a school chum what he knew sbout it and he had the same ideas. Of coursr highschool for us was over 25 years ago

        Perhaps fleas infected animals they ate but were immune to it

      • by gcmd ( 894557 )
        Once again, people who don't get their fact straight are confusing the issue. The Plague (Yersenia Pestis) is spread by fleas on rats. This is a well known and scientific fact. However, it can also be spread by airbourne particle if the infection moves from the lymph nodes (bubos or swollen lumps in the arm pits and groin is where the name bubonic plague comes from) to the lungs. Pneumonic Plague (Yersenia Pestis in the lung) is extremely contagious and universally fatal. The last I looked, there are no k
    • Scientists discovered this at least 6 years ago when I watched a documentary about it, and most likely quite a bit before that.

      I also recall reading about this years ago. Iceland was mentioned as a solid case of anti-rat evidence. Rats did not live there (and mostly still don't) but the Black Death still wiped out much of the population of Reykjavik.

      • Rats did not live there (and mostly still don't)

        Hahahah yea, sure they don't.

        There are rats on Antarctica, someone in Iceland is just living in denial.

        Where people go, rats and roaches go.

        • by gslj ( 214011 )

          Rats did not live there (and mostly still don't)

          Hahahah yea, sure they don't.

          There are rats on Antarctica, someone in Iceland is just living in denial.

          Where people go, rats and roaches go.

          Just for your information, there are no rats in Alberta [gov.ab.ca]. That may be a good place to go if bubonic plague breaks out again.

          -Gareth


      • if( $place->visited->means == 'ship' )
            $rats->present = TRUE;

        • Re: (Score:3, Funny)

          by knightghost ( 861069 )

          I have neither rats nor cockroaches where I live. Well, at least not counting the politicians.

    • Scientists discovered this at least 6 years ago when I watched a documentary about it, and most likely quite a bit before that.

      It's highly unlikely it was discovered when you were watching the documentary. "Quit a bit before that" seems a good guess.

    • Scientists discovered this at least 6 years ago when I watched a documentary about it, and most likely quite a bit before that.

      Exactly what I thought. In fact wasn't one of the hypotheses of the last investigation that the Black Death of the 1400s wasn't even plague, but rather a haemorrhagic fever like Ebola?

  • Virus? Plague? (Score:5, Insightful)

    by K. S. Kyosuke ( 729550 ) on Sunday March 30, 2014 @08:34AM (#46614473)
    Now I'm not sure they got even the disease right! How am I supposed to believe they got the minutiae of the actual new findings right?
    • by RDW ( 41497 )

      There's a better article on the UK Channel 4 site (C4 will broadcast the documentary):

      http://www.channel4.com/info/p... [channel4.com]

      • Re:Virus? Plague? (Score:5, Informative)

        by K. S. Kyosuke ( 729550 ) on Sunday March 30, 2014 @10:11AM (#46614857)

        At the risk of sounding pretentious, that page doesn't list anything I haven't already known for years - in fact, anyone interested in the Black Death should be already aware of all these things.

        We've known that some casualties were not bubonic but pneumonic cases, as well as that some were septicemic instead - even the contemporaries were aware of the three distinct forms of the disease, as manifested by their different symptoms, even if they misunderstood its bacterial underpinnings. We've also known that besides primary pneumonic plague (acquired through inhalation), there's secondary pneumonic plague that happens whenever Yersinia pestis spreads into a bubonic or septicemic plague victim's lungs through the bloodstream.

        Claiming that we found out that "Rats Didn't Spread Black Death, Humans Did" feels like disingenous piece of reporting, though, because one of the hallmarks of pneumonic plague is its much more rapid onset and considerable lethality (about half the time it takes for bubonic plague to kill you, or something like that?). Within a town, it's entirely possible that the spread of pneumonic plague overtook bubonic plague whenever it got established, but the "spread" of Black Death was global, and the typical progress of pneumonic plague put it at a serious disadvantage when it came to long-distance travel (especially on ships). So chances are that in many, if not most places removed from other places (towns, regions, countries, continents), the primary pneumonic cases were "jumpstarted" by a case secondary pneumonic plague infection resulting from an infected flea bite. (At least, that's how I interpreted the smart books.)

        • At the risk of seeming pretentious, the entire article is a crock. Y. pestis is a bacterium, not a virus. As has been mentioned, this is a well known hypothesis and the new information might expand that, but there is not way to determine that from TFA.

          Note to editors: The International Business Times is a poor source for scientific news.

        • Not only were such facts known to researchers, but most SF fans had a pretty good idea by reading the Doomsday Book by Connie Willis. It might be fiction, but it does get quite a few facts right, and overall is a great read.
        • by gcmd ( 894557 )
          Actually, one question that remains is was it the plague at all. There is still debate about some of the outbreaks across Europe. Were they in fact Plague, or influenza epidemics.
          • Influenza faces the same problem as the "overwhelmingly pneumonic plague" hypothesis: too many buboes in the contemporary descriptions for this hypothesis to make sense. As far as I'm aware, buboes either don't develop in pneumonic plague cases at all, or they only develop in those people who live long enough to give the plague bacteria the time necessary to spread into lymph nodes, which must be a tiny minority in primary pneumonic cases. Or does influenza often actually cause swollen, reddish or blackened
    • by 93 Escort Wagon ( 326346 ) on Sunday March 30, 2014 @11:52AM (#46615405)

      Cut the researchers some slack - it's a simple misunderstanding. One of these guys went to the dentist and was told they had plaque on their teeth.

  • by somepunk ( 720296 ) on Sunday March 30, 2014 @08:41AM (#46614487) Homepage

    Pneumonic plague being transmitted by air isn't news. It's a form of the disease that gets into your lungs, after all. Also, the primary vector isn't rats at all, but fleas, which often go directly from person to person.

    The article's credibility is not helped at all when it mentions the plague virus, when it is actually caused by a bacterium.

    • You know, I clicked on the story, saw that the link is from "ibtimes", and then your comment. Led me to guess it must be samzenpus.

      I suppose consistency is a virtue of a sort.

    • by hey! ( 33014 ) on Sunday March 30, 2014 @09:25AM (#46614643) Homepage Journal

      Person who worked for years in arthropod borne disease control here.

      Except for the reporting screw-up about virus vs. bacteria, this is all just quibbling. The reporters got it wrong as usual, but that doesn't mean that the researchers got it wrong.

      Zoonotic diseases (ones that spills over from one animal population to another) always have fantastically complex life cycles. In epidemics of zoonotic diseases it's common for epizootic transmission (transmission between species) to be overtaken by enzootic transmission (transmission *within* a species). For example influenza is a bird pathogen that can cross over into mammalian species like swine and humans. If flu epidemics didn't shift gears from epizootic transmission (bird to human) to enzootic (human to human), they wouldn't be as big a deal. Just stay away from chickens.

      So the idea that the black plague was primarily spread among humans enzootically is hardy groundbreaking epidemiology. It certainly doesn't mean that it's not dangerous to live in a place infested with plague-ridden rats. But the shift to enzootic transmission is something that's a bit different from the mosquito or tick borne diseases or occasional, isolated epizootic plague infections we're largely familiar with today.

      It's a neat finding, in that it wasn't necessarily expected, but it makes sense in retrospect. In something like West Nile Virus, the natural focus of the pathogen is migratory bird populations that fly thousands of miles. But while a rat can hop on a ship and travel thousands of miles, the vast majority of rats spend their entire lives in a radius of a few hundred feet. Humans are much more mobile than rats; even if a few rats hitch a ride on a ship, they never go anywhere far *without* humans.

      What's simplistic is the assumption there has to be only *one* factor involved in a zoonotic epidemic. Without epizootic transmission the plague would not have happened in the first place. That's not news. Without human-to-human enzootic transmission it would not have spread so widely or kill such a high percentage of the population. That is news (I guess -- I didn't work with people doing plauge so I have no direct knowledge of what people in that field thought). Of course before it becomes established science it's going to have to stand up to criticism for a few years.

      • Doesn't it kind of muddle things that people dislike rats so much they won't admit bubonic plague disappeared along with brown (Norway) rats replacing the black rats that transmitted the disease?
        • by arth1 ( 260657 )

          Doesn't it kind of muddle things that people dislike rats so much they won't admit bubonic plague disappeared along with brown (Norway) rats replacing the black rats that transmitted the disease?

          You're being close-minded here. They transported the fleas that was one vector for transmitting the disease.

          And what's with "won't admit"? Who's denying? Or do you mean they won't admit that that is enough evidence for a cause and effect conclusion? No, they won't admit that, because that would be rather unscientific.

          How about other factors like improvements in sanitation and transportation?

          Who gives a rats ass how you feel about rats. It doesn't do anything to illuminate history.

          • Well, it's rather a simple chain to follow. Black rats were associated with the plague. Brown rats replaced them, plague stopped. Still, the common wisdom still seems to remain "rats" were responsible for spreading the disease, sanitation measures, that apparently arrived after the disease was already gone, getting the credit. Even "transportation improvements", apparently, although those would tend to spread it more.
            • by hey! ( 33014 ) on Sunday March 30, 2014 @11:44AM (#46615347) Homepage Journal

              Well, the Norway (aka "brown") rats are carriers of an almost incredible variety of infectious agents that are human pathogens, including hantavirus and Toxoplasma.

              The issue with rats isn't that they're *particularly* susceptible to zoonotic pathogens. The issue is that they're well adapted to living around human habitations,which provide them with excellent protection from predation. With plenty food and shelter and no predators, they reach unnaturally high population concentrations. These populations are "preyed upon" by germs instead of carnivores, because inevitably everything in nature is food for something else. Some of those pathogens will also effect humans, and since those dense colonies are living in close proximity to dense colonies of *humans*, brown rats present a public health concern, even though none of their pathogens have quite the marquee name recognition of The Black Death.

              Another example of this phenomenon is the raccoon. Because raccoons are still frequently encountered in natural settings people don't have the same revulsion towards them as they do towards rats, but raccoons are just as well adapted to living with humans as rats are. In places where high raccoon populations live in close proximity to humans, they're a serious health concern. I've known natural science geeks -- people who have no qualms about handing dead animals or picking through animal scat -- to treat suburban raccoons with revulsion. A suburban raccoon can be a terrifying bag of disease, and there are documented cases of people dying as a result of handling their poop.

              It doesn't mean racoons are *bad*, or that rats are *bad*. It means that wild animal populations with nearly unlimited resources and no predation are an all-you-can-eat banquet for germs.

              • add to that in the typical medieval house and even castle it was very difficult to keep the rats out of the human food supply and tracking their dirty little feet and germs everywhere. That's why cupboards and barrels and pot and other stuff were invented to keep the critters out. all those critters crawling all over had to be spreading germs even when people thought their house was "clean".

              • by jfengel ( 409917 )

                Ya know... this is why I come to Slashdot: the comments that are more informative than the article. Doesn't happen often enough these days. Thank you.

              • Interesting arguments. And not all hollow, though I would have used typhus as an example. Just because an animal can be infected by a disease doesn't always mean it is a credible source for transmission to humans. Or that they serve as a reservoir for other animals to catch it. Perhaps Norway rats "can" carry hantaviruses, but the CDC page is quite specific about the rodents that pose a threat to humans carrying it; deer mice one strain, white footed mice another, a third wild "rice rats" and "cotton rats"
              • by fyngyrz ( 762201 )

                The issue is that [rats are] well adapted to living around human habitations,which provide them with excellent protection from predation.

                So, don't reflexively kill all the cats, then?

                By mid July of 1665 over 1,000 deaths per week were reported in the city. It was rumored that dogs and cats spread the disease, so the Lord Mayor ordered all the dogs and cats destroyed. Author Daniel Defoe (1660 – 24 April 1731) in his Journal of the Plague Years estimated that 40,000 dogs and 200,000 cats were killed.

              • Even if the only reason is that they carry Baylisascaris procyonis. They live around here and will get in the large, lidded garbage cans if given half a chance.

                My neighbor will throw old bread out for them to eat and it's a major temptation to use that as an opportunity to shoot them. Popular opinion and that of law enforcement prevents me from doing this.

              • by trawg ( 308495 )

                Your two posts were fascinating, thanks. It has never crossed my mind to think about rats that much, but the sentence about humans effectively keeping them safe from other predators is one of those obvious-in-hindsight things that I probably never would have realised.

                As an Australian that has recently relocated to the US, you have also inculcated a new fear of raccoons, which I will now go at lengths to avoid!

            • by arth1 ( 260657 )

              Well, it's rather a simple chain to follow. Black rats were associated with the plague. Brown rats replaced them, plague stopped.

              Where's the link between the two? How do you prove a cause and effect? Other things also happened at the same time. I'm not saying that this couldn't be the case, but I am saying that we need some evidence before concluding that this is the cause. Circumstantial evidence can be correct, but it can also be wrong.

              • Where's the link between Norway rats and the plague at all? Domesticated rat pictures published along with stories about the disease? Circumstantial evidence is also quite weak when totally absent. It might be considered "circumstantial" that Norway rats appeared along with the disappearance of the known disease-transmitting ones, in the same niche, but it is fairly well established.
        • by hey! ( 33014 )

          Well, I'm not sure what "people" you are talking about, but if you're talking about "researchers", the answer would be "no". Researchers are definitely not representative of general population of what they "like" and "dislike".

          Two war stories follow.

          Some researchers in a tropical medicine discovered that a mens room at the school had been infested with tiny little flies. Did they complain to the management? No. They trapped some of the flies, brought them back to the lab and bred them as pets.

          I was walkin

          • I was walking in the woods one day with a zoologist friend of mine, when we came upon a rotting coyote head in the middle of the trail. "Ooh!" she says, "I want to show that to my students!" Whereupon she picks up the head, maggot-ridden eyeholes and all, and pops it into the pocket of her windbreaker.

            How big was the dry-cleaning bill?

            Calls to mind the story of the young Darwin, who was faced with containing three beetles when he had only two hands. He put the third one in his mouth.

            And I tip my hat to your zoologist companion.

      • by jez9999 ( 618189 )

        So the idea that the black plague was primarily spread among humans enzootically is hardy groundbreaking epidemiology. It certainly doesn't mean that it's not dangerous to live in a place infested with plague-ridden rats. But the shift to enzootic transmission is something that's a bit different from the mosquito or tick borne diseases or occasional, isolated epizootic plague infections we're largely familiar with today.

        What I don't quite get is, if the plague was spread from human to human, how anyone surv

        • by hey! ( 33014 )

          Well, for one thing the fatality rate is less than 100%. And the infection rates were less than 100% too. Were the infection and fatality rates 100%, the epidemic would quickly burn itself out. You can set up a differential equation describing this situation: the rate of transmission is proportional to the chance of transmission and how frequently an infected person encounters an uninfected person. But that frequency of contact drops as populations are decimated, so that a particularly aggressive stra

        • by ceoyoyo ( 59147 )

          The word quarantine comes from the italian "quaranta giorni" (40 days) which was a requirement that ships wishing to land at Venice stand isolated offshore for forty days. The policy was enacted to try to stop the spread of a new disease (from the Orient) that had shown up in Venice. It was too late by that time, and the disease went on to kill a third of the population of Europe and became known as the black death.

          Beyond that, particularly virulent disease are often self-quarantining. They kill off ever

      • by Anonymous Coward

        Person who worked for years in arthropod borne disease control here.

        [...]

        It's a neat finding, in that it wasn't necessarily expected, but it makes sense in retrospect.

        Is everybody insane? Just read Albert Camus, "La Peste" (written in 1947). It describes in detail how the development from bubonic plague to pneumonic plague creates the human-human transmission path with a quite higher lethality rate and spread.

        While Camus takes care to get the medical stuff correct, the focus is on the psychology. He certainly was not going to propose any groundbreaking new medical theories. He just works carefully with what was known at the time.

        I am flabbergasted that this is now co

      • Humans are much more mobile than rats

        As a species yes, but much like rats - individuals not so much during the era of the Black Death.

        Without human-to-human enzootic transmission it would not have spread so widely or kill such a high percentage of the population.

        That's a stretch not clearly supported by the available evidence. That the pneumonic form that's spread human-to-human contributed has long been known, but the widest spread and most deaths came from the the rat borne bubonic form.

        • by hey! ( 33014 )

          Well, whole the point of the article is that the pneumonic transmission may have been responsible for more fatalities in the Black Death than previously thought. In any case, it's the same infectious agent, different tissues infected. So Y. pestis can be vectored as bubonic plague and then subsequently spread as pneumonic plague -- or vice versa. That's my understanding, although as I said elsewhere I've never worked on plauge projects so I may be wrong. But it doesn't seem like much of a stretch given po

    • Wikipedia has a good article on pneumonic plague, I'm sure that not "all" the victims were of the pneumonic form as the disease often starts in a population in the bubonic form frequently spread by fleas [wikipedia.org] which can progress into the more contagious and more virulent pneumonic form; so while rats and rat fleas don't get the sole blame, they still get their share.

    • I'd always heard rats carried fleas, not that they were the primary vector, and this is something I've carried around in my head for decades. So, even when quarantined, it was still a nasty situation of not really being able to completely contain the spread.

  • Maybe (Score:5, Informative)

    by dreamchaser ( 49529 ) on Sunday March 30, 2014 @08:42AM (#46614491) Homepage Journal

    The plague can take 3 forms, at least one of which, pneumonic, infects the lungs and spreads through the air, much like the common cold does. Just because humans had a role in helping to spread it doesn't leave the rats and their fleas off the hook. It is still quite likely that there were multiple vectors combined that caused the rapid spread of the disease.

  • by rmdingler ( 1955220 ) on Sunday March 30, 2014 @08:48AM (#46614513) Journal
    Famine was widespread. Perhaps this one group unearthed during construction developed a taste for the rat.

    Not normally considered a delicacy, when it's rat or nothing, well, sorry Templeton.

    • It could even be more simple than that; I don't remember 100% about the plague era history, but if I remember correctly near end symptoms were vomiting and swelling / cracking of the tongue. In both cases there is high probability that bacterium from the bloodstream would come in contact with the persons teeth. If you really want to get down to it, many victims were buried in mass graves and it is possible that there was cross contamination due to higher level corpses buboes rupturing when they had been to

    • by gmhowell ( 26755 )

      Rat may taste like pumpkin pie, but I won't eat the filthy motherfuckers.

      • I infer that means you've never been starving. It's a luxurious age in which men live.

        Hell, even our poor people are fat.

        Many of us are afforded the amenity of plentiful food and no daily fear for our own survival, but I assure you good poster, the veneer of civilization is a thin one.

  • What a terribly written article. What did the later deaths in the early 1900s have to do with the medieval plague? Did they find DNA on the victims from the 1900s or from the actual plague outbreak? What does DNA on the teeth have to do with and what does it indicate? Totally worthless crap article, through and through.

    • You have to re-read it at least twice to pick it up, as the connection with other points is very weak.

      "As an explanation for the Black Death in its own right, [bubonic plague spread by rat fleas] simply isn't good enough. It cannot spread fast enough from one household to the next to cause the huge number of cases that we saw during the Black Death epidemics," said Public Health England's Dr Tim Brooks.

      I.e. Flees are not a fast enough vector. It must have been something faster.
      Enter airborne plague. And the 1906 case as an example of how fast it moves.
      And the presence of "DNA of Yersinia pestis" on the teeth of the corpses of the people from the period, as a proof that they COULD HAVE been spreading it with their breath. Too.

      The find actually does not exclude fleas, it only (maybe) provides proof for YET

      • ah, so if true we rename the disease the Black Breath

      • by arth1 ( 260657 )

        I think you mean "evidence", not "proof". Proof concludes, evidence is fuel for theories.

        Otherwise, spot on. Give that man a karma cookie!

        • I was talking in the "spirit of the article".

          Which, lest we forget, is titled "Rats Didn't Spread Black Death, Humans Did, Say Researchers".

  • by account_deleted ( 4530225 ) on Sunday March 30, 2014 @09:19AM (#46614625)
    Comment removed based on user account deletion
    • This is pretty spot on. The whole issue appears to be the tendency of some people to try and condense the truth into a general statement, such as, "fleas on rats spread the bubonic plague." Of course the truth is more complex and may not be fully understood, but I don't think serious scholars ever asserted that fleas on rats were the only mechanism by which the disease was spread. The important part of the theory was that fleas on rats on boats brought the bacteria from China to Europe and then facilitated

  • Dental Hygiene (Score:1, Flamebait)

    by Teun ( 17872 )
    The only 'evidence' I read in this shoddy article is that Brits have a centuries old history of not cleaning their teeth...
  • Maybe now the prejudice will end and rats can finally get some respect!
  • Specifically: Brits did. Worse than rats.
  • If they vomited, and the vomitus contained the bacteria, would that account for these findings?

    • If they vomited, and the vomitus contained the bacteria, would that account for these findings?

      Only if one came into direct contact with the vomit.

  • Can't help but laugh at the heated comments in this thread over a non-Article that is little more than an Advert for a History Channel-esque show for Channel 4 in the UK next Sunday.

  • New Scientist magazine had an article in it about this very subject years ago!
  • Aliens. Its always aliens.

  • From the article (which is really a veiled advertisement for an upcoming tv show), researchers found the bacteria on the teeth of the skeletons and use this as proof that the plague spread by humans and not rats (the article actually calls it a virus, but that the black plague was bacterial, not viral).

    It is reasonable that if people died from a bacterial infection y.pesis, that said bacteria would remain on their dead bodies and be burried with them. The fact that they found DNA of the bacteria on the teet

  • Who would have thought it possible that the Brits might succumb to any disease related to dental hygiene.
  • We would be more doomed by the medical establishment than helped.
  • Having just done something very un-slashdot-like (well, it *used* to be what a lot of us did, but not the last few years), i noted that it was hitting in the midst of a famine... which is when a) many, many people would have weakened immune systems, and b) did you unbelievably rich folks, who can eat three meals a day (or more)(or supersized) without thinking about it think that the concept of stewed rat was only in, say, Monty Python?

    And if the fleas hit the folks catching them, and then it mutated, or the

  • There is some argument missing here. The usual story is that rats infected humans by spreading fleas that spread the microbe through bite.. I am not sure what the finding says about humans. Was mankind a vector of the flea? That might not be all that surprising as fleas and ticks often cam be spread by other mammals to humans. The novelty is that the flea could live on people without the rat host being necessary.

Keep up the good work! But please don't ask me to help.

Working...