Medieval plague bacteria strain probably extinct
This flea, X. cheopis, is responsible for transmitting the bacteria strain that causes plague.
August 30th, 2011
05:34 PM ET

Medieval plague bacteria strain probably extinct

Modern  outbreaks – swine flu, bird flu, SARS – have been scary and deadly, but they don't hold a candle to a plague called the Black Death. The disease killed an estimated one-third of Europe's population, perhaps 100 million people.

It's been a while, but scientists are now figuring out what caused the Black Death - at least, the one that swept through Europe from 1347 to 1351. They found evidence of the bacterium Yersinia pestis in the teeth of some of the medieval victims of the plague. Results are published in the Proceedings of the National Academy of Sciences.

Researchers screened more than 100 skeletal remains dating from 1348 to 1350 in the East Smithfield mass burial site, located in London, a place where plague victims were known to be buried.

They found a variation of Yersinia pestis that may no longer exist, as it has never been previously reported, study authors said. That suggests that this did not result from contamination from modern bacteria.

There had been some debate about whether there was some other explanation for the medieval plague, such as a different pathogen or bacterium.

The medieval plague is considered the second of three - the first was the Plague of Justinian in 541 A.D., and the third was noted in the 20th century; that disease represents about 2,000 cases per year, worldwide, on average.

A different form of Yersinia pestis is considered the cause of the plague that still exists today. As in the days of knights and castles, modern outbreaks of plague are associated with infected rats and rat fleas, according to the Centers of Disease Control and Prevention.

In the United States, plague cases in humans mostly occur in parts of New Mexico, Arizona, Colorado, California, Oregon and Nevada. Internationally, it can be found in Africa, Asia and South America. The plague can still be deadly without proper care, but antibiotics can fight it off.

Given that the World Health Organization has said that plague is a "reemerging infectious disease," further study of the spread of the older version may be worthwhile.

soundoff (528 Responses)
  1. Pope John XXIII

    Today's plague is reality TV and reality TV 'stars.' Wipe them out! And then wash your hands real good.

    August 31, 2011 at 15:06 | Report abuse | Reply
  2. Larry

    All I know is way back when, at Ft. Dix, plague was one of the things we were innoculated against in those two days of shots after enlisting.

    August 31, 2011 at 15:08 | Report abuse | Reply
  3. Anon

    It's largely extinct because we know to control the things that promote the disease, such as rats.

    August 31, 2011 at 15:10 | Report abuse | Reply
  4. flossmore

    Go dump some of this stuff down Amaneedajob's chimney.....and stuff some in Hugo Chavez's enchaladas. And how about some down Casey Anthony's throat !! Ya see......there's some good to come out of all of this ......

    August 31, 2011 at 15:10 | Report abuse | Reply
  5. juliang

    The differences between two bacterial strains are really small... we're talking smaller differences than that between two species; it's like the differences between two humans. The species of Yersinia that caused the Black Death is very much still around – in fact, I worked on it a few years ago – and can still take down a mouse like nobody's business. It's not a threat now because we have better health infrastructure and antibiotics.
    This science is cool because they managed to get a lot of genomic information from a difficult source (... decayed plague victims) about an ancient bacteria. Though to put "ancient" in perspective: if you were as old as Yersinia, the Black Death would seem like it happened this morning.

    August 31, 2011 at 15:15 | Report abuse | Reply
  6. Common Sense

    "Ring around the rosies,pockets full of posies,achew,achew we all fall down"

    August 31, 2011 at 15:15 | Report abuse | Reply
  7. Drew

    Sensationalism in disguise. It appears that the media is preparing us for flue season but it is good to know that the black death is almost extinct. Now it knows what it feels like.

    August 31, 2011 at 15:25 | Report abuse | Reply
  8. DavidF

    The population number for Europe cited int he article is wrong. The best guesstimate for a European-wide population prior to the BD is around 100 million. The EU's population today is over 300 million. The plague killed somewhere between 40 and 60% of the population–without census figures, demographic historians are only able to extrapolate population totals from other kinds of records, which are often biased due to the population groups they were intended for (i.e., monastic records, noble land holdings, etc.).

    August 31, 2011 at 15:29 | Report abuse | Reply
  9. James

    I had a vision of flea paleotologists digging up tiny little plauge fossils. ha ha

    August 31, 2011 at 15:40 | Report abuse | Reply
  10. Master Pathogen Creator

    The adaptive immune responses use selective and clonal expansion of the immune cells (T and B cells) to recognize antigens from a pathogen, providing the specificity and long-lasting immunological memory. Activation of the T and B cells not only depends on the TCR-MHC/peptide interaction and the costimulatory signals, but also the induction of costimulatory molecules and secretion of cytokines and chemokines by the cells of the innate immune system. Y. pestis reduces the host adaptive immunity by both influencing the cytokine induction and acting directly on the immune cells involved in the adaptive immune responses

    August 31, 2011 at 15:45 | Report abuse | Reply
    • G Force

      You are way above us in that statement

      August 31, 2011 at 15:50 | Report abuse |
    • Brian

      I LOVE it when you talk technical.

      August 31, 2011 at 16:12 | Report abuse |
    • mike

      I love well-informed comments such as this, although they are rare on CNN.

      August 31, 2011 at 16:19 | Report abuse |
    • Skeptical of the Master

      Nice use of cut and paste

      August 31, 2011 at 16:20 | Report abuse |
    • LL72

      In other words, it causes inflammation to overwhelm the body, and then further attacks the cells involved in the immune system so they're less effective.

      August 31, 2011 at 16:22 | Report abuse |
    • kurtinco

      That is exactly what I was going to say!!!

      August 31, 2011 at 16:25 | Report abuse |
    • mike

      This is actually very interesting – how Y. pestis evades macrophages and the cell death pathway, rendering the immune response immensely subdued.

      August 31, 2011 at 16:25 | Report abuse |
    • basketcase

      Copy and paste his comment to a google search, and you won't find it. I'd bet its not a copy paste (unless he found a non-internet source to copy from, in which case he put way to much time into it).

      August 31, 2011 at 16:57 | Report abuse |
    • Superchik

      Weren't there some people who came into direct contact with the bacteria and didn't die? These people had some sort of immunity to if both parents had the gene. I thought there have been some studies on how people with this immunity can survive AIDS. Anyone heard about that?

      August 31, 2011 at 18:55 | Report abuse |
    • Lou

      Most likely widespread vitamin D deficiency.

      August 31, 2011 at 19:22 | Report abuse |
    • caughtIn60seconds

      You're really not going to illustrate this properly without plagiarizing fig. 2 and the rest of page http://iai.asm.org/cgi/content/full/76/5/1804

      August 31, 2011 at 20:15 | Report abuse |
    • cosmicsnoop

      What Everrrr....... Just hurry up and bring out your dead.

      August 31, 2011 at 21:58 | Report abuse |
  11. LouAz

    We have not succeeded in solving all your problems. The answers we have found only serve to raise a whole new set of questions. In some ways, we feel we are confused as ever, but we believe we are now cornfused on a higher level and about more important things. The Management.

    August 31, 2011 at 16:03 | Report abuse | Reply
  12. FU


    August 31, 2011 at 16:15 | Report abuse | Reply
  13. The R.OT.P.

    medievel plague, time will tell.....

    August 31, 2011 at 16:35 | Report abuse | Reply
  14. mark

    The Black Death is alive and well. It has morphed into human form and goes by the names Dick Cheney, Sarah Palin, Michelle Bachmann, Rick Perry and lets not forget George Bush who killed many Americans in unnecessary wars.

    August 31, 2011 at 16:38 | Report abuse | Reply
    • M3NTA7

      True, and oh yeah, don't forget Obama and everyone else who is in Washington.

      August 31, 2011 at 19:31 | Report abuse |
  15. Richard Cheese

    We need another plague.

    August 31, 2011 at 16:39 | Report abuse | Reply
  16. dc

    Why can't anyone be nice anymore. Besides, now I can cross "dying of plague" off my list of things to worry about. 🙂

    (No, I don't really sit around the house worrying about getting the plague)

    August 31, 2011 at 17:44 | Report abuse | Reply
  17. thespiritguy

    They're so wrong. It didn't die off, it just mutated over the years, it now calls itself the "Tea Party".

    August 31, 2011 at 18:27 | Report abuse | Reply
    • Lou

      No, it's the idiots called regressive party.

      August 31, 2011 at 19:24 | Report abuse |
  18. san

    Why can't you so-called journalists learn that the word "bacterium" is singular and the word "bacteria" is plural?

    August 31, 2011 at 19:39 | Report abuse | Reply
  19. 2bits

    I would think Obama qualifies as a black death–to all Americans as he destroys this country–that's 330 million people and 3 times what the black plaque killed!

    August 31, 2011 at 20:10 | Report abuse | Reply
  20. Majorxerocom

    I'm sure they growing it in a lab just like h5n1, I saw a mutant bird flu article here http://majorxero.com/?p=201

    August 31, 2011 at 21:21 | Report abuse | Reply
  21. Nancy

    Stick to the point of the blog. The fleas caused 60% of Europeans to be wiped out by the Black Plague during the 1300's. Any European people alive today must be of the strongest ancestory to have survived. Doubt they are still immune to the disease after so many hundreds of years. My question to you all is why are people digging up the graves of the people who had the disease in the 1300's? Will some people dig up some still contagious bodies? Leave the disease underground where those poor people who got it during the past lie in death. Don't unearth it to us again.

    August 31, 2011 at 22:01 | Report abuse | Reply
  22. Mary

    Am I the only one who thinks that poking around in the graves of people who HAD THE PLAGUE was a bad idea? Weren't some of the tombs in the pyramids in Eygpt still toxic thousands of years later? I say let sleeping pathogens lie.

    August 31, 2011 at 22:55 | Report abuse | Reply
    • JLo

      Y. Pestis is a vector-borne disease, carried by the FLEA. You cannot get the plague by unearthing a gravesite. You have to be bitten by an infected flea. There's no public health threat from a 700 year old cemetery...you can't catch it if there's no way for you to actually be infected with it.

      November 1, 2011 at 16:34 | Report abuse |
  23. Debra

    To Superchik: yes, there was program on public television that talked about a study that was done of the descendants of plague survivors in a town in England; there was a genetic mutation that appeared as if it gave some protection against the plague bacteria; and researchers were looking a possible similar mechanism within AIDS patients. The program is called Secrets of the Dead; and the episode was Mystery of the Black Death.

    August 31, 2011 at 23:39 | Report abuse | Reply
  24. Blackbeered

    "scientists" are on the one hand "brilliant" and on the other "such fools".

    One thing we have always learned from science is that we don't [can't know] everything, nothing is certain, and we ceased to be amazed.

    September 1, 2011 at 05:55 | Report abuse | Reply
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