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The Mutant Genes Behind the Black Death

An anonymous reader writes: Each year, 4 million people visit Yosemite National Park in California. Most bring back photos, postcards and an occasional sunburn. But two unlucky visitors this summer got a very different souvenir. They got the plague. This quintessential medieval disease, caused by the bacterium Yersinia pestis and transmitted most often by fleabites, still surfaces in a handful of cases each year in the western United States, according to the Centers for Disease Control and Prevention. Its historical record is far more macabre. The plague of Justinian from 541 to 543 decimated nearly half the population in the Mediterranean, while the Black Death of the Middle Ages killed one in every three Europeans.

Now researchers are beginning to reveal a surprising genetic history of the plague. A rash of discoveries show how just a small handful of genetic changes — an altered protein here, a mutated gene there — can transform a relatively innocuous stomach bug into a pandemic capable of killing off a large fraction of a continent.

The most recent of these studies, published in June, found that the acquisition of a single gene named pla gave Y. pestis the ability to cause pneumonia, causing a form of plague so lethal that it kills essentially all of those infected who don't receive antibiotics. In addition, it is also among the most infectious bacteria known. "Yersinia pestis is a pretty kick-ass pathogen," said Paul Keim, a microbiologist at Northern Arizona University in Flagstaff. "A single bacterium can cause disease in mice. It's hard to get much more virulent than that."

12 of 132 comments (clear)

  1. Math is fun by Anonymous Coward · · Score: 5, Insightful

    "decimated nearly half the population"

    So it killed 5%?

    1. Re:Math is fun by Himmy32 · · Score: 4, Informative

      Do you? http://lmgtfy.com/?q=define%3A...


      decimate

      verb

      1. kill, destroy, or remove a large percentage or part of.

      "the project would decimate the fragile wetland wilderness"

      2. historical - kill one in every ten of (a group of soldiers or others) as a punishment for the whole group.

  2. But it did not kill all! by 140Mandak262Jamuna · · Score: 5, Insightful
    Half the population survived and got immunity to it. These pathogens traveled along the trade routes by land to three large population centers, India, China and Europe, Arabia and the Silk route forming land trading routes. They will leave behind an immunized population but sustain themselves by hitting these population centers and rebounding some 20 years later to find fresh unimmunized populations. And several such iterations strengthened the immunity of all the inhabitants of the old World. In each iteration these pathogens got more and more lethal. When the sea routes opened these pathogens "seeded" multiple locations simultaneously in Europe creating very virulent outbreaks.

    When Europeans arrived to colonize the New World, their small population should have been wiped out by the diseases unfamiliar to them in the New World. But they were not. Instead the much larger (than the colonists) New World population got devastated by the Old World diseases.

    This explanation came out as a 12 page (The arrow of disease) article by Jared Diamond in 1992 in the Discover magazine. Later it was expanded into a Pulitzer winning book, Guns, Germs and Steel

    --
    sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
    1. Re:But it did not kill all! by T.E.D. · · Score: 4, Interesting

      In each iteration these pathogens got more and more lethal....This explanation came out as a 12 page (The arrow of disease) article by Jared Diamond in 1992 in the Discover magazine. Later it was expanded into a Pulitzer winning book, Guns, Germs and Steel

      IIRC, Jared's argument in GG&S was that each iteration became less and less lethal. No only did the humans with better natural protections survive and have offspring, but the disease itself survived better if it didn't kill off all its hosts, so it had evolutionary pressure to be less deadly and more endemic.

  3. Re:Usage changes meaning by PopeRatzo · · Score: 5, Insightful

    If the soldiers grossly underperformed, the commander would line them all up and order that every tenth man be beaten to death by the nine men around him.

    Can we adopt that policy for GOP presidential candidates? It would make the debates more interesting and the base would love it.

    --
    You are welcome on my lawn.
  4. Re:Nature provides the solution by Feral+Nerd · · Score: 4, Informative

    The reason Europeans were so susceptible to the plague is that they were Europeans, just as the reason Native Americans were so susceptible to small pox was that they were Native Americans. Inbreeding leads to weakness, crossbreeding leads to strength.

    I agree that crossbreeding builds a strong population and pure bloodlines (aka. inbreeding) leads to weak populations but the rest of your post is wrong. There was steady gene flow between Asia and Europe for millennia whereas the aboriginals of the Americas were isolated after the end of the last ice age and the submergence of Beringia which cut the land bridge between Asia and North America. There were some old-world diseases that caused devastation among Native American populations and there were some new world diseases that caused devastation in the Old World. However, some of the pandemics that wiped out the native populations of the Americas (and that were previously thought to have been introduced pathogens) would in the light of modern research seem to have been entirely home grown. For example the pandemic that wiped out the Aztecs after the Spanish invasion seems to have been a hemorrhagic fever endemic to the Americas. Scholars in the past wrote a whole lot of stuff about pandemics without having the foggiest notion of which pathogens had been involved and those writings unfortunately remained gospel until very recently. Until only a couple of decades ago we had only a limited idea of whether the Black Death pathogen was the same as the modern plague bacteria, there were divided opinions. Some thought he plague of 1346 was an influenza. The last time I looked plague DNA had indeed been found in ancient remains but we still do not know if the Black Death and the Justinian plague were the same or not, the Justinian plague could have been something else altogether. There is also this persistent myth, born out of the 19th and early 20th century fascination with the orient, that all culture flowed from the east (i.e. Ex oriente lux = From the east the light), that medieval Europeans were somehow dirtier, more ignorant and more primitive than oriental people and that that is why the plague spread so rapidly in Europe. Roman bathing culture did not just evaporate with the fall of the old empire and throughout the Middle Ages there were bathhouses in many cities and towns in Europe (in the 13th century Paris had 32 bathouses). If the Medieval European really was so dirty and Asians so clean why did a pandemic spread by fleas spread from Asia to the West? You'd think it would originate among the dirty Europeans and then travel east and dissipate when it reached Asia because of the supposedly superior hygiene of medieval period Asians who would not, or so the conventional theory goes, have had fleas. In actual fact the Plague ravaged Europe and Asia pretty much equally and Asians of the 14th century seem to have been just as flea ridden as their European contemporaries. For example in 1334, a pandemic that was probably the same black death that ravaged Europe a decade later killed 5 million people in Hebei Province China with a death toll of about 90%.

  5. Re:And they say we have nothing to worry about by WOOFYGOOFY · · Score: 3, Interesting

    Exactly. To get some idea how well the democratization of knowledge serves as a defense against BadGuys, take a look at how we're doing on the internet. There we have full democratic access to a technology of mid-value intellectual difficulty. Do you feel like you can defend your computer against all created viruses trojans etc. or do you turn to professionals to provide you with tools to do that job?

    And about those professionals. How are they doing?

    Last I looked, they were basically getting a near zero-score for near zero-days.

    That's because they're good at defending themselves against what they recognize and know about and can fingerprint but essentially terrible at recognizing the uncatalogued attack, the novel approach, the slightly innovative variation.

    I point this out because I hear the argument that the more DIY biohacking we do, the better able we will be to defend ourselves. It really hasn't worked out that way. Things- people, cats dogs puzzles- go together one way. They can be taken apart in an infinity of ways.

    The surface of attack is infinite within the bounds of the target's particular characteristics. That's not a good castle to have to defend. The fewer people who can attack the castle, the better.

  6. Re: Nature provides the solution by Barsteward · · Score: 4, Insightful

    there is nothing like a good joke and that's nothing like a good joke

    --
    "The hands that help are better far than lips that pray." - Robert Ingersoll (1833-1899)
  7. As an upside of getting the plague by Khyber · · Score: 3, Informative

    Survivors of the Back Death seem to acquire part of a beneficial genetic mutation that gets passed on in full if they breed with another Black Death survivor - resistance to most known forms of HIV.

    http://www.eurekalert.org/pub_...

    --
    Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
    1. Re: As an upside of getting the plague by Anonymous Coward · · Score: 3, Informative

      This has been experimentally disproven. The CCR5delta32 mutation does not protect against plague: http://www.nature.com/nature/journal/v427/n6975/full/427606a.html

  8. Re:Usage changes meaning by JustAnotherOldGuy · · Score: 3, Informative

    My my, someone seems prickly today....too much starch in your undies? Why so much hatred? Is that your typical response to someone who disagrees with you? If so, that's kind of sad.

    Anyway, yes, words can change colloquial meaning over time.

    For example, "literally" has now come to mean "figuratively", due to the excessive hyperbole that most people seem to engage in these days.A complete reversal of meaning which seems stupid to me.

    That said, tthere are plenty of places where reversal of meaning has happened, such as the word "nice". It used to be an insult of sorts, meaning ‘stupid’ or ‘ignorant’. Later it came to mean ‘coy' or 'reserved’, and then it morphed again to mean 'subtle' and/or 'fine'. It finally became accepted in the current sense, which is 'good' or 'pleasant'.

    So yeah, it does happen. But as a cranky old word-Luddite, I'd prefer to use "devastated" in place of 'decimated'. Maybe in 50 years when I'm happily dead and buried the word will be uniformly accepted as having the same meaning as "devastated". :)

    And now I must go have lunch, because I'm literally starving to death here.

    Cheers

    --
    Just cruising through this digital world at 33 1/3 rpm...
  9. Bubonic Plague by tuxgeek · · Score: 3, Informative

    I used to live in Tahoe.
    Occasionally during the summer months, someone would contract bubonic plague after their house cats were outside and near ground squirrel burrows.
    It is transmitted by fleas of the common ground squirrel in the area. Don't remember the species.

    The infestation of infected fleas usually gets worse in drought years.

    Plague fleas are found all over the sierras, Yosemite as well.

    --
    "Suppose you were an idiot...and suppose you were a member of Congress...but I repeat myself." Mark Twain