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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."

24 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. Re:Math is fun by AthanasiusKircher · · Score: 2

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

      Just to be clear -- pedantic lunatics have been arguing about this word for years, but in modern English it basically never meant the same as Roman decimatio regarding military practice, except in specific historical discussions.

      Go ahead -- look up examples of people using the word back 300 years ago. You'll find that when the word is used to refer to destruction or killing, it means a LARGE AMOUNT, not just 10%. It never primarily meant decimatio in English, no matter how much the pedants want it to. (The word only became common in English in the mid-1600s, and by the late 1600s it clearly meant "to destroy/kill a large portion of" in most English usage.)

      Moreover, if you actually trace the early English usage of the word (back in the 1600s), you'll find that when it did mean 1/10th, it didn't necessarily refer to killing at all -- it came from the medieval Latin decimatus, which referred to a TITHE (i.e., 1/10th of your income donated to the church or to taxation). "Decimation" entered English in the 1500s as a synonym for tithing, and though there are a couple military references to "decimate" in the 1600s, the two dictionaries from the time that define the word both include the tithing sense (with only one mentioning the military sense).

      From the usage of tithing (and a few examples of a military sense), it rapidly turned into a word for large amount of destruction. Outside of a few random military quotations, it never had a primary English usage equivalent to the Roman army practice. It wasn't until about the 1860s -- over 200 years after decimate came to mean "destroy a large portion of" -- that wacko grammarians decided there was something "wrong" with that usage and have been complaining about it ever since.

  2. Usage changes meaning by drinkypoo · · Score: 2

    "Decimated nearly half the population" means less than 5%. You can't just ignore the prefix 'deci' because everyone uses it incorrectly, dictionary.

    "Decimate" hasn't meant "killed every tenth man by lot" for a lot of years. It's usually not used with exact percentages, but it's often used for percentages other than ten.

    --
    "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    1. Re:Usage changes meaning by Pseudonymous+Powers · · Score: 2

      "Decimated nearly half the population" means less than 5%. You can't just ignore the prefix 'deci' because everyone uses it incorrectly, dictionary.

      "Decimate" hasn't meant "killed every tenth man by lot" for a lot of years. It's usually not used with exact percentages, but it's often used for percentages other than ten.

      That is literally what I was just about to say. Words mean whatever we want, whenever we want! This is also why I pay all my debts in U.S. dollhairs.

    2. Re:Usage changes meaning by MyAlternateID · · Score: 2

      "Decimated nearly half the population" means less than 5%. You can't just ignore the prefix 'deci' because everyone uses it incorrectly, dictionary.

      "Decimate" hasn't meant "killed every tenth man by lot" for a lot of years. It's usually not used with exact percentages, but it's often used for percentages other than ten.

      It was a tactic used by the Roman military commanders. 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. The Romans didn't fuck around.

      From the psychological effect this inflicted on the remaining 90%, the word has a connotation of doing severe damage. Personally I might use it to illustrate this kind of meaning, but not in combination with an actual percentage. I would combine it with actual numbers only if I intended to convey the original meaning. That way it's clear whether the word is being used figuratively or literally. The wording of the summary is just sloppy; it's the kind of thing a competent editor would have corrected.

    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: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...
  3. 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.

  4. Re:So, what does all of this mean... by kav2k · · Score: 2

    Still easily treatable with antibiotics.

  5. Re:Nature provides the solution by WOOFYGOOFY · · Score: 2

    You have no idea what you're yacking on about. What you call a "European" circa 500 CE is some admixture of Mediterranean, Near Eastern, Middle Eastern, Eurasian, Russian , Ukrainian and Maikop. The LAST thing the European continent was ever is "isolated" at least not since 2500 BCE.

    If you want to see what happens with genes when they're isolated, go to the Galapagos Islands.

  6. Re:Ugh by Pseudonymous+Powers · · Score: 2

    Words mean what most of the speakers of the language mean. So your tirade is pointless, unoriginal, and wrong. Utterly wrong.

    I am aware that any language's mapping of letters and sounds to meanings is completely arbitrary, and furthermore that these mappings evolve continuously. So yes, if enough people start thinking that "chartreuse" means "pink", then indeed it does, at least to them. But for the rest of it, it still means greenish-yellow. The end result is a failure of communication. What I and people like me--pedants--are trying to do is preserve the integrity of communication by nipping some of these uglier and less consistent forms in the bud, before they metastasize and spread throughout the meme pool, and we all just have to live with them. That is literally all I'm saying.

  7. 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%.

  8. 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.

  9. Re:And they say we have nothing to worry about by ColdWetDog · · Score: 2

    Bacteria as a bioweapon probably won't ever work to wipe out populations. You certainly could wreck havoc in clusters of humans with poor infrastructure (refuge camps, slums, Trenton, New Jersey) but even without antibiotics we know enough to slow down the transmission to prevent mass catastrophe. Yes, it would be a good 'terror weapon' since at least the US population seems to be scared of it's own shadow much less any real boogy man (cf, the Ebola scare) but as far as a tactical weapon it has a lot of drawbacks.

    --
    Faster! Faster! Faster would be better!
  10. 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)
  11. Re:Ugh by Rufty · · Score: 2

    Decimate must always mean a tenth, just like December is always the tenth month.

    --
    Red to red, black to black. Switch it on, but stand well back.
  12. 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

    2. Re: As an upside of getting the plague by Anonymous Coward · · Score: 2, Informative

      They didn't say protects against plague, they said protects against HIV.

  13. Re:Ugh by rubycodez · · Score: 2

    But in the case of the "decimate" you'd be wrong. It absolutely does NOT mean killing a tenth of anything.

    Meriam-Webster says:
    Decimate: v

    : to destroy a large number of (plants, animals, people, etc.)

    : to severely damage or destroy a large part of (something)

  14. Re:And they say we have nothing to worry about by budgenator · · Score: 2

    Firstly there is a vaccine for Y. pestis, I know I've had it, and secondly a good stiff dose of Y. pseudotuberculosis is going to give you the shits, but most likely leave as immune to Y. pestis as you can get.

    --
    Apocalypse Cancelled, Sorry, No Ticket Refunds
  15. 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