New Evidence Exonerates Rats as Bearers of Black Death

By Carl Engelking | March 31, 2014 3:08 pm


After more than 660 years, rats may finally be off the hook for causing the Black Death pandemic, which claimed up to 100 million lives in just a few years during the 14th century.

The long-running assumption was that rats, infected with the bacterium Yersinia pestis, spread the infection to humans via fleas. However, DNA evidence from 25 skeletons of Black Death victims, uncovered last year during construction of a major rail line in northern London, indicates the plague spread too quickly to pin the blame on rats and fleas. Researchers now believe the plague spread from human to human via coughs and sneezes.

Bearers of Black Death

Tim Brooks, a scientist with Public Health England in Porton Down, told the Guardian:

“As an explanation [rat fleas] for the Black Death in its own right, it 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.”

Brooks identified a mutation that changed the bubonic plague, spread by rats, into the pneumonic plague variety, which settled in the lungs and was spread by coughing. This variant spread faster and killed within 24 hours, according to the Telegraph. The 25 skeletons are thought to represent a tiny fraction of an emergency burial of 5,000 to 50,000 people dug in 1348, when the Black Death reached Britain.

More Medieval Insights

The London skeletons also offered a glimpse at the brutal lives of Britons in the 14th century. Most of the skeletons from the dig displayed evidence of rickets, anemia, bad teeth and malnutrition. Many had serious spinal damage, suggesting a life of excruciating manual labor. Others had upper body injuries indicating they’d been in fights.

Another kind of skeleton from the time period is however curiously absent: according to the Telegraph, the lack of rat skeletons from those years is further evidence that there weren’t enough rats around to serve as the vectors for the disease.


Image credit: schankz/Shutterstock

CATEGORIZED UNDER: Health & Medicine, top posts
  • Ginger

    Rats and other rodents are the animal reservoir for Yersinia pestis. A person bitten by an infected louse most commonly acquires the bubonic version of the plague, infecting the lymph system. If the disease moves into the lungs, it becomes the pneumonic form, which can spread through the air. When the pnemonic form hit a malnourished and crowded populace, it could continue to spread rapidly. There’s no need to posit a mutation or piles of dead rats.

  • Saltine Cracker

    This theory was suggested years ago.It traveled 7-10 miles a day which was far faster then the rats could move in a day.

  • Renda Luvaas

    hungry people eat rats

  • Ed

    “bad teeth…upper body injuries indicating they’d been in fights.” Have the British really changed that much over the past 660 years? 😉

  • bosco49

    “…there weren’t enough rats around…”
    What? Rats abandon Brits?

  • Sygurd Jonfski

    It might have later on spread this way but rats and fleas had brought it to Europe, hadn’t they?

  • enginer

    Climate alarmists ignore the fact that the black death occur ed during a period of cooling after the Medieval Optimum. The argument that the rats moved indoors as it grew colder and crop failures removed the waste products they normally fed on, a mal-nurised population was ripe to pick up the disease.

    • Robert H. Pike

      First; we’re not climate alarmists; we’re simply trying to point out that our exploding population (230,000 more born than die daily; google population clock) is like an train of increasing mass accelerating toward the inevitable end of the line. Earth and its’ resources is not growing; its’ inhabitants are. We’re climate (change) awareness posters; you’re in the group called “climate change deniers”.

      If you are not aware of the basic facts, you have your head in the sand, or, if you’re getting wealthy from fossil fuel based industry, (as most “enginer’s” are) you’re intentionally lying and exaggerating the falsehoods that reduce our awareness so your addictive, toxic business keeps growing.

      We’re trying to “alarm” the naive and uneducated to help us reduce rampant growth and it’s accompanying pollution before wars, disease, storms, and famines from drastic climate change does it for us. We care about the welfare of humanity, you care about the welfare of yourself and your family. We’re altruistic, you’re not.

      • DutchS

        And let’s also add that every single threat to libertarian freedoms stems from population growth: taxes, regulation, demand for government services, crowding, crime. POPULATION EQUALS REGULATION.

        You’d expect an engineer to understand the implications of exponential growth.

    • Kyle

      A real engineer here. Please take your fossil fuel funded conspiracy theories and find your own planet.

  • DutchS

    Well, the record of engineers in supporting crank science is positively shameful. Just look at the ones involved in 9-11 and Moon Hoax theories for a start. I’ve been studying crank science as long as you’ve been an engineer, and whenever I find a “scientist” who supports a crank theory, the odds are very strong he’s an engineer or industrial scientist. They often justify their stance by saying they have “practical” as opposed to “ivory tower” training. What they generally have is lousy theoretical understanding and a narrow range of experience. They may have worked in many places, but they merely drilled the same oil well or ran the same chemical process for forty years.

  • D Sanchez

    I do hope you are attributing homosexuality to over crowding. I would hope, you would be a little more intelligent then that.

  • D Sanchez

    I do hope you are not attributing homosexuality to overpopulation. I assume you are more intelligent then that.

    • Robert H. Pike

      I assume you’re intelligent enough to read the research. It’s not only logical (the More crowded a population gets in an area the more interactions there are homosexual, heterosexual, etc.) Google ” population density and social pathology by John C Calhoun . I’m very supportive of homosexuality . I’m not homosexual myself but have homosexual friends. have even hosted a homosexual wedding at my home but I repeat I am not homosexual but I am empathetic to their situation.


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