SCIENCE

What?! New evidence suggests that rat fleas were not entirely responsible for the pandemic plague that devastated Europe in the 14th century. (the Guardian)

Use our resources to learn more about paleopathology and other disciplines of archaeology.

Discussion Ideas

• Read our paragraph on paleopathology, the study of disease in ancient cultures, in our encyclopedic entry on archaeology. Does the new analysis of plague victims in London support our definition of paleopathology?
  • Absolutely! It’s a near-perfect example of this discipline of archaeology.
    • “Paleopathologists may investigate the presence of specific diseases, what areas lacked certain diseases, and how different communities reacted to disease.”
      • In London, paleopathologists investigated the presence of Yersinia pestis, the bacterium linked to plague. By tracing the history of the Black Death with the development of Y. pestis, scientists have been able to identify the bacteria as arriving in London from central Asia in autumn 1348 and killing 60% of the population within a year. (Let Simon Schama tell you about the consequences of that here.)
    • “By studying the history of a disease, paleopathologists may contribute to an understanding of the way modern diseases progress.”
      • Paleopathologists studied the Y. pestis bacteria in the 14th-century skeletons, and compared it to a modern strain of the bacteria responsible for deaths in Madagascar. To their surprise, the DNA codes were almost a perfect match—the bacteria had not evolved much at all.
    • “Paleopathologists can also find clues about people’s overall health.”
      • Not surprisingly, analysis of the 14th-century plague victims revealed that medieval Londoners were not terribly healthy to begin with. Scientists found evidence of rickets, anemia, bad teeth, back damage, and malnutrition. (How do scientists determine this? Watch our video “Clues to Mayan Prosperity” to understand how ancient dental hygiene—or lack thereof—provides a wealth of information about culture, health, and diet.)
    • “By studying the teeth of ancient people, for example, paleopathologists can deduce what kinds of food they ate, and even where they came from.”
      • By studying the teeth of the London plague victims, paleopathologists were able to determine that almost half were immigrants to the city. “Forty percent grew up outside London, possibly as far north as Scotland—showing that 14th-century London attracted people from across Britain just as it does today,” according to the BBC. (How did scientists determine this? Watch our video “Clue to a People’s Origins” to understand how strontium analysis of a skeleton’s teeth provides archaeologists with “a perfect geo-locator.”)

• The Guardian article says the Black Death, long associated with the bubonic plague, was perhaps predominantly a form of pneumonic plague. What do you think the major differences between the diseases are?
  • The major difference is where the infection is located. Bubonic plague settles in the lymph system, leading to the telltale “buboes”, or darkened swellings around the lymph nodes of the armpit and groin. Pneumonic plague settles in the lungs. (A third plague sister, septicemic plague, infects the blood.) The Black Death was probably a pandemic that included all three plagues, so rats aren’t entirely off the hook.
  • Pneumonic plague spreads much, much more quickly than bubonic plague. This is because the diseases have different vectors. A vector is an organism that carries and transmits disease to another organism.
    • The vector in bubonic plague is mostly fleas, themselves carried by rats. A person has to be bitten by an infected flea to catch the disease.
    • The vector in pneumonic plague is mostly human beings. Pneumonic plague can be spread simply by the air we breathe.