Andrew Lawler in Science:
The medieval Silk Road brought a wealth of goods, spices, and new ideas from China and Central Asia to Europe. In 1346, the trade also likely carried the deadly bubonic plague that killed as many as half of all Europeans within 7 years, in what is known as the Black Death. Later outbreaks in Europe were thought to have arrived from the east via a similar route. Now, scientists have evidence that a virulent strain of the Black Death bacterium lurked for centuries in Europe while also working its way back to Asia, with terrifying consequences.
At the Society for American Archaeology meetings earlier this month in Orlando, Florida, researchers reported analyzing the remains of medieval victims in London; Barcelona, Spain; and Bolgar, a city along the Volga River in Russia. They determined that the victims all died of a highly similar strain of Yersinia pestis, the plague bacterium, which mutated in Europe and then traveled eastward in the decade following the Black Death. The findings “are like pearls on a chain” that begins in western Europe, said Johannes Krause at the Max Planck Institute for the Science of Human History in Jena, Germany, an author of a soon-to-be-published study. (The lead author is Maria Spyrou, also at Jena.) That chain may have stretched far beyond Russia. Krause argues that a descendant of the 14th century plague bacterium was the source of most of the world’s major outbreaks, including those that raged across East Asia in the 19th and 20th centuries and one afflicting Madagascar today.