Mystery of origin of the Black Death solved, researchers say | Science

At least tens of millions of people died as the bubonic plague swept across the continents, probably from spreading along trade routes. Despite frantic efforts to determine the source of the outbreak, the lack of hard evidence has never been conclusive.

“We have located the origin in time and space, which is really remarkable,” said Professor Johannes Krause of the Max Planck Institute for Evolutionary Anthropology in Leipzig. “We have not only found the ancestor of the Black Death, but also the ancestor of most of the plague strains circulating in the world today.”

The international team gathered to work on the puzzle when Doctor Philip Slavin, a historian at the University of Stirling, discovered evidence of a sudden increase in deaths in the late 1330s. Slavin made his discovery at two cemeteries in near Lake Issyk-Kul in the north of present-day Kyrgyzstan.

Among 467 tombstones dated between 1248 and 1345, Slavin discovered a huge increase in deaths, with 118 stones dated 1338 or 1339. Inscriptions on some tombstones stated the cause of death as “mawtānā”, the Syriac language term for “plague”.

Closer examination revealed that the sites had been excavated in the late 1880s, with approximately 30 skeletons recovered from their graves. After studying the excavations, Slavin and his colleagues traced some of the remains and linked them to certain headstones in the cemeteries.

The research then turned to ancient DNA specialists, including Krause and Doctor Maria Spyrou from the University of Tübingen in Germany. They extracted genetic material from the teeth of seven people buried in the cemeteries. Three of them contain DNA from Yersinia pestis, the bacterium that causes bubonic plague.

A full analysis of the bacterium’s genome revealed that it was a direct ancestor of the strain that caused the Black Death in Europe eight years later, and therefore likely killed more than half of the continent’s population in the following year. decade.

The tribe’s closest living relative was now found in rodents in the same region, the scientists said. Although people still become infected with bubonic plague, better hygiene and less contact with rat fleas have prevented further deadly plague pandemics.