The Black Death, the deadliest pandemic in human history, may have first reared its ugly head in Central Eurasia, according to a new study published in the journal Nature.
The geographic origins of the devastating plague in the 14th century CE have been long-disputed, with previous research making predictions as far-ranging as western Eurasia to China.
This latest estimation draws on numerous stands of evidence including a remarkable DNA analysis of people who died in the 14th century CE around modern-day Kyrgyzstan.
The work focuses on the deep Chüy Valley, close to Lake Issyk Kul in northern Kyrgyzstan, where a surprisingly high number of burials can be dated to 1338 and 1339 CE. Written sources from the area around this time are few and far between, but this date of 1338 is eight years before the Black Death is known to have arrived at Europe's shores in 1346 CE.
Many of the tombstones in the area are inscribed in Cyrillic, explaining the graves hold the bodies of people who died of “pestilence”. However, scholars have doubted they had much relevance to the Black Death since the dating was a number of years away from the established emergence of the plague outbreak in Europe.
Genetic evidence can now prove the graves do, in fact, contain the bodies of some of the earliest known plague victims. The team extracted ancient DNA from seven individuals buried at the sites and discovered traces of the bacteria that causes the plague, Yersinia pestis, in three of the samples.
After reconstructing the degraded and fragmented ancient bacteria DNA, they found the strain emerged around the dawn of the Black Death’s initial “big bang.”
“We found that the ancient strains from Kyrgyzstan are positioned exactly at the node of this massive diversification event. In other words, we found the Black Death’s source strain and we even know its exact date [ the year 1338 CE]”, said Maria Spyrou, lead author and researcher at the University of Tübingen in Germany.
The researchers also discovered that rodents currently living in this region are still infected with modern strains of plague closely related to the ancient strains that caused the Black Death. Since we know that plague outbreaks typically start with spill-over from an animal – often a rodent or its fleas – this further suggests that the emergence of the Black Death had some kind of origin here in Central Eurasia.
“We found ancient evidence, as well as modern evidence. At the same time, we have tombstones that even tell us when it happened,” Johannes Krause, study author from the Max Planck Institute for the Science of Human History, said at a press briefing on Tuesday.
“We have located its origin in time and space — which is really remarkable.”