Based on the work of historian Phil Slavin of the University of Stirling in Scotland, who had suggested that the rise of the disease could be linked to an unusual increase in deaths in a city in Central Asia in 1338-1339, researchers examined DNA from bodies found there.
They found genetic fingerprints of the bacterium Yersinia pestis in individuals buried with tombstones referring to a “plague” at the site near Lake Issyk Kul, in what is now Kyrgyzstan.
In a paper published Wednesday in the journal Nature, the researchers describe how the fingerprint reveals the species that devastated the ancient trading community in Issyk Kul and was the precursor to many others that emerged around that time.
“We found that the ancient tribes from Kyrgyzstan are positioned right at the nexus of this massive diversification event,” said Maria Spyrou, a disease history researcher at the University of Tübingen in Germany and lead author of the report. “In other words, we have found the source strain of the Black Death and we even know the exact date (1338).”
The disease, which is spread by rats and their fleas, is known to eventually make its way to the Sicilian port of Messina on trading ships that arrived from the Black Sea in 1347.
Sharon DeWitte, a biological anthropologist at the University of South Carolina who was not involved in the study, said it was exciting to have the DNA evidence to support the earlier theory that the disease originated in Central Asia.
“This study is important because the very accurately dated burials allow a direct study of the species as it existed at the time of the first emergence of the Black Death,” she said.
While the authors acknowledge that it’s theoretically possible that the bacterium originated elsewhere and spread to Central Asia without changing significantly, the evidence suggested this was unlikely, DeWitte said.