Even during the Great Plague of the late Middle Ages, people were concerned with the question of where the pandemic began. Seven centuries later, the answer seems to have been found. Gravestones and human bones provide the decisive clue.
In the 14th century, 60 percent of Western Europeans died within eight years from the so-called Black Death, the plague. Much like the coronavirus, there has long been speculation as to where this devastating pandemic began. An international research team has now found the answer to this question. The scientists published their findings in the journal "Nature".
One of the most popular theories put the source of the infection in East Asia, specifically China. However, the only archaeological finds available so far came from Central Asia. Findings from near Lake Issyk-Kul in present-day Kyrgyzstan showed that in 1338-1339 an epidemic swept a local community.
Nearly 140 years ago, tombstones inscribed in Syriac were found there, suggesting that people died of an unknown epidemic or "plague" during those years. In addition, there were an above-average number of funerals in a very short period of time.
In their study, the international research team analyzed ancient DNA from human bones as well as historical and archaeological data from two places where "plague" inscriptions were found. They were able to detect the plague bacterium Yersinia pestis on three out of seven people with the year 1338/39 on their gravestones. These were 14th-century precursors to all other known plague genomes.
"We were finally able to show that the epidemic mentioned on the tombstones was actually caused by the plague," said Phil Slavin, one of the lead authors of the study and a historian at the University of Stirling, UK, in a statement from the Max Planck Institute cited for evolutionary anthropology.
Before the plague spread worldwide in the 14th century, experts suspected a kind of big bang event, which could have resulted in a massive diversification of plague strains. The research team assigns this event to the find from near Lake Issyk-Kul. According to Tübingen archaeogeneticist Maria Spyrou, the ancient bacterial strains from Kyrgyzstan are positioned exactly at the hub of this massive diversification event. "In other words, we have found the origin tribe of the Black Death and even know its exact date."
The scientists also investigated how the plague strain got to this place. Did it develop locally or spread from elsewhere in this region? They point out that the plague bacterium survives within wild rodent populations around the world, in so-called plague reservoirs.
Therefore, the ancient Central Asian tribe that caused the epidemic around Lake Issyk-Kul in 1338/39 must have come from such a reservoir. "We found that modern strains, which are most closely related to the ancient tribe, are now found in plague reservoirs around the Tian Shan Mountains, very close to where the ancient tribe was found. That suggests point to an origin of the ancestor of the Black Death in Central Asia," explains Johannes Krause, first author of the study and Director at the Max Planck Institute for Evolutionary Anthropology.