In the 1300s, a jump in the number of burials in Kyrgyzstan’s cemeteries is linked by an international team to the beginning of a plague outbreak.

Researchers believe they have answered the nearly 700-year-old enigma surrounding the origins of the Black Death, the most lethal pandemic in recorded history, which swept across Europe, Asia, and North Africa in the middle of the 14th century.

At least tens of millions of people perished when the bubonic plague ravaged the continents, most likely via trade routes. Despite significant efforts to determine the origin of the outbreak, the question remains unanswered due to the absence of conclusive evidence.

Prof. Johannes Krause of the Max Planck Institute for Evolutionary Anthropology in Leipzig stated, “We have located the beginning in time and space, which is quite impressive.” We discovered not only the ancestor of the Black Death but also the ancestor of the vast majority of plague types currently circulating throughout the world.

Dr. Philip Slavin, a historian at the University of Stirling, discovered evidence of a significant increase in mortality in the late 1330s in two cemeteries near Lake Issyk-Kul in the north of modern-day Kyrgyzstan, bringing the worldwide team together to solve the mystery.

Among 467 tombstones dated between 1248 and 1345, Slavin discovered a significant increase in mortality, as evidenced by 118 tombstones dated 1338 or 1339. On several tombstones, the reason for death was recorded as “mawtn,” which is the Syriac word for “pestilence.”

The sites were excavated in the late 1880s, and approximately thirty skeletons were recovered from their graves. After reviewing the excavation records, Slavin and his colleagues retraced some of the remains and matched them to specific tombstones in the cemeteries.

The inquiry was subsequently entrusted to Krause and Dr. Maria Spyrou of the University of Tübingen in Germany, who specialize in ancient DNA. They retrieved DNA from the teeth of seven persons interred in the cemeteries. Three of them had DNA from the bubonic plague-causing bacterium Yersinia pestis.

A thorough examination of the bacterium’s genome revealed that it was a direct descendent of the strain that caused the Black Death in Europe eight years later and, as a result, was likely responsible for the deaths of more than half of the continent’s population during the next decade or so.

Scientists have discovered the strain’s closest living relative in rodents in the same region. People are still sick with bubonic plague, but improved cleanliness and less contact with rat fleas, which can transmit the disease to humans, have prevented further pandemics.