Lake Issyk Kul Zis the Wuhan of the Black Death

Thursday, June 16th, 2022

A new study of DNA from the “pestilence” victims in what is now northern Kyrgyzstan shows that they were indeed infected with the bacterium, Yersinia pestis, that caused the Black Death:

The Syriac engraving on the medieval tombstone was tantalizing: “This is the tomb of the believer Sanmaq. [He] died of pestilence.” Sanmaq, who was buried in 1338 near Lake Issyk Kul in what is now northern Kyrgyzstan, was one of many victims of the unnamed plague. By scrutinizing field notes and more photos from the Russian team that had excavated the graves in the 1880s, historian Philip Slavin found that at least 118 people from Sanmaq’s Central Asian trading community died in the epidemic.

Slavin was on the trail of the origin of the Black Death, which devastated Europe a decade after the Kyrgyzstan burials. But he knew the medieval diagnosis of “pestilence” encompassed many horrific diseases. “I was almost 100% certain it was the beginning of the Black Death,” says Slavin, a medieval historian at the University of Stirling. “But there was no way to prove it without DNA.”

Now, Slavin is senior author of a new study of ancient DNA from the “pestilence” victims showing they were indeed infected with the bacterium, Yersinia pestis, that caused the Black Death. The strain that killed them was ancestral to all the strains that rampaged across Europe a decade later and continued to kill for the next 500 years. The bacterium jumped from rodents to humans just before the Kyrgyzstan burials, perhaps after sudden changes in rainfall or temperature, the researchers propose this week in Nature.

“This is the place where it all started — the Wuhan of the Black Death,” says senior author and paleogeneticist Johannes Krause of the Max Planck Institute for Evolutionary Anthropology.

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The strain was closely related to ones found in rodents near Issyk Kul today. The authors suggest it spilled over to humans, perhaps from a marmot, which are abundant in the Tian Shan mountain region of northern Kyrgyzstan, southern Kazakhstan, and northwestern China. Sudden changes in rainfall or temperature could have led to surges in local rodent populations and the fleas or other insects they harbor. More rodents and their pests meant more opportunities to hop to a new host—humans—and adapt to it, says population biologist Nils Christian-Stenseth of the University of Oslo, who has shown a correlation between outbreaks of plague and warm, wet weather in Central Asia. He adds: “There are many good possibilities for plague reservoirs; you have the great gerbils, marmots, voles.”

The remaining mystery, he says, is how the Black Death traveled 3500 kilometers from Central Asia to the Black Sea, where historical accounts describe the Mongolian army hurling the bodies of plague victims into the besieged city of Caffa in Crimea in 1346 in an early form of biological warfare.

The meticulous archaeological records for each Kyrgyzstan grave offer hints, Slavin says. Many people were buried with pearls, coins, and other goods from the Indian Ocean, the Mediterranean, and Iran; some were apparently traders. As they traveled, their camel wagons may have harbored rats and fleas, long considered likely vectors for plague.

Comments

  1. Jim says:

    Very cool.

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