By Will Dunham
(Reuters) – Ancient DNA from bubonic plague victims buried in cemeteries on the former Silk Road trade route in Central Asia has helped solve an enduring mystery, pointing to an area of northern Kyrgyzstan as the focal point launching the Black Death that killed tens of millions of people. people in the middle of the 14th century.
Researchers said on Wednesday that they had recovered ancient DNA traces of the bacterium Yersinia pestis from the teeth of three women buried in a medieval Christian community in Nestorian in the Chu Valley, near Lake Issyk Kul, in the foothills of the Tian Shan Mountains. , who died between 1338 and 1339.. The first documented deaths elsewhere in the pandemic were in 1346.
Reconstruction of the genome of the pathogen showed that this strain not only resulted in the one that caused the black plague that affected Europe, Asia, the Middle East and North Africa, but also most of the existing plague strains. today.
“Our finding that the Black Death originated in Central Asia in the 1330s highlights the centuries-old debates,” said historian Philip Slavin of the University of Stirling in Scotland, co-author of the published study. in the journal Nature https://www.nature.com/articles/s41586-022-04800-3.
The Silk Road was a land route for caravans transporting a range of goods back and forth from China through the sumptuous cities of Central Asia to places such as the Byzantine capital Constantinople and Persia. It may also have served as a death conduit if the pathogen stuck to the caravans.
“There have been a number of different hypotheses suggesting that the pandemic may have originated in East Asia, specifically in China, Central Asia, India, or even near where the first outbreaks were documented in 1346 in the Black Sea and Caspian Sea regions. “
“We know that trade was probably a determining factor in the spread of the plague in Europe during the onset of the Black Death. It is reasonable to hypothesize that similar processes led to the spread of the disease from Central Asia to in the Black Sea between 1338 and 1346. “Spyrou added.
The story goes on
The origins of the pandemic are hotly debated, as evidenced by the debate over the emergence of the current COVID-19 pandemic.
The Black Death was the deadliest pandemic on record. He said he could have killed between 50 percent and 60 percent of the population in parts of Western Europe and 50 percent in the Middle East, killing about 50-60 million people, Slavin said. An “unexplained number” of people also died in the Caucasus, Iran and Central Asia, Slavin added.
“As early as the Middle Ages, we saw the high mobility and rapid spread of a human pathogen,” said Johannes Krause, an archaeogenetist and co-author of the study, director of the Max Planck Institute for Human Science. Human History in Germany. “We should not underestimate the potential of pathogens to spread around the world from rather remote places, probably due to a zoonotic event,” an infectious disease that jumps from animals to people.
The researchers analyzed the teeth, a rich source of DNA, of seven people buried in cemeteries in communities called Burana and Kara-Djigach, obtaining DNA from the plague of three in Kara-Djigach.
The cemeteries, excavated in the 19th century, included tombstones that attributed deaths to “pestilence” in the Syriac language. Objects such as pearls, coins and clothing from distant places indicated that cities were involved in international trade, perhaps offering stop and rest services for long-distance caravans.
Bubonic plague, intractable at the time but now curable with antibiotics, caused swollen lymph nodes with leaking blood and pus, and the infection spread to the blood and lungs.
In Europe, it was transmitted mainly by flea bites taken to infected rats. The pandemic originated in wild rodents, probably groundhogs, a type of terrestrial squirrel, Slavin said. Rodents tagged in caravans may have helped spread it, but other mechanisms of transmission may have included human fleas and lice.
“We have found that the closest living relatives of this strain of Y. pestis that gave rise to the Black Death are still found today in groundhogs in this region,” Krause said.
(Report by Will Dunham in Washington, edited by Rosalba O’Brien)