They manage to trace the origin of the Black Death, the worst pandemic that hit humanity

German and British experts in Evolutionary Anthropology found the origins of the first strain of the disease-causing bacteria. The disease killed 200 million people in the 14th century.

German and British experts in Evolutionary Anthropology found the origins of the first strain of the disease-causing bacteria. The disease killed 200 million people in the 14th century.

The Black Death it was the most devastating pandemic in human history, affecting Europe and Asia in the 14th century and reaching a peak between 1347 and 1353 when it killed between 80 and 200 million people.

Expert historians estimate that this disease decimated the European population, causing the death of between 30% and 60% of the inhabitants of that continent due to the bacterium Yersinia pestis.

According to contemporary knowledge, the pandemic first broke out in Asia, later reaching Europe through trade routes.

The epidemic reached Europe through the Mediterranean basin in 1346, transported by trading ships from the Black Sea, and spread throughout Europe, the Middle East and North Africa in a first large-scale outbreak that dragged on into a pandemic. until the beginning of the 19th century (in different waves) and which caused the death of more than half of the European population.

Now a multidisciplinary team of scientists has succeeded in locating the origin of the Black Death, the greatest pandemic in history, in the Tian Shan Mountains region of Central Asia in the first half of the 14th century, thus clearing up one of the greatest mysteries of history. science, in a study published today in the journal Nature.

In this study, a group of scientists from the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany), the University of Tübingen (Germany) and the University of Stirling (United Kingdom) traced the origins of the first strain of the bacteria that causes from the Black Death, Yersinia pestis, to the Issyk Kul Lake region in present-day Kyrgyzstan.

An engraved tombstone of a person who died of the Black Death from the Kara-Djigach cemetery in present-day Kyrgyzstan (Credit: P.-G. Borbone, M.A. Spyrou)

Many theories placed the origin of this pandemic in places in Asia, such as China or Mongolia, but in this study the researchers showed that the initial outbreak occurred in this region of Central Asia, an area crossed by important trade routes of the route of the silk in the Middle Ages.

This finding was possible thanks to the investigation of human remains that were discovered in two cemeteries in this region of Asia in excavations carried out almost 140 years ago.

Some inscriptions found on the tombstones of these niches indicated in the Syriac language that the individuals buried there died in the years 1338 and 1339 due to an unknown epidemic.

The researchers analyzed the ancient DNA of these human remains, as well as historical and archaeological data from these two communities affected by this mysterious disease, and certified the presence of the bacterium Yersinia pestis. The epidemic disappeared and reappeared in waves, over 500 years.

Until now, one of the most mentioned clues was China, but no robust evidence allowed this theory to be verified. “I was always fascinated by the Black Death, and one of my dreams was to solve the mystery of its origins”explained the specialist historian of catastrophes Phil Slavin, one of the authors of the study, at a press conference.

“The most important thing is not only that we detected the Yersinia pestis bacterium in these burials, but also that, in terms of evolution, that same bacterium is at the origin of the Black Death pandemic,” said Slavin.

“In other words, it is an older strain than the Black Death strain from Europe. To be more precise, it is the strain that exactly coincides with the start of the pandemic,” he added.

Studies of ancient pollen suggest that the Black Death eluded some regions of Europe and devastated others (By Jonathan Corum | Sources: Adam Izdebski et al., Nature Ecology & Evolution. Modern borders shown)

Studies of ancient pollen suggest that the Black Death eluded some regions of Europe and devastated others (By Jonathan Corum | Sources: Adam Izdebski et al., Nature Ecology & Evolution. Modern borders shown)

The study suggests that at some point in the 14th century there was an event that researchers call the “Big Bang”, a massive diversification of plague strains, which they associate with the genesis of the first major wave of the Black Death in Europe between 1346 and 1353. The team succeeded in sequencing the complete genomes of that first plague from the burials of Kyrgyzstan and discovered that these ancient strains “are located exactly at the node of origin of this massive diversification event”, in the words of Maria Spyrou, a researcher from the University of Tübingen and also author of the work.

A hundred of the approximately 400 gravestones had precise dates, between 1338 and 1339. The epitaph mentioned an elliptical “death by pestilence” in Syriac. These signs indicated an abnormal excess mortality within a community, seven or eight years before the Black Death arrived in Europe. To find the cause of death, the researchers obtained DNA from dentures belonging to seven skeletons. “The dental pulp is a valuable clue, because it is a highly vascular area that offers a high probability of detecting pathogens in the blood,” explained Spyrou. The DNA could be sequenced (an extremely difficult job because it was so fragmented) and then compared to a database containing the genomes of thousands of bacteria.

The scientists concluded that the ancient Central Asian strain that caused the 1338-1339 plague epidemic in Kyrgyzstan jumped to humans from populations of marmots in this region, which act as reservoirs for the bacterium, and then mutated into different variants that spread throughout the world.

“This strain precedes this ‘Big Bang,’ which was a pivotal evolutionary event, and any such event has to evolve from an earlier strain,” Slavin said.

Obtaining genomes of plague bacteria ancestral to those behind the Black Death is “a breakthrough,” says Monica Green, a medieval historian and independent scholar in Phoenix, Arizona. “Headstones are the closest thing we’ll ever get to ‘death certificates.’ So we know that this lineage of Y. pestis existed back then.”

But she is less sure of the study’s conclusion, that the plague’s ‘big bang’ occurred around the time of the Kyrgyz deaths in 1338-1339. Green has hypothesized, based on genetic, ecological, and historical evidence, that the expansion of the Mongol Empire in the 13th century catalyzed the spread and diversification of the Y. pestis strains responsible for the later Black Death.

The researcher made an analogy with the coronavirus pandemic: “We have Alpha, Beta, Gamma, Delta, Omicron… Omicron evolved from Delta, and Delta evolved from Gamma. It may not be the best comparison, but what we do know is that this strain preceded the Black Death strain.” Precisely the recent coronavirus pandemic, Slavin points out, contributed to increasing the interest of society and the scientific community in infectious diseases and epidemics caused by microorganisms such as viruses and bacteria.

“This was one of the biggest hotbeds of debate in history, especially now with COVID,” Slavin concludes. In addition, he added that although these findings “end all speculation about the origins of the Black Death, they also raise new questions” about the context in which this first outbreak developed.

“We have not only found the ancestor of the Black Death, but also that of the plague strains currently circulating around the world,” added Johannes Krause of the Max Planck Institute. The rodents that currently live in that region of the Tien Shan are carriers of a strain of the bacteria very close to those of the human victims of 1338-1339. The plague has not yet been eradicated: thousands of people contract this disease, particularly in Central Asia. In the Tien Shan mountains, marmots are the main animal reservoir of the disease. However, thanks to antibiotics and the development of hygiene, the pandemic is a limited phenomenon.

By: Infobae

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