An earlier, more elusive version, long before the Black Death killed millions across Europe in the Middle Ages of plague It spread over most of Eurasia.
For years, scientists were unsure how this ancient disease spread so widely during the Bronze Age, which lasted from about 3300 BC to 1200 BC, and persisted for nearly 2,000 years, especially since it was not spread by fleas like later plagues. Researchers say a surprising clue may help explain it: domesticated sheep that lived more than 4,000 years ago.
Researchers have discovered DNA from the plague bacterium Yersinia pestis in the teeth of a Bronze Age sheep found in what is now southern Russia, according to a study recently published in Russia. journal cell. This is the first known evidence that the ancient plague infected animals as well as humans, providing a missing clue as to how the disease spread.
Scientists crack the code for a new vaccine for the deadly plague bacterium
“This was a wake-up call for my team,” said study co-author Taylor Hermes, an archaeologist at the University of Arkansas who studies ancient livestock and the spread of disease. In a statement. “This was the first time that the Y. pestis genome was recovered from a non-human sample.”
According to the researchers, it was a fortunate discovery.
“When testing livestock DNA “Ancient samples give us a complex gene soup of contamination. This is a big barrier, but it also gives us an opportunity to look for pathogens that infected the herd and its keepers,” Hermes said.
Deadly bacteria that destroyed Napoleon’s army discovered 213 years after Russia retreated
This highly technical and time-consuming task requires researchers to isolate small, damaged pieces of ancient DNA from soil, microbes, and even contaminants left behind by modern humans. The DNA they recover from ancient animals is often broken into small pieces just 50 letters long, but a complete human DNA strand contains more than 3 billion letters.
Animal remains are particularly difficult to study because they are often poorly preserved compared to carefully buried human remains, the researchers said.
Click here to sign up for our lifestyle newsletter
The discovery sheds light on how plague likely spread through close contact between humans, livestock and wild animals, as Bronze Age societies kept larger herds and traveled greater distances on horses. The Bronze Age saw more widespread use of bronze tools, extensive animal husbandry, and increased travel. These conditions may have made it easier for the disease to move. animals and humans.
During the Middle Ages in the 1300s, another outbreak of the plague known as the Black Death killed an estimated one-third of Europe’s population.
“It had to be more than just moving people,” Hermes said. “Our plague sheep gave us a breakthrough. We now see it as a dynamic between humans, livestock, and an as-yet-unidentified ‘natural reservoir.’ ”
For more lifestyle stories, click here
Researchers believe the sheep likely picked up the bacteria from another animal, such as a rodent or migratory bird, that carried the bacteria without getting sick, and then passed it on to humans. Researchers say the findings highlight how many deadly diseases start in animals and jump to humans, and that the risks continue today as people move into new environments and interact more closely with wild and domestic animals.
“It’s important to have more respect for the forces of nature,” Hermes said.
The researchers noted that because the study was based on a single ancient sheep genome, scientists were limited in how much they could draw conclusions from, and that more samples were needed to fully understand the spread.
Test yourself with our latest lifestyle quiz
Researchers plan to study more ancient human and animal remains. region The aim is to find out how widespread the plague was and which species were involved in its spread.
They also hope to identify the wild animals that first carried the bacteria, insights that will help them better understand how human movement and livestock farming helped the disease travel long distances, and better predict transmission routes. diseases of animal origin It keeps appearing.
The study was led by scientists at the Max Planck Institute for Infection Biology and included lead authors Felix M. Kee from the Max Planck Institute for Infection Biology and Christina Werner from Harvard University and the Max Planck Institute for Geoanthropology.
The study was supported by the Max Planck Society, which is also funding follow-up activities in the region.
