Researchers have revealed that the hunter-gatherer who lived more than 5,000 years ago was the first person to die from the plague.
Stone Age societies in Western Europe experienced a massive population decline about 5,500 years ago, an event that is believed to have subsequently enabled the migration of large numbers of people from the East.
Plague was put forward as an explanation after it was previously found in Stone Age individuals, including a 20-year-old woman from a rural farming community in Sweden.
However, the researchers claim that their new finding casts doubt on the idea that the breed’s hunter-gatherer nature is unlikely to cause a rapid spread.
“We believe that these early forms of Y. pestis “It cannot cause large outbreaks,” said Professor Ben Krause-Kura, co-author of the study at Christian Albrecht University in Kiel, Germany.
Krauss-Kura and colleagues describe in the journal Cell Reports how they analyzed ancient DNA extracted from the teeth and skull bones of four individuals buried in a prehistoric litter, or hidden cochlea, at a site in Latva called Riņņukalns.
The remains, dating between 5,300 and 5,050 years old, of a young woman, a child and two men, were discovered in two excavations, one in the 19th century and one just a few years ago.
The team scanned the genetic material for signs of known pathogens, including بما Y. pestis Plague-causing bacteria, which revealed that one of the men, aged 20-30, had not only DNA fragments, but also proteins, indicating that he died of a now-extinct form of plague in his bloodstream.
“Until now [it is], the oldest known victim of the plague,” Krause-Kura said.
Additional analysis revealed that the strain likely split from all forms Y. pestis It was about 7,200 years old, making it the oldest known strain of plague, and was distinctly different from those found later in the Neolithic and Bronze Age.
The researchers added that the strain lacked the gene that allowed the plague to be spread by fleas.
“Fleas seem to be one of the main vectors that leads to really rapid spread and rapid infection during the Middle Ages,” Krauss-Kura said, adding that blackheads caused by infected lymph nodes are associated with this pathway of spread.
Instead, the team said, the man might have septicemic plague, a blood infection, caused by a rodent bite or pneumonic plague, that infects the lungs and is spread by droplets. While the latter is usually more virulent than bubonic plague, the team says genetics of the early strain suggest its ability to spread may have been compromised.
The researchers also said they found high levels of Y. pestis DNA in the Stone Age man, indicating that he may have lived with the plague for some time, and so the disease may have been mild.
Krause-Kiorra said the results – together proof of Y. pestis In ancient populations outside of Western Europe, the paucity of Stone Age plague digging, and the careful burial of man in Latvia – suggest that it is unlikely that plague was the cause of the Stone Age population decline. Instead, he supported the idea that factors such as climate change played a role.
Professor Simon Rasmussen of the University of Copenhagen, who was a co-author of the research on a Swedish Stone Age plague victim, welcomed the new study but said it did not rule out the possibility that the plague had caused a significant reduction in the stone-age population, adding that there was little evidence for That Stone Age strains only cause mild illness
“The individual actually overlaps the Neolithic decline and it is very likely that he died of the plague infection.”
“We know that large settlements, trade and movement occurred in this period and therefore human interaction is still a very plausible reason for the spread of the plague in Europe at this time.”