Researchers Found Oldest Known Plague Evidence
Scientists identified the Yersinia pestis pathogen in 5,500-year-old remains near Lake Baikal.
Updated on Oct. 5, 2026 in Life Sciences
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Researchers identified the oldest known evidence of the plague in ancient teeth from Siberia dating back 5,500 years. This discovery pushes back the timeline of the first outbreaks by 200 years.
Why it matters
Understanding the early history of the plague reveals how the pathogen spread between people and developed in stages among ancient hunter-gatherer groups. These findings highlight how the bacteria, originally hosted by marmots, evolved long before the 14th-century Black Death.
Researchers extracted DNA from remains found in 4 burial sites, with carbon dating confirming the outbreak originated 5,500 years ago. The study identified the Yersinia pestis bacterium in 18 hunter-gatherer individuals.
The players
University of Copenhagen
This is a public research university in Denmark that frequently leads international genomic and archaeological studies.
The details
The plague strain identified in these ancient remains featured genetic traits that are absent in modern versions of the pathogen. It likely spread through the consumption of raw marmot organs, contact with infected hides, and respiratory transmission between members of nomadic families.
Timeline
The earliest known plague outbreak occurred 5,500 years ago.
The 14th century saw the Black Death wipe out a chunk of Europe's population.
A grave photograph near Lake Baikal was taken in 1993.
A photograph of the excavated grave was released on June 17, 2026.
The study findings were published in October 2026.
The Big Picture
This discovery shifts the scientific understanding of the plague by establishing an evolutionary baseline that predates the 14th-century Black Death by thousands of years. It reveals that the pathogen existed and spread in complex stages long before it reached the pandemic levels observed in history.
This research provides a clearer understanding of how zoonotic diseases emerge and adapt to human hosts over thousands of years. Such studies help scientists model the transmission pathways of modern pathogens by identifying the ancestral traits of ancient bacteria.
The takeaway
The discovery highlights that the plague has been a persistent threat to human populations for over five millennia. By identifying the initial host species and transmission methods, researchers can better track the long-term evolution of dangerous respiratory pathogens.
Further reading
For more on how genomic sequencing is revealing the origins of ancient diseases, visit Life Sciences.
Source note: This article includes information reported by Economic Times.
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