Ancient DNA from Baikal hunters sheds light on deadly plague's origins
Scientists have uncovered evidence of deadly plague outbreaks among hunter-gatherer communities near Lake Baikal in Siberia around 5,500 years ago, pushing back the known history of lethal plague epidemics and challenging long-held assumptions about how the disease emerged, Qazinform News Agency correspondent reports.
The study, published in the journal Nature, analyzed ancient DNA from 46 individuals buried at four prehistoric cemeteries along the Angara River. Researchers detected the plague bacterium Yersinia pestis in 18 people, revealing two separate outbreak periods that occurred several centuries apart. The infection rate reached 39% among the individuals examined, an unusually high level for ancient disease studies.
Scientists have long debated whether early forms of plague were relatively mild because they lacked genetic features associated with the bubonic plague that devastated later populations. The newly identified strains, however, appear to have caused severe and often fatal disease despite lacking those traits.
Researchers found signs that entire families were affected. By reconstructing family relationships from ancient genomes, they identified relatives buried together who carried the plague bacterium, suggesting person-to-person transmission. Some burial sites contained multiple children interred in the same grave, indicating deaths occurred within a short period.
The evidence also points to unusually high mortality among children. Two of the affected cemeteries showed a striking concentration of deaths among children aged roughly 8 to 11, while young adults were underrepresented. Researchers suggest children may have been particularly vulnerable to the disease, although the reasons remain unclear.
Genetic analysis suggests the strains represent some of the earliest known forms of Yersinia pestis. The findings indicate the bacterium had already emerged by at least 5,700 years ago.
The researchers believe the outbreaks likely began through transmission from wild rodents, particularly marmots, which remain a source of plague infections in the region today. They argue that the disease may have spread among humans through respiratory transmission rather than flea bites, which became characteristic of later bubonic plague outbreaks.
The discovery challenges the idea that large farming settlements and animal domestication were necessary for major plague outbreaks, suggesting even small hunter-gatherer communities could experience devastating epidemics.
Earlier, Qazinform News Agency reported that archaeologists in Pompeii identified a victim of the 79 AD Mount Vesuvius eruption as a doctor after discovering surgical instruments inside a plaster cast.