OLDEST KNOWN PLAGUE OUTBREAK IDENTIFIED IN SIBERIAN HUNTER-GATHERERS

Ancient DNA evidence has revealed the earliest known outbreak of plague, which devastated hunter-gatherer communities in south-eastern Siberia approximately 5,500 years ago. Researchers analysed dental pulp from skeletal remains excavated from four cemeteries along the Angara River, north-west of Lake Baikal. Of the 42 individuals tested, 18 contained DNA from Yersinia pestis, the bacterium responsible for plague. The findings challenge the assumption that major disease outbreaks only emerged following the development of farming and large settlements.

The outbreak began at least two centuries after Yersinia pestis first emerged as a pathogen. Hunter-gatherers likely contracted the disease through butchering or consuming raw marmots, the primary animal reservoir in the region, before person-to-person transmission accelerated the outbreak. The disease struck with particular severity at one cemetery, Ust-Ida, where at least two-thirds of the dead were children under 15 years old. Younger individuals possessed no acquired immunity to the bacterium, making them exceptionally vulnerable, whilst older survivors of previous exposures may have developed some resistance. Many deceased were buried in shared graves with siblings and family members, suggesting rapid familial transmission.

An international research team from Copenhagen, Alberta, Cambridge, London and Oxford conducted the analysis. The proportion of plague victims identified in these Siberian cemeteries—39 per cent—exceeds rates found in some medieval plague pits from substantially later periods. The discovery establishes that epidemic disease outbreaks affected small, dispersed populations long before urbanisation, fundamentally altering understanding of human disease history.