Ancient DNA Uncovers Earliest Known Plague Outbreak in Siberia

The Discovery of Ancient Plague Outbreak

The earliest evidence for an outbreak of plague has been uncovered at late stone age cemeteries in south-eastern Siberia where dozens of hunter-gatherers and their children were buried. Ancient DNA collected from the remains suggests the disease tore through the sparse communities in devastating waves that began about 5,500 years ago, at least two centuries after the bacterium responsible, Yersinia pestis, first emerged.

The Spread of Disease Among Hunter-Gatherers

The hunter-gatherers probably became infected after butchering or eating raw marmots, a risky practice that still causes plague deaths today. After spilling over from the chunky ground squirrels, the primary animal reservoir in the area, the disease spread from person to person, decimating families and others in close contact.

The Impact on Children and Communities

While older hunter-gatherers might have survived past brushes with the disease and gained some immunity, young children were exceptionally vulnerable. At least two-thirds of the dead at two of the cemeteries were under 15 years old. Many who died shared graves with siblings or other family members.

The Analysis of Ancient DNA

The international team, including researchers in Copenhagen, Alberta, Cambridge and London, analysed dental pulp in the teeth of skeletons excavated from the cemeteries. Tests on 42 hunter-gatherers buried at four cemeteries on the Angara river found that 18 of them (39%) contained Y. pestis DNA, a higher proportion than is seen in some medieval plague pits.

The Future of Plague Research

The work resolves a longstanding mystery of why so many children were among the dead at one cemetery in particular, named Ust-Ida, on the bank of the Angara River north-west of Lake Baikal, the oldest and deepest lake in the world. The findings provide new insights into the history of plague and its impact on ancient human populations.