Ancient DNA has uncovered the earliest known plague outbreak among hunter-gatherer communities in southeastern Siberia, about 5,500 years ago. The discovery, published in Nature, suggests the disease spread from marmots to humans and then from person to person, decimating families.
Discovery at Ust-Ida Burial Ground
At the Ust-Ida cemetery on the Angara River, northwest of Lake Baikal, the remains of dozens of hunter-gatherers, predominantly children, were found. Researchers analyzed dental pulp from 42 skeletons across four cemeteries and detected Yersinia pestis DNA in 18 individuals (39%), a higher proportion than in some medieval plague pits. The team suspects all buried may have died from plague due to the high chance of false negatives.
Two Distinct Outbreaks
The ancient DNA points to two outbreaks: the first around 5,500 years ago and a second 400–600 years later. Y. pestis emerged at least 5,700 years ago, splitting from its ancestor Yersinia pseudotuberculosis. The earliest plague evidence in Britain is 4,000 years old.
Transmission and Vulnerability
Hunter-gatherers likely contracted pneumonic plague after butchering or eating raw marmots, a practice still causing plague deaths. The disease spread person-to-person, with children most vulnerable due to lack of immunity. At least two-thirds of the dead at two cemeteries were under 15.
Implications
The study resolves why so many children were buried at Ust-Ida. The Y. pestis strain carried a superantigen that triggered severe immune reactions, particularly lethal for children. Samuel Cohn of the University of Glasgow called the findings “groundbreaking,” showing that isolated hunter-gatherers, not just urban populations, suffered early plague outbreaks.
