DNA analysis has revealed the earliest known outbreak of plague more than 5000 years ago among hunter-gatherers near Lake Baikal in Siberia. The finding challenges long-held views that major disease outbreaks began only after the rise of farming.
Researchers examined ancient DNA from 42 individuals buried at four sites around Lake Baikal. They detected the plague bacterium Yersinia pestis in 18 of them.
The study identified two outbreaks, with the first beginning around 5500 years ago. Many victims were children or teenagers, and some shared graves suggest entire families died at once.
Ruairidh Macleod of the University of Oxford said the evidence shows a devastating community-wide outbreak among hunter-gatherers. The team believes the infection likely spread from marmots through pneumonic transmission.
The research, published in Nature, places the evolution of Y. pestis between 9800 and 5700 years ago. It provides the oldest, easternmost case of plague in non-farming societies.