Ancient DNA shows plague infected Siberian hunter‑gatherers 5,500 years ago

Ancient DNA analysis has confirmed that Yersinia pestis was responsible for lethal infections among hunter‑gatherer groups in Siberia around 5,500 years ago, predating the rise of cities and the flea‑borne epidemics traditionally associated with the Black Death. Researchers extracted bacterial genomes from skeletal remains uncovered in the Lake Baikal region and identified them as early‑branching plague strains, establishing that the disease was already active in human populations long before settled agriculture.

The prehistoric Y. pestis variants carried a specific genetic element that amplifies host immune responses, potentially triggering severe, often fatal, inflammation. This virulence factor, absent in many later strains, suggests that early plague outbreaks could have been especially deadly. The findings broaden the timeline of plague’s evolutionary history, indicating that its impact on human health began in nomadic societies and offering new perspectives for studying pathogen adaptation and ancient disease dynamics.