New analysis of ancient DNA reveals that plague was killing hunter-gatherers in Siberia around 5,500 years ago, well before the rise of cities or the flea-borne transmission that fueled later pandemics such as the Black Death. The discovery pushes the known impact of plague on human populations much further back in time.
The prehistoric strains appear to have been especially dangerous because they carried a genetic factor capable of provoking a severe immune response, according to the researchers. This may explain why the disease was lethal even in small, dispersed groups that lacked the dense populations typically associated with epidemic outbreaks.
These findings indicate that plague was a deadly threat long before it became a hallmark of urban societies, and they offer a new window into how ancient pathogens shaped human health and survival.