Plague was killing entire families thousands of years before the Black Death

Plague is often linked to rats, packed medieval cities, and the devastating epidemics that tore through Europe during and after the Middle Ages.

But new research published in Nature suggests the disease was already a deadly threat 5,500 years ago. At that time, it was killing people in small, mobile hunter-gatherer groups - long before farming and urban life created the crowded conditions usually associated with major plague outbreaks.

An international research team studied ancient DNA recovered from human remains at four hunter-gatherer burial sites in the Lake Baikal region of East Siberia. By sequencing genetic material preserved in teeth, the scientists were able to reconstruct ancient bacterial genomes and identify previously unknown early forms of plague.