Ancient Teeth Reveal Plague Was Killing Humans 5,500 Years Ago

A new international study published in Nature has pushed back the known history of plague by about 200 years. Researchers from the University of Copenhagen and the University of Oxford found DNA from the plague bacterium in the teeth of 18 hunter-gatherer skeletons buried near Lake Baikal in Siberia, and carbon dating suggests the people lived about 5,500 years ago.

The findings indicate that plague existed long before the medieval Black Death. According to the researchers, this early form of the disease likely spread in stages among small family groups. They believe the first infections probably came from contact with marmots, large local rodents, possibly while people ate raw organs or handled infected skins.

After entering humans, the disease appears to have spread through coughs and sneezes. Many of the skeletons were children aged 8 to 11, which the scientists say may show that younger people were especially vulnerable. One of the researchers, Ruaridh McLeod, said,