Ancient DNA provides evidence of earliest known plague outbreak

The earliest evidence for an outbreak of plague has been uncovered at late stone age cemeteries in south-eastern Siberia where dozens of hunter-gatherers and their children were buried. Ancient DNA collected from the remains suggests the disease tore through the sparse communities in devastating waves that began about 5,500 years ago, at least two centuries after the bacterium responsible, Yersinia pestis , first emerged. The hunter-gatherers probably became infected after butchering or eating raw marmots , a risky practice that still causes plague deaths today . After spilling over from the chunky ground squirrels, the primary animal reservoir in the area, the disease spread from person to person, decimating families and others in close contact. The work resolves a longstanding mystery of why so many children were among the dead at one cemetery in particular, named Ust-Ida, on the bank of the Angara River north-west of Lake Baikal, the oldest and deepest lake in the world. The shared graves uncovered at Ust-Ida predominantly contained the remains of children. Photograph: Vladimiri Bazaliiskii While older hunter-gatherers might have survived past brushes with the disease and gained some immunity, young children were exceptionally vulnerable. At least two-thirds of the dead at two of the cemeteries were under 15 years old. Many who died shared graves with siblings or other family members. …