Ancient DNA provides evidence of earliest known plague outbreak

Willerslev and other researchers looked for traces of plague-causing bacteria in remains from four cemeteries near Siberia's Lake Baikal.

The discovery, described in a study published Wednesday in the journal Nature, rewrites the history of one of the most consequential diseases in human history.

Examining skeletons of hunter-gatherers who lived 5,500 years ago, the researchers have isolated DNA from the bacteria that cause the plague.