Researchers studying ancient human remains report evidence of the oldest known plague dating to more than 5,500 years ago. Multiple outlets describe the findings as revising the previously accepted timeline for when plague first appears in human history, with the new estimate placing it roughly 200 years earlier than earlier evidence suggested. The work focuses on traces of plague-causing bacteria recovered from human remains, including teeth, associated with burials near Siberia’s Lake Baikal. According to the reports, researchers examined remains from four cemeteries in the region to identify biological signatures consistent with plague. By using these traces to establish dates for the individuals, the study places the earliest evidence of plague in the Late Neolithic period, based on the age of the remains. The outlets agree that the discovery is significant because it pushes back the earliest known occurrence of plague and provides a broader early geographic and historical context for the disease. The reporting indicates the key evidence comes from ancient dental material rather than from modern samples or later historical records.