Ancient teeth from Siberia rewrite the plague’s timeline, dating back to over 5,500 years ago

A team of researchers has identified the oldest known evidence of the plague, dating back approximately 5,500 years, in teeth from 18 ancient hunter-gatherers near Siberia’s Lake Baikal. The findings, published in *Nature*, reveal two plague outbreaks, with the first cases appearing around 5,500 years ago—200 years earlier than previously documented. The study, led by evolutionary geneticist Eske Willerslev of the University of Copenhagen, analyzed remains from four cemeteries. Traces of plague-causing bacteria were detected in the teeth, indicating the disease spread from marmots to humans through consumption of raw organs or contact with infected hides. Transmission between people also occurred via coughing and sneezing. Many victims were young children aged 8 to 11, including three girls buried together, two of whom were likely cousins. The study suggests children may have been more vulnerable due to weaker immune systems. Researchers noted that the plague’s presence in small, nomadic groups demonstrates its potential to devastate populations beyond crowded cities. The ancient plague evolved differently from the bubonic plague responsible for the Black Death, but evidence indicates it was equally deadly. Understanding its progression could offer insights into how pathogens develop and emerge in the future, according to study co-author Aida Andrades Valtueña of the Max Planck Institute for Evolutionary Anthropology. The discovery underscores the importance of studying historical diseases to grasp their evolution and potential future threats. The team’s work highlights both the scientific and human elements of ancient outbreaks, including the deliberate burial of the dead by those who knew them.