🌅 The Plague Is Older than Previously Believed

SOURCE

Macleod et al. (2026)

WHAT TO KNOW

• A new study by researchers at the University of Cambridge in the U.K. found evidence of a lethal plague outbreak among nomadic Siberian hunter-gatherers around 5,500 years ago, long before the Black Death struck medieval Europe. The team found traces of the bacterium that causes the plague, Yersinia pestis, in 18 of the 46 skeletons examined in the study, a detection rate of 39%, higher than that found at many medieval burial sites. The discovery, based on an analysis of DNA extracted from the teeth of people buried at four different prehistoric cemeteries, predates the previously oldest known evidence of plague by around 500 years, and upends our understanding of one of humanity’s most notorious diseases.

WHY IT MATTERS

• Until now, scientists believed the plague only became a deadly threat after the emergence of agriculture and densely populated settlements, which gave rodents and fleas the ability to transfer the disease between humans. The study also contradicts the long-held notion that the earliest versions of Y. pestis only caused mild illness, since it was believed the bacteria hadn’t yet mutated to the point of becoming deadly. The authors of the present study believe the plague first spilled over to humans in the grasslands of Central Asia, rather than in cities or dense settlements, likely after hunter-gatherers came into contact with wild marmots.

CONNECT THE DOTS

• Y. pestis causes four different types of plague: bubonic (affecting the lymph nodes), septicemic (affecting blood), pneumonic (affecting the lungs), and pharyngeal (affecting the throat). Each type is deadly unless treated. To date, the world has experienced three massive plague outbreaks: the Plague of Justinian, which devastated the Byzantine Empire in the sixth century, the Black Death, which killed half the population of Europe in the 1300s, and the Third Plague Pandemic, which began in China in the 1850s.