Oldest known plague outbreak occurred in Siberia 5,500 years ago, study finds (opens in new tab)

Plague is commonly associated with rats, crowded medieval cities, and the epidemics that swept across Europe during and after the Middle Ages. But a new study published in Nature shows that the disease was already lethal 5,500 years ago, when it killed humans in small, mobile hunter-gatherer communities—long before the rise of agriculture and cities created the conditions usually associated with plague epidemics.