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News
Plague was deadlier, earlier, and more persistent than we thought. New ancient DNA studies reveal that Yersinia pestis was killing hunter-gatherers in Siberia 5,500 years ago — and kept returning to Europe for 400+ years after the Black Death, evolving new lineages and spreading through war and migration.
Two landmark ancient DNA studies are reshaping our understanding of one of history's deadliest pathogens. The first, published in Nature, found that Yersinia pestis was already killing people in small hunter-gatherer communities near Lake Baikal in Siberia around 5,500 years ago — thousands of years before the crowded cities and flea-ridden rats typically associated with plague. Researchers detected plague DNA in 18 of 46 individuals studied (nearly 40%), a rate exceeding some medieval plague burial sites. The ancient strains lacked the gene for flea-borne transmission but carried a potent superantigen — a toxin-producing factor capable of triggering severe immune reactions — which may explain the disproportionately high mortality among children and young teens.
A second study from the University of Tartu traced plague's long shadow over post-Black Death Europe, reconstructing 26 Yersinia pestis genomes from 11 archaeological sites across Estonia, Russia, England, the Netherlands, and Switzerland. Rather than a single persistent source, plague repeatedly re-entered Europe over four centuries, spawning new lineages — especially around 1450–1500 — and spreading along the routes of armies and displaced populations during conflicts like the Thirty Years' War and the Great Northern War.
By the Numbers
Why it matters: These findings challenge long-held assumptions — that early plague was mild, and that the Black Death was a singular event. Understanding how plague established reservoirs, evolved, and followed human movement could sharpen modern disease surveillance in regions where Y. pestis still circulates today.
