Sheep DNA Unlocks Bronze Age Plague Mystery

A breakthrough in understanding the Bronze Age plague has emerged, revealing that domesticated sheep may have played a key role in spreading the ancient disease. Scientists identified DNA of the plague bacterium, Yersinia pestis, in the tooth of a sheep that lived over 4,000 years ago in present-day southern Russia. This discovery is the first to show the plague infecting animals, offering a vital piece of the puzzle regarding its persistence for nearly 2,000 years.

The findings suggest that the plague's broad reach during the Bronze Age was facilitated by increased interaction between humans, their livestock, and wild animals. As societies began herding larger numbers of animals and traveling greater distances with horses, conditions became more favorable for diseases to jump between species. This contrasts with later plagues, like the Black Death, which were primarily understood to be spread by fleas.

This research highlights the crucial link between animal health and human disease, a risk that persists today. Scientists believe sheep likely contracted the bacteria from another animal, possibly rodents or migratory birds, before transmitting it to humans. Further studies on ancient human and animal remains are planned to map the plague's ancient distribution and identify its original wild reservoir.