Genetic traces explain why the Black Death recurred for centuries

Genetic research into the traces of the plague-causing bacterium, Yersinia pestis, is providing new insights into why the Black Death and subsequent outbreaks recurred for centuries following the initial 14th-century pandemic in Europe and Eurasia.

Studies of ancient remains show that the plague was not a static phenomenon. Instead, different bacterial lineages moved and evolved, creating a dark, continuous map of infection. The research suggests the bacteria could persist in environments where humans were not present, circulating among rodents and their parasites, allowing the disease to resurface in various ports and cities long after initial outbreaks appeared to subside.