Origins and Spread of the Black Death

The Black Death was a devastating pandemic of the bacterium Yersinia pestis that swept across Eurasia and North Africa between 1347 and 1353, with its ultimate origin in Central Asia. Ancient-DNA research published in 2022 traced the pandemic's founding strain to the Tian Shan mountains of present-day Kyrgyzstan, based on the study of gravestones from Nestorian Christian cemeteries near Lake Issyk-Kul dated to 1338-1339, in which the bacterium's DNA was identified in human remains. The pathogen circulates naturally among wild rodent populations of the Central Asian steppe, chiefly marmots, within stable endemic foci from which it occasionally spills over into other species, including humans, through the bite of infected fleas.