DNA analysis shows Yersinia pestis strains infected people long before Black Death
Plagues killed millions of Europeans and Asians starting around 1,500 years ago. But previously unknown variants of the plague-causing bacterium Yersinia pestis infected people several thousand years earlier, a new study finds.
The infectious microbes’ DNA has been found in the teeth of Bronze Age and early Iron Age people who lived between 4,800 and 3,000 years ago, say evolutionary geneticist Eske Willerslev of the University of Copenhagen and his colleagues. Y. pestis was initially passed from person to person — say, when an infected individual coughed on a healthy person — and most likely caused lung infections known as pneumonic plague or blood infections called septicemic plague, the researchers report October 22 in Cell.