The earliest form of the plague was not carried by fleas, an adaptation that the bacterium is believed to have gained in the first millennium BC.
Therefore, the prehistoric plague would not have caused bubonic plague, which led to swollen lymph nodes that formed lumps on the body.
Rather, an early version of the plague likely affected the lungs, causing "desperate, hacking coughing fits just before death," and was transmitted simply by breathing near infected people, according to the University of Cambridge.
The findings also suggest that illnesses caused by the plague may have shaped large-scale human migrations.
"Our study changes the historical understanding of this extremely important human pathogen and makes it possible that other so-called plagues, such as the Plague of Athens and the Antonine Plague, could have been caused by Y. pestis," said co-author Simon Rasmussen of the Technical University of Denmark.
Researchers said their scientific approach could also be used to shed light on other diseases through history, even using ancient material that shows no obvious sign of disease.afp