An international team of scientists has discovered that the plague of Justinian and the Black Death are the two of the world's most devastating plagues.
And each responsible for killing as many as half the people in Europe were caused by distinct strains of the same pathogen, one that faded out on its own, the other leading to worldwide spread and re-emergence in the late 1800s.
These findings suggest a new strain of plague could emerge again in humans in the future.
"The research is both fascinating and perplexing, it generates new questions which need to be explored, for example why did this pandemic, which killed somewhere between 50 and 100 million people die out?" questions Hendrik Poinar, associate professor and director of the McMaster Ancient DNA Centre and an investigator with the Michael G. DeGroote Institute for Infectious Disease Research.
The findings are dramatic because little has been known about the origins or cause of the Justinian Plague- which helped bring an end to the Roman Empire - and its relationship to the Black Death, some 800 years later.