New strains of deadly plague could emerge
The study, which was conducted by researchers from a number of different international institutions, used the latest computer technology to better understand the strain of plague bacteria that caused the Plague of Justinian, which killed approximately 100 million people in sixth through eighth centuries AD. The plague was seen by many historians as contributing to the fall of the Roman Empire and the onset of the Dark Ages.
Researchers extracted DNA from the teeth of two people who died at the time of the plague and found it was caused by a bacteria strain unrelated to the Black Death. The Black Death was the second plague pandemic, and may have killed up to 200 million people between the 14th and 17th centuries in Europe.
The findings that the two pandemics were caused by two independent strains of Y. pestis suggest that fresh strains of plague could be passed into human populations through rodent carriers.
Plague infections continue to occur in humans today, predominantly in Asian and African countries. Plague can now be treated with antibiotics.
According to the U.S. Centers for Disease Control and Prevention, Yersinia pestis is considered a category A bioterrorism agent by the U.S. government. Category A biological agents require special action for public health preparedness, may cause social disruption and panic, can be easily transmitted from person to person and result in high mortality rates.