For the first time, researchers have sequenced the full genome of the bacterium that caused a plague that killed millions of people in the 6th century A.D., and discovered to their surprise that the outbreak was caused by a different strain of the same germ that was to blame for the more famous Black Death 800 years later. Their findings offer insight into the genetic factors that influence the virulence of the plague bacterium as well as other pathogens.
For the complete story, please visit:
http://www.scientificamerican.com/artic ... D_20140129
The article goes on to state that the plague is rarely fatal today due to the arsenal of antibiotics. However, Third World countries still suffer fatalities due to the rats and fleas that are everywhere.