TUESDAY, Aug. 30 (HealthDay News) -- Using bones retrieved from London's medieval graveyards, scientists have isolated the strain of bacteria thought to be responsible for the Black Death, and determined that it is most likely now extinct.
The plague, caused by a strain of flea-borne bacteria called Yersinia pestis, ravaged Europe close to seven centuries ago. But the variant of the bacterium behind that scourge is different from the modern strain that still causes about 2,000 new cases of bubonic and pneumonic plague each year, researchers said.
The new research also confirms Y. pestis as the culprit behind the medieval outbreak, the study authors said.
"The controversy as to what caused the Black Death is now resolved," said study co-author Hendrik Poinar, associate professor in the department of anthropology at McMaster University in Hamilton, Ontario, Canada. "It clearly was the bacterium Yersinia pestis that was responsible for 30 million deaths some 660 years ago."
Poinar and colleagues from the United States, Germany, and Britain discuss their findings in the Aug. 29 issue of the Proceedings of the National Academy of Sciences.
By it's conclusion, the Black Death outbreak (1347-1351)was responsible for killing off about one-third of Europe's population.
A subsequent 19th century pandemic involving Y. pestis took the lives of roughly 12 million Chinese. And the threat has endured: in the 21st century about 10 to 20 Americans (and more than 2,000 people worldwide) will develop plague each year. Fortunately, experts note that the germ is susceptible to antibiotics so the disease is not as deadly as it once was.
For the new study, the researchers turned to skeletal remains retrieved from the East Smithfield mass burial site in London. The plot is one of only several in the world that archeologists have conclusively li
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