August 30, 2011
14th Century Plague Lives On Via New Strain
According to a study published Tuesday, a less virulent version of the 14th century's Black Death plague is still present today.
DNA testing on the skeletons of plague victims unearthed in a medieval London mass grave revealed part of the same gene sequence as the modern bubonic plague.
"At least this part of the genetic information has barely changed in the past 600 years" said Johannes Krause, one of the authors of the study published in the Proceedings of the National Academy of Sciences (PNAS).
"Without a doubt, the plague pathogen known today as (yersinia) pestis was also the cause of the plague in the Middle Ages," he added.
The Black Death claimed the lives of a third of Europe's population in just five years from 1348 to 1353, but modern outbreaks have been less deadly.
An outbreak in Bombay, India in 1904 killed just three percent of the population despite the fact that it happened before the advent of antibiotics.
Researchers from the University of Tubingen's Institute of Scientific Archaeology in Germany and the McMaster University in Canada extracted DNA from 109 skeletons from a mass burial site in London.
They compared the DNA to that of 10 skeletons excavated from a site pre-dating the Black Death. The team proved that it had not been contaminated by modern genetic material or bacteria in the soil.
The authors of the study said that the version of the disease that caused the medieval plague is likely extinct, but suggest that further study could reveal how it may have evolved into another strain.
Image Caption: A scanning electron microscope micrograph depicting a mass of Yersinia pestis bacteria. Credit: Rocky Mountain Laboratories, NIAID, NIH
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