MicrobeWorld

A new post on Small Things Considered by S. Marvin Friedman, Professor Emeritus in the Department of Biological Sciences at Hunter College of CUNY in New York City, discuses a recent paper in Nature, "A draft genome of Yersinia pestis from victims of the Black Death," that suggests comparisons of ancient Yersinia pestis from the time of the Black Death (1348-1350) against modern genomes of Y. pestis "reveal no unique derived positions in the medieval organism, indicating that the perceived increased virulence of the disease during the Black Death may not have been due to bacterial phenotype."

The paper's authors believe that external factors such as environment, vector dynamics and host susceptibility, should be the focus of epidemiological discussions regarding emerging Y. pestis infections. In addition, Friedman writes "this conclusion led this team to question the etiology of the Justinian plague, which ravaged the population of the Byzantine Empire from the sixth to the eighth century and is commonly thought to have been caused by the same pathogen."

However, this conclusion was recently challenged in a New York Times article by Mark Achtman, an expert on ancient plague at University College in Cork, Ireland, who says "researchers had chosen to exclude DNA sequences available from other plague victims that would have moved the date for the emergence of the common ancestor much further back in time, prior to the Justinian plague."

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