CHICAGO In the evolutionary blink of an eye, a bacterium that causes mild stomach irritation evolved into a deadly assassin responsible for the most devastating pandemics in human history. How did the mild-mannered Yersinia pseudotuberculosis become Yersinia pestis, more commonly known as the Plague?
Now, scientists from Northwestern University Feinberg School of Medicine, with the use of new DNA sequencing techniques, offer long sought after evidence of how these two pathogens with virtually identical genetic matter could produce two such vastly different diseases. The Feinberg School team used the new DNA sequencing techniques to identify an unexpected source for these differences, which may help explain the Plague's rapid evolution.
The findings, to be published Aug. 29 in the journal Proceedings of the National Academy of Sciences, offer a glimpse into how the new technology might aid in the development of therapeutics to fight deadly diseases, including the Plague.
"Most people think of the Plague as a historic disease, but it's still a public health issue today, both in the human population and in animals," said Wyndham Lathem, lead author of the study and assistant professor of microbiology-immunology at Northwestern's Feinberg School. "It's extremely dangerous and highly virulent. Without treatment, it can take as little as three to five days from infection to death."
Globally, the World Health Organization reports 1,000 to 3,000 cases of Plague every year, and Y. pestis exists on every continent except Antarctica. The United States Department of Homeland Security classifies Y. pestis as a Category A biological agent, a group that also includes anthrax, smallpox and Ebola.
The Plague's ancestor, Y. pseudotuberculosis, still exists and infects humans, but it causes a mild gastrointestinal disease and most people don't show symptoms.
Lathem and colleagues have discov
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