As first reported by the U.S. Centers for Disease Control and Prevention on Feb. 25, the case of the American lab researcher began in September 2009, when he sought care at a hospital emergency room following several days of breathing difficulties, dry coughing, fevers, chills, and weakness. Thirteen hours after admission, he was dead.
An autopsy and blood tests showed that the man had an underlying blood disorder called hemochromatosis, which involves harboring too much iron, according to the CDC report. The strain of the microbe he was working with in the lab was weak because it didn't have enough iron. But once the bacteria entered his body, his extra iron might have been enough to overcome the bacteria's weakness, rendering it as virulent as some of its cousins.
The case was the first since 1959 involving plague transmission in a laboratory setting -- and it remains unclear exactly how the virus entered the lab researcher's body. It was also the first ever to be linked to a weakened plague strain that had not been considered a threat to human health.
The strain was thought to be so safe that it was routinely used as a subject for basic scientific research. Such experiments are typically conducted under relatively moderate security conditions, compared with those in place when researchers are in contact with highly communicable diseases.
In the new report, the investigators emphasized the need for vigilance in following lab safety protocols and suggested that researchers consider testing for the hemochromatosis mutation before coming into contact with Y. pestis.
Dr. Steven Hinrichs, chairman of the department of pathology and microbiology at the University of Nebraska Medical
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