Daily Archives: September 22, 2009

The Plague Kills Researcher. Maybe.

This is one for all you doomsday-scenario writers. Seems that a Chicago researcher who dealt with plague organisms recently died and the bug was found in his bloodstream. A medieval death in modern times?

Actually, the Plague is not so medieval. A dozen cases are reported in the US each year. Not exactly an epidemic but it’s still around.

Not like in the 14th century when plague swept Europe in what became known as The Black Death. It arrived in 1348 on the backs of black rats brought from Central Asia aboard sailing vessels and spread rapidly, killing between 30-60% of Europe’s population, depending on who you read. It altered everything: travel, trade, religion, social interactions, governmental institutions, and of course the practice of medicine. If churches and doctors couldn’t save the victim’s of this scourge, then of what use were they?

We now know that the plague is caused by the Yersinia pestis bacterium and that it reaches humans through the bites of fleas that have fed on plague-infested rats. It is easily curable with antibiotics once the diagnosis is established.

Professor Malcolm Casadaban studied the genetics of plague bacteria at the University of Chicago. He died on September 13th. His autopsy showed no identifiable cause of death but he did have the weakened strain of the plague bacterium, Yersinia pestis, in his bloodstream. Fully-active plague is controlled and available only in labs equipped to isolate and handle it. The one Professor Casadaban studied was so weak as to be deemed dafe for use in less-controlled environments, such as his lab in Chicago.

Did the plague kill him? Maybe, maybe not.

Most infections kill after the bacteria damage vital organs, usually the lungs, the brain, or the kidneys, or after they spread throughout the blood and cause what we term septic shock–an infection in the blood that causes a dramatic drop in blood pressure, shock, and death if not treated promptly and aggressively. From what I’ve read about the professor’s autopsy none of this was found.

Add to this the fact that this was a weakened and non-virulent strain of the plague organism, one that should not cause death or major illness according to the Center For Disease Control and Prevention (CDC), and it muddies the water. Did the professor get a not so weak batch? Did he have some underlying medical problem that made him susceptible to such a weakened bug?

So the question becomes: Did the professor die from a more-virulent plague strain, or did he have a weakened immune system or some illness that made him susceptible, or did he die of something totally unrelated, such as a cardiac event, and the finding of the bacteria in his blood is a classic red herring? Any of these is possible.

He is not the first medical researcher to die from something contacted in the lab. Marie Curie, who studied and even coined the term radioactivity, died in 1934 from aplastic anemia, a disease most certainly caused by radiation-induced bone marrow damage. Dartmouth chemistry professor Karen Wetterhahn, who specialized and did research in toxic metal exposures, died of Mercury poisoning in 1997 after a tiny amount of dimethylmercury found its way through her latex gloves and contacted her skin.

Bad bugs, raging through labs and escaping into the real world, have been a staple plot in fiction for many years. The presence of an unseen, microscopic killer is a frightening scenario and the source of great suspense. I’m sure those who lived in 14th Century Europe would agree.

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