First U.S. scientist to die of plague in 50 years worked in labs with 'harmless' bacteria



A scientist died after becoming the first American researcher to contract the plague in 50 years, it has been revealed.

Malcolm Casadaban, 60, was working with a weakened form of the plague's bacteria thought to be harmless to humans when he died in September 2009, a report said.

The University of Chicago genetics and cell biology professor's work with the live bacteria was not even noted when he fell ill and he followed proper safety protocols.

Dead: Chicago genetics and cell biology professor Malcolm Casadaban, 60, is the first U.S. scientist to die after contracting the plague in 50 years

Dr Casadaban was researching the chain of events that happens when a person is made sick by the bacteria Yersinia Pestis, which are behind the plague.

The bubonic plague, which killed at least a third of the population of medieval Europe in the 14th century, still infects more than 2,000 people annually worldwide today.

But the weakened bacteria have never previously been linked to human illness and are not covered by strict safety measures that regulate studying other deadly germs.

‘The severe outcome experienced by the patient was unexpected,' the U.S. Centers for Disease Control and Prevention report said.

Tests: Infectious disease specialist Ken Alexander said lab results were positive for the plague after Dr Casadaban died

‘Researchers always should adhere to recommended use of personal protective equipment.’

Dr Casadaban had the hereditary condition ‘hemochromatosis’, causing an excessive build-up of iron and potentially making people more vulnerable to the plague, an autopsy said.

This is based on evidence that injecting mice with iron while they are exposed to the plague makes them more likely to become ill.

Ken Alexander, University of Chicago infectious disease specialist, said lab results were positive for the plague and their ‘biosafety fire alarm’ was raised.

He told Bloomberg: ‘The first question was: “Do we think this is real?”



‘The answer was “yes”. So the onus was upon us to do two things - to notify the health infrastructure and act as if this were a worst-case scenario.'

Hemochromatosis affects one in 400 people and goes unnoticed in half of patients, but the problems arose because Yersinia Pestis needs iron to survive.

Yersinia Pestis: The bacteria causes pneumonic, bubonic and septicemic plague, which killed millions of people in medieval Europe and still affects others today

‘It’s like having a lion, where we took out all its teeth and all its claws,’ Dr Alexander said.



‘But in the case of Dr Casadaban, the lion didn’t even need to have teeth. There was so much iron that it was freely available and easy to get.’

YERSINIA PESTIS: Meet the bacteria that causes the plague Yersinia Pestis causes pneumonic, bubonic and septicemic plague

The bacteria needs iron to survive, but the weakened lab form has never been seen as dangerous to humans

It affected Dr Casadaban as he had ‘hemochromatosis’, which causes an excessive build-up of iron in the body

Yersinia Pestis causes pneumonic, bubonic and septicaemic plague, but scientists found the version Dr Casadaban was working with had not evolved to become more infectious.

Only 10 per cent of reported cases of the plague result in death, thanks to earlier diagnosis and treatment, the World Health Organisation said.



It is spread by rodents and fleas feeding on them and there are usually under ten cases in America each year. The last scientist it affected was in 1959.

Dr Alexander said he believed Dr Casadaban would have had one comment for the university officials and scientists meeting after the tragic event.



'Listen guys, I’m trying to teach you something - and you better damn well learn it.'