Legionnaires' disease: Questions and answers

Entrance of the JW Marriott Chicago in Chicago, (Heather Charles, Chicago Tribune)

It's hard to overstate the fear that arrived with reports of people mysteriously falling ill and even dying after attending an American Legion convention in Philadelphia during the summer of 1976.

"We don't know what we're dealing with," Pennsylvania's secretary of health was quoted as saying at the time.

The culprit, it turned out, was a bacterium. The microscopic organism was christened Legionella pneumophila; the serious infection it causes, Legionnaires' disease. Discovered in 1977, Legionella has sickened hotel guests, hospital patients, hot tubbers, cruise ship passengers, elderly nursing home residents, tourists and office workers.

This week, Chicago public health officials announced that two people had died of Legionnaires' disease, and six others are reported to have been sickened. The connection appears to be their presence at downtown's JW Marriott Hotel between mid-July and mid-August.

The Tribune contacted experts on Legionnaires' disease to talk about this infamous illness.

Q: How much time should I spend worrying about Legionnaires' disease?

A: For most people, not much.

"I don't think people should be super worried about it," said Dr. Emily Landon, hospital epidemiologist at University of Chicago Medicine. "We don't see a huge number of cases in this hospital and at hospitals in Chicago. I think this is a very unfortunate event, but it does not happen a lot."

There are an estimated 20 to 80 cases of Legionnaires' disease in every 1 million people in developed countries each year, said Dr. Paul Edelstein, director of the Clinical Microbiology Laboratory at the University of Pennsylvania. That adds up to 200 to 800 cases a year in the Chicago area.

And the cases don't occur randomly, Edelstein said. The elderly, smokers and people with compromised immune systems are most susceptible to developing Legionnaires' disease. All of the known victims of the Chicago outbreak were at least 49, according to public health officials.

Q: I would still like to avoid it if I can. Is that possible?

A: The good news is that the infection is not spread from person to person, so coming into contact with people with Legionnaires' disease is not risky, Edelstein said.

The bad news is that it is hard to avoid all possible sources of the bacteria, which grow well in warm water found in places like the tanks and pipes of industrial cooling systems of large buildings as well as in hot tubs and fountains. It is easier to stay out of hot tubs than to avoid cooling tower water vapor. Edelstein said some of the most spectacular outbreaks have been linked to large buildings, either from contamination of circulating hot water or cooling towers.

In 2001, 449 cases of confirmed Legionnaires' disease were reported in and around Murcia, Spain, according to a scientific paper. The most likely source was hospital cooling towers spewing contaminated vapor into the summer air.

Q. What happens if I am infected?

Breathed in, the bacteria may multiply in the lungs, causing a serious and sometimes deadly pneumonia. High fever, chills, body aches, cough, difficulty breathing and pain in the chest are associated with Legionnaires' disease, Landon said.

"Legionnaires' pneumonia can be nasty," she said. "It can really take you down."

Q: Is Legionnaires' disease treatable?

A: "Legionella is a pretty easy bug to kill," Landon said. Antibiotics — specifically quinolones and macrolides — are effective.

That said, deaths are associated with outbreaks, particularly because people who tend to come down with Legionnaires' disease often are medically fragile.

Q: Is it possible to prevent the bacteria from becoming a public health problem?

A: Yes. Even though hospitals are known as a source of Legionnaires' disease, University of Chicago Medicine has not had a case in more than 14 years, Landon said. That's because officials are hypervigilant about testing and treating potential sources of Legionella transmission, she said.

A fountain in one of the hospital lobbies doesn't run, she said, because the amount of chlorine needed to use it safely would make people standing nearby cough.

People who maintain buildings with large cooling systems need to be similarly vigilant, testing the water regularly as well as disinfecting and cleaning the systems, Landon said.

Hot tubs also should be checked and cleaned regularly, Edelstein said, and maximum guest limits observed. If there are too many people in a hot tub, their dead skin cells and other organic matter can overwhelm the disinfectant added to water, allowing Legionella to grow.

"It is a real art to maintain swimming pools and recreational spas correctly," he said, adding, "which is why I avoid rooms with spas in them as much as I can."

ttsouderos@tribune.com

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