Pattern of disease puzzles health experts Cases occur erratically, always linked to water

October 07, 1998|By Douglas M. Birch and Dennis O'Brien | Douglas M. Birch and Dennis O'Brien,SUN STAFF

When it comes to Legionnaires' disease, the puzzling question isn't why it strikes so many. The mystery is why more don't get sick.

The illness is caused by a microbe that can thrive wherever warm stagnant water sits in ponds, lakes, tanks or even shower heads and spas.

What scientists don't understand is what triggers thousands of isolated infections each year, much less the relatively rare outbreaks.

And diagnosing it is difficult.

Dr. Lewis J. Rubin, chief of pulmonary and critical care medicine at the University of Maryland Medical System, said when physicians try to culture the bacterium, it doesn't survive on a slide or in an incubator the way other bugs can.

Doctors must treat suspicious cases of pneumonia as Legionnaires' disease while they wait three to six weeks for the results of an antibody test.

People don't seem to get infected by drinking water or by contact with a sick person. Nor have home and auto air conditioners been implicated.

Instead, it appears that it can spread only when people breathe in the mist churned up by water that is sprayed or bubbled -- such as the water shooting out of a shower head or water droplets spread through a building by an air-conditioning system.

More than 10,000 people get Legionnaires' disease each year in the United States. Physicians at University of Maryland Medical Center see about one case a month, Rubin said.

Otherwise healthy people can get it, but middle-age and older people are more vulnerable, especially cigarette smokers or those with respiratory problems.

About one in 10 will die, mostly because they don't get the proper treatment.

The microbe resists some antibiotics. But doctors today can control it with erythromycin, administered intravenously in large doses. In severe cases, physicians use rifamprin.

The disease was discovered in July 1976, when the American Legion Department of Pennsylvania held its annual convention in Philadelphia's Bellevue-Stratford Hotel. After they went home from the four-day convention, 255 Legionnaires fell ill and 34 of them died.

Almost immediately, the mysterious illness was called Legionnaires' disease. But it took six months for health officials to track down the source, a previously unknown bacterium, which came to be called Legionella pneumophila.

Since the Philadelphia incident, Legionnaires' disease has been recognized as a widespread illness.

Confirmed or suspected cases of Legionnaires' disease have been found in diverse places. An engineer died of it at the Johnson Space Center in Houston in 1982. Last year, a 59-year-old revenue officer working in the IRS building in the same city died of it.

In 1994, an outbreak occurred aboard the cruise ship Horizon. One Long Island, N.Y., man died and 29 other people fell ill.

In that incident, the ship docked in Baltimore while health investigators took samples. The U.S. Centers for Disease Control ultimately traced the cases to the ship's spas.

Between 1980 and 1997, 44 people died of the illness at the Wadsworth Veterans Administration Center in Los Angeles.

Investigators said they couldn't explain why the bacteria found in the water system at that hospital seemed to trigger cases, while other hospitals harboring the bug did not see any cases.

Pub Date: 10/07/98

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