Monday, July 14, 2003

By Christopher Snowbeck, Post-Gazette Staff Writer

Legionnaires' disease cases in Pennsylvania have almost doubled so far this year, part of a broader trend that federal officials say they can't explain.

As of July 4, the Pennsylvania Department of Health had recorded 84 confirmed or probable cases of the bacterial disease, which can cause pneumonia or fever. That compares with 46 cases at this time in 2002 and 51 in 2001.

The increase seems inexplicable, Richard McGarvey, spokesman for the state health department, said yesterday. It is not due to outbreaks of the disease, which often generate public interest, but to reports of individual cases, McGarvey noted.

"Is it seasonal? Is it the weather? There just doesn't seem to be an answer yet," he said.

Pennsylvania officials joined their counterparts from Delaware, Maryland, Virginia and North Carolina in a conference call on Friday to discuss the issue with the Centers for Disease Control and Prevention.

The CDC has reported 624 cases so far this year compared with 436 for the same time period last year, according to The Associated Press.

"There don't seem to be any explanations yet," Brendan Flannery, an epidemic intelligence officer with the CDC, told the AP.

Allegheny County has not seen the same increase in Legionnaires' cases, said Dr. Bruce Dixon, director of the county Health Department.

The fact that Pennsylvania is getting more reports of individual cases, as opposed to cases that stem from outbreaks, matches Allegheny County's experience for the past several years, Dixon said.

"Legionnaires' has been on top of the radar here for many years," he said, saying he believed the increase elsewhere was likely because of better reporting rather than more cases. "I think people generally are more astute [now] in thinking about Legionnaires' as a possible cause of a pneumonia for an older person."

But McGarvey said he didn't think better reporting explained the jump.

Why, he asked, would so many states have improved their tracking of the disease just in the last year?

People of any age may get Legionnaires' disease, but the illness most often affects middle-age and older persons, particularly those who smoke cigarettes or have chronic lung disease.

Also at increased risk are those with suppressed immune systems due to illness or medicines.

An estimated 8,000 to 18,000 people get Legionnaires' disease in the United States each year. About 5 percent to 30 percent of people who have Legionnaires' die, according to the CDC.

The disease got its name from an outbreak among visitors to the American Legion convention in Philadelphia in 1976.

Outbreaks have occurred among people who have breathed mists that come from contaminated water sources such as air conditioning cooling towers, whirlpool spas and showers.

People may be exposed to these mists in homes, workplaces, hospitals or public places.

The bacteria that cause the disease are not passed from person to person, and Legionnaires' is often successfully treated with antibiotics.

Christopher Snowbeck can be reached at csnowbeck@post-gazette.com or 412-263-2625.