Outsized Legionnaires' rate unexplained
The Legionnaires' form of pneumonia found in a months-long outbreak in the Pittsburgh VA system might appear disproportionately in Allegheny County, which accounts for a fifth of state-recorded cases in Pennsylvania.
But doctors warn there's no clear explanation for county figures that show reported rates of the disease at more than twice state averages. They said testing practices for pneumonia patients might be more thorough in Pittsburgh, an historical leader in Legionnaires' prevention, or environmental factors in the region could encourage the waterborne Legionella bacteria that cause the ailment.
“It's not an easy question to answer,” said Dr. Ronald Voorhees, the acting county health director. “The possibilities are, it's either a high level of real cases or a high level of reported cases.”
He said detailed studies to explore the discrepancies with other regions “just haven't been done,” though county health officials intend to do so and are exploring strategies for Legionella monitoring and prevention.
State rules mandate that hospitals and other health care providers report Legionnaires' cases to public health officials within 24 hours of identification, said Department of Health spokeswoman Kait Gillis. The requirement depends on health care providers to test aggressively for the bacteria.
Department reports show 417 of at least 1,910 Legionnaires' cases statewide since 2008 sickened Allegheny County residents. Nearly 8 percent of the local cases were fatal, above the statewide death rate of about 5 percent.
Eighty Legionnaires' patients were in neighboring Westmoreland County, which ranked fourth statewide in cases.
“If there is a higher rate of Legionnaires' in your region, there is not a specific explanation that we are aware of,” Gillis wrote in an email. She said some areas “have a higher awareness and reporting of Legionella” and that the disease “most often affects middle-aged or older men, particularly those who smoke, have chronic lung disease or drink heavily.”
Public health officials identified a number of suspected Legionnaires' “hot spots” over the years, including in Barcelona; Halifax, Nova Scotia; and eastern Ohio, said Dr. Paul Edelstein of the University of Pennsylvania.
He said factors ranging from water treatment and disinfection methods to underground pipes and virulent Legionella strains could be to blame for reported regional outbursts. Still, “it's pretty much an open question.
“There may be different explanations for different regions,” said Edelstein, a professor of pathology at Penn's Perelman School of Medicine in Philadelphia. “There's so much we don't know about this. They're all answerable questions, but it's generally not something people have focused on.”
Legionnaires' gained widespread attention in the late 1970s because of a deadly outbreak in the Bellevue-Stratford Hotel in Philadelphia. It captured prominence again in Pittsburgh last fall when the VA Pittsburgh Healthcare System revealed an outbreak tied to bacteria in tap water at its Oakland and O'Hara hospitals.
The federal Centers for Disease Control and Prevention in Atlanta uncovered 21 Legionnaires' cases since January 2011 that probably originated in the Pittsburgh VA system. Five of those cases were fatal. A sixth pneumonia patient at the Pittsburgh VA died in late January, though it remains unclear whether that veteran contracted Legionella in the Oakland hospital or elsewhere.
CDC reviewers are looking for Legionnaires' cases as far back as 2007 that might have begun with Legionella at the Pittsburgh VA, spokeswoman Alison Patti said on Wednesday.
A complete count of cases could help determine how much the VA problem has contributed to Legionnaires' tallies for Allegheny County, said Dr. Gary W. Procop, chairman of the clinical-pathology department at the Cleveland Clinic.
Voorhees said he was not aware of individual facilities or neighborhoods that account for spikes in the county case volumes.
“Whenever there's a rate of infection above a standard, then it's worth an investigation to ask the reason why and to continue to ask that question until there's an answer,” Procop said. “The answer might be that region has a higher rate. The answer also could be we found practices that were not the best and may have contributed to more infections.”
Procop pointed out that arid regions in Western states record relatively few Legionnaires' cases. He wondered whether Pittsburgh, with its three rivers, might offer a fertile environment for the bacteria.
“I don't know if, with a water-associated organism, places that are more humid with more fresh water might have more possibilities of more cases,” Procop said.
Adam Smeltz is a staff writer for Trib Total Media. He can be reached at 412-380-5676 or firstname.lastname@example.org.