An outbreak of Legionnaires’ disease in the Bronx, New York, has sickened nearly 100 people and left at least eight dead, mainly those with underlying health conditions. It marks the city’s largest reported outbreak to date.
But the disease and the bacteria are more common than one might think, and its history can be traced to a hotel near City Hall in Philadelphia.
Legionnaire’s disease is a lung infection characterized by fever, cough and chills. It’s caused by a bacteria that may be found in the water of cooling towers or air conditioners, and then spread through its mist.
No one realized that back in the summer of 1976, when more than 200 people fell ill around the American Legion convention in Philadelphia. 34 deaths were related to the incident.
“We didn’t know the cause of the pneumonia. We didn’t know the treatment of the pneumonia. We didn’t know the source, if it spread from person to person or from the environment,” recalled David Fraser, an epidemiologist with the Centers for Disease Control at that time, who was charged with leading an investigation into the mysterious illness.
It took months of detective work to identify a bacteria as the cause — and many more months to figure out the likely source: the cooling towers at the hotel where the convention took place.
“There seemed to be an increased risk of interest according to how much time people spent in the lobby of the hotel or on the sidewalk around the Bellevue-Stratford Hotel,” Fraser said.
The discovery served as a reminder that infectious diseases were out there and could be deadly.
“There was a bit of overconfidence that we’d licked infectious diseases,” he said.
Legionnaires’ disease can be treated with a special antibiotic. It’s not contagious. Those most at risk of suffering from complications are older, have underlying health conditions and smoke.
But Dr. Neil Fishman, an infectious disease doctor and colleague of Fraser’s at Penn, said nowadays the disease is actually pretty common.
“We see an increase in Legionnaires’ disease every summer, and that goes along with increases in heat, humidity and the warming of cooling towers,” said Fishman.
The Centers for Disease Control and Prevention estimates there are anywhere from 8,000 to 18,000 Legionnaires’ hospitalizations a year. Pennsylvania records anywhere from 300 to 500 cases annually.
Meanwhile, the source and cause of many other lung infections around the country annually remain unknown.
An isolated case of Legionnaires’, such as the one identified last month at West Chester University, is not in itself a big deal in terms of public health, Fishman said. (The university has decontaminated its cooling systems.)
“A single case does not raise suspicion about the integrity of the tower. We only get concerned with large groups of cases,” he said.
And, just because a cooling system tests positive for the bacteria does not mean it’s the cause of illness.
“One of the problems is lots of cooling towers have Legionella in them,” said Fraser. “That doesn’t mean they’re causing the outbreak.”
Fishman said New York City’s outbreak, on the other hand, raises questions about the surrounding building’s maintenance of its cooling towers and the measures it takes to prevent the growth of harmful levels of bacteria.
That has city officials there calling for stronger safety regulations.