Over an 11-year period there has been a 249 percent increase in the bacteria that causes Legionnaires’ disease, federal investigators have found.
Public health investigators with the Centers for Disease Control and Prevention (CDC) also found that at least one in every 10 people infected with Legionella pneumophila—a form of pneumonia—dies of the disease, Newsday reports.
Investigators found that blacks were more likely to be infected than whites, a disparity they attributed to housing differences. Blacks more often live in older and poorly maintained multi-resident structures. The new federal data come after a Legionnaires’ outbreak over the summer that killed 13 people in the Bronx.
Earlier this month, state health officials mandated routine testing of air conditioning and water systems at schools, hospitals, dialysis centers and other sensitive sites in an effort to thwart future outbreaks. Cooling systems in several Long Island school districts were discovered to be colonized by the bacteria, Newsday reports.
Dr. Pascal Imperato, a former New York City health commissioner and founding dean of the School of Public Health at SUNY Downstate Medical Center in Brooklyn, said that though the CDC data is startling, it is consistent with what is already known. “We have known for quite some time that about 20 percent of the general population will have antibodies to this organism,” said Imperato, who was not connected with the CDC research. He said Legionella bacteria are ubiquitous.
Imperato explained that the presence of antibodies in the blood suggests that a significant segment of the population has been exposed to Legionnaires, but most are probably unaware of it. Legionella bacteria thrive in air conditioning systems and cooling towers and can cause infection when inhaled in droplets of water. Older people and those with impaired immune systems are more likely than health younger individuals to become infected than are healthy younger individuals.
“Even though these structures may be cleaned very well, the organism can reappear very soon afterward. And it’s not a period of year or two, it can be a matter of months,” Imperato said. Hot tubs, hot water tanks and decorative fountains can also harbor the bacteria.
The CDC investigators found not only that the incidence of the bacteria has risen, but also that the bacteria are more prevalent in some parts of the country, according to Newsday. New York has the highest rates of infection nationwide. State health officials estimate the bacteria infect 200 to 800 people a year.
The 249 percent jump in disease prevalence occurred between 2000 and 2011. Between 2011 and 2013, half the people included as part of the research were admitted to hospital intensive care units. All told, there were 1,426 cases from Jan. 1, 2011, to Dec. 31, 2013, Newsday reports.