The most recent example of this is happening currently at University Hospital in Madison, Wisconsin, where an outbreak of Legionnaires’ disease has resulted in 14 patients being sickened – and three of them dying. The primary suspect in the outbreak: a change in the hospital’s hot-water system, which was adjusted to save water.
“The flow was altered in the system,” Nasia Safdar, medical director of infection control for UW Health, said on Nov. 28, when the outbreak was first reported. “So, instead of being at a consistent high flow, it was altered to be more flexible to be on demand.”
Data from 2015 cases
The 2017 CDC report, using data from 2015, showed that Legionnaires’ disease kills 10 percent of those who are diagnosed from the general population. In a long-term care facility, such as University Hospital, that rate increases to 25 percent.
There were 2,809 cases of Legionnaires’ disease confirmed in the U.S. in 2015, including 85 (3 percent) considered “definite” and 468 (17 percent) considered “possible” health-care-associated cases. The study used information only from long-term-care patients, or anyone who had been in a health-care facility for 10 days or longer.
“In health-care facilities, people are more vulnerable and more likely to get sick if they are exposed to the pathogen,” Anne Schuchat, then-acting director of the CDC, said during a 2017 media telebriefing on the report. “Everything from shower heads, to decorative fountains, to respiratory equipment, could house Legionella.”
The three patients who died at University Hospital all had “serious, life-limiting health conditions,” UW Health officials said, underscoring the vulnerability of bed-ridden hospital patients.
UW Health officials reported that test results from three patients showed the strain of Legionella was identical to that found in University Hospital’s water system. Samples were not taken from the other 11 patients.
University Hospital officials said the water system had been flushed with high levels of chlorine to eliminate Legionella, and the procedure has worked. “Testing completed so far continues to show the expected reduction in the bacteria,” officials said in a statement. “UW Health will continue intensive monitoring of its water system to ensure patient safety.”
University Hospital officials also said they have been working with the CDC, and a review and analysis from the federal organization are expected in about three months.
A disease on the rise
Legionnaires’ disease is “an emerging disease in the sense that the number of recorded cases of Legionnaires in the United States continues to increase,” according to Laura Cooley from the Respiratory Diseases Branch of the CDC.
Cooley said she believes that increase is due to the susceptibility of the general population, as well as the likelihood that there is more Legionella in the environment since warmer temperatures are creating the optimal conditions for bacterial growth.
Seventeen of the 18 warmest years since modern record-keeping began have happened since 2001, according to both the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA). The four warmest years all have occurred since 2014, with 2017 being the warmest non-El Niño year ever.
This year is shaping up to be the fourth-hottest year on record. The only years hotter were 2015, 2016 and 2017.
The CDC estimates that there are about 25,000 yearly cases in the United States, although only 5,000 are reported because of the disease’s nonspecific symptoms.
Those symptoms, which develop from two to 10 days after exposure to Legionella, usually start with:
- fever, which can reach 104 degrees Fahrenheit or higher
- severe headaches
- muscle pains
By the second or third day, symptoms can worsen and include:
- dyspnea (shortness of breath)
- pleuritic chest pain (pleurisy), which occurs when the lining of the lungs is inflamed
- cough, which can bring up mucus or blood
- gastrointestinal symptoms, such as nausea, diarrhea, and vomiting
- mental agitation.
Legionella bacteria, which cause Legionnaires’ disease, are contracted by inhaling microscopic water droplets (vapor or mist). The bacteria grow best in warm water, and they are found most commonly in human-made environments.
In addition to large water systems like those in health-care facilities, Legionella can be found in:
- large plumbing systems
- hot-water tanks and heaters
- physical-therapy equipment
- bathroom showers and faucets
- decorative fountains
- swimming pools, whirlpools, and hot tubs
- mist machines, like those in the produce sections of grocery stores
- hand-held sprayers
- cooling towers of air conditioning systems.