In 1976, several thousand members of the American Legion were celebrating the bicentennial in Philadelphia, and many were staying at the Bellevue-Stratford Hotel. Within a week of the convention, more than 182 attendees, mostly men, had been hospitalized with tiredness, chest pains, congestion, and fever, and 29 had died.
Finally, a year later the deadly bacterium infecting them was identified. Although also responsible for earlier outbreaks, Legionella pneumophila had been breeding in the hotel’s cooling towers. An important overlooked clue was that even people simply walking by the hotel got sick.
Although that outbreak led to changes in how water management and climate control systems are monitored, the bacterium still takes about 5,000 lives a year. According to the CDC, between 2000 and 2014, reported cases of legionellosis, which comprises both Legionnaire disease and a milder form, Pontiac fever, jumped 286%.
The data come from 27 field investigations of outbreaks, involving 415 cases. Of those, health care-associated outbreaks accounted for 57%. Although 44% of the cases were travel related, the health care-related outbreaks resulted in more deaths.
The CDC-investigated outbreak sources all had at least 1 deficiency, and half had deficiencies in more than 2 categories. Most cases were linked to process failures, such as contaminated potable water and human error.
The infection is fatal for about 1 in 10 people. Those at highest risk are people aged ≥ 50 years, smokers, and those with chronic lung disease, weakened immune systems, or other underlying medical conditions.
The CDC says the federal government is improving health care for veterans by requiring plans for prevention of Legionnaires disease at VHA hospitals and long-term care facilities. Health care providers can test (using a urinary antigen test and a culture from a lower respiratory specimen) for Legionnaires disease in people with serious pneumonia, especially those in intensive care or who recently stayed in a health care facility or hotel, or on a cruise ship.
Widespread use of effective water management programs, the CDC advises, in addition to early diagnosis, might reduce the number and size of Legionnaires disease outbreaks.