Five deaths and 82 illnesses reported in New York City Legionnaires' disease outbreak

New York City health officials said five people have died and 82 have been diagnosed with Legionnaires' disease in an outbreak centered on the Upper East Side, according to data released on July 21. Eight patients remain hospitalized, but no new cases have been reported in the last six days, suggesting the source of exposure may have been removed while the investigation continues.

Legionnaires' disease, a severe form of pneumonia caused by Legionella bacteria, spreads primarily through inhalation of aerosolized water droplets from contaminated sources such as cooling towers, hot tubs, or building plumbing, the Centers for Disease Control and Prevention (CDC) explains. The bacteria are not typically transmitted from person to person.

"We get infected when it gets aerosolized in the water droplets, usually, and we breathe those droplets in," said Dr. Dana Mordue, an associate professor at New York Medical College.

Dr. Mordue noted that while home exposure is possible, most outbreaks are linked to water systems in commercial buildings. She added that unmaintained humidifiers can also become contaminated.

Common symptoms include cough, shortness of breath, fever, muscle aches, and headaches, with some patients experiencing diarrhea, nausea, or confusion. Symptoms appear two to 14 days after exposure, and treatment typically involves antibiotics.

"If you have certain risk factors, particularly advanced age, get help as quickly as you can," Dr. Mordue advised.

The CDC recommends several preventive measures: implementing comprehensive water-management programs for building systems, regularly cleaning and disinfecting cooling towers, preventing water stagnation by maintaining flow and flushing infrequently used pipes, and controlling water temperature and disinfectant levels to inhibit bacterial growth.