The New York City Department of Health and Mental Hygiene announced the outbreak last week, initially reporting one death and 22 cases. The cases are concentrated in central Harlem, and the department has stated that the outbreak is unlikely to spread to other areas.

"People who live or work in the area and have flu-like symptoms such as cough, fever, chills, muscle aches, or shortness of breath should contact a healthcare provider immediately," the health department advised in a statement on 3/8. "This is especially important for high-risk groups, including people 50 and older, smokers, those with chronic lung disease or weakened immune systems."

Legionnaires' disease is caused by Legionella bacteria, which thrive in warm water and spread when people inhale water vapor containing the bacteria. The current cases are not linked to the water systems of any specific building. Residents in the affected area can still use water for drinking, bathing, cooking, and air conditioning, officials said.

Legionnaires' bacteria. Photo: Mayo Clinic

Legionnaires' bacteria. Photo: Mayo Clinic

Legionella bacteria can grow in improperly maintained water systems, such as cooling towers, hot tubs, humidifiers, hot water tanks, and evaporative condensers of industrial air conditioning systems.

Legionnaires' disease is not typically transmitted from person to person and can be treated with antibiotics. The disease's name originates from a July 1976 outbreak at an American Legion convention at the Bellevue-Stratford Hotel in Philadelphia.

In response to this situation, the New York City Department of Health and Mental Hygiene continues to urge residents to be vigilant and monitor their health. Regular inspections and treatment of water systems in public facilities and high-rise buildings are also being implemented to prevent further spread.

Thuc Linh (GMA)