The New York City (NYC) Department of Health and Mental Hygiene is investigating a community cluster of 10 cases of Legionnaires’ disease in the Upper East Side neighborhoods of Yorkville and Carnegie Hill.
“Any New Yorkers who currently live or work in this area or people who have visited the area since late June and are experiencing flu-like symptoms, such as cough, fever, or difficulty breathing, should contact a health care provider immediately,” the department said in a July 3 update. “To date, there are no deaths associated with this cluster.”
“This is not an issue with any building’s plumbing system,” NYC Health clarified. Residents in the affected ZIP codes of 10028 and 10128 “can continue to drink tap water, bathe, shower, cook, and use your air conditioner at home.”
Legionnaires’ disease, a type of pneumonia, is caused by Legionella bacteria that grow in warm water. People can get sick when they breathe in such water vapor. Most individuals exposed to the bacteria do not develop the illness, which only occurs after repeated exposure.
People at higher risk of Legionnaires’ disease include those 50 or older, who have chronic lung disease, smoke or vape, and have a weakened immune system or take medicines that cause such weakness. The department clarified that the disease is not contagious. As such, a person cannot contract it from someone else. Nor can they get it by drinking, using air conditioning, or cooking.
Typically, when multiple individuals in a neighborhood get sick, the common sources of exposure are hot tubs, spray fountains, and cooling towers. In cases of cluster infections within a building, exposure is usually linked to the plumbing system, especially the hot-water system.
The department said in a July 2 statement that it was sampling and testing water from all cooling tower systems in the affected regions.
Previous Legionnaires’ disease outbreaks have been caused by bacteria spreading through the air from mist generated by cooling towers, according to the department.
If any towers test positive for the bacteria during the investigation, building owners will be directed to resolve the matter.
“Legionnaires’ disease is deadly but can be effectively treated if diagnosed early,” said NYC Health Commissioner Dr. Alister Martin.
“New Yorkers at higher risk, including anyone who is 50 and older, those who smoke, or people with chronic lung conditions, should be especially mindful of their symptoms and seek care as soon as symptoms begin.”
Last year, a community cluster of Legionnaires’ disease infections had broken out in Central Harlem and bordering communities in July.
In an Aug. 29 statement, the NYC Health Department announced the end of the disease, by which time there were a total of 114 infections, out of which 90 were hospitalized, and seven people were dead.
All facilities in the cluster area that had cooling towers with positive legionella test results “completed full cleaning and disinfection as directed,” the department said at the time.
According to an August 2025 report from the Centers for Disease Control and Prevention, symptoms of Legionnaires’ disease typically appear two to 14 days after exposure to the bacteria. In some cases, this can take longer.
Symptoms are similar to those of other types of pneumonia and include fever, cough, headache, shortness of breath, muscle aches, nausea, diarrhea, and confusion. The illness is treated with antibiotics.
“Most cases of this illness can be treated successfully. Identifying and treating the illness early can increase the chances of getting better,” the agency said. “Healthy people usually get better after being sick with Legionnaires’ disease, but they often need care in a hospital.”
However, potential complications, including lung failure or death, can arise among infected individuals.
“About 1 out of every 10 people who get sick with Legionnaires’ disease will die due to complications from their illness,” according to the CDC.
