Map reveals Legionnaires’ disease hotspots as third death confirmed in NYC
New York City health officials have confirmed a third death linked to an ongoing Legionnaires’ disease cluster on Manhattan’s Upper East Side.
In an update on Sunday evening, the New York City Health Department said that a total of 74 cases had been identified in relation to the outbreak, as authorities continue to investigate.
As of July 19, eight people had also been hospitalized. The outbreak has been identified in the Upper East Side neighborhoods of Carnegie Hill and Yorkville.
Health authorities have emphasized that the cluster is not related to the city’s drinking water system or residential plumbing and that residents can safely drink tap water, bathe, shower and use home air conditioning units. Mayor Zohran Mamdani has also said that the city’s tap water is safe to use.
This is not the first Legionnaires’ disease outbreak in New York City in recent years. In July through August 2025, a Legionnaires’ outbreak in Central Harlem led to 114 cases, which left 90 people hospitalized, as well as seven dead.
Newsweek has contacted the New York City Health Department outside of regular working hours via email for comment.
Which ZIP Codes Are Impacted?
The city’s health department said the outbreak is concentrated in three Upper East Side ZIP codes: 10028, 10128 and 10075. Officials are urging anyone who lives, works or has spent time in those areas since late June to monitor for symptoms and seek medical care if they become ill.
As part of the investigation, the city found more than 30 cooling tower systems tested positive for traces of living or dead Legionella bacteria.
The owners of all the towers have been ordered to immediately drain, clean, and disinfect their cooling towers to reduce
the risk of further exposure. Most of the identified towers have already been cleaned, according to the latest updates.
Legionella bacteria can spread through tiny droplets of contaminated water released into the air. Cooling towers, decorative fountains and certain water features are among the most common sources identified in community outbreaks.
What Is Legionnaires’ Disease?
Legionnaires’ disease is a severe form of pneumonia caused by Legionella bacteria, which thrive in warm water. People become infected after inhaling contaminated water mist, rather than by drinking contaminated water. The disease is not contagious and cannot be spread from person to person.
According to the city’s health department, symptoms commonly include fever, chills, muscle aches and cough. Some patients may also experience headaches, fatigue, confusion, diarrhea or loss of appetite.
Certain groups face a higher risk of severe illness, including adults aged 50 and older, smokers and vapers, people with chronic heart, lung, kidney or liver disease, those with diabetes and individuals with weakened immune systems.
Health officials stress that the disease can be treated with antibiotics, particularly when diagnosed early.
Around one in 10 people who get sick with Legionnaires’ disease will die due to complications from their illness such as lung failure, according to the Centers for Disease Control and Prevention (CDC).
More Patients Diagnosed in Upper East Side Cluster
On July 2, the New York City Health Department said that it was launching an investigation into a “likely community cluster” of Legionnaires’ disease in the Upper East Side neighborhoods of Carnegie Hill and Yorkville.
In an update three days later, the investigation had expanded to the ZIP code 10075 as well, and a total of 18 cases had been identified.
By July 10, that number had climbed to 65 identified cases. Since then, over the last few days, a smaller number of cases have been identified each day.
Contact Newsweek editors on this story: Matthew Robinson and Yannick Demoustier
