How does Legionnaires' disease spread? What to know on NYC outbreak

A cluster of Legionnaires' disease continues to grow in Manhattan's Upper East Side.

But, how does it actually spread, and who is most at risk?

Here's what to know on the disease and when to see a doctor.

Legionnaires' disease outbreak in Upper East Side

NYC Health says it is investigating a community cluster in Carnegie Hill and Yorkville, two areas in the Upper East Side.

The reported ZIP codes affected include: 10028, 10128, and 10075.

How does Legionnaires' disease spread?

"This is not an issue with any building's plumbing system," the department said on its website.

"Residents in these ZIP codes can continue to drink tap water, bathe, shower, cook, and use your air conditioner at home."

People are at risk of getting Legionnaires' disease if they breathe in water vapor contaminated with the bacteria. The health department emphasized that residents cannot get it through drinking water, cooking or from using AC units, and Legionnaires' disease is not contagious.

If multiple people become infected within a neighborhood, a typical source would be a cooling tower, hot tub or spray fountain, NYC Health wrote on its website. Mark Levine, the city's comptroller, said that this current cluster of cases is from a contaminated cooling tower, and that the city is currently investigating.

"All cooling towers in area are being sampled and tested in the NYC Public Health Lab," he wrote on X Sunday night.

"It unfortunately takes several weeks for cultures to grow."

Symptoms of Legionnaires' disease

According to the Mayo Clinic, Legionnaires' disease can present itself in the following symptoms:

• headaches and muscle aches
• fever
• coughing and shortness of breath
• chest pain
• nausea
• confusion

Who is most at risk of Legionnaires' disease?

According to the city's agency, the most at risk include people 50 and over, smokers, those with chronic lung disease or people who have weakened immune systems.

This article originally appeared on USA TODAY: How does Legionnaires' disease spread? What to know on NYC outbreak

Reporting by Amethyst Martinez, USA TODAY NETWORK / USA TODAY

USA TODAY Network via Reuters Connect

Copyright Reuters or USA Today Network via Reuters Connect

This story was originally published July 6, 2026 at 9:10 AM.