A Legionnaires’ disease outbreak continues to spread in Manhattan’s Upper East Side as officials investigate its source.

Cases continue to rise daily in the neighborhoods, with a majority of those infected becoming hospitalized.

Here’s the latest update on the cluster.

Latest on the Upper East Side Legionnaires’ disease community cluster

The city’s health department continues to investigate 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. 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 not a water system. In another post, Levine said that “it takes two weeks or so to grow legionella samples in the lab so we will not get the location of contaminated towers right away.”

Legionnaires’ disease cases

As of late July 7, there has been 28 cases and 21 hospitalizations. No cases have been fatal so far.

The city continues to urge those who live in or have visited the ZIP codes above to get medical care if they show flu-like symptoms, including:

  • headaches and muscle aches

  • coughing and shortness of breath

Source: Mayo Clinic

How does Legionnaires’ disease spread?

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.

This article originally appeared on USA TODAY: Here’s the latest on the Legionnaires’ outbreak in Upper Manhattan