NYC Reports 18 Legionnaires’ Disease Cases on Upper East Side, No Deaths

The New York City Department of Health and Mental Hygiene confirmed 18 cases of Legionnaires’ disease in Manhattan zip codes 10028, 10128 and 10075 as of July 5, 2026. The total rose from 14 cases reported earlier that day and 10 cases on July 4. The first two diagnoses in the current outbreak were announced on July 2.

The cases are clustered on the Upper East Side. Health Commissioner Dr. Alister Martin said people who live in the affected zip codes or who have recently visited the east side of Central Park should monitor for symptoms and contact a health care provider if they appear.

Many of the 18 patients are hospitalized, with some in critical condition in intensive care units. One patient had been discharged by July 5. No deaths have been reported. Health officials stated that the probable source of the bacteria is a water cooling tower in the area.

The department is testing all cooling towers in the affected zone. Any owners of buildings where towers test positive for Legionella bacteria will be directed to carry out full remediation. Officials emphasized that the situation does not involve building plumbing systems.

“This is not an issue with any building’s plumbing system. It is safe for you to drink water, bathe, shower, cook, and use your air conditioner,” health officials said in a notice to residents. They added that continued use of air conditioning is especially important during extreme heat.

Legionnaires’ disease is a form of pneumonia caused by Legionella bacteria that grow in warm water. People contract it by breathing in water vapor or mist containing the bacteria; it is not transmitted person to person. Symptoms include fever and chills and can be fatal if left untreated.