Legionnaires' Disease

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Legionnaires’ Disease cluster in Morris Park, Bronx (updated 9/29/15)


  • Reported individuals with Legionnaires': 10


  • On Sept. 21, when the first case was reported, the Health Department’s disease detectives began investigating immediately.
  • Since Saturday, environmental scientists visited all cooling towers and took samples.

Download the Morris Park LD Fact Sheet (PDF) Other languages: [Español]
View the Legionellosis Cluster in Morris Park by Diagnosis Date
View the Legionellosis Cluster in Morris Park by Onset Date

Legionella Bacteria Testing at Melrose Houses in the South Bronx


  • An early test found evidence of Legionella pneumophila bacteria in the water distribution system at 681 Courtlandt Ave. in the Melrose Houses in the South Bronx. This is a separate incident from the broader South Bronx outbreak that occurred in July and August, and has been declared over by the Health Commissioner.
  • The Health Department and the New York City Housing Authority (NYCHA) are taking immediate steps to keep residents of Melrose Houses healthy.

Legionnaires’ Disease information for Melrose Houses Residents:

Download the Legionnaires’ Disease Information for Melrose Houses Residents Card (PDF) Other languages: [Español]

Read the Commissioner’s Statement (PDF)

Legionnaire’s Disease cluster related to the Opera House in the South Bronx


  • Reported individuals with Legionnaires': 133
  • Individuals with Legionnaires' deceased: 16
  • All deceased individuals were adults with underlying medical conditions.


  • Health officials remain confident that one or more of the five locations that initially tested positive was the source of the outbreak, and that through disinfection of the source, the outbreak has been contained.

Locations and Remediation

  • All sites will submit long-term plans as to how they will maintain the cooling towers to protect against any future growth of Legionella.
  • The Health Department convened a panel of experts in the field of infectious disease to discuss the work the City has done so far and to ensure that all the appropriate steps are being taken to find and eliminate the source of the outbreak.

Ongoing Actions

  • Continued monitoring for new cases
  • Close collaboration with area hospitals
  • Disease detectives conducting epidemiological investigation
  • Interviews with all individuals reported with Legionnaires’ disease to support source identification
  • Providing updates to elected officials and Bronx residents
  • Outreach to vulnerable populations – senior centers, homeless shelters, and other locations
  • Monitoring of disinfection of affected cooling towers
Download the Legionnairres' Disease Outbreak Timeline (PDF)
Download Find the Source (PDF), a map that links colling towers and patients by DNA.
Download the South Bronx-specific Legionellosis FAQs (PDF)
Download a graph of the Legionellosis Cluster in the South Bronx by diagnosis date (PDF)
Download a graph of the Legionellosis Cluster in the South Bronx by onset date (PDF)

Commissioner’s Order
Commissioner’s Order regarding cooling towers

Legionnaire’s Disease Frequently Asked Questions

Download a PDF version of the Legionellosis Basics FAQs Other languages: [中文] [Français] [Español]

What is Legionnaires’ disease?

Legionnaires’ disease (or Legionellosis) is a type of pneumonia. It is caused by bacteria (Legionella) that grow in warm water.

Is the disease contagious?

No. Legionnaires’ disease is not spread from person to person. People only get sick by breathing in water vapor containing the bacteria. People who are sick cannot make others sick.

Who is at risk?

Groups at high risk include people who are middle-aged or older—especially cigarette smokers—people with chronic lung disease or weakened immune systems and people who take medicines that weaken their immune systems (immunosuppressive drugs).

What are the symptoms of Legionnaires’ Disease?

Symptoms are like the flu and can include fever, chills, muscle aches and cough. Some people may also have headaches, fatigue, loss of appetite, confusion or diarrhea.

What should I do if I think I have Legionnaires’ disease?

If you have flu-like symptoms, seek medical attention right away, especially if you have a medical condition that affects your breathing, like emphysema, or if you are a smoker.

What is the treatment for Legionnaires’ disease?

The disease is treated with antibiotics. Most people get better with early treatment, although they may need to be hospitalized. Some people may get very sick or even die from complications of the disease. That’s why it is important to get medical help right away if you develop symptoms.