NYC Legionnaires’ Disease Cluster Expands: Health Officials Investigate Spike in Cases

Legionnaires’ Disease Alert Issued for Several Bronx Zip Codes

Bronx, NY – August 5, 2025 – New York City health officials are urging residents in several Bronx zip codes – 10027, 10030, 10035, 10037, and 10039 – to be vigilant for flu-like symptoms following the identification of a cluster of Legionnaires’ disease cases.

Acting Health Commissioner Dr. Michelle Morse emphasized the importance of prompt medical attention. “Anyone in these zip codes experiencing symptoms should contact a healthcare provider immediately,” she stated in a recent press release. “Early diagnosis is crucial for effective treatment, notably for those at higher risk.”

Those considered most vulnerable include individuals aged 50 and older, smokers, and people with underlying chronic lung conditions.

What is Legionnaires’ Disease?

Legionnaires’ disease is a severe form of pneumonia contracted by inhaling microscopic water droplets containing Legionella bacteria. Symptoms typically develop within two weeks of exposure and can mimic the flu, including:

Cough
Fever
Headaches
Muscle aches
Shortness of breath

While most healthy individuals recover with antibiotic treatment, the CDC reports a fatality rate of approximately 10% among those infected.

No Plumbing system Involved,Officials Say

The NYC Department of Health has confirmed that this outbreak is not linked to any building’s water plumbing system. This means tap water remains safe for drinking, bathing, showering, cooking, and use in air conditioning units.

Understanding Legionnaires’ Disease: A Persistent Public Health Concern

Legionnaires’ disease isn’t a new threat. Frist identified after an outbreak at an American Legion convention in 1976, it remains a significant public health concern globally. The bacteria thrives in warm water environments, making cooling towers, hot tubs, decorative fountains, and even household plumbing susceptible to contamination.

Protecting Yourself and Your Family

While this current cluster doesn’t stem from building plumbing, preventative measures are always recommended:

Flush infrequently used faucets and showerheads: Regularly running water thru these fixtures helps prevent bacterial growth.
Maintain water systems: Owners of cooling towers, hot tubs, and decorative fountains should adhere strictly to manufacturer guidelines for cleaning and maintenance.
Home water safety: The CDC offers detailed guidance on preventing waterborne germs in your home: https://www.cdc.gov/drinking-water/prevention/preventing-waterborne-germs-at-home.html

Stay Informed

The NYC Department of Health will continue to monitor the situation and provide updates as they become available. Residents with concerns are encouraged to visit the department’s website: https://www.nyc.gov/site/doh/about/press/pr2025/nyc-health-provides-second-legionnaires-cluster-update.page

For more information on Legionnaires’ disease, consult the CDC: https://www.cdc.gov/legionella/about/index.html

What are the primary sources of Legionella bacteria that contribute to the spread of Legionnaires’ disease?

Understanding the Recent Outbreak

New york City is currently facing a concerning expansion of a Legionnaires’ disease cluster, prompting a thorough inquiry by the NYC Department of Health and Mental Hygiene. As of August 5, 2025, officials report a significant increase in confirmed cases, primarily concentrated in the South Bronx.This outbreak underscores the importance of understanding Legionella, the bacteria responsible for this severe form of pneumonia, and taking preventative measures. The current spike surpasses levels seen in recent years,raising public health concerns.

What is Legionnaires’ Disease?

Legionnaires’ disease is a severe type of pneumonia caused by Legionella bacteria. It’s not contagious from person to person.Rather, people get sick by breathing in small droplets of water containing the bacteria.

Here’s a breakdown of key facts:

Cause: Legionella pneumophila is the moast common culprit, but other Legionella species can also cause illness.

Transmission: Inhalation of contaminated aerosols – mist, vapor – is the primary route of infection. Sources include cooling towers, hot tubs, showerheads, and plumbing systems.

Symptoms: Symptoms typically appear 2-10 days after exposure and can include:

Cough

Shortness of breath

Fever

Muscle aches

headache

Fatigue

Severity: legionnaires’ disease can range from mild illness to severe pneumonia requiring hospitalization. It can be fatal, particularly in individuals with weakened immune systems.

Risk Factors: age (over 50), smoking, chronic lung disease, and weakened immune systems increase susceptibility.

The Current NYC Outbreak: Details & Affected Areas

The current Legionnaires’ disease outbreak in NYC is focused in the South Bronx, with cases identified since July 15, 2025. Health officials are actively working to pinpoint the source of the contamination.

Confirmed Cases: As of today, August 5th, there are 28 confirmed cases, with 5 hospitalizations reported.

Geographic Focus: The majority of cases are clustered within a 1.5-mile radius in the South Bronx. Specific areas under investigation include buildings with cooling towers and large water systems.

Investigation Status: The NYC Department of Health is conducting environmental testing of potential sources,including cooling towers,water tanks,and plumbing systems in the affected area. They are also interviewing patients to identify common exposures.

Previous Outbreaks: NYC has experienced legionnaires’ disease outbreaks in the past, notably in 2015, which prompted stricter regulations for cooling tower maintenance.

Identifying Potential Sources of Legionella

Legionella bacteria thrive in warm water environments. Common sources include:

cooling Towers: Used in large buildings for air conditioning, these are frequently identified as outbreak sources.

Hot Tubs & Spas: Warm, aerated water provides an ideal breeding ground.

Plumbing Systems: Legionella can colonize pipes, especially in large or complex systems.

Showerheads & Faucets: Biofilm buildup can harbor the bacteria.

Decorative Fountains & Water Features: Aerosolization increases the risk of exposure.

hospital Water Systems: Vulnerable populations and complex plumbing make hospitals high-risk environments.

Prevention Strategies: Protecting Yourself & Your Community

Preventing Legionnaires’ disease requires a multi-faceted approach, focusing on water safety and building maintenance.

Building Owners & Managers:

Regularly maintain and disinfect cooling towers according to NYC Department of Health guidelines.

Implement a water management plan to minimize Legionella growth in building water systems.

Flush infrequently used water outlets.

Ensure hot water systems are maintained at a temperature of at least 140°F (60°C).

Individuals:

Avoid inhaling water vapor from possibly contaminated sources (e.g., hot tubs, showers).

* If you have symptoms of pneumonia, especially after exposure to potential sources, seek medical attention promptly.