NYC Health Department urges immediate medical attention for flu-like symptoms in affected ZIP codes in Central Harlem amid ongoing investigation.
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Image credits: NYC Health Department
The New York City Department of Health and Mental Hygiene (DOHMH) has reported an increase in the ongoing Legionnaires’ disease outbreak in Central Harlem, with 67 confirmed cases and three deaths as of August 5, 2025. The outbreak, first reported in late July, continues to affect residents and workers in ZIP codes 10027, 10030, 10035, 10037, and 10039.1
Health officials emphasize that the overall risk to the general public is low, but urge individuals in the affected area who are experiencing flu-like symptoms, especially cough, fever, chills, muscle aches, or shortness of breath, to seek medical care promptly.
“If you live or work in the impacted ZIP codes and have symptoms, see a health care provider right away,” the Health Department advised. “You are especially at risk if you are 50 or older, smoke, or have an underlying lung or immune condition."1
The cluster is linked to environmental exposure from contaminated water systems. DOHMH confirmed that 11 cooling towers in the affected area previously tested positive for Legionella pneumophila. Remediation procedures for these towers have been completed, in accordance with city regulations.2
Importantly, the outbreak is not connected to building plumbing systems, and tap water is safe for drinking, bathing, cooking, and use in residential air conditioning units.1
Legionnaires’ disease is a severe, sometimes fatal, form of pneumonia caused by Legionella bacteria. Infection occurs when people inhale aerosolized water containing the bacteria, typically from cooling towers, hot tubs, showers, humidifiers, or decorative fountains. The disease is not spread person-to-person, nor is it contracted by drinking contaminated water.3
Symptoms often resemble other respiratory illnesses and generally develop 2 to 14 days after exposure. These include:3
Eleven cooling towers in Central Harlem tested positive for Legionella and have been remediated, with tap water confirmed safe for use.
People aged 50 and older, smokers, and those with chronic lung or immune conditions are at higher risk and should seek immediate care if symptomatic.
Legionnaires’ disease is a severe pneumonia caused by inhaling aerosolized water containing Legionella bacteria and is treatable with early antibiotic intervention.
Although most healthy individuals exposed to Legionella do not become ill, some populations are at increased risk for severe outcomes. These include:3
Infections can lead to respiratory failure or death if untreated. The CDC estimates a case-fatality rate of about 10%; this increases to approximately 25% among people who acquire the disease in healthcare settings.3
Diagnosis typically involves:
DOHMH continues environmental testing and building inspections throughout the outbreak zone. Per city ordinance, building owners must:1
The outbreak investigation in Central Harlem remains ongoing. While public health officials stress that the risk of infection remains low, clinical vigilance is essential, especially in high-risk individuals presenting with pneumonia-like symptoms. Health care providers in the area should maintain a high index of suspicion and report confirmed cases to local health departments as required.
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