"No deaths have occurred. Most exposed individuals do not develop symptoms."
Legionnaires' Disease Cluster Hits Upper East Side
In early July, a cluster of Legionnaires' disease cases emerged on the Upper East Side of New York City. The outbreak has since prompted widespread testing and remediation across the city.
Affected Landmarks and Buildings
The Guggenheim Museum and the Metropolitan Museum of Art both tested positive for Legionella bacteria. On the Upper West Side, the Ardsley co-op also reported Legionella in its hot-water system. As of Tuesday, cooling towers in 76 buildings across the city tested positive for Legionella.
Public Health Impact
The city Health Department reported 63 hospitalizations, with 40 discharged. No deaths have occurred.
How It Spreads
Legionella bacteria spread through mist or vapor from cooling towers on large buildings. The bacteria multiply in cooling towers and are dispersed in vapor that settles in the air or on surfaces. Infection occurs by inhaling the mist; it is not transmitted person-to-person.
Legionella is not in the plumbing for the Upper East Side cluster; it is not spread through drinking water, showers, or cooking.
Risk Factors and Symptoms
Most exposed individuals do not develop symptoms. When symptoms occur, they include:
- Aches
- Fever
- Cough
- Shortness of breath
Vulnerable groups include older adults, smokers, and individuals with chronic lung disease, kidney disease, or heart disease.
Remediation and Monitoring
Buildings with positive tests drain and treat their cooling towers. New York City has regulations requiring frequent sampling and testing of cooling towers.
"Vulnerable individuals may consider wearing a mask in affected areas. The general public is advised not to be overly concerned."
Investigation and Public Health Response
Rapid tests identify Legionella in water; genetic testing links specific cooling towers to patient cases. It is unlikely that bacteria spread across Central Park; Ardsley's positive test may result from increased vigilance.
The city disseminates information about Legionnaires' disease and provides guidance on testing frequency. Climate change may contribute to faster bacterial growth due to more hot days.