Thursday, August 06, 2015

Updating NYC’s Legionnaire’s Outbreak


Legionella Bacteria - Photo Credit CDC PHIL


# 10,389


In a story we’ve been following for more than a week (see Monday’s Updating The NYC Legionella Outbreak), the number of Legionella infections reported in the South Bronx continues to rise, with the total nearing 100. As many people who contract this type of bacterial infection experience only minor symptoms, this is likely an undercount.


Those who are susceptible (often smokers, the elderly, immunocompromised, etc.) can develop serious – even life threatening – pneumonia.


The Legionella bacteria thrives in warm water, such as is commonly found in air-conditioning cooling towers, hot tubs, and even ornamental water fountains. When water is sprayed into the air the bacteria can become aerosolized and inhaled.


The CDC estimates that between 8,000 and 18,000 Americans are hospitalized with Legionnaire's Disease each year. While large outbreaks of Legionella are often traced to specific causes, quite often the source of the infection for individual cases remains unknown.  


Overnight posted the following update.

Bronx Legionnaires' Disease Cluster Updated Fact-Sheet 8/5/15


  • Individuals with Legionnaires' deceased: 8
  • All deceased individuals were older adults and had additional underlying medical problems.
  • These patients are connected to the current cluster.
  • Reported individuals with Legionnaires': 97
  • Individuals with Legionnaires' hospitalized: 92
  • Of the 92, the number of individuals with Legionnaires' treated and discharged: 48


  • New York City's drinking water supply and other water features, like fountains, shower heads and pools, are safe throughout New York City and are unaffected by legionella
  • Water towers are unaffected by legionella
  • Home air conditioner units are unaffected and walking into air conditioned environments is safe, as well.

Locations and Remediation

  • 17 cooling towers were tested
  • 5 locations tested positive, and all have been remediated. Health officials are confident that one or more of the five locations that tested positive was the source of the outbreak, and the risk has been removed through disinfection.
  • All sites will submit long-term plans as to how they will maintain the cooling towers to protect against any future growth of legionella – those plans are due Friday.
  • 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 DOHMH Actions

  • Continued monitoring for new cases
  • Close collaboration with area hospitals
  • Disease detectives conducting epidemiological investigation
  • Interviews with all individuals reported with Legionnaires' 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


For more information on the disease, the CDC maintains a fact sheet at Patient Facts: Learn More about Legionnaires' disease.

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