What is Legionella?

November 2016 Safety Topic

October 28, 2016

Legionella is a rod-shaped bacterium naturally found in water. It is the causative agent of a very well-known illness known as Legionnaires’ disease. The symptoms of Legionnaires’ disease include fever, chills, cough, tiredness, and vomiting.

The first recognized outbreak of the disease occurred in 1976 in Philadelphia. As many as 221 people were treated and 34 deaths occurred. The source was identified as the Legionella bacterium found in the cooling tower of a hotel’s air conditioning system. In 2015, New York City also experienced an outbreak in the Bronx, where 128 people were infected and 12 deaths occurred. This outbreak was also linked to the cooling tower in a hotel (Opera House Hotel).

The risk factors for developing Legionnaires’ disease are as follows:

  • Age
    • Highest risk in elderly ages 65+
    • Not common in people under 50
    • Very rare in people under 20
  • Smoking
  • Pre-existing chronic obstructive pulmonary disease (COPD)
  • Diabetes
  • Compromised immune system

Infection and transmission is usually from the inhalation of aerosols or soil.

Because Legionella is present in the plumbing systems of buildings, effective water management is required in commercial, institutional, multiunit residential, and industrial buildings (excluding single family homes).

In 2015, New York City passed new legislation to regulate the testing of cooling towers, making it the first major city in the U.S. to regulate cooling towers. Columbia University Medical Center is in full compliance with this new legislation.

Compliance includes the registration of all our cooling towers (not every building has one), their annual certification, quarterly inspection, and ongoing reporting of increased microbes to the NYC Department of Health and Mental Hygiene. The legislation also mandates the disinfection of cooling towers if levels of microbes increase to where they pose potential health risks.

For more information about Legionella, please speak to your supervisor or a member of the Facilities Compliance team.

Download the Legionella flyer to share with your family, friends, and colleagues.