What is legionella and Legionnaires’ disease?


What is legionella and Legionnaires’ disease?

Legionnaires’ disease. The mere sound of it sends shivers down the spines of building owners and managers. In 2015, the Legionnaires outbreak crisis in New York made headlines as being responsible for the death of 12 people. As a result, government officials are under increased scrutiny to demonstrate that commercial buildings are responding to increasing legionella outbreaks believed to come from cooling towers. In the wake of this crisis, New York has adopted both city and state rules that govern how building owners must manage their cooling towers for proactive Legionella prevention.

History on Legionnaires’ Diseases and Legionella

Legionnaires’ disease entered the property manager’s lexicon in July 1976 when over four thousand members of the American Legion arrived in Philadelphia to attend their 58th annual convention at a downtown hotel. A few days later, 221 of the attendees contracted a mysterious pneumonia that eventually killed 34 of them, sparking a worldwide scientific investigation to identify the responsible agent. The widely publicized illness became known as Legionnaires’ disease, and it was determined that the responsible agent was a microbe harbored in the hotel‘s cooling tower and distributed by the air conditioning system. After months of extensive research, scientists discovered that the culpable organism was a bacterial species and named it Legionella pneumophila (Legionella). From that moment on, the world viewed the impact commercial buildings can have on public health and safety in a new way.

More than 25 species of Legionella have now been recognized, with many more serotypes. Legionella is a naturally occurring bacterium found in most natural and man-made fresh water reservoirs. It thrives in a temperature range of 68-113 degrees Fahrenheit, and prefers stagnant water conditions. As such, it easily colonizes both hot and cold domestic water systems – in fact it is estimated that up to 70% of all building water systems are contaminated with Legionella. As mentioned previously, Legionnaires’ disease is a serious form of pneumonia. It is most commonly contracted via the inhalation of mist carrying Legionella, though infection via aspiration can also occur. While the entire population is vulnerable, most at risk include smokers, the elderly, and immune-compromised persons. The U.S. Center for Disease Control estimates there are 8,000 to 18,000 cases of Legionnaires ’ disease in the U.S. annually, with 10-15% of them fatal. The diagnosis of Legionnaires’ disease has increased 217% from 2000 to 2009.

How does Legionnaires’ Disease affect Commercial Real Estate?

The costs to commercial building owners and managers of having an outbreak of Legionnaires’ disease in their building can be huge, particularly if the event is publicized. These costs include a reduction to the bottom line, disruptive emergency disinfection, legal liability, diminished property value, negative publicity, and a damaged (potentially permanent) reputation. Performing an ASHRAE 188 Legionella Compliance Assessment is a first step in developing a preventative plan.

Stay tuned for part two of this post on how to prevent legionella in commercial buildings.

By | 2019-04-05T13:25:11+00:00 November 16th, 2015|Blog, Commercial Real Estate|Comments Off on What is legionella and Legionnaires’ disease?

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