Legionella on Cooling Towers

A number of cooling towers around the Bronx have been found to be the source of a Legionella outbreak. A number of buildings in the area tested positive for contamination, including a drug manufacturer (thankfully the medicine was not contaminated, at least according to the company representatives). Legionella is a waterborne pathogen that can grow in water towers and other water systems that are poorly kept since the conditions of such structures are ideal for harboring this microbe.

According to the New York Times article, as of August 16, this outbreak “has claimed 12 lives and sickened more than 120 people in the South Bronx” and is “the worst flare-up of the disease in the city’s history.” The towers are now being cleaned, which will hopefully stem the number of cases.


Legionella outbreaks are fairly common. Here are some past posts from microBEnet on these outbreaks:

Source of Legionella outbreak in Quebec located: Cooling tower

Legionella outbreak in Edinburgh

The Playboy Mansion Legionella outbreak story continues: becoming a social media epidemiological case study

4 thoughts on “Legionella on Cooling Towers

  1. The five cooling towers that initially tested positive have not as of yet been definitively identified as the source for the outbreak despite what the media and politicians would lead you to believe. As a microbiologist, you should know that (according to WCPF’s at the CDC) rarely do the strains isolated from those infected correlate w/ environmental isolates and w/o said correlation a finger can not be pointed at a probable definitive source.

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Alex Alexiev

Alex Alexiev is a recent UC Davis graduate with a BS in microbiology working in Jonathan Eisen’s lab on aquariums as part of the microbiology of the built environment.