The Legionnaires’ Disease Threat From Public Hot Tubs

A new scientific study by Japanese researchers lends force to the increasing realization by state health departments that building owners must be proactive and vigilant in testing water features like hot tubs, baths, and showers for Legionella pneumonia bacteria.

Legionella Bacteria CDC

The study, reported in this February’s issue of the Centers for Disease Control (CDC)’s journal, Emerging Infectious Diseases, describes how a 2015 Legionnaires’ disease outbreak which sickened 7 patients began at a spa house (1). In Japan, where there is a strong cultural preference for public baths, the highly-frequented spa houses and hot springs are the primary sources for Legionnaires’ disease (also called legionellosis). Researchers ascertained that the 2015 outbreak was caused by two separate strains of L. pneumophila bacteria – serogroups 1 and 13 – that had proliferated in a spa house visited by all 7 victims:

“Among Legionella species, L. pneumophila serogroup 1 accounts for most human infections. Legionellosis outbreaks caused by a combination of L. pneumophila serogroup 1 or other serogroups have rarely been reported.” (2)

Five of the seven victims had underlying medical conditions that made them more susceptible to Legionnaires’ disease infection – four had diabetes mellitus, and one had hepatic cirrhosis and liver cancer. All seven, fortunately, recovered and were released from the hospital.

Upon testing the nine baths at the spa house, the researchers concluded that L. pneumophila had contaminated five of the baths because of inadequate chlorination of the bath water and attendant circulating systems.

The Problem with Hot Tubs

In an informational brochure, the Centers for Disease Control has alerted the general public about the dangers of the Legionella pneumonia bacteria that lurk in under-maintained hot tubs:

“Legionella is naturally found in water, especially warm water. Hot tubs (or spas) that are not cleaned and disinfected enough can become contaminated with Legionella. A person can get infected with Legionella when they breathe in steam or mist from a contaminated hot tub … Because high water temperatures make it hard to maintain the disinfectant levels needed to kill germs like Legionella, making sure that the hot tub has the right disinfectant and pH levels is essential.” (3)

Disinfection is particularly important when therapeutic hot tubs are used by people who are highly susceptible to the disease: those who are 50 years of age or older, smokers, individuals with chronic lung disease, and people with weakened immune systems.

Should You File a Legionnaires’ Disease Lawsuit?

Fred Pritzker and Eric Hageman
Attorneys Fred Pritzker and Eric Hageman

If you or a loved one has contracted Legionnaires’ disease from a public hot tub or spa, you may have grounds to file a lawsuit for personal injury or wrongful death. Fred Pritzker and Eric Hageman are our lead attorneys for Legionnaires’ disease cases:

“It is the hot tub owner’s responsibility to keep the hot tub clean and free of dangerous pathogens like Legionnaires’ disease,” notes Fred, who has successfully represented numerous Legionnaires’ disease victims in personal injury lawsuits against hotels, fitness clubs, nursing homes, hospitals and others.


  2. Kuroki T, Amemura-Maekawa J, Ohya H, Furukawa I, Suzuki M, Masaoka T, et al. Outbreak of Legionnaire’s Disease Caused by Legionella pneumophila Serogroups 1 and 13. Emerg Infect Dis. 2017;23(2):349-351.

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Category: Legionnaires' Disease
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