By WC&P Staff

Is there a danger lurking in your customers’ hot tubs? The answer is yes—one that causes shortness of breath, pneumonia-like symptoms and in some extreme cases, can be fatal.

Initially easy to misdiagnose, by the time doctors know what’s causing the problem, ‘Hot Tub Lung’ can be a serious ailment that requires hospitalization and a heavy antibiotic regimen. In the past six months, more than a dozen people in the U.S. have been diagnosed with the infectious agent that leads to Hot Tub Lung.

For all its potential dangers and recent press, it remains a relatively uncommon upper respiratory infection. But as the cases of Hot Tub Lung increase throughout America, many of the 3.3 million spa owners who typically use their hot tub for a relaxing respite are beginning to question its safety and are seeking out water treatment professionals for answers.

Hot Tub Lung is caused by the infectious agent Mycobaterium avium, part of the Mycobactirum avium complex (MAC) normally present in the environment. Typically, the growth of M. avium is mitigated by cooler, dry temperatures. A hot tub provides ideal conditions for rapid reproduction of M. avium(and most other bacteria). Where swimming pools and hot tubs are disinfected properly, few of these bacteria can cause any ill health effects. However, in poorly maintained hot tubs, where water is not circulated properly and disinfection is insufficient, M. avium thrives.

As the hot tub steams, these bacteria become airborne and are inhaled by bathers. Under the right conditions, any person who bathes in a contaminated hot tub is at risk of this airborne infection. However, it typically is more like to affect immunocompromised people (children, the elderly and those suffering from immune deficiency diseases such as AIDS).

Hot Tub Lung is associated with a host of flu-like symptoms, such as:

  • Shortness of breath
  • Fatigue
  • Fever or chills
  • Wet cough
  • Tightness in the chest

Because of these symptoms, the disease is commonly misdiagnosed as acute asthma, pneumonia or bronchitis. Treating for these ailments only prolongs the disease in the afflicted, since the M. avium bacteria actually causing the infection requires a regimented antibiotic treatment with as many as three separate medications. When compounded by the fact that few people tell their doctor that they have recently bathed in a heated spa (and few doctors ask for that information), Hot Tub Lung regularly becomes more than just a passing sickness. While it can be treated very easily if caught quickly, the lack of prompt diagnosis typically leads to months of illness and eventual hospitalization.

Hot Tub Lung is easily preventable with a consistent and thorough disinfection process. Water treatment professionals should always make sure their customers are aware of the factors that can compromise spa water and educate them on how to best defend themselves from the sickness.

For more Hot Tub Lung and spa-related resources on the web, visit:

Centers for Disease Control and Prevention

Association of Pool and Spa Professionals

National Swimming Pool Foundation


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