Two outbreaks of bacterial Legionnaires disease on separate cruise ships were traced to germs from passengers' in-cabin hot tubs These more private tubs aren't subject to the same disinfectant protocols as more public water features onboard Most of the passengers affected were so ill they required hospitalization THURSDAY, Oct. 24, 2024 (HealthDay News) -- Next time you're on a cruise, be wary of your (or your neighbor's) private balcony hot tub, researchers warn. These luxe cabin features were pinpointed as a source of outbreaks of the respiratory illness Legionnaires disease that broke out on two ships.

The Legionella bacterium thrives in wet, warm conditions, so "hot tubs offer favorable conditions for Legionella growth and transmission when maintained and operated inadequately, regardless of location," said a team of researchers from the U.S. Centers for Disease Control and Prevention.

And while more public bathing spots onboard may be rigorously cleaned by staff, "private hot tubs on cruise ships are not subject to the same maintenance requirements as are public hot tubs in common areas," said a team led by Sooji Lee , an epidemiologist at the CDC's National Center for Immunization and Respiratory Diseases. Legionnaires disease is a rare form of pneumonia caused by Legionella bacteria. The germ is sometimes found in fountains, spray parks, hot tubs, showers and faucets.

People can contract the disease by breathing in a mist or vapor containing the bacteria. The first cru.