According to the Centers for Disease Control and Prevention, December 2024, was a bad month for the cruise industry. There were numerous outbreaks of Legionnaires’ disease on different cruise ships. These outbreaks point out the need for strict water maintenance, e.g. draining water from hot tubs between uses, removing heating elements, and increasing cleaning and disinfection of the hot tubs, on these ships. Legionnaires’ disease is a severe form of pneumonia caused by the bacterium Legionella pneumophila. The bacteria thrive in warm, stagnant water environments and are commonly transmitted through inhalation of contaminated water droplets. Symptoms include cough, shortness of breath, high fever, muscle aches, and headaches. Individuals over 50, smokers, and those with weakened immune systems are particularly susceptible. Investigations by the Centers for Disease Control and Prevention (CDC) identified private balcony hot tubs as the likely source of these outbreaks. Between November 2022 and June 2024, the CDC was notified of 12 cases of Legionnaires’ disease among travelers on two cruise ships; eight on cruise ship A and four on cruise ship B. Epidemiologic data collected from patient interviews and environmental assessment and sampling results identified private hot tubs on selected cabin balconies as the most likely exposure source. The CDC’s findings highlighted that these private hot tubs were operating under conditions conducive to Legionella growth. Factors included maintaining water temperatures between 77°F and 113°F for extended periods without adequate disinfection or water replacement. Additionally, the design and maintenance protocols for private hot tubs were less stringent than those for public hot tubs in common areas, increasing the risk of bacterial proliferation. The outbreaks have prompted a reevaluation of maintenance protocols for private amenities on cruise ships. The CDC emphasized the importance of cruise ship operators inventorying hot tub–style devices across their fleets, assessing design features that increase the risk for Legionella growth and transmission, and implementing regular testing for the bacteria. The December 2024 outbreaks of Legionnaires’ disease on cruise ships serve as a stark reminder of the importance of rigorous maintenance and monitoring of water-based amenities. Want more information? Click HereUnderstanding Legionnaires' Disease
Recent Outbreaks Linked to Private Hot Tubs
Broader Implications for Cruise Ship Amenities
Conclusion
