Cruise passengers are once again confronting a health risk that lurks in warm, recirculating water: Legionnaires’ Disease.
On November 4, 2025, passengers aboard the Norwegian Epic received an alert no traveler wants to see: they might have been exposed to the bacterium Legionella pneumophila. The notice, sent during the fourth day of a 12-night Mediterranean voyage from Rome to Lisbon, advised guests to seek medical attention if symptoms developed within 14 days of disembarkation and to share the notice with their physicians.
The cruise line disclosed that two recent passengers had been diagnosed with Legionnaires’ Disease, but the source of exposure remains unknown.
“It is currently unknown whether the diagnosed guests were exposed to the bacteria through the ship’s water system or another source,” the notice stated.
Public reporting confirms the cases occurred after the passengers’ voyages, but no further personal details or sailing dates have been released. As of the latest reporting, there are no confirmed additional cases from this November voyage, and the investigation with the Centers for Disease Control and Prevention (CDC) remains ongoing.
Legionnaires’ Disease is a severe form of pneumonia caused by Legionella, which thrives in warm water environments. Infection typically occurs when individuals inhale tiny contaminated water droplets, making showers, whirlpools, hot tubs, and in-cabin jetted spa tubs potential points of exposure. Hot tubs are frequently implicated because warm water, recirculation systems, and jet-driven aerosolization can allow Legionella to grow if disinfection and maintenance are inadequate.
While Legionnaires’ Disease outbreaks on cruise ships are relatively rare, they are recognized risks — particularly where private water amenities are involved. Between November 2022 and June 2024, the CDC documented 12 cases of Legionnaires’ Disease on two ships and identified “private hot tubs on selected cabin balconies” as the most likely exposure source. The report noted that epidemiologic, environmental, and laboratory evidence pointed to these private features, highlighting a persistent gap between maintenance of public versus private amenities.
It should be emphasized that the Norwegian Epic notice did not identify a specific water feature as the confirmed source. However, previous CDC findings have shown the vulnerability of in-cabin jetted tubs and balcony hot tubs, especially when maintenance falls short. The CDC’s Vessel Sanitation Program (VSP) establishes broad standards for cruise ship water hygiene, covering pools, whirlpools, drinking water, and recreational water facilities.
Updated VSP guidance in 2025 requires all spa pools, whirlpool spas, and heated jetted tubs to be sampled at least quarterly for Legionella. Detection triggers immediate remediation, including closure, cleaning, disinfecting, and draining. Routine maintenance also requires monitoring halogen residuals, pH control, filtration, water turnover, and thorough recordkeeping.
Nonetheless, a 2024 CDC study showed that private hot tubs on cruise ships “were found to be operating for months in a manner conducive to Legionella growth … including maintaining a water temperature in the Legionella growth range … for multiple days without draining and … with no residual disinfectant.”
The Norwegian Epic notice may serve as a reminder of the special maintenance requirements of publicly-used hot tubs. Another recent incident shows that neglecting these requirements can result in serious health and legal ramifications.
In September 2025, a North Carolina passenger filed a federal maritime lawsuit against Carnival Cruise Line, alleging he contracted Legionnaires’ Disease aboard the Mardi Gras after using a hot tub on Deck 16. The complaint claims Carnival failed to comply with CDC sanitation standards, including maintaining halogen levels, monitoring water chemistry, performing batch chlorination, and keeping detailed inspection logs.
The passenger required hospitalization, including intravenous antibiotics and respiratory support, and continues to experience longterm complications. The passenger’s attorneys cited prior passenger claims, industry research, and even a 2006 Carnival-commissioned report that identified biofilms and oils in spa systems as potential breeding grounds for Legionella.
As the Norwegian Epic investigation continues and the Carnival case proceeds through the courts, the cruise industry — and anyone responsible for spa-style water amenities — faces heightened scrutiny.
For operators and service techs, adherence to CDC and industry water management protocols is not just best practice — it is essential to prevent a public-health crisis and protect both guests and reputations.
