Eight individuals traveling on the same cruise ship (Cruise Ship "A") were diagnosed with Legionnaires disease. Five passengers (4 laboratory confirmed and one probable case) traveled on the ship in November 2022. Between August and September 2023, two additional laboratory-confirmed cases who traveled on later dates on Cruise Ship A were detected. In April 2024, an eighth case who traveled on Cruise Ship A in March 2024 was reported. Six cases were hospitalized. No one died.

All 8 cases reported using hot tubs located on private cabin balconies. Legionella was detected in 6 private balcony hot tubs. The hot tubs were closed until their operation and maintenance protocols were modified and nondetectable Legionella sampling results were obtained. During March 2024, when patient 8 traveled on Cruise Ship A to August 2024, approximately 300 samples were collected and no Legionella was detected.