Carnival Cruise Line is working with the Centers for Disease Control and Prevention (CDC) after being informed that two passengers who traveled with the cruise line contracted Legionnaires’ disease. The ship in question, Carnival Horizon, has undergone extensive testing before the next voyage departed.
The disease is often associated with areas with aerosolized water, such as jacuzzies and fountains. Still, it is also at home when water remains stagnant for a long time, such as when a cabin is unoccupied for some time, and water in the tap remains stagnant. The cruise line did not divulge whether or not the cases did originate onboard.
Cases Occurred In July and August
Two cases of legionnaires disease have been confirmed for two passengers that sailed onboard Carnival Horizon during July and August of this year. The disease, which manifests itself as a severe type of pneumonia caused by the Legionella bacteria, is spread through tiny droplets of water that carry the disease. Legionnaires disease cannot be spread between humans.
Carnival Cruise Line is currently working with the CDC to see if the cases originated from the Carnival Horizon.
In the meantime, the cruise line has started conducting additional extensive Legionella testing and mitigation measures that will be completed before the next cruise departs. The testing includes all devices and fixtures that use water, including whirlpools onboard, spas, showers, and faucets.
In a letter sent to guests who were on board during the start of cruising for Carnival Horizon, the cruise line stresses that it is not known whether the cases did originate onboard, but the cruise line is investigating.
Legionella thrives in environments with warm water or water that is stagnant for a considerable amount of time. Carnival Horizon has been out of service for a considerable amount of time.
The cruise ship ceased operations in March of last year and only commenced in July of this year. The CDC states the following on its website:
“After prolonged no-sail period or reduced operation of cruise ships, stagnant water in ship water systems can increase the risk of Legionella growth and transmission when operations resume. Stagnant water can create favorable conditions for Legionella growth by reducing water temperatures to the Legionella growth range, encouraging biofilm growth in areas of stagnation, and reducing disinfectant levels.”
Is Legionnaires Disease Common on Cruise Ships?
In most cases, healthy people exposed to Legionella do not get sick and are not affected by the disease. People in higher-risk categories, such as (ex-) smokers, those with severe lung diseases, and people with a weakened immune system, are at risk of getting ill.
The disease is usually not deadly, and most people recover with the use of antibiotics in hospitals.
The disease is extremely rare onboard cruise ships, mainly due to the extent of turnaround the ships experience, coupled with high levels of disinfectant used onboard. From 1977 through 2012, only eight ship-associated outbreaks of Legionnaires’ disease have been reported to the CDC. The outbreaks include 83 cases, with a median of 4 cases per outbreak.
In contrast, health departments reported nearly 10,000 cases of Legionnaires’ disease in the United States in 2018. The number is likely much higher as Legionnaires’ disease is likely underdiagnosed, according to the CDC. Illustrating again the safety of cruise ships compared to land-based establishments.
Carnival Cruise Line, in the meantime, has put Carnival Horizon through extensive testing of the water systems and disinfecting of onboard water systems as it continues its itinerary in the Caribbean and Bahamas.
The vessel started operations early in July and was the first vessel to start operations from Miami. The 133,500 gross tons cruise ship has space for 3,960 guests and is currently at Carnival’s private island of Half Moon Cay in the Bahamas.