Cruise Ship Restrooms Aren't as Clean as You Think

A recent study of cruise ship cleanliness shows a link between poorly cleaned cruise ship restrooms and the likelihood of an outbreak of norovirus infection.

The study, which is the first study of environmental hygiene on cruise ships, focused on 56 cruise ships from July 2005 through August 2008. Six standardized objects were identified as potential breeding grounds for infection: toilet seats, flush handles, inner toilet stall handles and handholds, restroom inner door handles, and baby changing table surfaces. These items were studied in 273 randomly selected public restrooms aboard various ships.

Only 37 percent of the restrooms were found to be cleaned daily over the course of the study, which was comprised of 1,564 hygiene samples. Overall cleanliness of the standardized surfaces throughout the study ranged from four to 100 percent.

Overall, toilet seats were rated the best-cleaned object, while baby changing tables were recognized as the least thoroughly cleaned object. On three ships, the baby changing tables went untouched by sanitation workers for the duration of the cruise.

Toilet area handholds also ranked as one of the most neglected objects, accounting for more than half of uncleaned objects on 11 ships.

Even by avoiding specific high-germ areas and thoroughly washing their hands, cruisers can still be at risk of infection.

"Although hand hygiene with soap after toileting may diminish the transmission of enteric pathogens via bathroom door knobs or pulls, hand washing is unlikely to mitigate the potential for any of the other toilet area contact surfaces to serve as a source of transmission of enteric pathogens," Philip Carling, MD, lead author of the study, said in a recent press release. "Furthermore, there was a substantial potential for washed hands to become contaminated while the passenger was exiting the restroom, given that only 35 percent of restroom exit knobs or pulls were cleaned daily. Only disinfection cleaning by cruise ship staff can reasonably be expected to mitigate these risks," he added.

Researchers have found that the level of cleanliness did not differ by cruise line, and that their findings did not correlate with previous Disease Control and Prevention Sanitation Program inspection scores, where the vessels studied averaged a 97 percent cleanliness rating.

Carling continued to say that even though near-perfect cleaning was documented on several of the ships studied, additional research must be conducted to determine whether improved environmental hygiene will decrease the incidence and severity of norovirus outbreaks.

The study was conducted by scientists from Boston University School of Medicine, Carney Hospital, the Cambridge Health Alliance and Tufts University School of Medicine and appears in the November 1st issue of Clinical Infectious Diseases.

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