A new studyis available online in the Oxford journal “Clinical Infectious Diseases” detailing the findings of an investigation into an outbreak of norovirus on a cruise ship in 2009. Norovirus is the most common type of food-poisoning in the United States. Usual symptoms of norovirus infection include nausea, vomiting, diarrhea, and abdominal pain. Headache and low-grade fever may also accompany this illness. The illness develops 24 to 48 hours after contaminated food or water is ingested and lasts for 24 to 60 hours.
According to the abstract, the study was based on a questionnaire placed in passenger cabins after the outbreak of illness. The questionnaire sought information on whether and when people sought medical care, personal hygiene, and potential norovirus exposures.
83% of the roughly 1,500 passengers returned the questionnaires. Of those who did, 15% were persons who met the case definition of an outbreak member. A full 40% of the ill persons did not report to the ship infirmary.
Two factors that appeared to increase the likelihood of illness were having an ill cabin mate, or residing or dining on a deck where a vomiting incident had occurred during boarding. Darrhea and vomiting were the two most common symptoms. Several ill persons did submit positive stool cultures.
Study Author Mary Wikswo, MPH, of CDC, was quoted in a report on Medical News Today:
“Cruise line personnel should discourage ill passengers from boarding their ships. Once on board, passengers and crew who become ill should report to the ship’s medical center as soon as possible. These quick actions are crucial in preventing the introduction and spread of norovirus on cruise ships and allow ship personnel to take immediate steps to prevent the spread of illness.”