Passenger behaviors associated with norovirus infection on board a cruise ship--Alaska, May to
June 2004
Chimonas MA, Vaughan GH, Andre Z, Ames JT, Tarling GA, Beard S, Widdowson MA, Cramer EH
- Background
- During May 2004, the Vessel Sanitation Program (VSP) investigated an outbreak
of norovirus gastroenteritis on board a cruise ship sailing in Alaska waters. The objectives
were to identify a common food item source and explore behavioral risk factors for person-to
-person transmission among passengers.
- Methods
- A case was defined as three or more episodes
of loose stools within 24 hours or two or fewer episodes of loose stools accompanied by
one or more episodes of vomiting. Vomitus and stool samples from affected passengers were
tested for norovirus by reverse transcriptase-polymerase chain reaction. Environmental
health officers performed an environmental investigation following VSP protocol.
Questionnaires about food items consumed and behavioral risk factors were placed in cabin
mailboxes (n = 2,018). A case-control study design using multivariable logistic regression
tested associations between risk factors and disease.
- Results
- A total of 359 passengers
(24.1% of respondents) met the case definition. Four of seven clinical specimens tested
positive for norovirus. No significant deficiencies in environmental health practices were
identified, and no meal servings were associated with disease. Having a cabin mate sick
with diarrhea or vomiting [odds ratio (OR): 3.40; 95% confidence interval (CI) =
1.80-6.44] and using a specific women's toilet that was contaminated with vomit
(OR: 5.13; 95% CI = 1.40-18.78) were associated with disease. Washing hands before
meals was protective (OR: 0.25; 95% CI = 0.12-0.54) against disease.
- Conclusion
- Widespread person-to-person norovirus outbreaks can occur on board cruise
ships, even with appropriate environmental health practices. Programs to prevent and
control norovirus outbreaks on board cruise ships should involve strategies that disrupt
person-to-person spread and emphasize hand washing.
- You can find this article in the Journal of Travel Medicine, May-Jun 2008; Volume 15
Issue 3, PP. 177-83
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