International Centre for Cruise Research
A virtual centre for research and for researchers

Lawrence DN. "Outbreaks of Gastrointestinal Diseases on Cruise Ships: Lessons from Three Decades of Progress," Current Infectious Disease Report, 2004 6:2 (April), 115-123

Dramatic improvements in sanitary engineering and, especially, operational procedures aboard cruise ships began in the mid-1970s after several large outbreaks of acute gastroenteritis. The US Centers for Disease Control and Prevention's Vessel Sanitation Program, working with the cruise industry, conducts ship inspections, provides public access to ship sanitation scores, and reports outbreak investigations. The significant increase in median ship sanitation scores over the past decade has been concomitant with a reduction in outbreak frequency to 3.7 per 1000 cruises. Most outbreaks of the past decade were linked to noroviruses (Norwalk-like viruses), enterotoxigenic Escherichia coli, or the residual "unknown" causes. Although norovirus outbreaks may begin as foodborne or waterborne disease, easy person-to-person transmission occurs through fecal- or vomitus-splattered surfaces, other items, clothing, and especially, hands. Control of person-to-person spread of illness among crew and passengers becomes the major objective. Rigorous handwashing, environmental disinfection, and other food service job-related restrictions are required to prevent multiple outbreaks on the same ship. Vigilance by public health and industry officials has prevented many thousands of illnesses and some associated deaths. Clinicians providing pretravel health advice and post-travel diagnoses and care can benefit from and contribute to epidemiologic investigations and thereby enhance the health of cruise passengers individually and collectively.

Lawrence DN, Blake PA, Yashuk JC, Wells JG, Creech WB, Hughes JH. "Vibrio parahaemolyticus gastroenteritis outbreaks aboard two cruise ships,"
American Journal of Epidemiology, 1979, 109:1 (Jan), 71-80

Outbreaks of Vibrio parahaemolyticus gastrointestinal illness occurred on two Caribbean cruise ships in late 1974 and early 1975. In all, 697 passengers and 27 crew were affected. Epidemiologic evidence incriminated seafoods served on the ships as the vehicles of transmission. The seafoods were probably contaminated by V. parahaemolyticus after cooking in seawater from the ships' internal seawater distribution systems. Use of seawater in foodhandling areas was discontinued, and no further outbreaks occurred.