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Miller, J. M.; Tam, T. W. S.; Maloney, S.; Fukuda, K.; Cox, N.; Hockin, J.; Kertesz, D.; Klimov, A. and Cetron, M.  "Cruise ships: High-risk passengers and the global spread of new influenza viruses," Clinical Infectious Diseases, 2000, 31:2, 433-438

In 1997, passengers on North American cruises developed acute respiratory illnesses (ARIs); influenza was suspected. We reviewed 1 ship's medical records for 3 cruises: cruise 1 (31 August to 10 September 1997), cruise 2 (11-20 September 1997), and cruise 3 (20-30 September 1997). Medically attended ARI was defined as any 2 of the following symptoms: fever (temperature, more than or equal to 37.8 deg C) or feverishness, sore throat, cough, nasal congestion, chills, myalgia, and arthralgia. During cruise 2, we collected nasopharyngeal swabs for viral culture from people with ARI and surveyed passengers for self-reported ARI (defined as above except feverishness was substituted for fever). The outbreak probably began among Australian passengers on cruise 1 (relative risk, 3.3; 95% confidence interval, 1.89-5.77). Of 1284 passengers on cruise 2, 215 (17%) reported ARI, 994 (77%) were aged more than or equal to 65 years, and 336 (26%) had other risk factors for respiratory complications. An influenza strain not previously identified in North America was isolated. We concluded that an "off-season" influenza outbreak occurred among international travellers and crew on board this cruise ship.

Miller, J.; Tam, T.; Afif, C.; Maloney, S.; Cetron, M.; Fukata, K.; Klimov, A.; Hall, H.; Kertesz, D. and Hockin, J.  "Influenza: An outbreak on a cruise ship," Canada Communicable Disease Report, 1998, 24:2, 9-11

During 31 August-10 September 1997, a total of 39 (2.7%) of 1445 passengers and 3 (0.5%) of 631 crew members on a cruise from New York City, USA, to Montreal, Canada, presented with acute febrile respiratory illness. All passengers disembarked in Montreal; 9 (0.6%) were referred to area hospitals for respiratory complications and 6 were hospitalized. Influenza A was confirmed by culture. During the return voyage to New York City on 11 September-20 September, a total of 19 (1.3%) of a new cohort of 1448 passengers and 17 (2.7%) of the same crew presented with influenza-like illness (ILI). Investigation of the outbreak was initiated on 15 September. Influenza A was identified on 17 September from one nasopharyngeal swab by rapid viral antigen detection test. Crew members with ILI were confined to their cabins and given rimantadine; non-ill crew members were started on rimantadine prophylaxis for 14 days. All 631 crew members were given the 1997-98 influenza vaccine. Of the passengers, those presenting with ILI were given rimantadine for 5 days and non-ill passengers were offered rimantadine prophylaxis. During 17-18 September, 1284 passengers were surveyed. Of these, 994 (77.4%) were aged more than or equal to 65 years, 336 (26.2%) had chronic health conditions associated with increased risk for severe complications of influenza, 52 (4.1%) reported an ILI, and 1020 (80.8%) of 1262 passengers reported using rimantadine prophylaxis. Two passengers who disembarked in New York City on 20 September were referred to area hospitals for respiratory complications. 13 isolates were characterized at the Centers for Disease Control and Prevention (CDC) in the USA as influenza A/Sydney/05/97-like(H3N2).