The agony and the ecstasy.

The authors, who are from the Vessel Sanitation Program of the Centers for Disease Control and Prevention (CDC), summarize the recent outbreaks of acute gastroenteritis (AGE), which occurred on five different cruise ships. Attack rates among passengers ranged from 4% to 13% and among crew members from 0.2% to 3.3%. Subsequent epidemiological investigations by the CDC suggested that the incidence was higher, approaching 19-41% of passengers. Overall there were 21 outbreaks of AGE on 17 cruise ships, of which nine were documented to be due to norovirus, three due to bacterial agents, and nine of unknown cause. In general, subsequent outbreaks on each cruise ship were of the identical strain of norovirus by reverse transcriptase polymerase reaction, which suggests an embedded source. The authors conclude that in addition to emphasizing basic food and water sanitation measures, control efforts should include thorough and prompt disinfection of ships during cruises and isolation of ill crew-members and passengers for 72 hours.