Norwalk Virus Affects Passengers on Cruise Ship

The Centers for Disease Control and Prevention’s (CDC’s) Vessel Sanitation Program (VSP) has responded to an outbreak of gastrointestinal illness caused by a Norwalk virus aboard Holland America’s Ryndam by recommending that the cruise line implement aggressive sanitation and disinfection procedures. Although these measures were implemented by the crew on July 25, additional cases continued to develop, and on July 31, Holland America Lines elected to take the Ryndam out of service from August 1 through August 7 to break the cycle of the Norwalk virus being spread among passengers and crew. While the vessel is out of service, Holland America will also continue with a systematic cleaning and sanitizing of the vessel. The ship took on passengers in Vancouver, British Columbia, on July 18 and was en route to Ketchikan, Alaska, after stopovers in Juneau and Skagway. Of the 1,318 passengers on board, 33 reported gastrointestinal symptoms. In addition, two of the 564 crew members also reported symptoms. On July 23, Holland America notified CDC of an outbreak of gastrointestinal illness aboard the Ryndam. The cruise ended in Vancouver on July 25 with 167 passengers and nine crew members reporting gastrointestinal symptoms. Laboratory analysis has confirmed that the illness was caused by a Norwalk virus. The Ryndam took on a new group of passengers in Vancouver the afternoon of July 25, 2002, for a 7-day cruise to Juneau, Skagway, Glacier Bay, and Ketchikan, with a return date to Vancouver of August 1. CDC and Health Canada have been monitoring cases of illness on the vessel on a daily basis; as of 6:00 p.m., Tuesday, July 30, 189 of 1,336 passengers and 30 of 571 crew reported gastrointestinal symptoms to the ship’s infirmary. CDC and Health Canada officials boarded the vessel in Vancouver on July 25 and again in Ketchikan on July 30. Food service and potable water practices have been reviewed, and no deficiencies have been identified. Epidemiologic data collected to date point to person-to-person contact as the most likely source of transmission for this outbreak. Outbreaks of gastrointestinal illness caused by Norwalk virus have also been reported in other travel conveyances and in shore-side establishments in both Alaska and Canada. Holland America’s decision to take the vessel out of service and cancel a 7-day Alaska cruise is strongly supported by CDC and Health Canada. Representatives of Health Canada will continue to monitor the cleaning and sanitizing of the vessel while it is out of service.