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.