The Ruby Princess departed San Francisco on June 12 with 3,032 passengers, according to the CDC, and completed its 20-day Alaska voyage on Thursday.
Norovirus, a highly contagious virus, is the leading cause of vomiting, diarrhea, and foodborne illness in the United States, according to the CDC.
Princess Cruises and the ship’s crew consulted with the CDC’s Vessel Sanitation Program, a federal surveillance system for gastrointestinal illness on cruise ships. Crew members isolated ill passengers and collected stool specimens for laboratory testing to confirm the cause, the agency said.
The CDC said the ship’s outbreak prevention and response plan was activated, with enhanced cleaning and disinfection procedures implemented to prevent further spread.