More than 120 passengers and crew members became sick during a Princess Cruises voyage to Alaska and Canada, health officials said.
The outbreak happened aboard the Ruby Princess, which left San Francisco on June 12 for a 20-day cruise.
According to the Centers for Disease Control and Prevention, 102 passengers and 23 crew members reported becoming ill during the trip.
The most common symptoms were vomiting and diarrhea.
Health officials later identified the illness as norovirus, a highly contagious virus that can spread quickly in crowded environments such as cruise ships.
Shared dining areas, public bathrooms and frequently touched surfaces can make it difficult to stop an outbreak once it begins.
Symptoms typically appear within 12 to 48 hours of exposure, allowing the virus to spread rapidly among passengers and crew members.
The Ruby Princess continued its planned route through Alaska and Canada before returning to San Francisco on Thursday as scheduled.
Princess Cruises described the situation as involving “a limited number of guests” who reported mild gastrointestinal illness.
“Our crew responded promptly by implementing enhanced sanitation protocols across the ship, and cases have since decreased and remain low,” the company said in a statement.
Passengers and crew members who became sick were isolated, while workers increased cleaning and disinfection procedures throughout the ship, according to the CDC.
Princess Cruises said the vessel would undergo a comprehensive cleaning and disinfection process before departing on its next scheduled trip.
This marks one of several gastrointestinal illness outbreaks reported aboard cruise ships this year.
Seven outbreaks have met the CDC’s requirements for a public notice. Five were linked to norovirus, while two were caused by E. coli.
Two of the earlier norovirus outbreaks also occurred aboard Princess Cruises ships.
