Officials say more than three dozen people are possibly ill with the highly contagious norovirus while onboard a cruise ship sailing to ports in California.
Princess Cruises spokeswoman Karen Candy says about 37 passengers on the Crown Princess reported being sick while the ship was in San Francisco on Monday.
Candy said Tuesday that cruise officials believe the cause of the illness is the norovirus. That family of viruses is spread person-to-person and causes flu-like symptoms including nausea, vomiting, diarrhea and stomach cramping.
Candy says the ship's staff began intense disinfecting of surfaces, and all sick passengers are being encouraged to remain in their rooms.
The Crown Princess is on a seven-day California cruise that began in Los Angeles on Saturday and ends in Santa Barbara.