What Is Norovirus? More Than 200 Cruise Ship Passengers Sickened

Passengers on two cruise ships, each bound for San Diego, were recently struck with norovirus, a "very contagious virus" that sickened a total of more than 200 people aboard the ships. News of the second outbreak surfaced Tuesday, after a ship with infected passengers had already docked in San Diego, been inspected, cleaned and sent off to Florida with new passengers Monday.

Monday's ship, the Celebrity Infinity, had 112 sick passengers aboard, and Tuesday's ship, the Royal Caribbean Legend of the Seas, had 114 sick passengers aboard, a count by the U.S. Centers for Disease Control and Prevention (CDC) said, as KGTV in San Diego reported. Both ships are owned by divisions of Royal Caribbean Cruises. In total, about 5 percent of the 2,117 passengers aboard Infinity fell ill, and about 6.5 percent of the 1,763 passengers aboard Legend of the Seas fell ill. In addition, six Infinity crew members and two Legend of the Seas crew members were sickened.

Norovirus is known as a leading cause of viral gastroenteritis. The symptoms of the illness, which can be passed through contaminated food, water or contact with an infected person, included vomiting and diarrhea.

"Royal Caribbean is undertaking direction from the CDC to inhibit the sickness and prevent further outbreaks, including increasing cleaning and disinfection procedures [and] making announcements to notify onboard passengers and crew of the outbreak, encourage case reporting, and encourage good hand hygiene," read a statement from company officials.

The CDC's website indicated that norovirus infects 19-21 million people in the U.S. every year, hospitalizing 56,000-71,000 people and resulting in 570-800 deaths. The CDC lists "closed places like daycare centers, nursing homes, schools, and cruise ships" as locations where the virus can spread quickly. Last year a cruise ship leaving from New York Harbor experienced a high-profile outbreak that affected more than 500 passengers.

The Legend of the Seas was set to be disinfected later Tuesday before leaving the dock and was undergoing a CDC inspection, the Guardian reported. After testing was done on the Legend of the Seas, lounge chairs by the pool were found to have eight times the normal amount of bacteria. The worst item, a spoon used on the buffet line, was found to have 20 times the normal amount of bacteria, KGTV reported.