(CNN) -- A cruise ship returned to Charleston, South Carolina, on Friday after more than 400 passengers got sick during a trip to the Caribbean.
The Celebrity Cruises' ship Mercury ended a voyage marked by an outbreak of a gastrointestinal illness that sickened 435 of 1,838 passengers, said Cynthia Martinez, a company spokeswoman.
The Centers for Disease Control and Prevention in Atlanta, Georgia, said the outbreak was the result of norovirus, which can spread from contact with contaminated food or drink, by touching objects infected by people who are already sick, or through close contact with people who are infected, the agency says.
Norovirus is a common cause of viral gastrointestinal illness outbreaks on cruise ships, the CDC says.
So far this year, three such outbreaks have occurred on cruise ships that docked at U.S. ports, according to the CDC. And in 2009, norovirus was the cause of two outbreaks on the Mercury, the CDC reported.
The outbreaks reported and investigated by the CDC infected at least 3 percent of the people aboard cruise ships carrying at least 100 passengers on cruises lasting between three days and three weeks.
The Mercury left Charleston last week for the eastern Caribbean. In addition to sick passengers, at least 32 crew members became ill, Celebrity Cruises has said.
Symptoms included upset stomach, vomiting and diarrhea, the cruise company said this week. The sickened passengers and crew responded well to over-the-counter medicine, it said.
A doctor and two nurses joined the cruise medical staff Monday to help deal with the outbreak when the ship stopped in Tortola in the British Virgin Islands, the cruise company said.
Guests who were in isolation during the cruise received compensation in the form of a credit to their onboard account, Martinez said Friday.