Ten days into the 15-day voyage from Los Angeles to four Hawaiian islands, Princess Cruises diverted the Sun Princess to Honolulu so nearly 2,000 passengers could take flights home.
About 100 passengers, about half of whom were sick, stayed with the ship as it left Tuesday for Los Angeles, Princess Cruises spokesman Tom Dow said. He noted that the cruise appeals to some people who are wary of air travel.
Most people who contracted the Norwalk or Norwalk-like virus recovered before the end of the voyage, cruise officials said.
After four new cases were reported Monday, the cruise line, in consultation with health officials, decided to divert the ship, Dow said.
The cruise line paid to fly passengers home and offered partial refunds, he said. All crew stayed aboard, along with a team sanitizing the ship.
Norwalk or Norwalk-like viruses, which afflicted more than 1,500 passengers on several cruise ships in recent months, cause diarrhea, stomach pain and vomiting for up to 48 hours. They are spread by close contact with infected people or the things they have touched.
Health officials estimate there are about 23 million cases of those and similar viruses a year - most on land. They believe there were more cases than usual last year, but do not know how many more because the disease is not tracked regularly.
By David Briscoe