Hundreds of passengers on a British cruise ship docked in the US have fallen ill with norovirus, health officials say.
The US Centers for Disease Control (CDC) said 252 of the 919 passengers on board the Balmoral cruise ship had fallen ill with the stomach virus.
Most of those on board are British, the ship’s owners, Fred Olsen Cruise Lines, said in a statement.
The ship has suffered other outbreaks of norovirus in previous years.
Fred Olsen Cruise Lines said it was “undertaking extensive sanitisation measures and cleaning of the ship” adding that at no point during the cruise had the ship been quarantined.
The Balmoral docked in Portland, Maine, on Sunday, having left Southampton on England’s south coast on 16 April.
It is expected to arrive in Saint John, in the Canadian province of New Brunswick, on Monday.
While docked in Baltimore on 30 April and 1 May, experts from the CDC boarded to carry out tests on people who had fallen ill, the organisation said in a statement.
Since then, the number of patients with norovirus, also known as winter vomiting bug, has increased. As well as the 252 passengers, eight of the 520 crew have also contracted the illness, the CDC said.
Fred Olsen Cruise Lines said cases were “particularly highlighted” on cruise ships, where people were in close confines. There were 15 passengers confined to their cabins, it said.
The company said it was “co-operating fully” with maritime authorities and would “continue to make every effort possible to ensure the safety and well-being of all its guests and crew”.
An eight-day Scandinavian cruise on the same ship was cut short last May after a number of people fell ill with norovirus.
In 2010, at least 310 people on board the ship were reported to suffering diarrhoea and vomiting when it docked in Los Angeles.
And an outbreak of norovirus hit more than 100 people on the Balmoral on a cruise of Scotland in 2009.
The CDC has reported 10 outbreaks on ships docked in the US so far this year, compared to 12 for the whole of last year.
Symptoms of the illness include a sudden onset of vomiting and/or diarrhoea and some people may have a temperature, headache and stomach cramps.
The sickness, spread by human or surface contact, usually lasts one or two days.