Passengers on Royal Caribbean's Oasis of the Seas, at one point the largest cruise ship in the world, were reportedly not allowed to disembark when it reached Falmouth, Jamaica on a scheduled seven-day cruise.
The boat is turning around to return to Port Canaveral.
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Royal Caribbean on Thursday said 277 passengers and crew were ill, but the number jumped on Friday.
One passenger, Abby Perrin, told ABC that she and her mother began experiencing symptoms after the lunch.
Because of the illness, the ship will return to Port Canaveral, Florida, on Saturday, a day earlier than expected.
Torres previously told Florida Today that almost 9,000 passengers and crew were on the vessel, which is one of the largest cruise ships in the world. "We've been pretty much confined to our rooms". "Then we were supposed to be in Mexico tomorrow, which we were really excited about, and it turns out we're going back to Florida instead". "We think the right thing to do is to get everyone home early rather than have guests worry about their health".
The company said it hoped that returning home early would give the company time to fully sanitize the ship before its next outing.
"Our guests sail with us to have great vacations, and we are sorry this cruise fell short", Torres said.
Norovirus outbreaks are not all that uncommon on land and at sea.
Norovirus, which is also referred to as the "winter vomiting bug", is the most common cause of gastroenteritis - characterised by diarrhea, vomiting and stomach pain. Royal Caribbean's last outbreak was in 2017 on the Independence of the Seas, according to the Centers for Disease Control and Prevention.
Cruise ships have faced a number of other unfortunate events in recent months.
A person can catch it from people infected by it and by touching contaminated surfaces or eating or drinking contaminated food and water.