Transcript for Hundreds of passengers sickened on Royal Caribbean ship

Next here tonight, to the nightmare at sea. A cruise ship struck by a potential outbreak of the norovirus. Nearly 300 people falling ill on the royal caribbean oasis of the seas. Here's ABC's Victor Oquendo tonight. Reporter: Tonight, one of the world's largest cruise ships heading back to port early. Royal caribbean telling ABC news 277 people suffered "An episode of gastrointestinal illness" onboard the oasis of the seas. The CDC now investigating as sick passengers like Abby perrin and her mother say it came on suddenly. In the middle of the night, we both started feeling like we had food poisoning. So we had fevers and were throwing up. They're recommending everyone who's sick to stay in their room. Reporter: On Sunday, about 9,000 guests and crew departed president canaveral on the seven-day caribbean cruise. By Tuesday night, passengers reportedly started feeling symptoms that included nausea, vomiting and diarrhea as the ship approached Jamaica. Tonight, passengers sharing video of crews trying to sanitize common areas as the ship is urging passengers to wash their hands. David, royal caribbean tells us that rather than have everyone worry about their health, the ship will be returning a day early, and all passengers will be receiving a full refund. David? All right, Victor Oquendo, thank you. Next, there is new fallout

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