Nearly 500 cases of Norovirus have been reported on two Florida-based cruise ships.
Princess Cruises says the Crown Princess returned from a Caribbean cruise with more than 10% of the 3100 passengers listed as being ill, along with 30 crew.
Ninety-two passengers and 13 crew members fell ill on a sister ship, the Ruby Princess.
The virus can cause vomiting, diarrhea and stomach pain.
Princess Cruises is part of Carnival Corp which came under scrutiny in January for the Costa Concordia cruise ship disaster in Italy.