Four crew members and one passenger on the Ruby Princess are currently isolated on the ship and being treated for flu-like symptoms by the ship’s medical team.
Princess Cruises said the patients will not be allowed to go ashore until they are no longer contagious, and that it is not seeing an increased number of flu cases among passengers or crew.
Princess said that the because H1N1 swine flu is the predominant flu strain circulating worldwide, it is treating all flu-like illness as H1N1 as a precaution.
To contain the spread of illnesses onboard ships, including influenza, the line said that it uses enhanced screening practices for passengers and crew embarking ships.
Ruby Princess is currently sailing on a 12-day Mediterranean itinerary, which concludes in Venice on July 27.