Gastrointestinal illness sickened more than 130 cruise ship passengers aboard a Royal Caribbean cruise earlier this month. The cause of the outbreak has not been determined.

Royal Caribbean's Navigator of the Seas was on a week-long, round-trip cruise when passengers became sick, the CDC said.

A dream vacation quickly turned into a nightmare for more than 140 people aboard Royal Caribbean’s Navigator of the Seas, as a mysterious illness swept through the ship during a weeklong cruise to Mexico,