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

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.

Over 140 people have been affected by a gastrointestinal outbreak on a Royal Caribbean International cruise, according to the Centers for Disease Control and Prevention. The round-trip from Los Angeles to Mexico began on July 4.