Over 140 Royal Caribbean cruise passengers and crew sickened by unknown illness

Over 140 passengers and crew members aboard a Royal Caribbean International ship have been sickened by an unidentified illness, the Centers for Disease Control and Prevention's Vessel Sanitation Program said Wednesday.

The ship, the Navigator of the Seas, was on a week-long, round-trip cruise that departed from Los Angeles on July 4. The ship made three stops in Mexico, according to ship tracking site CruiseMapper, then returned to Los Angeles on July 11, which is when the outbreak was reported to the CDC.

Of the ship's 3,914 passengers, 134 reported being ill during the trip. Seven crew members out of 1,266 reported illness. The symptoms they experienced included diarrhea, vomiting and abdominal cramps, the CDC said.

Royal Caribbean told the CDC that its crew increased cleaning and disinfection procedures according to their outbreak prevention and response plan, collected stool specimens for testing, isolated ill passengers and crew members, and consulted with the Vessel Sanitation Program. The program remotely monitored the situation, the CDC said.

The CDC said more work will be done to determine the cause of the outbreak. Often norovirus, a contagious stomach bug, is to blame for gastrointestinal illness outbreaks on cruise ships, the agency said.