Cruise ship-illnesses are all too common and it appears that passengers on yet another cruise ship have become sick with the highly contagious norovirus. This time it's on the Crown Princess which was sailing around ports in California.

At least 66 passengers and 17 crew members were sick with a gastrointestinal illness on the Princess Cruise ship, spokeswoman Karen Candy said according to CNN. The ship was in San Francisco when the illness was first reported on Monday.

Cruise officials believe the cause of the illness is the Norovirus. Norovirus is highly contagious and is spread from person to person. It causes flue-like symptoms including nausea, vomiting, diarrhea and stomach pain.

Those who are sick are isolated in their rooms while the staff has begun to intensely disinfect public surfaces. The ship has implemented sanitation procedures developed in coordination with the Centers for Disease Control and Prevention to try to slow the spread of the illness.

They have been isolated in their quarters, and the ship has implemented sanitation procedures developed in coordination with the Centers for Disease Control and Prevention to slow the disease's spread.

The Crown Princess, which can carry more than 3,000 passengers, is on a seven-day California  cruise. It left from Los Angeles on Saturday and is set to return to Los Angeles.

Norovirus is common on cruise ships. In February, 114 passengers and 10 crew members came down with the illness on Holland America's ms Veendam during a week long cruise. The month before that, there was an even bigger outbreak when more than 600 people of cruise ships in the Caribbean became ill.