A norovirus outbreak sickened more than 150 passengers and crew aboard a Princess cruise ship as it sailed through the Caribbean last week, the U.S. Centers for Disease Control and Prevention announced.

A total of 104 guests and 49 crew members reported symptoms of gastrointestinal illness during their voyage. There were 4,307 guests and 1,561 total crew members on board, the health agency said. The cruise company notified the CDC of the outbreak on March 11, after the ship had already spent several days at sea.

The cruise liner, called Star Princess, set out on March 7 for an eight-day voyage that was scheduled to end on March 14, according to the CDC. The tracking site CruiseMapper.com showed that the vessel departed from Fort Lauderdale, Florida, and traveled through the Caribbean, making stops in Honduras, Belize and the Mexican Riviera, before returning to its original port. When the outbreak was reported, the Star Princess would have been sailing from Belize City to Cozumel, according to that itinerary.

Those who fell ill during the norovirus outbreak predominantly experienced diarrhea and vomiting, which are among the most common symptoms of the infection colloquially known as the “stomach bug.”

In response to the outbreak, Princess Cruises and the crew of the Star Princess ship told the CDC that they followed their outbreak response plan, which calls for increased cleaning and disinfection procedures on board, the health agency said. Crew members also collected stool samples from people experiencing symptoms to undergo testing, and isolated sick passengers and crew, according to the CDC. 

The agency’s Vessel Sanitation Program, which was developed to help the cruise industry prevent and control outbreaks of gastrointestinal illnesses on ships, “is doing a field response to conduct an environmental assessment and outbreak investigation,” the CDC said.

Princess Cruises did not immediately reply to a request for comment.

Norovirus outbreaks happen relatively often on cruise ships, especially those operated by major cruise lines. In early January, the CDC reported that an outbreak on board a Holland America cruise ship had sickened more than 80 people after departing from Fort Lauderdale at the end of December.

In February, the agency said 27 people were sickened in an outbreak of an unknown gastrointestinal illness on board a luxury cruise ship, the Regent Seven Seas, which was sailing from Miami to Honolulu.