A slew of recent norovirus outbreaks on passenger cruises, including two on the same ship, have prompted the Centers for Disease and Control and Prevention to investigate, according to a report by CNN.

Several passengers aboard Royal Caribbean’s Grandeur of the Seas began experiencing symptoms of the disease, which causes vomiting and diarrhea. About 105 of the approximately 3000 passengers and crewmembers onboard were said to be impacted during the ship’s April 5 – 12 cruise.

The week before, another breakout of the disease afflicted 117 passengers and crew members, the CDC said in a news release. The ship docked in Baltimore to allow to health officers and an epidemiologist to board and conduct and initiate and investigation.

Another 152 people were affected by an outbreak aboard Princess Cruises' Crown Princess that ended Saturday in Los Angeles affected. A CDC health officer will evaluate the situation on that ship.

Read the full report here.