A gastrointestinal illness has broken out this week on the Radiance of the Seas cruise ship, according to the US Centers for Disease Control and Prevention.

Over 90 people contracted gastrointestinal illnesses from an unknown source on a week-long Royal Caribbean cruise, the CDC said Wednesday. Both passengers and crew aboard the Radiance of the Seas have experienced vomiting and diarrhea.

An outbreak of an unknown illness with primary symptoms of diarrhea, vomiting has stricken 89 of 2,164 passengers as well as 2 of 910 crew on board the Radiance of the Seas, according to a report on the CDC’s Vessel Sanitation Program website.