Norovirus sickened 102 passengers and 13 crewmembers aboard the Caribbean Princess as the ship sailed through the Caribbean on an April 28 to May 11 voyage, but passengers were still taking part in onboard activities as the cruise continued.

The Centers for Disease Control and Prevention said the outbreak was reported Thursday and that the predominant symptoms were vomiting and diarrhea. Princess Cruises said a limited number of people reported mild gastrointestinal illness during the trip from Port Everglades in Florida, and the ship was north of the Dominican Republic en route to Nassau when the illness count was reported Saturday.

Jan van Milligen, a passenger on the ship, said the disruption had not erased the mood on board. “The normal atmosphere is still here,” he said, adding, “We went to a show last night, had dinner and breakfast this morning.”

That continued routine mattered because the Caribbean Princess was carrying 3,116 passengers during the outbreak, turning what could have been an isolated illness report into a shipwide sanitation and operations problem. Princess Cruises said it quickly disinfected every area of the ship and added extra sanitizing throughout the voyage, while the CDC said sick passengers and crewmembers were isolated and stool samples were collected for testing.

The buffet changed, too. Passengers were no longer allowed to serve themselves, a small but telling shift that showed how the ship was trying to limit spread while the voyage carried on. Jan van Milligen said the precautions were visible and effective, saying, “The cruise line made all precautions to stop the spread,” and adding that “they were very professional.”

Donna Leonte, another passenger, said the ship remained orderly despite the outbreak. “We are doing well. Safety precautions are in place, but nothing deadly,” she said. “Washing stations are manned so people do not pass them up, and Purell sanitizers are everywhere.” She added, “People need to be mindful and take precautions. We are not missing any activities.”

Princess Cruises said Caribbean Princess would undergo comprehensive cleaning and disinfection upon arrival to Port Canaveral on May 11 before departing for its next voyage. With the CDC identifying norovirus as the cause, the question now is not whether the ship responded, but whether those measures were enough to keep the outbreak from following the passengers and crew ashore.