The AIDAdiva, operated by Aida Cruises, reported that 95 passengers out of 2,007 onboard and 6 crew members out of 640 became sick during the voyage running from Nov. 10 through Dec. 16.
That means roughly 5 percent of the ship's passengers got sick. The illness was reported to the CDC's Vessel Sanitation Program on Nov. 30.
Passengers and crew experienced the typical symptoms of norovirus infection—diarrhea and vomiting. The CDC notes that reported cases represent the total number of people who became sick during an entire voyage and do not indicate that all affected individuals were ill at the same time.
In response, Aida Cruises increased cleaning and disinfection procedures following their outbreak prevention and response plan. Crew members collected stool specimens from gastrointestinal illness cases for testing and isolated the sick passengers and crew.
The cruise industry has been rocked by multiple norovirus cases in recent months, raising concerns about the spread of illness in environments where thousands of people live in close quarters.
Earlier in the year, Royal Caribbean's Serenade of the Seas faced its own outbreak in late September during a 13-day voyage from San Diego. The ship reported 94 sick passengers out of 1,874 total and four ill crew members out of 883 staff as of early October. The outbreak was reported to the Vessel Sanitation Program on Sept. 28, nine days after the ship departed. The ship eventually docked in Miami following the outbreak.
Norovirus, commonly called the stomach flu or stomach bug, spreads easily through contaminated food, water, or surfaces, or through person-to-person contact. Most of those who become infected recover within one to three days, though they can continue spreading the virus for several days after feeling better.
When someone becomes ill on a cruise ship, the medical center evaluates whether their symptoms fit the CDC's definition for acute gastroenteritis. According to the CDC, the definition includes three or more loose stools within a 24-hour period or more than normal for that person, or vomiting along with diarrhea, muscle ache, headache, abdominal cramps, or fever.
Cruise ships are required to report these cases to the CDC.
"When passengers and crew tell the medical center onboard about their symptoms, it helps GI illness outbreaks get detected quickly. This allows steps to be taken to limit the spread of illness,” the CDC said.
Health officials recommend frequent handwashing and avoiding public areas when feeling sick. For those planning a cruise, practicing these simple precautions can help reduce the risk of becoming infected or spreading illness to others.