Norovirus causes an inflammation of the stomach or intestines called acute gastroenteritis, according to the CDC. The virus is “very contagious,” and symptoms include vomiting, diarrhea, stomach pain, fever, headache and others.

Last year, there were 16 outbreaks on cruise ships, from norovirus, salmonella, E. coli or other unidentified pathogens that cause gastrointestinal symptoms such as diarrhea or vomiting. That's the largest number of cruise ship outbreaks in 12 years.

The Centers for Disease Control and Prevention says reported illnesses on cruise ships have hit a 12-year high.

Illnesses on cruise ships have hit a 12-year high. New data from the Centers for Disease Control and Prevention show there were outbreaks on 16 different cruise ships in 2024. The majority of the illnesses were norovirus cases.