2024 was the worst year for gastrointestinal illness outbreaks on cruise ships in over a decade, according to newly released data from the Centers for Disease Control and Prevention. The majority of these outbreaks were a result of the highly contagious norovirus, the data said, which is spread through direct contact with an infected person, touching contaminated surfaces, or consuming contaminated food or drinks. Norovirus symptoms include sudden vomiting and diarrhea, as well as nausea, stomach pain, body aches, headache and fever.RELATED STORY | CDC data shows surge in norovirus cases in parts of the USIn December alone there were five notable outbreaks on cruise ships believed to be caused by norovirus, according to the CDC. The ships belonged to a variety of cruise lines. This season has seen an increase in norovirus cases on land as well, the CDC said.