A gastrointestinal outbreak aboard a Royal Caribbean cruise sickened more than 140 people earlier this month, according to a report from the Centers for Disease Control and Prevention’s Vessel Sanitation Program.
The illnesses were reported among both passengers and crew members on a voyage of the Navigator of the Seas, which had departed Los Angeles for a round-trip cruise to ports in Mexico on July 4, according to the report.
The report indicated that 134 of the 3,914 passengers and seven of 1,266 crew members experienced symptoms such as diarrhea, vomiting, and abdominal cramps at some point during the cruise.
The full details of the outbreak were reported to the CDC’s Vessel Sanitation Program (VSP) on July 11, the same day the ship returned from its voyage.
The “causative agent” of the outbreak is currently listed as “unknown,” but CDC’s report said norovirus — which is actually a term for a group of very contagious viruses, according to the Cleveland Clinic — “is often a cause of gastrointestinal illness outbreaks on cruise ships.”
In response to the outbreak, Royal Caribbean International implemented increased cleaning and disinfection procedures, collected stool specimens for testing, and isolated affected passengers and crew members.
VSP “remotely” monitored the crew’s response to the outbreak, according to the report.
“The health and safety of our guests, crew, and the communities we visit are our top priority,” a spokesperson for Royal Caribbean Group wrote in an emailed statement shared with Nexstar. “To maintain an environment that supports the highest levels of health and safety onboard our ships, we implement rigorous cleaning procedures, many of which far exceed public health guidelines.”
There have been 18 outbreaks of illness aboard cruise ships within the VSP’s jurisdiction in 2025, the majority of which were caused by norovirus. Despite being a common cause for illness among passengers, cruise ships are relatively rare settings for such outbreaks, accounting for 1% of the reported outbreaks in the U.S., the CDC says.
Long-term health facilities and hospitals, meanwhile, are a more common setting for norovirus outbreaks, as are restaurants, catered events, schools and childcare facilities.