More than 125 passengers and crew members aboard a Princess Cruises ship have been sickened by a norovirus outbreak, according to reports from multiple outlets. Norovirus, commonly known as the stomach flu, spreads rapidly in enclosed environments such as cruise ships and can cause vomiting, diarrhea, and stomach cramping.

The outbreak is among the more significant cruise ship illness events reported this year. Health authorities typically track such incidents through the Centers for Disease Control and Prevention's Vessel Sanitation Program, which monitors gastrointestinal illness outbreaks on ships sailing to U.S. ports.

Princess Cruises has not publicly disclosed the name of the specific vessel involved or the full extent of measures being taken to contain the spread. Cruise lines are generally required to report outbreaks when illness rates exceed two percent of passengers or crew to trigger federal oversight protocols.

Norovirus is the leading cause of acute gastroenteritis in the United States and is known for its resilience on surfaces and rapid person-to-person transmission, making cruise ships a particularly vulnerable setting. Enhanced cleaning procedures and isolation of ill passengers are among the standard containment measures employed by cruise operators.

The outbreak comes during the busy summer travel season, when cruise ship passenger volumes are at their peak. Public health officials generally advise travelers to practice frequent handwashing and to report symptoms promptly to ship medical staff to help limit the spread of illness.