The U.S. cruise ship “Caribbean Princess,” carrying thousands of passengers, was suddenly hit by a norovirus outbreak while underway.

According to the latest statistics, more than 100 passengers and 13 crew members on board have developed symptoms such as vomiting and diarrhea. Although the infection rate is not particularly high at this time, this marks the fourth reported outbreak of gastrointestinal illness on a cruise ship this year.

Why Are Cruise Ships So Prone to Outbreaks?

A cruise ship is essentially a massive “closed community.” With passengers living and dining onboard in such close quarters, it doesn’t take much for the virus to spread. If just one person brings the virus aboard, it can spread extremely quickly through contact with doorknobs, cutlery, or simply sharing a meal.

Currently, the cruise line has launched a full-scale disinfection effort in accordance with CDC (U.S. Centers for Disease Control and Prevention) guidelines. Sick passengers are being isolated in their cabins, and disinfection procedures are being carried out more frequently each day to minimize the impact.

Another cruise ship, the “Honduras,” has reported cases of Hantavirus, but this is entirely different from the current Norovirus outbreak. The former primarily causes gastrointestinal symptoms, while the latter mainly leads to respiratory infections; they belong to different viral categories.

In short, when traveling—especially in such enclosed environments—personal hygiene must be treated as the highest priority.