Almost 200 passengers on Royal Caribbean’s Ovation of the Seas cruise ship have been sickened with what officials believe is norovirus, according to the line and news reports. That ship can carry almost 6,000 people.
The liner left Singapore on November 23, 2017. The outbreak began soon after.
Cruise ships, just like other places where many gather in a relatively confined space, are notorious for norovirus outbreaks. The Centers for Disease Control and Prevention (CDC) posts outbreak updates for international cruise ships that sail from a foreign port to a U.S. port. The ships which participate in the Vessel Sanitation Program report the number of gastrointestinal illnesses, including zero, which have been evaluated by medical staff at least 24 hours before the ship arrives at port.
The Vessel Sanitation Program also requires the ships to send a separate notification when the GI illness count is more than 2% of the total number of passengers or crew onboard. In this outbreak on Ovation of the Seas, almost 3% of the passengers are sick.
In 2017, there have been ten outbreaks on cruise ships. The illnesses ranged from Clostridium perfringens to norovirus to an unknown pathogen or toxin.
In 2016, there were 13 outbreaks on these ships. The causative agent in those illnesses were norovirus, Enterotoxigenic E. coli, and “unknown.”
The Ovation of the Seas will be sanitized and cleaned when it docks on Sydney today before the next group of passengers board. Cruise ships usually have their own medical teams onboard and are familiar with outbreak control measures.
The symptoms of a norovirus illness include severe vomiting and diarrhea, along with cramps, muscle pain, and a low grade fever. Symptoms usually appear quickly, within 12 to 48 hours after exposure, and leave just as quickly. Most people get sick through contaminated food or drink, but the illness can also be spread person-to-person.
Other places that often experience norovirus outbreaks include hospitals, child care centers, nursing homes, and schools. The number of norovirus outbreaks tend to increase in the winter when more people are indoors.