Nearly one-third of the passengers aboard a National Geographic expedition cruise off the coast of Alaska have fallen ill with a gastrointestinal infection, marking the third outbreak reported on the same vessel in just three months.
The Centers for Disease Control and Prevention confirmed Tuesday that 18 of the 62 passengers aboard the 152-foot Sea Bird had developed symptoms including vomiting and abdominal cramps.
Health officials have not yet confirmed the cause of the latest outbreak. However, norovirus was identified as the source of illnesses during the vessel’s two previous voyages.
The CDC’s Vessel Sanitation Program said it is remotely monitoring the situation and reviewing the ship’s response to the outbreak, including its cleaning and sanitation procedures.
Passengers who became sick have also been asked to provide stool or vomit samples for laboratory testing. Results were still pending.
Norovirus is a highly contagious illness that can spread quickly in enclosed environments such as cruise ships, schools and nursing homes. It commonly causes vomiting, diarrhea, stomach pain and nausea.
The Sea Bird is used for scenic expedition cruises through Alaska, where passengers travel through remote coastal areas while viewing wildlife and natural landmarks.
The latest outbreak comes as health officials are also tracking a separate surge of cyclosporiasis cases across the United States.
That infection is caused by the Cyclospora parasite and can trigger severe or prolonged diarrhea, along with stomach cramps, nausea and fatigue. The two outbreaks have not been linked.
The cruise operator’s response to the latest illnesses was not included in the report.
