Nearly 20 guests sick in cruise ship's third GI outbreak in two months

Nearly 20 people got sick with gastrointestinal illness on a National Geographic-Lindblad Expeditions ship, the vessel’s third outbreak in less than two months.

Among the 62 guests onboard, 18 reported being ill during the National Geographic Sea Bird’s July 10 voyage, according to the Centers for Disease Control and Prevention. Their main symptoms were abdominal cramps and vomiting.

The cause is unknown. The ship is operating in Alaska, according to CruiseMapper.

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The cruise company implemented heightened cleaning and disinfection measures and isolated sick passengers, among other steps, the health agency said on its website. National Geographic-Lindblad Expeditions did not immediately respond to a request for comment.

The news comes after two other outbreaks on the same ship during cruises in June and May. Both were caused by norovirus.

The CDC told USA TODAY in an email that norovirus is behind more than 90% of cruise gastrointestinal illness outbreaks with a confirmed cause.

"People joining the cruise ship may bring the virus to other passengers and crew," the agency said. "Characteristics of norovirus that facilitate outbreaks include a low infective dose, easy person-to-person transmissibility, prolonged viral shedding, absence of long-term immunity, the ability of the virus to survive routine cleaning procedures, and the absence of a vaccine."

The CDC has logged eight outbreaks of gastrointestinal illness on cruises that met its threshold for public notification this year. Two were caused by E. coli, and norovirus was listed as the cause of five.

Twenty-three outbreaks that met that threshold in 2025, 18 of which were caused by norovirus. Norovirus also was behind 15 out of 18 outbreaks the year before. The illness is often associated with cruise ships, but those instances account for only 1% of all reported outbreaks.

Outbreaks are "often taking place within the community, and oftentimes we don't know that they're happening," Sarah R. Michaels, an assistant professor at Tulane University’s Celia Scott Weatherhead School of Public Health and Tropical Medicine, told USA TODAY. "Really, when we have these areas where people … are in really close contact, things like day care facilities, nursing homes and cruise ships, it’s more likely (to be) diagnosed, reported and brought to our attention."

This story was updated to add new information.

Nathan Diller is a consumer travel reporter for USA TODAY based in Nashville. You can reach him at [email protected].

This article originally appeared on USA TODAY: Nearly 20 guests sick in cruise ship's third GI outbreak in two months