177 sickened with norovirus on the Celebrity Summit. Gastrointestinal illness outbreaks on ships are on the rise this year.

• Nearly 200 people were sickened with norovirus on the Celebrity Summit cruise ship in May.
• It was the 12th CDC-reported outbreak of a gastrointestinal illness onboard a cruise ship this year.

More than 175 people felt more than seasickness onboard a Celebrity Cruise ship last month.

Twenty-five crew members and 152 of the 2,144 passengers onboard the May 15 to May 25, 2023 voyage of the Celebrity Summit reported norovirus symptoms, according to a notice issued by the Centers for Disease Control and Prevention.

Norovirus, often called the stomach flu, can quickly spread via particles from vomit and poop, through contaminated surfaces, tainted food and water, and contact with people who have the virus.

It is also notoriously difficult to contain.

"If you get norovirus illness, you can shed billions of norovirus particles that you can't see without a microscope," according to the CDC. "It only takes a few norovirus particles to make you and other people sick."

Washing your hands is the gold standard to prevent the spread

Washing your hands with water and soap after you use the restroom or change a diaper and before you prepare food or eat is the best way to avoid spreading norovirus.

Hand sanitizer, the CDC notes, "does not work well against norovirus."

(Insider has great guides on prevention, disinfection, and treatment. Spoiler alert: There's no antiviral for norovirus. You must ride it out, isolate, and keep hydrated.)

The 'cruise ship disease'?

Norovirus is sometimes known as the "cruise ship disease" because it can spread quickly in close quarters, like a cruise ship, dorm rooms, or a nursing home.

In response, Celebrity increased cleaning and sanitation, notified guests, encouraged reporting symptoms and good hygiene, and sent stool samples to the CDC for testing, among other protocols.

It is the 12th such CDC-reported outbreak of a gastrointestinal illness on a cruise ship in 2023: five of the 12 are known to be norovirus, though the CDC notes that "acute gastrointestinal illness is relatively infrequent on cruise ships" and the rate of acute gastroenteritis decreased between 2006 and 2019.

However, with the rebound of the cruise industry, it does look like there's been an uptick in GI illness on ships compared to 2019 — before the cruise industry was briefly shut down due to COVID-19 — when there were 10 outbreaks reported for the entire year versus 12 reported outbreaks in the first five months 0f 2023.

Celebrity did not immediately respond to Insider's request for comment.