6.6% of Cruise Ship Passengers Confirmed Sick

The U.S. Centers for Disease Control and Prevention (CDC) today announced details of a gastrointestinal illness (GI) outbreak on the Silversea Cruises ship Silver Ray.

On January 16, 2025, the CDC reported that 38 guests and five crew members were ill among the 681 people onboard Voyage RA250104016. 

This data represents 6.6% of all people onboard the Silver Ray.

The main symptoms of the patients were diarrhea and abdominal cramps. The CDC reported that the causative agent remains unknown.

This incident is the second GI outbreak aboard a cruise ship in 2025.

Last year, the CDC confirmed 18 outbreaks aboard cruise ships, with norovirus as the primary disease agent.

'Norovirus is often a cause of GI outbreaks on cruise ships, but we don't always know the cause of the outbreak when investigations begin, writes the CDC.

A study published in January 2025 identified cruise ship dining areas as priorities for preventing disease outbreaks. However, the probability of airborne infection in a speaking normal condition is low (<3 %).

As of January 2025, norovirus vaccine candidates are conducting clinical research, but none have been U.S. FDA-approved.

For a potential treatment, Travelan®, an orally administered passive immunotherapy, prophylactically reduces the likelihood of contracting travelers' diarrhea. In the U.S., Travelan is sold as a dietary supplement for digestive tract protection.

Note: This article was updated on Jan. 17, 2025, to include a reference link.