(NewsNation) — A norovirus outbreak has sickened over 70 people aboard a 13-day Royal Caribbean Cruise, the Centers for Disease Control and Prevention reported.

Royal Caribbean’s Serenade of the Seas departed from San Diego on Sept. 19 and is scheduled to arrive in Miami on Thursday, Oct. 2.

71 out of 1,874 passengers and one out of 883 crew members have “reported being ill during the voyage.” The predominant symptoms include diarrhea and vomiting.

In response to the outbreak, Royal Caribbean has increased cleaning and disinfecting procedures, collected stool specimens for testing, isolated sick passengers and crew and consulted with the CDC’s Vessel Sanitation Program (VSP) about cleaning procedures and reporting cases.

19 gastrointestinal outbreaks on cruise ships in VSP’s jurisdiction in 2025

So far in 2025, there have been 19 gastrointestinal outbreaks on cruises within the Vessel Sanitation Program’s jurisdiction.

Of those 19 cases, 14 have been caused by norovirus.

According to the VSP, an outbreak is defined as when a ship “has 3% or more of passengers or crew reporting symptoms of GI illness to the ship’s medical staff.” In such cases, cruise lines are required to report these incidents.

What is norovirus?

According to the CDC, norovirus is a highly contagious virus that can cause diarrhea, vomiting, nausea and stomach pain with symptoms typically developing 12 to 48 hours after exposure.

The virus is usually spread through contact with infected individuals or contaminated surfaces, food or water.