More than 140 passengers and crew aboard Navigator of the Seas, operated by Royal Caribbean International, have fallen ill with a gastrointestinal illness during a seven-night cruise, according to the US Centers for Disease Control and Prevention (CDC). The outbreak affected 134 passengers and 7 crew members, the CDC’s Vessel Sanitation Program confirmed on Wednesday.

The voyage, which departed from Los Angeles to the Mexican Riviera, hosted 3,914 guests and 1,266 crew members aboard the 139,999 gross-ton ship. The outbreak occurred during the sailing that began on July 11.

Norovirus suspected

While the exact cause of the illness has yet to be officially confirmed by the CDC, it is suspected to be norovirus, a highly contagious virus known to spread through contaminated food, water, or surfaces. Common symptoms include vomiting, diarrhoea, and abdominal cramps.

To control the spread, Royal Caribbean implemented enhanced cleaning protocols, isolated affected individuals, and collected stool samples for laboratory testing.

“The health and safety of our guests, crew, and the communities we visit are our top priority,” a Royal Caribbean spokesperson told USA TODAY. “We implement rigorous cleaning procedures, many of which far exceed public health guidelines.”

This marks the second gastrointestinal outbreak aboard a Royal Caribbean ship this year. Earlier, in February, Radiance of the Seas experienced a norovirus outbreak that sickened 160 passengers and 8 crew members. That voyage, which sailed from Tampa, Florida to the Western Caribbean, had to delay its next embarkation for extensive sanitation.

Second incident in a year

Another notable incident this year involved Sea Cloud Cruises, though the illness in that case was presumed to be caused by ciguatera, not norovirus.

The CDC publicly reports cruise outbreaks when certain thresholds are met that the voyage must be under the jurisdiction of the Vessel Sanitation Program (VSP), and at least 3% of passengers or crew must report gastrointestinal symptoms.

For Navigator of the Seas, 3.4% of passengers and 0.6% of crew reported symptoms during the affected sailing surpassing the CDC’s reporting threshold.