SAN DIEGO — Federal health officials say 106 passengers and six crewmembers aboard the Celebrity Infinity cruise ship were sickened by the gastrointestinal illness norovirus.

The Centers for Disease Control and Prevention says an environmental health officer and an epidemiologist boarded the ship Monday after it arrived in San Diego.

The CDC says the highly contagious virus can be acquired from an infected person, contaminated food or water, or by touching contaminated surfaces.

The CDC says staff on the Infinity stepped up cleaning and disinfection in response to the outbreak.

Symptoms of norovirus include vomiting, diarrhea, fever and body aches. According to the CDC, most people recover within three days.

The Infinity was on a 15-night cruise.