Miami ? At least a dozen passengers aboard the Carnival Liberty’s latest cruise reported a gastrointestinal illness after a four-day Caribbean voyage, according to one of the passengers.

Carnival spokesman Vance Gulliksen said he didn’t know how many passengers got sick, but that it was fewer than 2 percent of the 3,100 people aboard the 13-deck, 110-ton cruise liner, one of the world’s largest. The number of illnesses was within the “normal range,” for a vessel of that size, he said.

“We don’t know whether it’s sea sickness or people are overindulging with food,” Gulliksen said.

On the Liberty’s previous voyage, close to 700 people fell ill from the highly contagious norovirus, a stomach bug. The outbreak, during the 16-day transatlantic trip that left Rome on Nov. 3, was one of the largest in recent memory, according to the Centers for Disease Control and Prevention, which is investigating the cause.