PASADENA, Texas >> A cruise ship that had more than 180 passengers and crew fall sick with an apparent stomach virus returned to a Houston-area port early due to a dense fog advisory and not because people were vomiting and had diarrhea, a Princess Cruises spokeswoman said today.

But passengers whose seven-day vacation was cut short, missing their last stop in Belize, questioned that version of events. They said the crew announced on the second day of the cruise that people were sick, apparently with highly contagious norovirus, and that extra precautions were being taken to ensure it didn’t spread.

“I was worried I might come down with the illness, but as days went by I didn’t, so I felt more comfortable,” said Doris Hajewski, 66, of Waukesha, Wis., a suburb of Milwaukee.

“Really, if you didn’t get sick, you didn’t notice much, just the extra hand sanitizers and the extra precautions at the buffet,” she added, explaining that crew served at the buffet instead of passengers being allowed to handle the food themselves.

It was on Tuesday, when the crew announced the ship would return a day early due to a sea fog advisory that could close the Pasadena port that passengers began questioning the validity of the information, Hajewski said.

“People were unhappy with that and the sentiment on the ship became more that it wasn’t because of the possible fog,” she said.

A Royal Caribbean cruise returned early to New Jersey on Wednesday after nearly 700 people became ill with the same suspected gastrointestinal illness.

But Princess Cruises spokeswoman Julie Benson said the situation aboard the Caribbean Princess was not the same.

“If we did not have the potential of the closure of the port because of fog we would not have come in early,” Benson said.

The National Weather Advisory says it issued a warning about sea fog from Friday through Sunday. The Port of Houston says pilots halt all docking activity if fog is too dense.

The Caribbean Princess departed Jan. 25 for the Caribbean with more than 4,200 people on board. It returned Thursday night instead of Saturday. Cruise liners are required to report to the Centers for Disease Control and Prevention if more than 3 percent of the passengers on board the ship become sick.

According to the CDC website, there are about a dozen cases annually where so many people become ill on a cruise, the vast majority with norovirus. This year there have already been three reported cases, including on the Caribbean Princess, and at least two appear to be due to that stomach virus. Cruise Lines International Association reports that more than 20 million people took cruises in 2012.

Officials with the CDC boarded the Caribbean Princess early today and are overseeing sanitation of the vessel before it departs for its next journey on Saturday, she added. Crew will clean all surfaces of the ship — from elevator buttons to railings — with a special liquid disinfectant.

“To have people come on board when they are ill is, unfortunately, not a rare occurrence,” Benson said. She said crew members confirmed the virus in a lab on board the ship and closely monitored everyone who reported to the infirmary, especially with gastrointestinal problems.

Jay Herring, a senior officer for Carnival Cruise Lines from 2002 to 2004, said norovirus spreads easily on a cruise ship where thousands of people travel together in a confined space.

“One time we had three consecutive cruises that had norovirus and it wasn’t until we got serious about disinfecting that we got rid of it,” said Herring, also the author of “The Truth About Cruise Ships.”

“Every casino chip, every elevator button, every hand rail was disinfected,” he added.

Herring doesn’t believe having just over 3 percent of the passengers and crew ill was enough to cut short the voyage. But he doesn’t recall fog ever ending a voyage when he worked for Carnival Cruises.

“I think the norovirus and the fog combined together is what ended this cruise early. I think the norovirus played a role,” Herring said.

By and large, Hajewski said that for those who didn’t become sick the cruise was fairly normal. She said she and her traveling companion were not infected. The pools remained open, the food was good and, at first, the weather was pleasant. Unlike the reports from the Royal Caribbean cruise that people were vomiting in bags, buckets and even on the floor, she said she didn’t see anyone get sick.

She said the crew handled the situation professionally and were strict about quarantining ill passengers.

“It’s just a disappointment to miss a port,” said Hajewski.

“When you travel, there are no guarantees that everything will go as planned no matter where you travel, whether it’s a cruise, whether it’s land travel, you’re always taking a risk,” she said.