The Associated Press

ST. LOUIS -- More illnesses aboard a riverboat have forced cancellation of a third trip before it began.

About two dozen passengers on the Mississippi Queen became ill late last week on a seven-day cruise from St. Louis to St. Paul, Minn. The outbreak was similar to illnesses on the same boat that caused the company to disembark nearly 500 passengers in Cape Girardeau on Oct. 23.

Crew members had replaced pillows, scrubbed the riverboat down with bleach, put bottles of hand sanitizer everywhere. The company hired five nurses to accompany the cruise.

But on Friday, two days into the trip, ambulances greeted sickened passengers when the riverboat docked at Hannibal, about 100 miles north of St. Louis. A day later, the Delta Queen Steamboat Co. bused more than 400 passengers back to St. Louis and made train and flight arrangements for their return home.

The gastrointestinal virus usually lasts a day or two, with symptoms that often include vomiting and diarrhea. It is highly contagious and spreads rapidly on cruise ships and in nursing homes.

A cruise scheduled to leave today from St. Paul to St. Louis on the same boat was called off. The Seattle-based steamboat company is continuing to work with health officials and hopes to have the issue under control to proceed with a round-trip cruise from St. Louis set to depart Nov. 8, said company spokeswoman April Matson.

Matson said officials from the Centers for Disease Control and Prevention, as well as from the Food and Drug Administration, gave the company the go-ahead on its cruise last Wednesday after the previous outbreak.

"We moved ahead with what we believed was the best decision," Matson said. "You can't predict these things."

Passenger Marlyce Barker, who took the cruise with her husband to celebrate their 50th anniversary, thinks the ship should never have left St. Louis.

"This was our gift to each other, which turned out to be miserable," the California resident said.

Another passenger, June Behrens, 81, spent all day Sunday and much of Monday in bed recovering from the virus at her home in Santa Barbara, Calif. Her main complaint is that the company did not notify passengers of the outbreak before they left home.

The Mississippi Queen first ran into problems on a cruise that left Cincinnati Oct. 18 for St. Louis. More than 100 people among 528 crew members and passengers came down with a virus. Sick passengers disembarked at stops in Kentucky before the operators decided to cancel the rest of the trip at Cape Girardeau and disembark the remaining passengers. Sixteen of those passengers were suffering from flu-like symptoms, one severe enough to be taken to a local hospital for observation.

Kentucky state epidemiologist Dr. Kraig Humbaugh said samples from passengers sent to the CDC tested positive for norovirus, a group of viruses that cause stomach flu.

Matson said the boat has been taken out of service for more than a week to make sure the cycle of the bug will be broken. The boat is docked in Grafton, Ill., near St. Louis, for deep cleaning.

Passengers scheduled to leave this week will be given full refunds or credit for a future trip with an extra $250 credit, Matson said. The company is offering partial refunds or credits on a future cruise for passengers whose trips were canceled mid-voyage.