(CNN) -- The Celebrity Mercury cruise ship is returning to port a day early and delaying its next sailing to address an outbreak of gastrointestinal illness that sickened 350 passengers. The outbreak is the third consecutive outbreak on the ship in a month.

"I have made this decision to end the current sailing early and delay the next sailing because we want to maintain our high health standards onboard our ships, while providing our guests with the best cruise experience possible," Daniel Hanrahan, president and CEO of Celebrity Cruises, said in a statement.

"The extra time we are taking to sanitize the ship will help prevent any additional guests from becoming ill," he said. The cleaning will delay Mercury's next sailing by two days.

The Centers for Disease Control and Prevention made a no-sail recommendation for the ship on Monday to investigate the recurring outbreaks.

"The CDC and the cruise line corporate staff have not yet determined why the controls that they were following have not been effective," said CDC spokesman Ricardo Beato.

The CDC's no-sail recommendation was for four full days. Celebrity Cruises spokeswoman Cynthia Martinez said the cruise line worked with the CDC on a sanitation plan "that was agreeable to both parties."

Working closely with the CDC, cruise staff is performing enhanced cleaning on board the Mercury to help prevent the spread of illness. The ship is scheduled to arrive Thursday morning in Charleston, South Carolina, where it will receive an extensive sanitation before sailing again, Celebrity Cruises said in a statement. The cruise terminal also will be sanitized.

Members of the CDC's Vessel Sanitation Program, which works with the cruise industry to prevent and control gastrointestinal illnesses, are on the ship looking for causes of the latest wave of illness. About 350 of the 1,829 passengers on board have been ill, according to Martinez.

Norovirus, which causes vomiting and diarrhea, was identified as the source of the first two outbreaks, according to Beato.

VSP personnel inspected the ship after the first outbreak in February, which sickened more than 20 percent of passengers, and made recommendations to prevent further outbreaks. The ship's next sailing was delayed by a day for a full cleaning.

Despite those measures, about 10 percent of passengers on the next sailing became ill with norovirus.

About 19 percent of passengers have become ill on the latest sailing, prompting Celebrity to skip a stop Monday in Tortola, British Virgin Islands, and return a day early.

Passengers have been compensated for the interrupted itinerary, Martinez said.

"Guests currently onboard Celebrity Mercury received an onboard credit in the amount of one day of the cruise fare paid for their sailing, as well as a future cruise certificate for 25 percent of the cruise fare paid," she said in an e-mail.

Martinez said Celebrity customer service agents will be contacting passengers on the next sailing about an adjusted trip itinerary. The ship is scheduled to board on Sunday.

The latest outbreak is the ninth incidence of gastrointestinal illness reported to the VSP this year affecting more than 2 percent of passengers on a cruise ship.

A high incidence of norovirus in many parts of the world this year is likely to translate to cruise ships, according to Capt. Jaret Ames, branch chief of the VSP.

