More than 230 passengers and crew members have been sickened in an outbreak of norovirus during a 29-day round-trip luxury cruise from England to the Eastern Caribbean, according to the Centers for Disease Control and Prevention.

The Queen Mary 2, the flagship ocean liner of Cunard Lines, left from Southampton, England, on March 8, according to Cruise Mapper, a tracking site. An outbreak was reported on March 18, the C.D.C. said, after the ship had stopped in New York City. Passengers and crew had reported symptoms of diarrhea and vomiting, the agency said.

The C.D.C. said the outbreak spread to 224 passengers, out of 2,538 onboard, and 17 crew members. The ship has isolated them and has taken sanitizing measures, it said.

In addition to New York, the ship had stops in St. Maarten, St. Lucia, Grenada, Barbados, Dominica, St. Kitts and Tortola. On Tuesday, the Queen Mary, or QM2 as it’s known, was traveling through the Atlantic Ocean on its way back to Southampton, where it was scheduled to arrive on April 6, Cruise Mapper shows.

Cunard said in a statement on Tuesday that the guests were being closely monitored and the ship deep cleaned. “Thanks to the swift response from our crew and the additional measures that we have in place, we are already seeing a reduction in reported cases,” the statement said.

The vessel, launched in 2004, is 1,132 feet long, one of the world’s largest ocean liners. In 2013, a Times reporter described his voyage on the QM2, which included a departure delay triggered by a “near-military-level” eradication operation after a norovirus outbreak sickened more than 200 people.

Norovirus, a gastrointestinal illness, thrives in closed areas such as health care facilities, dormitories and cruise ships, where people are traveling and working in close quarters. The illness infects up to 21 million Americans a year, according to the C.D.C. It spreads by contact or through contaminated food or water. There is no treatment, and most people recover in a few days.

Cruise ships are required to report to the C.D.C. when there is an outbreak, which refers to the total number of people sickened throughout the voyage, not the number of sick people at the same time.

The C.D.C. has reported other cases of norovirus outbreaks on cruise ships. Twelve of 461 passengers and 22 crew members of a Seabourn Encore cruise were sickened on a voyage that left Japan on March 16 and was scheduled to dock in the United States on April 9, it said.

Last month, a Holland America ship reported a norovirus outbreak affecting 89 of its 2,670 passengers and four of its crew during a nine-day cruise from Fort Lauderdale, Fla., to the southern Caribbean.