(12:05 p.m. EST) -- Celebrity Cruises says a massive outbreak of gastrointestinal illness on Celebrity Mercury has left 419 of the ship's 1,838 passengers -- or almost 23 percent -- ill.
Celebrity Mercury is in the midst of an 11-night Caribbean cruise that departed from Charleston on February 15. The ship is due to arrive back in Charleston this Friday.
According to a statement from the line, sick passengers "are responding well to over-the-counter medication being administered onboard the ship." Symptoms of gastrointestinal illness typically include vomiting and diarrhea.
To better assist the medical team already onboard, an additional doctor and two nurses joined the ship yesterday in Tortola; the hired help will stay onboard for the remainder of the cruise.
Celebrity spokesperson Cynthia Martinez tells us that passengers who were quarantined -- standard protocol when dealing with gastro outbreaks -- will be compensated for each day spent in isolation. Compensation is given in the form of an "future cruise certificate," based on the number of days a passenger is isolated divided by the total cruise fare paid.
Martinez adds that the outbreak isn't expected to have an impact on the next cruise, which is scheduled to depart from Charleston on Friday.
The CDC investigates whenever more than 2 percent of people on a particular ship fall ill, to determine if Norovirus is at play.
--by Dan Askin, Associate Editor