ABC’s Good Morning America (GMA) discusses Celebrity Cruises’ sick cruise ship, the Mercury, in this morning’s program. 

The Mercury has been hit with three continuous outbreaks of sickness which has plagued hundreds of passengers.  We have covered the outbreaks in prior articles

GMA begins its show by describing the Mercury as the "cruise ship which just can’t seem to be cleaned."

The video contains the caption – "Sickest Ship at Sea – Can Cruise Ship Be Cured?" and explains how norovirus can thrive on cruise ships.

In the GMA video, one passenger asks: "Why do you keep on letting people on this ship when people continuously get sick?"

ABC interviewed its senior health and medical editor Dr. Richard Besser to explain noro virus and how passengers are infected on cruise ships: 

"The norovirus is highly contagious and its symptoms include nausea, vomiting, diarrhea, cramps and chills, Besser said.

The illness typically lasts 12 to 72 hours and usually occurs in places where people are in close quarters, such as schools, hospitals, nursing homes and cruise ships, according to Besser. It is the leading cause of foodborne outbreaks of diarrheal disease, accounting for more than 50 percent of these outbreaks

It spreads through food, water, contaminated surfaces and person-to-person contact, Besser said. He added that the reason it could be so hard to get rid of on a cruise ship is because people can also bring it on board and it can live on surfaces for more than a week.

Cruise ships often visit places that have poor sanitation, so passengers can easily catch it from a restaurant they visited at a port, Besser explained.

Additionally, the infection dose of norovirus is very low, Besser said. It takes only 10 particles of the virus to make you stick, as opposed to the 100,000 particles of salmonella you would have to be exposed to in order to get sick."

The Mercury returns to Charleston tomorrow.  The CDC issued a "no sail" advisory for the sick ship.  It will undergo another round of "enhanced cleaning" – as the cruise line calls it.