1. Royal Caribbean Cruise LineExplorer of the Seas
Current number sick (including both passengers and crew members): 626
The ship is currently on its way to dock in New Jersey. CDC members are on board to monitor the cases and advise the cruise line on its response. The CEO of Royal Caribbean Cruises Ltd. told NBC News that the company screens its passengers for visible signs of illness as best they can and that their personnel has reacted as quickly as possible to the problem.

2. Celebrity CruisesMercury (February 2010)
Total number sick: 443
“I never had anything like this,” Kenneth Thompson a 71-year-old from Concord, S.C. told NBC News about his vomiting symptoms on the cruise. “It just came out of me in streams, just gushes of it.”

3. Celebrity CruisesMercury (March 2010)
Total number sick: 419
A second Celebrity Cruise ship is harbors norovirus, one month later, raising concerns about the line’s sanitation practices.

4. Princess CruisesCrown Princess (January 2010)
Total number sick: 396
In 2010, there were 14 outbreaks of illnesses on ships , including this one. Eight were attributed to norovirus.

5. Princess CruisesCrown Princess (February 2012)
Total number sick: 363
The cruise, which embarked just a month after another outbreak on the ship, returned to Ft. Lauderdale two days early as passengers started falling ill.

6. Celebrity Cruise LinesCelebrity Summit (September 2013)
Total number sick: 335
Many of the infected experienced severe stomach pains along with vomiting and diarrhea and were confined to their cabins to prevent spread of the virus.  In 2013, the CDC reports that there were nine cases of widespread illness on cruises, and seven were caused by norovirus.

7. Fred Olsen Cruise LinesBalmoral (January 2010)
Total number sick: 310
The world cruise started in Dover, England and after visiting several countries, was supposed to finish the trip in Los Angeles, California. Fifteen days before reaching L.A., the first of the 293 passengers and 17 crew who were infected started getting sick.

8. Princess CruisesRuby Princess (March 2013)
Total number sick: 276
The cruise returned from what was a week long trip in the Eastern Caribbean to Fort Lauderdale, Fla. New passengers scheduled on the next cruise were not allowed on the ship until the CDC finished a required sanitation assessment.

9. Princess CruisesCoral Princess (February 2009)
Number sick: 271
This cruise also had the distinction of sickening passengers with E. coli as well as norovirus.

10. Carnival Cruise LineCarnival Liberty (April 2009)
Total number sick: 265
The ship was cleaned and disinfected when it pulled into Miami, causing a delay for the next set of passengers.

11. Royal Caribbean Cruise LineVoyager of the Seas (January 2012)
Total number sick: 259
Several sick tourists were quarantined while the ship was delayed at various ports to sanitize.

12. Cunard LineQueen Mary 2 (December 2012)
Total number sick: 220
All the tables and seating on this trip had to be sanitized and disinfected before the crew served the buffet meals, and crew members reported any cases of gastrointestinal illness to the CDC twice a day.

13. Princess CruisesSun Princess (July 2012)
Total number sick: 216
As with the other major outbreaks, two CDC VSP members boarded the ship to conduct health assessments and gauge how the situation was being contained. Many passengers on the ship provided stool samples for testing, which helped to verify norovirus as the cause.

Read more: New norovirus outbreak on cruise ship sickens 600 | TIME.com http://healthland.time.com/2014/01/27/cruise-out-of-control-the-13-worst-norovirus-outbreaks-on-cruise-ships/#ixzz2sQWcXDA6