The CDC (Centers for Disease Control and Prevention) reported that the noro-infected travelers comprised 3.63% of the total number of passengers on the Princess Cruises' ship. 6 crew members (out of 881) were also infected.
The CDC determined the gastrointestinal outbreak was norovirus but was unable to conclude where it came from: shipsick galley worker, contaminated cruise ship water or food, or brought aboard by sick guests and then spread because of poor cleaning procedures or inadequate hygiene.
Time magazine titled last year "The 13 Worst Norovirus Outbreaks on Cruise Ships" and the overall winner of top 13 list was Princess Cruises whith 5 outbreaks on its brand: Coral Princess (Feb 2009, 271 ill); Crown Princess (Jan 2010, 396 ill); Crown Princess (Feb 2012, 363 ill); Sun Princess (Jul 2012, 216 ill) and Ruby Princess (Mar 2013, 276 ill).
Coral Princess has been one of Princess Cruises' vessels most likely to be infected. Princess and Holland America historically have the sickest ships in cruise industry.