I'm also onboard, and I think there is a bit of misinformation in this thread.
Yes, there is a persistent outbreak of noro onboard.
I don't think it's anywhere near 500 (e.g., 20% of passengers). I think reporting is mandatory at a much lower level of outbreak.
The restaurants are still full.
The Captain last night recommended that people take all of their meals in the full-service restaurants rather than the buffet, but the buffet remains open as of this morning.
We've been kept informed daily of the persistent cases, although there has been no official word on the number of cases (just that "cases have been continuing to be reported"). Again, it's nowhere near 500 to my observation.
We ate lunch with some passengers who had made the crossing and they said that after the normal 3-day period at the start of the voyage when things are more restrictive it was more relaxed than there was no apparent outbreak on the crossing.
In my opinion this is not really unusual in a winter cruise, especially considering the current European outbreak. You bring a lot of people together from around the world and confine them for a few days at sea and there is bound to be some exchange of sickness. The crew has justifiably been reacting to this but I think the quickness and extent of their reaction suggests a more widespread outbreak than is the case.
If I were to guess I'd say the extent is 75 people, or about 3%. Just a guess based on the number of cleaners I've seen in the passageways outside of staterooms.
Carnival Pride (Bahamas) - October 2013
Queen Mary 2 (Caribbean Holiday) - December 2012
Caribbean Princess (Scandinavia) - July 2012
Queen Victoria (Hawaii) - February 2012
Queen Mary 2 (Eastbound Transatlantic Crossing) - October 2011
Queen Victoria (Panama Canal Transit) - March 2011
Queen Mary 2 (New England/Canada) - September 2010