Norovirus on the Oriana

Tonight on the news I listened to a Director of P&O blaming passengers for the outbreak of the norovirus on their cruise ship Oriana.  It has been well documented in the mainstream media but I think that we are not being told the whole truth.
My wife and I had a wonderful cruise on the Oriana which began on 17 October and ended on 16 November.  On the third day out we learned that norovirus was on board and that people were being taken ill. I got the impression from the staff that it was not the first time.
Immediately the crew swung into action and the passengers all cooperated and although we lost some luxury items like salt cellars and other condiments the captain kept people in touch and they contained it. They put into operation an extensive cleaning plan.
Two days before the cruise ended everything went back to normal but we were surprised that they had not continued their ‘austerity’ programme until the end of the cruise.  P&O turn their ships immediately around.  As we got off they were preparing for their next cruise that day. There is no time for extra maintenance.
Therefore to maintain that the new passengers had brought that virus onto the ship only 10 days ago is rather disingenuous.  Clearly the ship has a problem as this norovirus has returned yet again.  Would it not be more realistic to look closely at the crew.
They are very professional but they are a league of nations from many different communities. They are also the only constant factor of this repeat outbreak.