Daybreak's Health Editor, Dr Hilary Jones, has told viewers how to stop the spread of the winter vomiting bug, the norovirus.
Health measures have been put in place on the cruise ship Oriana to prevent the spread of norovirus.
Suffering passengers have been asked to isolate themselves in their rooms and not leave the boat for day trips.
A spokeswoman for P&O Cruises said that six people on board have active symptoms today, but she was not able to confirm how many people have been affected in total.
Any medical charges incurred as a direct result of the outbreak will be covered by the company, the spokeswoman confirmed.
The Health Protection Agency (HPA) has warned that for every confirmed case of the stomach bug, there are likely to be a further 288 unreported sufferers.
There have been 2,630 confirmed cases so far this season, meaning that the real number could be 757,440.
A spokesperson for the HPA said: "Laboratory confirmed reports represent only a small proportion of the actual amount of norovirus activity in the community, because the vast majority of affected people do not access health care services as a result of their illness."
VIDEO: Over 150 passengers on the Oriana are reported to have been struck down by a vomiting bug. The P and O cruise ship is due to dock in Southampton on Friday. Fred and Stacey link to Mel Bloor.