3B - Stomach bug -- norovirus -- on cruise ship

Here is the link to a TV news video on the norovirus on a cruise ship: http://www.youtube.com/watch?v=VLNw2oIH_fU   Can you try to understand the story?  If you read about the topic first, it will be easier to follow the video. Here is an article about the norovirus in the UK: http://news.bbc.co.uk/2/hi/7169347.stm