I have only seen one mention of sickness of a Disney cruise on this board, it was the flu. Any other issues of the flu or stomach ailments?
Any time you put hundreds (or thousands) of people together in 1 space there is great likelihood someone in that crowd has a "bug" of some sort. Whether it's a simple cold, a GI issue, or the flu. It happens. DCL does a terrific job at trying to reduce the spread of germs by handing out hand wipes at every restaurant. If there is a bad case of illness (I'm not sure the exact definition that's used, but it has to be a % of the cruising population) - they will man and serve at all buffets and drink stations to further reduce spread of germs.
Generally speaking, you aren't really any more likely to get sick on a cruise than if you go to work, school, the grocery store, etc.
We've cruised three times for a total of sixteen nights and never gotten sick.
Like others here have mentioned- if you go to the store, go to school, go to work, go ANYWHERE...you are exposed to several viral things every time. I have been reading that Disney does a wonderful job at keeping wipes available and washing/cleaning the surfaces continously.
Kids are exposed to TONS of things at school every day! And, at least we know (or HOPE) that sick people aren't boardig the ship- at least they are SUPPOSED to be symptom free. Kids get sent to school, people go to work, people go shopping when they are sicker than ever!!! Plus, if someone is sick or catchy with something, they are supposed to stay in their room!!!
So, lets hope that people follow the rules and not board the ship if they aren't supposed to!