James, if your husband has U.C., it cannot be 'caught.' And it's a good question you're asking because it sounds as though the doctor didn't do a heck of a lot of 'teaching' or informing you about what your husband has. U.C. is a form of inflammatory bowel disease (IBD) and it's categorized as an autoimmune problem. Evidently your husband's immune system has gone a bit 'whacky' and it's unfortunately attacking his own tissues.
If you want to learn more about this condition, ask all the questions you want. There is also some extemely good information about the subject on a number of websites including the Crohn's and Colitis Foundation of America's site, ccfa.
There is no such thing as a dumb question. The only question that is dumb is the one that is in a person's head that is left unasked. This person is asking the question because they evidently don't know what causes U.C. You'd do a much better job of helping others to learn if you could manage to tamp down your sarcasm and spend the same amount of time imparting good information. For everyone person that learns a single fact, they can pass along that information to others and knowledge can spread.
thats got to be th dumbest question ive ever heard,,,how old are you 15?