Is it wrong to "train", meaning practice martial arts, or work in a restaurant, when you have a contagious blood borne disease such as aids or hepatitis c?

To train in martial arts would mean to risk bleeding, that blood would be contagious, do I tell them? If I’m working in a restaurant, and I have aids, do I owe it too the customers, I know this sounds crazy, to let them know? I personally feel that it is wrong to do certain things when you have a contagious disease. What do you think?