Forget the
I got the swine flu comment today, as well! I get some pleasure out of watching people on the bus or in classes try to inconspicuously lean away from me. If they're considerate enough to ask, I'm happy to talk about CF. They're usually more curious than freaked out.
On a different note, a girl (to whom I've already explained CF) showed up to a lecture today, sat down next to me, and proclaimed that she has contagious pneumonia. Having had the CF conversation allowed me to move away from her without hurting her feelings. At first I was concerned about being inconsiderate, but I also thought it was pretty inconsiderate of her to come to class when she knew she had a contagious illness!