I have written of this before, but it is worth repeating. The secret to continued good health in this flu season is to wash your hands frequently. With soap. Do not forget to keep scrubbing your hands with soap until you have sung The ABC Song in its entirety. This helps to insure a thorough scrubbing.
Again, I have found here in México that if you are in a public restroom, it is best to sing The ABC Song silently--to yourself. Or at least sotto voce, as the Italians say. Singing it loudly has an odd effect on the other patrons in the restroom.
If you have forgotten the lyrics to The ABC Song, let me know in a comment. I will be happy to print them out for you. Or you can seek the assistance of any bright three-year-old in your area.