At varying times I may have a head cold or something similar that I don't want to share with my cheeses. At those times, I will wear a throwaway surgical mask to limit my exposure to a cheese I may be turning, washing, rubbing, brushing, etc. I also typically wear blue nitrile gloves when dealing with my cheeses, regardless whether I'm sick. So far it has been a good policy, but then I wasn't deathly ill either.
-Boofer-