Over the years I have worked in many salons as well as have been a beauty school instructor, and have been fortunate to have had managers and co-workers that really care about the welfare and safety of their clients, therefore, I have never worked in a salon where a client was infected with some kind of bacteria or fungus that was dangerous to them.
http://hubpages.com/hub/Bacteria-and-Fungus-That-You-Can-Encounter-In-Your-Hair-Salon