I'd like to clear up a few facts regarding ringworm-first of all I have been involved on the medical side for quite some time and have discussed and researched this issues with several of the world's leading authorities in infectious diseases, pediatrics and NIH and the CDC.
In the 1990s Dr. David Vasily and Jack Foley of Leigh (dermatologist and director of sports medicine) wrote the original NCAA guidelines and were the major factors in mandating skin inspections and developed protocols for various skin problems.
In their research, and others, ringworm was shown to be spread from person to person contact. In review of the literature, the only published study of looking at wrestling mats as a source of infection (Thomas Kohl, M.D. Journal of Athletic Training,2000;35(4)427-430 showed that wrestling mats were not the source of ringworm infection. In that study, mats were cultured on a weekly basis immediatly after practice and before cleaning and no ringworm was cultured, however, there was still significant ringworm outbreaks. Also, in that study, ringworm applied to the mats was not viable past a very short period. Enough said-
there are still multiple studies showing the spread of other diseases from dirty mats and cleaning before and after practice is imperative! Skin inspect wrestlers daily and use other preventative measures as astutely outlined by others. One of the better preventative medication options includes fluconazole 100mg once a week to help prevent ringworm. Also note, there is no good data to truely say when a wrestler is non-contagious but probably within about 72 hours of topical treatment.