Had it here a couple years ago, uggg! I do everything still to keep it out of my home!!! I would quarantine the cat with the ringworm ASAP! I would use health guard on all your clothing and cat stuff(as Patti suggested) EVERYTHING!!! I still wash my towels and bedding always with health guard. Their are a few products you can try and use, shampoo and sprays from Revial health. I would shampoo and used two sprays and I also got Itraconazole from the vet and gave for six weeks! I also use sani guard bombs in my entire house, they are hospital grade that kills everything including ringworm. Mine was a mild case went horrible bad! thanks to a horrible vet I will never use again. thanks to the new vet and cat friends, it finally got IT under control. if you have it too I would make sure it is securely cover with a band aid. You can put ointment(lotrimin) on it and cover it, so important to cover it. this is nasty and can spread fast and get bad. really important to clean, I mean everything. I ordered a product that killed the fungus instead of messing with bleach.
I would sit in there room with them in a hazard waste outfit, so I would not spread it(outfit stayed in room) and just cried one day, it was that bad!