Cilla, remember that the spores will float around like dust. Sometimes it won't matter how careful you are, the spores will get around anyhow.
I remember one foster having ringworm. I was SO careful. I caged them all separately and I wore a hospital gown and changed it and washed my hands after handling each kitten. It spread anyway. So I let them all out of their cages. And BOY, did they all PLAY and PLAY and PLAY. They were so happy!