This was the first time that any microscopic organism was ever proven to cause human disease. It has no connection at all with worms, other than the similar appearance of the skin lesions. Fungi are tiny plants that survive by eating plant or animal material. These fungi thrive best on skin that is moist, hot, and hidden from the light. Up to 20 percent of the population has one of these infections at any given moment.
Ringworm is very mildly contagious.
Some people are much more susceptible than others. Those with eczema or other skin problems get ringworm more easily because the protective barrier of the skin's outer layer is less intact. Children are more susceptible before puberty. Boys get it more easily than girls. Several of these antifungal creams are now available without a prescription.