How to i find the real culprit of ringworm. there are a few variables but someone also has moved in with us. possibly from the towel or tinactin (tolnaftate) usage?

Ringworm: Ringworm often spreads by direct, skin-to-skin contact with an infected person.You can contract ringworm by touching an animal with ringworm.Ringworm can spread by contact with objects or surfaces that an infected person or animal has recently touched or rubbed against, such as clothing, towels, bedding and linens, combs, and brushes. Ringworm can also be spread to humans by contact with soil.