Ringworm in humans stops being contagious within 24 to 48 hours after commencing treatment, according to WebMD. Ringworm is caused by a fungus, according to eMedicineHealth, and it is treated for a specific length of time with a topical anti-fungal medication.
Ringworm is spread by direct contact or by contact with contaminated objects, according to VCA Animal Hospitals. Some species of ringworm are spread from animals, such as cats, to humans.
There are different species of ringworm, and they have different names depending upon the affected body part. For example, an infection on the face, torso, arms or legs is ringworm of the body, according to eMedicineHealth.