Dr. Byrne explains that three types of ringworm are most commonly seen in dogs and cats. A few cats can be symptomatic carriers of M. canis. These carrier cats can transmit the spores to other cats or to other animals and humans. Dogs and cats can become infected with M. gypseum by digging in the soil. Often, it is very difficult to identify the source of infection.
Veterinarians can use a number of methods to diagnose ringworm.
The most reliable test is a fungal culture. This involves culturing hairs or scales from the infected animal and observing the culture for a color change. If your pet has ringworm, your veterinarian will develop a treatment program depending on the extent of the infection and number of animals involved. Trimming around the lesions may also be helpful. Scratching can cause further trauma to the lesion and spread spores.