Canine and Equine Ring Worm
Where is the fungus found?
Ringworm is not caused by a worm; however, it is caused by several types of fungi which live on the skin, like athlete's foot in people. The medical term for ringworm is 'dermatophytosis.' Several different fungi found throughout the world can cause ringworm. The vast majority of cases in dogs are caused by Microsporum canis, Microsporum gypseum, or Trichophyton mentagrophytes. Ringworm in the horse, frequently called girth itch, is caused by a group of fungi of which the two most common are Trichophytrm and Microspmztm. The fungus is most commonly found either on or in the living quarters of infected animals. Spores from infected animals can be shed into the environment and live for over 18 months. Most healthy animals do not carry spores on their skin or hair. The ringworm fungus is found mostly in hot, humid climates, but most cases of ringworm occur in the fall and winter.
How is ring worm transmitted?
Ringworm can be transmitted by direct contact with an infected animal (the ringworm fungus knows no barriers and can infect many species), any environment where an infected animal has visited like a boarding kennel, or contact with a contaminated item such as grooming equipment, brush, tack, blanket or dog bed. As the fungus grows on the skin it produces tiny spores which are spread to other parts of the body by brushing, grooming, or by the rubbing action of tack and blankets and can then transmitted to other animals. Because of the spore's ability to survive for long periods of time in the environment, your animal can contract ringworm just about anywhere other animals have been. Fortunately, most healthy adult dogs have some resistance to ringworm and never develop symptoms from the fungus. Young dogs are most often infected. Dogs with a suppressed immune system from other diseases or overuse of steroids are also more susceptible to contracting the disease. Ringworm is contagious to people, so it is very important to handle infected animals with care. Persons should wear gloves when handling affected animals and wash hands well afterwards.
What are the signs of ring worm?
The classic symptom is a small round lesion that is devoid of hair. After fungal spores enter the skin, they start to grow and infect the hair, causing each hair to break off just above the skin surface, or in the outer layer of skin. The lesion will often have scaly skin in the center. Small pustules are often found in the lesion. The lesion may start as a small spot and continue to grow in size. The lesion may or may not be irritated and itchy. The lesions are most common on the head but can also occur on the legs, feet, or tail. The condition can often appear like, and be confused with, demodectic mange. In some infections, the fungus will not be in a circle and can spread across the face or nose and look like an autoimmune disease.
How is ring worm treated?
Most small, isolated lesions on healthy dogs and puppies will heal on their own within 4 months. In more severe cases, several different treatments are used. For isolated lesions, the area around the lesion should be thoroughly clipped down close to the skin. Care should be taken when clipping not to irritate the skin, as this may promote spreading of the infection. Wash or spot treat the infected area with a medicated shampoo such as Equine Elite Canine Antimicrobial Bodywash or Equine Antimicrobial Bodywash until the lesions have healed.