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Ringworm: preventing the spread of infection

Ringworm is a skin disease caused by parasitic fungi, which thrive on the skin of animals, including the horse. Young horses are usually more susceptible, especially in warm and moist or humid conditions. It is very common in stables where the equipment of the horses is shared, such as in riding schools.

Ringworm infection can be spread directly from horse to horse and by using common grooming tools, saddle pads, harnesses, and saddles. Ringworm is an infection by one of several types of fungi; the most common ringworms affecting horses are the Microsporum and Trichophyton species.  One type of ringworm produces skin lesions that appear as small, rounded spots, a quarter of an inch to an inch in diameter. The lesions eventually form blisters and break, leaving scabs. This form of ringworm is easily transmitted to humans and is a notoriously itchy form of the disease. Other ringworm forms cause lesions to first make their appearance on the forehead and face, neck, and at the root of the tail, but also can spread to other parts of the body. The lesions are grey in colour and form crusts on their surface, from which broken hairs protrude.


When ringworm strikes, immediate treatment is required. The horse and all grooming equipment should be disinfected. If possible, the horse should be isolated to prevent further spread of the disease. For treatment, many topical medications work well to prevent progression of existing lesions and, at the same time, serve as a barrier to contaminating other horses. Thick crusts should be removed gently with a brush and mild soap and the contaminated material burned. It is recommended that anti-microbial solutions be applied to the entire body of the affected animal on a daily basis for five to seven days, then weekly until the infection is controlled. Ringworm is more common during the winter when animals are stabled and therefore in closer proximity, but it can occur at any time. Regular cleaning of yards, equipment and stables with disinfectant can help in preventing cross contamination.

Follow these steps if you suspect your horse has ringworm

1.       Although this isn't an emergency requiring immediate veterinary care, you should inform your vet about your horse's condition as quickly as possible. Although the lesions are probably caused by a local fungal infection they might signify something more serious, requiring veterinary treatment.

2.       Clip hair away from the affected area to remove the fungus' main food source: keratin, the protein that makes up your horse's hair and outer skin cells. Use electric clippers and a surgical blade; clip any remaining hair from each bald spot. Extend the shaved area so there's a 1/2-inch margin of unaffected skin around each lesion.

3.       Spot-bathe the lesions to help kill the fungus. Wet the shaved area with a sponge, and apply antifungal antiseptic, such as Betadine. Lather up the scrub, and let it stand for 10 minutes to give it time to thoroughly kill the fungus, then rinse thoroughly with water. Dry the affected area and apply an anti-fungal dressing to kill any remaining fungus and discourage new infections.

4.       Keep lesions clean, dry, and exposed to air and sun. Fungus thrives in dark, damp conditions, such as a wet, dirty winter coat. Dry conditions and ultraviolet light (sunlight) kill fungus.

5.       Disinfect your premises and yourself. Ringworm is highly contagious to horses and other livestock, house pets, and humans. Clean up all clipped hair and grooming debris in the treatment area, and discard them in a knotted plastic garbage bag. Thoroughly clean grooming equipment in disinfectant concentrate, rinse, and allow todry. Bathe and shampoo yourself and any house pets that may have come into contact with these materials.


The best way to prevent spread is to avoid sharing of saddles and tacks, grooming kit such as brushes, riding boots and rugs, and even buckets. Sometimes the fungus is known to produce spores, which survive even on the woodwork in stables. We recommend the use of disinfectants such as Virkon-S or Mirakil.

·         Use separate saddles and equipment for each horse.

·         Wash and disinfect saddlecloths and girths daily using a non irritant disinfectant

·         Avoid foam and rubber pads, which can cause sweating, which can help the fungus thrive.

·         Consult a veterinarian.