Hervey Foundation

Despite the name, ringworm is not a worm, but rather a contagious fungal infection of the skin. Ringworm can affect many animals including cats and dogs, as well as people. Spread of this fungus can occur by direct animal-to-animal contact, animal to person, or from contaminated objects. The fungal spores are very resistant in the environment and can survive for many years. Infection can occur with any contact of skin to spore. Some cats can be carriers of the disease. This means they can spread the disease without actually showing clinical signs.

Ringworm typically affects those animals and people with suppressed immune systems. The young and the old are more commonly affected, as well as cats with systemic infections (e.g. viral diseases such as Feline Leukemia, and Feline Immunodeficiency Virus). Himalayans and Persians tend to be over presented in the cat population.

The classic lesion in humans is a circular area of redness. This lesion can sometimes be quite itchy. In cats, the lesion is not as classic, and often appears as an area of hair loss with an inflamed, dry and scaly area. Some cats will have severe skin disease, while others (carriers) will show no signs at all.

Carrier cats make it more difficult to treat and control. Carriers can shed spores into the environment through shedding of hair and dead skin, affecting those cats living in the same household. Ringworm can spontaneously cure itself over a few months, but often treatment is initiated to speed up the recovery.

Anti-fungal topical creams are good ways in treating small lesions. Shampoos help treat the lesions and may decrease the spread of ringworm by decreasing the number of spores attached to the hair of the cat. Systemic therapies such as griseofulvin are commonly used to treat individual cats, however side effects may be severe and treatment times over 1-2 months. Program, a flea control product, was shown in a study in the year 2000, to be an effective method of ringworm control, especially in large populations of cats where topical treatments or griseofulvin are not feasible. Lime sulfur dips can be used and cats need to be dipped twice a week until culture is negative. This process can be very messy, and the dips have been shown to stain clothing and jewelry. As well, have you ever tried dipping a cat!!!!

If your cat has been diagnosed with ringworm, either through culture, Wood’s lamp, or microscopic examination of the hair, cleaning of the environment is necessary to prevent re-infection. Vacuuming, and cleaning with a 1:10 dilution of bleach will decrease the number of spores in the environment. New cats to the household should be quarantined in a separate room to prevent contamination of the environment and infection of other pets. Hands should be washed after handling of the cat to decrease the risk to family members.

Dr. Tammy Wilde
Tudor Glen Veterinary Clinic

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