Ringworm: Human to pet transmission

Q:My son, a high school wrestler, and several of his wrestling friends have ringworm. I know cats are susceptible. Can my son give ringworm to our cat?

A:Yes. Ringworm, a fungal infection of the skin, hair or nails, is zoonotic, which means it’s a disease shared by humans, cats, dogs and other animals.

Ringworm—which is caused by a fungus, not a worm—go  its name because in humans, it often appears as a round, raised, pink, flaky lesion. Most cases of ringworm in cats and dogs are caused by Microsporum canis. Half the people exposed develop the disease.

People can infect their pets, and an animal that contracts ringworm can pass it to humans. Transmission may be direct or through contact with contaminated bedding, carpet, clipper blades or other surfaces. Soil is another source of infection.

The typical ringworm-infected cat develops patchy hair loss with skin crusting and, sometimes, itchiness. Occasionally, however, cats may carry the ringworm fungus and appear completely normal.

If you see changes in your cat’s coat or skin, or if your son’s ringworm disappears and then recurs, contact your veterinarian, who can test your cat, make a diagnosis and recommend treatment if it’s needed.

Lee Pickett, V.M.D. practices companion animal medicine. Contact her at askdrlee@insurefigo.com.