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Is Dog and Cat Ringworm Contagious?

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

Can Humans Get Ringworm From a Pet?

The term "zoonosis" is used to describe diseases communicable to humans from animals. There are a variety of diseases that can be passed from four-legged friends to humans. Ringworm, unfortunately, is one of them. What makes ringworm easily contagious is the fact that many pet owners may not know it is contagious. Another big contributing factor is the fact that ringworm spores cannot be seen, and what cannot be seen is what ultimately creates trouble.

What Is Ringworm?

Despite its name, ringworm has little to do with a worm. Ringworm is a fungus that infects the skin of both humans and animals. A pet infected with ringworm typically develops characteristic patches with visible hair loss. These round, hairless patches are mostly seen on the pet's head, tail, paws, legs, and belly. A pet may also develop tiny scabs or red raised lesions. In humans, ringworm generally develops a characteristic ring-like lesion that can be scaly and very itchy. These lesions, however, do not always develop.

How Do Humans Get Ringworm?

Ringworm, as already mentioned, is a fungal infection of the skin. This fungus reproduces by releasing spores that are invisible to the eye. Ringworm spores are capable of living for many years. In order to get infected, you would have to come in contact with a pet with ringworm or get in contact with any surface the pet has touched (bedding, brushes, blankets, toys). However, the good news is that not all skin gets infected with ringworm. The skin must be slightly abraded for the spores to penetrate the skin.

This means that skin that is healthy generally cannot be infected, whereas skin that is slightly scraped or scratched may be vulnerable to ringworm, according to Mar Vista Animal Medical Center. Individuals who have a vulnerable immune system may be particularly prone to ringworm. Young children, the elderly, and those with a compromised immune system are predisposed to developing ringworm if their skin is slightly abraded.

One big problem with ringworm is that not all pets affected by ringworm may show the typical tell-tale hairless lesions. Humans may touch a pet with ringworm and get the disease without ever imagining they would. These pets are defined as "carriers" and they are either pets that were apparently cured but are still infected or simply pets that carry spores on their fur just as other items around the house, explains veterinarian Wendy C. Brooks in an article for Veterinary Partner.

According to veterinarian Shawn Messonnier in an article for the Whole Cat Journal, in about 30 to 70 percent of households with pets infected with ringworm, at least one family member gets infected.

Characteristic ringworm lesion.

Characteristic ringworm lesion.

How to Avoid Getting Ringworm

If your pet has ringworm, most likely it is shedding spores all over the place. For this reason, disinfection and proper treatment of the pet are of primary importance. Proper diagnosis and treatment should be started immediately. The following tips will be helpful in preventing ringworm.

Tips to Help Prevent Ringworm

  1. The pet should be isolated in an area while its living spaces are properly disinfected.
  2. Clean surfaces with soap and water rising carefully at least three times a week.
  3. Afterward, products meant to kill ringworm (bleach diluted to 1:10 solution that is 1 part bleach, 10 parts water is capable of killing ringworm spores and so is a commercial product known as "Virkon S" explains veterinarian Janet Tobiassen Crosby. It is important to allow the surfaces to be wet with these solutions for at least 10 minutes before rinsing.
  4. The area should be vacuumed on a frequent basis to collect hair and skin cells that are full of spores. Much care must be dedicated to the disposal of vacuum bags.
  5. Hands should always be washed after touching or bathing the pet.
  6. To determine if your home has been successfully de-contaminated it may be a good idea to dust with a Swiffer cloth for about five minutes until it is dirty and then bring the cloth to the vet to be cultured.


  • According to Mar Vista Animal Medical Center, if allowed to live, ringworm fungus is capable of remaining infective for up to 18 months or more!
  • According to Mansfield Veterinary Clinic, "infected pets remain contagious for about three weeks if aggressive treatment is used."

What If I Get Ringworm?

Once your pet is diagnosed and initiated on a treatment plan for ringworm, you must also treat yourself at the same time. Topical products often found over the counter such as Clotrimazole (Mycelex) and Terbinafine (Lamisil) may be helpful according to Mayo Clinic Staff. Often such products are used for a couple of weeks and up to three weeks. Oral medications are needed for severe cases affecting large areas.

Further Reading

  • How to Tell if Your Dog has Ringworm
    dog ringworm fungal skin disorder,emmiP, You groom your dog one morning and you find a hairless patch the size of a quarter. Then some time later you find another one and then another one....

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2012 Adrienne Farricelli


Adrienne Farricelli (author) on March 14, 2012:

Oh wow, that sure seemed like a difficult treatment! Yes, happy it is easier to treat today. Thank you for stopping by.

Pamela Dapples from Arizona. on March 13, 2012:

You really did your homework on this subject. You've included very good tips on how to prevent getting the ringworm spores if the family pet is found to have ringworm. As you've explained, topical products or oral medication can eradicate the problem -- depending on how severe a case it is.

'Back in the day' it wasn't very easy to get rid of ringworm once a child was infected with it. I became infected twice with ringworm when I was six years old. I had to sit under an ultraviolet light for about an hour every evening in a dark room. My mom would tweeze each hair off my head that glowed green under the purple light. It was very painful. The doctor told my parents it was either that -- or have my head shaved. They should have had my head shaved.

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