Despite the name, ringworm is actually caused by a form of fungus. Over 35 different species of this fungus exists, but only about four can cause ringworm in dogs. Of these four, Microsporum Canis is the most common. Ringworm is very contagious, and can be passed from dogs to humans. The risk of catching ringworm is especially high in young children. Infection can be spread by direct contact with an infected animal, or by contact with the spores which can live in sheets and carpeting for several months.
Ringworm can take as much as two weeks to develop into visible lesions after initial infection. The fungus grows within hair follicles in the skin, and causes hair in the infected area to break off at the root. As a result, ringworm infections often manifest in dogs as circular patches of missing fur. Many cases of ringworm can be identified by examination under ultra-violet light. However, only two of the four species of fungi that cause ringworm will fluoresce. The most accurate test is to have your veterinarian perform a hair culture on fur from the infected area, although this form of testing can take 2-3 weeks to perform.
If left untreated, ringworm will spread and cause painful sores, but once identified, infection can be treated fairly easily through anti-fungal medications. Unfortunately, ringworm is much more difficult to remove from the home, and reinfection will occur until remaining spores are dealt with. After an infection, it is recommended that you destroy and replace your dog’s bedding, brushes, and other objects which frequently come into close contact with your dog’s fur. Items that cannot be destroyed can be soaked in a mixture of hot water and iodine, and rinsed with water and diluted bleach. Clean the house thoroughly, and have carpets and upholstery steam-cleaned.
While ringworm is not often a dangerous or life-threatening illness, its persistence can make it difficult to deal with. In a guard dog, the skin irritation caused by ringworm can have a detrimental effect on concentration and overall performance. Weather you have a German Shepherd, Belgian Malinois, or Dutch Shepherd, it is important to check your guard dog regularly for signs of ringworm and other signs of skin irritation. Do not hesitate to contact your veterinarian if you detect any signs illness.