Ringworm DNA Test

Ringworm is an infection caused by a fungus that grows in the dead, surface layers of the skin, hair or claws. The scientific name for ringworm is dermatophytosis, and the fungi which cause the disease are called dermatophytes. There are approximately 40 different species of dermatophyte, each tending to cause infection in particular species of hosts. In the cat, the cause of more than 90% of cases of ringworm is Microsporum canis. This organism can also cause infection in many other species, including dogs and humans. Other pathogens that may cause ringworm in cats are Trichophyton mentagrophytes and Microsporum gypseum, which can be acquired by contact with infected wild rodents.

Ringworm is contagious. Spores are the infectious stage of dermatophytes. They are typically found in clusters around infected hairs and can only be seen using a microscope. Infected hairs are shed into the cat’s environment. Cats may become infected either by direct contact with an infected animal or by exposure to a contaminated environment or object, such as grooming tools, clippers or bedding. Spores in the environment are very robust and without treatment can remain infectious for approximately two years.

The appearance of cats with ringworm is variable. Some cats have severe skin disease while other cats have only minor lesions or no lesions at all and look completely normal. Typical skin lesions are discrete, roughly circular areas of hair loss, particularly on the head, ears or extremities of the paws. The hairs surrounding affected areas appear broken. The affected skin is often scaly and may look inflamed. However, ringworm can look very similar to many other feline skin diseases, such a flea allergic dermatitis, symmetrical alopecia and feline acne. Some loss of hair is usually involved, but the amount of inflammation, scaling and itchiness can be variable. In very unusual cases, cats may appear just to have an ear infection or infection of the claws.

It is impossible to diagnose a cat as having ringworm based on its appearance alone because this is so variable and can easily be confused with other skin diseases. Commonly used, a fungal culture enables precise identification of the species of dermatophyte involved, but because dermatophytes are slow growing it may take several weeks for laboratories to report a result. Recently, a DNA test was developed to detect most common dermatophyte species. Ringworm DNA test provides a rapid and practical tool for identification of dermatophytes (Microsporum canis, Microsporum gypseum and Trichophyton mentagrophytes) in biological samples that is independent of morphological or biochemical characteristics, and enhances laboratory diagnosis of fungal species.