Demonstration by culture on agar medium of pathogenic fungi of the genus Microsporum and Trichophyton responsible for dermatomycoses.
Dermatophyta (moths) are an important cause of skin infection in cats, dogs, rabbits and horses. They are due to dermatophytes, filamentous microscopic mushrooms belonging to the genera Microsporum, Trychophyton and Epidermophyton. Very contagious, they are transmitted either directly from one animal to another, or indirectly (grooming equipment, sleeping place, spores in the soil, etc.).
A contamination by the fungus is not systematically followed by a development of lesions: some animals can be healthy carriers and are therefore able to disseminate or transmit the fungus. In addition, there is a risk of contagion from animals to humans (zoonosis). The most reliable method of demonstrating dermatophytes is culture. Dermatophytes, fungi.
Ringworm is a mycosis, which can reach our dogs, cats, horses, domestic rodents ... and humans. The most common species are Microsporum canis, and Trichophyton mentagrophytes.
. The transmission is by direct contact, or indirectly via tissues, in particular.
. Diagnosis is made mainly by direct demonstration of the fungus under the microscope or by culture.
How are dermatophytes transmitted?
Ringworm is very contagious. The spores of the fungus pass from one animal to another, or from an animal to a human, in two ways:
Or by direct contact with the skin or hair of an animal carrying the fungus,
- or indirectly, by contact with a tissue (wool, carpet ...) to which the spores have hung. For the anecdote, this property is used for diagnosis, with the so-called "carpet square" technique: a carpet square, or other similar, slightly raspy tissue, is rubbed on the skin of the animal suspected of ringworm, Then applied to a culture medium. This means that a carpet, a couch or a sweater can hang and transmit mushroom spores!
To top it all, the latter are very resistant in the outside environment (they can retain their infectivity up to 1 year!)
And what does it look like on my pet?
In dogs and cats (especially the kitten), roughly circular lesions, fairly well defined and containing no hair, are usually seen on the head. Dandruff is present on the skin. In general, the animal scratches little.
A more advanced tine may spread to the whole body, with crusty lesions, accompanied by itching. On the contrary, some animals (especially cats) may be ringworm - and contagious - without showing any lesion.
More rarely, at the tip of a dog's dog, there is a circular lesion, prominent, very inflammatory and sometimes purulent, called "keron". The dog contracts this dermatophyte by digging in the ground ... or playing with a hedgehog carrying Trichophyton erinacei!