Skin Zoonotic Diseases  Ringworm  Scabies  Lice

Ringworm  This disease is also called cutaneous mycoses, dermatophytoses, and tinea.  Dermatophytoses are infections of human and animals epidermal tissues caused by fungi known as dermatophytes.  They penetrate and parasitize the keratinous body tissues such as skin, hair, feathers, horns or nails.

Ringworm Classification  The most important genera of dermatophytes are Microsporum and the Trichophyton.  Individual species differ with respect to their host preferences.  Species can be either zoophilic, geophilic, or anthrophilic. Zoophilic species are adapted to a specific animals, but can also infect man. Geophilic species are adapted primarily to live in the soil, but can also infect animals and man. Anthrophilic species are adapted to infect humans but can infect animals, these species are rare in the USA.

Classification of Important Ringworm Species (The four in green are most important.) GenusZoophilicGeophilicAnthrophilic Microsporum M. canis M. gypseumM. audouinii M. equinumM. nanum Trichophyton T. equinumT. rubrum T. gallinae T. mentagrophytes T. verrucosum

Microsporum canis  M. canis has been estimated to cause over 98% of the feline and 70% of dog ringworm infections  M. canis occasionally infects other animal species.  In the USA, M. canis is responsible for the great majority of human ringworm cases.

M. canis Infections in Domestic Animals  Dogs and cats are the reservoir of infection for humans. Human to human infection is rare.  The disease in cats is frequently subclinical or mild. It might cause mild hair loss or encrustation. More severe lesions may become generalized to many other parts of the body.  The lesions caused by this disease in dogs are usually more evident than cats (but subclinical infection is still the most common situation).  Very young and old debilitated animals are more commonly infected.  Transmission may be direct or indirect.

Trichophyton spp.  Trichophyton equinum This species is more specifically adapted to the equine species than M. equinum. Other animals and man are rarely infected.  Trichophyton gallinae Principle form of ringworm in birds, especially chickens. Usually affected birds have a thick white crusting of the comb and wattles. Severe cases can become more generalized.

Trichophyton spp.  T. verrucosum Most common kind in cattle  T. mentagrophytes Most common kind from rodents

M. canis

M. canis - Wood’s lamp is neither sensitive nor specific.

T. verrucosum

Ringworm

T. mentagrophytes

M. gypseum