Microsporum canis . [Descriptions of Fungi and Bacteria

Abstract

Abstract A description is provided for Microsporum canis . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Primarily a pathogen of the cat and dog, frequently transmitted to man. Also recorded from the chimpanzee, chinchilla, fox, lion, monkey, pig, rabbit, sheep and tiger. Experimental animals are susceptible to infection. DISEASE: Ringworm (dermatophytosis, tinea). Infected hairs and animal claws usually fluoresce bright green under Wood's light and hairs are surrounded by ectothrix sheaths of small spores in a mosaic arrangement. In cats the lesions are usually inconspicuous. They may occur on any part of the body, but particularly the face and paws, and the whiskers and claws may be involved. In dogs infection is more noticeable, and is characterized by small circular areas of scaling and alopecia, sometimes with oedema and crust formation, on any part of the body. The claws may also be infected. Infections in dogs have a well defined seasonal incidence with a peak in Oct. -Feb., but the incidence in cats is poorly defined (Kaplan & Ivens, Sabouraudia 1: 91-102, 1961). In man the scalp (tinea capitis), glabrous skin (tinea corporis), and rarely the beard (tinea barbae), foot (tinea pedis) and nails (tinea unguium, onychomycosis) may be infected (mycoses). Children are most susceptible, particularly to scalp infection which is very rare in adults. Scalp lesions are scaling, inflammatory areas containing broken hairs or with total hair loss. Pustulation and kerion formation are not uncommon. Skin lesions are circinate, with a scaling centre and vesicular border. Kligman (RMVM 1, 2510; 2, 2484) studied the pathogenesis of tinea capitis caused by M. canis . GEOGRAPHICAL DISTRIBUTION: Africa (Algeria, Angola, Cape Verde Islands, Egypt, French W. Africa, Sahara, Tunisia, Union of S. Africa); Asia (Ceylon, India, Philippines, Turkey); Australasia & Oceania (Australia (N.S.W.), New Zealand); Europe, North America, Central America and West Indies (Costa Rica, Cuba, Guatemala, Mexico, Panama, Puerto Rico); South America (Argentina, Brazil (south of Pernambuco), Chile, Colombia, Ecuador, Peru, Uruguay, Venezuela).