An imposing number of fungi have been incriminated as agents of ringworm in man and lower animals. Individual dermatophytes differ considerably in their host range and importance as incitants of disease in man.
From an epidemiologic standpoint these organisms can be classified into the following three groups: zoophilic, geophilic, and anthropophilic. Zoophilic dermatophytes are basically lower animal pathogens, but most have the ability to infect humans. Geophilic dermatophytes are soil fungi that have the additional capacity to cause ringworm in some species of lower animals and also in man. Anthropophilic dermatophytes are primarily adapted for parasitism of man, but some species occasionally cause ringworm in animals.
The principal agents of ringworm in animals are discussed individually in terms of their host range and patterns of spread among susceptible host species. The public health significance of these infections in lower animals is presented.