Dermatophytosis in pigs is usually caused by Microsporum nanum. Lesions are rings of inflammation or brown discoloration that spread centrifugally up to a diameter of 6 cm. Lesions are fairly asymptomatic in adults, and ringworm in swine is generally of little economic consequence. Zoonotic infections in farm workers are not common.
Ringworm is a common, troublesome problem in show lambs but is otherwise uncommon in production flocks of sheep and goats. The infecting species include M canis, M gypseum, and Trichophyton verrucosum. Lesions in lambs are most often noticed on the head, but widespread lesions under the wool may be apparent in lambs sheared for show. Infected lambs should not be issued certificates for transport to show until the infection is cleared. Because there is little evidence that lambs with a functional rumen will absorb griseofulvin to effective levels, treatment is best accomplished with sodium hypochlorite solutions or enilconazole rinses (where available). In healthy lambs, as in other species, these infections are self-limiting, but resolution may not be evident in time to salvage the use of the animal in the show ring.
Last full review/revision July 2011 by Sandra R. Merchant, DVM, DACVD