Favus in a backyard flock of game chickens.

Favus, or avian ringworm, was diagnosed in a backyard flock of game chickens from which Microsporum gallinae was isolated. Infected birds had white crusts on the comb and on the skin of the head and neck. Histopathological lesions included hyperkeratosis of the skin epithelium with invasion of the stratum corneum by fungal mycelia, acanthosis, acantholysis, and hydropic degeneration of cells in the stratum spinosum. The underlying dermis was infiltrated by mononuclear cells and contained lymphoid foci. Daily topical treatment with miconazole was applied in the field and in the laboratory, with apparent success.