Geotrichosis is a rare mycosis due to infection with Geotrichum candidum, a ubiquitous saprophytic fungus of soil, decaying organic matter, and contaminated food. G candidum is part of the normal flora of the mouth and intestinal tract in humans. The organism has caused systemic disease in dogs, abortion and mastitis in cattle, and caseous nodules in the lymph nodes of pigs. It has been isolated from feces of dogs, ocelots, and apes with enteritis; cutaneous lesions in snakes and flamingos; and the respiratory system of horses, penguins, chickens, and humans.
Clinical Findings and Lesions
Clinical signs vary with organ involvement and may be nonspecific. In dogs with disseminated geotrichosis, clinical signs may include coughing elicited by tracheal palpation, fever, anorexia, polydipsia, progressive dypsnea, vomiting, and icterus. Radiographic findings include nodular densities with confluence in some regions of the lungs. Disseminated disease progresses rapidly. Lesions, found in various organs, appear as multiple, yellow-gray, firm, fleshy nodules, which microscopically are well-defined granulomas.
Definitive diagnosis is based on cultural and microscopic characteristics. Fungal elements may be abundant, both free and in macrophages and multinucleated giant cells, as ovoid yeast-like cells (3–7 μm in diameter) and as short, jointed chains of round yeast cells forming pseudohyphae. In histologic sections of tissues stained with H&E, G candidum resembles Candida albicans and Histoplasma capsulatum.
Nystatin given as an oral suspension was effective in treatment of gorillas with watery diarrhea associated with isolation of G candidum from fecal wet mounts. The use of antifungal drugs for treating disseminated geotrichosis in animals has not been reported.
Last full review/revision March 2012 by Joseph Taboada, DVM, DACVIM