Vet. Pathol. 22: 540-547 (1 985) The Pathology of Disseminated Aspergillus terreus Infection in Dogs M. J. KABAY, W. F. ROBINSON, C. R. R. HUXTABLE, AND R. MCALEER Division of Veterinary Biology, School of Veterinary Studies, Murdoch University, Murdoch, Western Australia; and Medical Mycology, State Health Laboratory Services Branch, Queen Elizabeth I1 Medical Centre, Nedlands, Western Australia Abstract. Disseminated Aspergillus terreus infection was diagnosed in ten previously healthy adult dogs-nine German shepherds and one dalmatian. The disease was characterized by the presence of multiple granulomas and infarcts in a wide range of organs. The kidney, spleen, and skeletal system were most commonly and severely affected. Fungal hyphae were demonstrated in large numbers within granulomas and thrombi, and A. terreus was readily isolated by culture. This disseminated mycosis appears unique; in this series of cases there was no apparent predisposing factor, portal of entry, or primary focus for dissemination of the infection. Disseminated aspergillosis in dogs is rare. There are only seven reported cases18.28.29. 31348-49 and of these only fi~e~~.~~.~~,~~ were confirmed by culture to be due to Aspergillus species. Species identification was at- tempted in only two cases, where both fungi were identified as Aspergillus t erre~s.~~.~~ Aspergillosis in dogs is usually an upper respiratory tract disease confined to the nasal cavity, and A. fumi- gutus is the most common pathogenic specie^.^-^* A. terreus is a rare pathogen but is widespread in the environment and an easily cultured saprophytic fungus.34 It has been reported as a cause of cutaneous granuloma,’ I and mas ti ti^^^ in cattle. In man, it has been recognized to cause allergic broncho- pneumonia, focal pulmonary and disseminated infec- tion.24.47 We report the pathological features of ten cases of disseminated A. terreus infection in dogs. 8, 12.25.45 Materials and Methods During the past three years (1981-84) disseminated A. terreus infection was diagnosed in 12 (8 female, 4 male) previously healthy dogs, ranging in age from two to seven years. Eleven were German shepherds and one a dalmatian. Affected dogs were presented with a history of gradual weight loss, malaise, and lameness or lumbar pain. Two cases cul- minated in the sudden onset of hind-limb paraplegia. On physical examination, dogs were pyrexic, had enlarge- ment of some or all peripheral lymph nodes, and localized painful swelling of joints, various vertebrae, sternebrae, or limbs. Where there were no vertebral lesions, the lumbar pain appeared to be localized to the kidneys. Three dogs had unilateral or bilateral uveitis. A clinical diagnosis of disseminated mycosis was made when fungal hyphae were detected in aspirates from skeletal lesions, enlarged lymph nodes, and in the sediment from centrifuged urine samples. In all cases the pathogen was identified as A. lerreus by cultural isolation. Three dogs that presented in the terminal stages of the disease died and the remainder were killed after the diagnosis was made. Ten dogs were necropsied routinely and all organ systems were examined. In the earlier dogs, only a limited range of tissues were collected for histological examination. In the four latter dogs, however, all organ systems were sampled compre- hensively. Tissue samples were fixed in 10% buffered for- malin, embedded in paraffin, and 5-pm sections were cut and stained with hemotoxylin and eosin (HE). Selected sections also were stained with Grocott’s modification of Gomori’s silver method for fungal elements. Specimens taken at necropsy were cultured on sheep blood agar under microaerophilic and aerobic conditions and on MacConkey’s agar under aerobic conditions at 37°C. Samples were also cultured at room temperature under aerobic con- ditions on Sabouraud dextrose agar. Results Gross lesions Six of the ten necropsied dogs were in poor condition and had generalized muscle atrophy; the degree of emaciation was proportional to the duration of the dog’s illness. The remaining four were in fair condition. The characteristic gross lesions were multiple, discrete, pale and sometimes friable foci of variable size in a 540
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