Oxalate-producing pulmonary aspergillosis in an alpaca

An aging lactating alpaca was presented in sternal recumbency. Although bri ght and alert, she did not respond to symptomatic treatment and was euthani zed 5 weeks after initial presentation. Gross post-mortem examination revea led purulent material in the pulmonary airways. Histologic examination of t he lungs revealed an extensive pyogranulomatous pneumonia with bronchiectas is. There were abundant fungal hyphae and high numbers of associated oxalat e crystals, which were presumed to have been produced by the fungus. Low nu mbers of yeast cells were also present. Microbiological culture of tissues on horse blood agar and Sabouraud's agar identified the fungus to be Asperg illus niger. There was also moderate growth of Candida albicans. Calcium ox alate crystals in cytologic and histologic preparations can suggest an unde rlying Aspergillus infection. This is the first reported veterinary case of pneumonia due to Aspergillus niger infection and the associated production of oxalate crystals.