Avian cryptococcosis.

Clinical and laboratory findings in 15 unreported cases of avian cryptococcosis from Australia were collated and contrasted with 11 cases recorded in the literature. Cryptococcus species produced localized invasive disease of the upper respiratory tract of captive parrots living in Australia. This resulted in signs referable to mycotic rhinitis or to involvement of structures contiguous with the nasal cavity, such as the beak, sinuses, choana, retrobulbar space and palate. Parrots of widely differing ages were affected and of the seven birds for which sex was determinable, six were male. Cryptococcus bacillisporus (formerly C. neoformans var. gattii) accounted for four of five infections in which the species or variety was determinable, suggesting that exposure to eucalyptus material may be a predisposing factor. In these cases, Cryptococcus appeared to behave as a primary pathogen of immunocompetent hosts. One tissue specimen was available from an Australian racing pigeon with minimally invasive subcutaneous disease; immunohistology demonstrated a C. neoformans var. grubii (formerly C. neoformans var. neoformans serotype A) infection, presumably subsequent to traumatic inoculation of yeast cells into the subcutis. Two similar cases had been reported previously in pigeons domiciled in America. Data for parrots, one pigeon and other birds studied principally in America and Europe (and likely infected with C. neoformans) suggested a different pattern of disease, more suggestive of opportunistic infection of immunodeficient hosts. In this cohort of patients, the organism was not restricted to cool superficial sites such as the upper respiratory tract or subcutis. Instead, infections typically penetrated the lower respiratory tract or disseminated widely to a variety of internal organs. Finally, three captive North Island brown kiwis, one residing in Australia, the other two in New Zealand, died as a result of severe diffuse cryptococcal pneumonia (two cases) or widely disseminated disease (one case). C. bacillisporus strains were isolated from all three cases, as reported previously for another kiwi with disseminated disease in New Zealand.

Central nervous system toxoplasmosis in Roller canaries.

Several birds in a flock of 40 Roller canaries (Serinus canaria) from an outdoor aviary in Victoria, Australia, developed central nervous system signs that included blindness, nystagmus, ataxia, and head rotation. Four died, and four were euthanatized. Two euthanatized birds were submitted for microscopic examination of tissues. Brain lesions in both birds consisted of scattered foci of nonsuppurative meningoencephalitis with gliosis, mild to moderately extensive lymphocytic/plasmacytic perivascular cuffs, and a patchy increased prominence of cerebral blood vessels associated with hypertrophy of the vascular endothelium and/or thickening of their connective tissue walls. These lesions were associated with the presence of Toxoplasma gondii tissue cysts. Lesions in the eyes of both birds were bilateral and consisted of severe plasmacytic/granulomatous ophthalmitis. Surviving birds were treated with trimethoprim and sulfadiazine, no subsequent deaths occurred, and no new cases developed over an 8-month period.