Chronic Lymphocytic Leukemia in a Cockatiel (Nymphicus hollandicus).

A 24-year-old, female cockatiel (Nymphicus hollandicus) was diagnosed and treated for chronic lymphocytic leukemia. Diagnosis was based on a persistent lymphocytosis, with counts increasing 10 times from reference intervals with a high percentage of well-differentiated lymphocytes in the bone marrow. Immunohistochemical staining confirmed neoplastic cells of T-cell origin. Specific treatment for the disease was initially withheld but commenced based on an increasing lymphocytosis and decreasing packed cell volume. Therapeutic management of the cockatiel's chronic lymphocytic leukemia was based on human protocols. Treatment with chlorambucil stabilized the disease but did not result in a significant regression of the neoplasm. The bird was euthanatized 15 months after the initial diagnosis and 8 months after treatment commenced. On the postmortem examination, extensive T-cell lymphocytic infiltration was found throughout the internal organs.

Diplotriaena-An Air Sac Nematode Found in a New Holland Honeyeater (Phylidonyris novaehollandiae).

A New Holland honeyeater (Phylidonyris novaehollandiae), a common species found mostly in the southern parts of Australia, was examined after a presumed traumatic incident but died several hours after presentation. At necropsy, a Diplotriaena nematode was found in a cranial air sac. Although no obvious gross pathologic changes were attributed to the nematode, histologic changes of bronchial epithelial hyperplasia and goblet cell metaplasia, consistent with chronic airway irritation were found in the lungs associated with Diplotriaena eggs. Diplotriaena species are parasitic nematodes found in the air sacs of birds. These parasites have an indirect life cycle; larval stages develop in insects, and when eaten by the host, these larvae migrate to the air sac and become adults. Although Diplotriaena species have been found in birds worldwide, none, to our knowledge, have previously been described in New Holland honeyeaters.

Giant axonal neuropathy-like disease in an Alexandrine parrot (Psittacula eupatria).

A chronic progressive neurological condition in an Alexandrine parrot (Psittacula eupatria) was manifest as intention tremors, incoordination, and seizure activity. Histology revealed large eosinophilic bodies throughout the central nervous system, and electron microscopy demonstrated that these bodies were greatly expanded axons distended by short filamentous structures that aggregated to form long strands. The presence of periodic acid-Schiff-positive material within the neuronal bodies of Purkinje cells and ganglionic neurons is another distinctive feature of this disease. The histological features of this case display some features consistent with giant axonal neuropathy as reported in humans and dogs. Based on investigation of the lineage in this case, an underlying inherited defect is suspected, but some additional factor appears to have altered the specific disease presentation in this bird.