Abstract
Lymphosarcoma is commonly reported in parrots; no viral or specific genetic etiology has been described.1 Beginning in 2011, five blue-crowned parrots (Loriculus galgulus) from the North Carolina Zoological Park have been diagnosed on autopsy with lymphoma or leukemia. These cases represent half of total submissions for full necropsy from this species over this eight-year time period. All affected birds were male and ranged in age from 3.9 to 10.8 years (mean 5.75 years). In three cases, the birds died spontaneously after a short period of clinical decline, and a fourth case died with no premonitory signs. Hepatomegaly and splenomegaly were observed grossly in these cases corresponding to splenic and hepatic lymphosarcoma; neoplastic infiltrates were also observed in kidneys (4 cases) and throughout the body (2 cases). A fifth case was euthanized for refractory, systemic mycobacteriosis and neoplasia was limited to the spleen and bone marrow. In this last case and in one of the spontaneous deaths, neoplastic cells showed myeloid differentiation. The only two birds with available pedigrees shared both sets of grandparents. This close relationship taken together with the male bias strongly suggests an inherited, possible sex-linked predisposition. However, an underlying infectious etiology cannot be completely ruled out, and screening for retroviruses and herpesviruses is being pursued.
Acknowledgments
The authors would like to thank Dr. Oscar Fletcher for case review, the histopathology technicians at the North Carolina State College of Veterinary Medicine for slide preparation and immunohistochemistry, and the Poultry Tumors Disease Laboratory at the North Carolina State College of Veterinary Medicine for viral testing.
Literature Cited
1. Souza MJ, Newman SJ, Greenacre CB, Avenell JS, Wall JS, Phillips JC, Fry MM, Donnell RL, Daniel GB. Diffuse intestinal T-cell lymphosarcoma in a yellow-naped Amazon parrot (Amazona ochrocephala auropalliata). J Vet Diagn Invest. 2008;20:656–660.