1William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, Davis, CA, USA; 2Zoo/Exotic Pathology Service, West Sacramento, CA, USA; 3Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA; 4Department of Pathology, Microbiology and Immunology, University of California, Davis, CA, USA; 5Department of Medicine and Epidemiology, University of California, Davis, CA, USA
Psittacine circovirus, the causative agent of psittacine beak and feather disease (PBFD), is typically characterized by symmetric feather loss, abnormally shaped feathers, and beak abnormalities. The disease has been associated with immunosuppression, and most affected birds eventually succumb to secondary infections.1 Juvenile African grey parrots (Psittacus erithacus) can develop a peracute to acute form of the disease leading to death without feather abnormalities.2,3 Current literature on this syndrome is limited, and there are no detailed descriptions of cases within the United States, despite anecdotal reports of its presence.
A 5-month-old male Congo African grey presented for a 2-day history of anorexia and lethargy. Hepatomegaly and yellow urates were noted on physical exam, and diagnostics revealed severe leukopenia and anemia, hepatomegaly, and an opacity in the right caudal lung. Despite aggressive supportive therapy, the bird died 2 days after presentation. Histopathology revealed profound lymphoid depletion of the cloacal bursa and botryoid intracytoplasmic viral inclusions. In addition, acute multifocal hepatic necrosis, and a large pulmonary fungal granuloma were noted. Electron microscopy, in situ hybridization of the cloacal bursa, and whole genome amplification and sequencing confirmed the presence of psittacine circovirus strain J.4 Review of an avian pathology database revealed fifteen similar cases in juvenile African grey parrots, with characteristic intracytoplasmic inclusions within the bursa. Circoviral infection was confirmed with PCR and in situ hybridization. Peracute circoviral infection in juvenile African grey parrots causes severe leukopenia, liver necrosis, immunosuppression, and opportunistic infections but lacks the characteristic feather and beak abnormalities.
1. Ritchie, B.W. 1995. Circoviridae, In: Ritchie, B.W. (ed.) Avian Viruses: Function and Control, 1st ed. Wingers Publishing, Inc., Lake Worth, Florida.
2. Doneley, R.J. 2003. Acute beak and feather disease in juvenile African Grey parrots - an uncommon presentation of a common disease. Aust. Vet. Journal. 81: 206–207.
3. Schoemaker, N.J., G.M. Dorrestein, K.S. Latimer, J.T. Lumeij, M.J. Kik, M.H. Van der Hage, and R.P. Campagnoli. 2000. Severe leukopenia and liver necrosis in young African grey parrots (Psittacus erithacus erithacus) infected with psittacine circovirus. Avian Dis. 44: 470–478.
4. Varsani, A., G.L. Regnard, R. Bragg, I.I. Hitzeroth, and E.P. Rybicki. 2011. Global genetic diversity and geographical and host-species distribution of beak and feather disease virus isolates. J. Gen. Virol. 92: 752–767.