JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
November 2018
D-V13

Signalment (JPC #1712658):  Adult cockatoo

HISTORY:  One of several psittacine birds in a pet shop that died after exhibiting acute, profuse, green, watery diarrhea.

HISTOPATHOLOGIC DESCRIPTION:  Liver:  There is diffuse, random hepatocellular necrosis, characterized by disruption and loss of the hepatic architecture with replacement by abundant eosinophilic cellular and karyorrhectic debris, few heterophils, and individualized hepatocytes with hypereosinophilic cytoplasm and nuclear pyknosis, karyolysis or karyorrhexis.  Remaining adjacent hepatocytes are swollen, with pale vacuolated cytoplasm (degeneration).  Approximately 90% of the viable hepatocytes contain round, 4-8 um diameter, eosinophilic intranuclear viral inclusion bodies that marginate chromatin and completely fill the nucleus or are surrounded by a clear halo. Randomly, there are few multinucleate hepatocytes that contain 8-10 karryorhectic or karryolytic nuclei (viral syncytia).  Multifocally, there are periportal aggregates of low numbers of lymphocytes and fewer heterophils.

MORPHOLOGIC DIAGNOSIS:  Liver:  Hepatocellular necrosis and degeneration, acute, diffuse, severe, with eosinophilic intranuclear viral inclusion bodies and viral syncytia, Cockatoo (Cacatua galerita), avian.

ETIOLOGIC DIAGNOSIS:  Alphaherpesviral hepatitis

CAUSE:  Psittacid herpesvirus 1 (PsHV-1)

CONDITION:  Pacheco"s disease

SYNONYMS:  Herpesvirus of psittacine birds, Amazon parrot herpesvirus, Pacheco"s parrot disease virus

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

DIFFERENTIAL DIAGNOSIS:

For hepatic necrosis:

COMPARATIVE PATHOLOGY:

Abortigenic alphaherpesviruses causing fetal/newborn hepatic necrosis:

Other significant alpha herpesviruses:

REFERENCES:

  1. Brown DL, Van Wettere AJ, Cullen JM. Hepatobiliary system and exocrine pancreas. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:441.
  2. Gabor M, Gabor LJ, Peacock L, Srivastava M, Rosenwax A, Phalen D. Psittacine herpesvirus 3 infection in the eclectus parrot (Eclectus roratus) in Australia. Vet Pathol. 2013; 50(6): 1053-7.
  3. Schmidt RE, Reavill DR, Phalen DN. Pathology of Pet and Aviary Birds. 2nd ed. Philadelphia, PA: John Wiley & Sons, Inc.; 2015:29-30, 96-98; 183.
  4. Tomaszewski EK, Wigle W, Phalen DN. Tissue distribution of psittacid herpesviruses in latently infected parrots, repeated sampling of latently infected parrots and prevalence of latency in parrots submitted for necropsy. J Vet Diagn Invest 2006; 18: 536-544.


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