February 2017



Signalment, Slide A (JPC #2389731):  1 1/2-year-old male cockatoo

HISTORY:  The bird was lethargic and anorexic for some time.  It seemed to be wasting away and had been regurgitating food off and on for several weeks.  Grossly, the proventriculus and ventriculus were dilated.


  1. Small intestine and mesentery: Multifocally there is an infiltrate composed of moderate numbers of lymphocytes and plasma cells that centers on the myenteric plexuses and extends into the adjacent tunica muscularis.  Within affected myenteric ganglia, there are decreased numbers of ganglion cells.  Similar inflammatory cells are also present within nerve bundles of the adjacent mesentery.  There is diffuse mesenteric fat atrophy with reduced adipocyte cytoplasm containing one or more varisized intracytoplasmic lipid vacuoles, prominence of nuclei, and blood vessels in close proximity to one another.
  2. Cerebrum: Multifocally there are perivascular infiltrates of low numbers of lymphocytes and plasma cells within the gray and white matter and the leptomeninges.
  3. Peripheral nerve: Multifocally within the nerve and surrounding epineurium, there are perivascular aggregates of lymphocytes and plasma cells.


  1. Small intestine and mesentery: Ganglioneuritis and leiomyositis, lymphoplasmacytic, subacute, multifocal, mild, with ganglion cell loss, cockatoo, avian.
  2. Cerebrum: Meningoencephalitis, lymphoplasmacytic, subacute, multifocal, mild.
  3. Peripheral nerve: Epineuritis, lymphoplasmacytic, subacute, multifocal, mild.
  4. Adipose tissue, mesentery: Fat atrophy, diffuse, moderate.
  5. Kidney: No significant findings.

Signalment, Slide B (JPC #2820183):  Female psittacine

HISTORY:  Chronic weight loss


  1. Heart: Diffusely, nerves subjacent to the epicardium contain an infiltrate of low numbers of lymphocytes and plasma cells that occasionally extend into the surrounding connective tissue.
  2. Liver: Multifocally within portal areas, there is an infiltrate composed of low numbers of lymphocytes and plasma cells, and rare heterophils.


  1. Heart, epicardial nerves: Neuritis, lymphoplasmacytic, subacute, diffuse, moderate.
  2. Liver: Hepatitis, portal, lymphoplasmacytic and heterophilic, subacute, multifocal, mild.

ETIOLOGIC DIAGNOSIS:  Bornaviral ganglioneuritis, leiomyositis, meningoencephalitis, neuritis, and hepatitis

CAUSE:  Avian bornavirus (ABV)

CONDITION:  Proventricular dilatation disease (PDD)

CONDITION SYNONYMS:  Psittacine proventricular dilatation syndrome (PDDS), neuropathic gastric dilatation (NGD), macaw wasting disease, lymphoplasmacytic ganglioneuritis and encephalomyelitis








For gross finding of proventricular dilation:

For lymphoplasmacytic meningoencephalitis in birds:

Intestinal poxvirus infection and Pacheco’s disease can lead to proventricular lesions grossly and histologically similar to PPD



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