December 2018

Signalment (JPC #1941253):  A 90-day-old chicken.

HISTORY:  This bird was from a flock of 21,000 layers that had experienced 8% mortality and a sudden drop in egg production.

HISTOPATHOLOGIC DESCRIPTION:  Pancreas:  Affecting approximately 75% of the pancreas are multifocal to coalescing areas of pancreatic acinar architecture loss and stromal collapse with replacement by eosinophilic cellular and karyorrhectic debris, fibrin, edema, and hemorrhage (lytic necrosis).  Multifocally, scattered acinar cells are shrunken and individualized with vacuolated cytoplasm and pyknotic or karyorrhectic nuclei (single cell necrosis).  In less affected areas, acinar cells are shrunken with loss of zymogen granules (atrophy).  Low to moderate numbers of lymphocytes, fewer heterophils, and macrophages are scattered throughout the parenchyma and interlobular connective tissue extending into the adjacent mesentery.  Areas of necrosis and inflammation also extend into the peripancreatic adipose tissue, where adipocytes at the periphery exhibit loss of cellular detail (fat necrosis) and replacement by fibrin, necrotic debris, basophilic finely granular mineral and acicular cholesterol clefts (fat saponification). Lymphatics are mildly ectatic (edema) with intraluminal protein and fibrin. 

MORPHOLOGIC DIAGNOSIS:  Pancreas:  Pancreatitis, necrotizing, subacute, multifocal to coalescing, severe, with serositis and peripancreatic fat necrosis and saponification, chicken, avian.

ETIOLOGIC DIAGNOSIS:  Orthomyxoviral pancreatitis and serositis

ETIOLOGY:  Avian orthomyxovirus

CONDITION:  Highly pathogenic avian influenza (HPAI)

SYNONYMS:  Fowl plague










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