Proliferative Ileitis in a pig – Lawsonia intracellularis


History: A 20 lb pig of unknown age had a history of diarrhea. (Thats all we know)

Gross Lesions:

The ileum and distal jejunum were diffusely thickened, with a cobblestoned appearance to the serosa and corrugated mucosa which was covered in a moderate amount of green to yellow fibrin. The serosal surface of the colon had multiple focal pale grey nodules protruding from the surface.

(sorry no pictures)

Histopathology:

Ileum: There is marked superficial necrosis of the mucosa with abundant fibrin accumulation on the mucosal surface. Crypts are multifocally dilated with neutrophils and cellular debris. Warthan-Starry silver stain was positive for intracellular curved bacteria in the apical enterocyte cytoplasm (Lawsonia intracellularis).

Ileum- mucosal hyperplasia

Ileum- mucosal hyperplasia with crypt abscesses

The mucosal epithelium is hyperplastic lined by pseudostratified columnar cells and crypts occasionally herniate into the submucosa.

Ileum- branching and dividing crypts

Ileum- branching and dividing crypts

The crypts are often branched and there are moderate numbers of neutrophils and macrophages in the lamina propria.

Ileum- Warthin Starry silver stain with intracellular bacteria

Ileum- Warthin Starry silver stain with intracellular bacteria

Lawsonia are intracellular bacteria that reside usually in the apical cytoplasm.

Ileum- Warthin-Starry silver stain showing bacteria in the apical cytoplasm of enterocytes

 

Morphologic Diagnosis:

Ileum: Fibrino-necrotic ileitis, moderate, multifocal, pyogranulomatous, with mucosal hyperplasia and intracellular bacteria consistent with Lawsonia intracellularis

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About Brian

Anatomic Pathologist, VetPath Services, Stone Ridge, NY- musculoskeletal, oral/dental, and sinonasal diseases
This entry was posted in Necropsy Cases and tagged , , . Bookmark the permalink.

One Response to Proliferative Ileitis in a pig – Lawsonia intracellularis

  1. Laura Iglesias says:

    Excellent this site. Congratulations to those responsible.

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