JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
AUGUST 2018
D-B09

SIGNALMENT (AFIP #2741081):  5 year old, female Angus-cross cow

HISTORY:  This cow had chronic weight loss and diarrhea for 2 months.  Four herdmates died with similar clinical signs.  At necropsy, the small intestinal mucosa was markedly thickened with prominent corrugated mucosal folds, and the mesenteric lymph nodes were markedly enlarged and firm.

HISTOPATHOLOGIC DESCRIPTION:  Small intestine:  Diffusely and markedly expanding the lamina propria and submucosa up to 5 mm, and replacing and widely separating crypts, are numerous epithelioid macrophages arranged in dense sheets. Macrophages have abundant, finely-granular pale eosinophilic cytoplasm and an eccentric round to oval nucleus with finely-stippled chromatin.  Villi are blunted and fused, and form prominent mucosal rugose folds.  Multifocally, moderate numbers of lymphocytes, plasma cells, eosinophils and rare multinucleated giant cells are admixed with macrophages.  Multifocally, crypt epithelial cells have increased cytoplasmic basophilia, vesicular nuclei, and mildly increased numbers of mitotic figures, and pile up to 5 cell layers deep (regeneration).  Low numbers of lymphocytes are present within the muscular layers and subserosal adventitia.  Diffusely, within the submucosa, tunica muscularis, and serosa, there is increased clear space and mildly ectatic lymphatics (edema).  Diffusely, there is marked fat atrophy within the serosa, which is often lined by hypertrophied (reactive) mesothelium.

Slide B (acid fast): Small intestine:  Diffusely, macrophages contain large numbers of 1 x 2 um acid-fast bacilli.

MORPHOLOGIC DIAGNOSIS:  Small intestine: Enteritis, granulomatous, diffuse, marked, with villus atrophy, edema, and numerous intrahistiocytic acid-fast bacilli, Angus-cross, bovine.

ETIOLOGY: Mycobacterium avium subspecies paratuberculosis (MAP)

ETIOLOGIC DIAGNOSIS: Mycobacterial enteritis

CONDITION: Johne"s disease, paratuberculosis

GENERAL DISCUSSION:

PATHOGENESIS:

 TYPICAL CLINICAL FINDINGS:

 TYPICAL GROSS FINDINGS:

 TYPICAL LIGHT MICROSCOPIC FINDINGS:

 ADDITIONAL DIAGNOSTIC TESTS:

 DIFFERENTIAL DIAGNOSIS:

 COMPARATIVE PATHOLOGY:

 REFERENCES:

  1. Balseiro A, Garcia Marin JF, Solano P, Garrido JM, Prieto JM. Histopathological classification of lesions observed in natural cases of paratuberculosis in free-ranging fallow deer (Dama dama). J Comp Pathol. 2008;138:180-188.
  2. Constable PD, Hinchcliff KW, Done SH, Grunberg W. Diseases of the alimentary tract-ruminant. In: Constable PD, Hinchcliff KW, Done SH, Grunberg W, eds. Veterinary Medicine, A Textbook of the Diseases of Cattle, Horses, Sheep, and Goats. 11th ed. St. Louis, MO: Elsevier; 2017:552-573.
  3. Fernandez M, Benavides J, Castano P, et al. Macrophage subsets within granulomatous intestinal lesions in bovine paratuberculosis. Vet Pathol. 2017: 54(1): 82-93.
  4. Gonzalez J Geijo MV, et al. Histopathological classification of lesions associated with natural paratuberculosis infection in cattle.  J Comp Pathol. 2005;133:184-96.
  5. Huntley JFJ, Whitlock RH, Bannantine JP, Stabel JR. Comparison of diagnostic detection methods for Mycobacterium avium subsp. paratuberculosis in North American bison. Vet Pathol. 2005;45:42-51.
  6. Matos AC, Figueira L, Martins MH, et al. Disseminated Mycobacterium avium subsp, paratuberculosis infection in two wild eurasian otters (Lutra Lutra L.) from Portugal. J Zoo Wildl Med. 2013;44(1):193-195.
  7. Naylor AD, Richardson D, Sellar M, Harley J, et al. Clinical signs, antemortem diagnostics, and pathological findings associated with Mycobacterium avium subspecies paratuberculosis infection in Mishmi takin (Budorcas Taxicolor Taxicolor). J Zoo Wildlife Med. 2018: 49(2):412-419.   
  8. Plattner BL, Chiang YW, Roth JA, Platt R, Huffman E, Zylstra J, Hostetter JM. Direct inoculation of Mycobacterium avium subspecies paratuberculosis into ileocecal peyer’s patches results in colonization of the intestine in a calf model. Vet Pathol. 2012;48:584-592.
  9. Smith SL, Wilson PR, Collett MG, et al. Liver biopsy histopathology for diagnosis of Johne’s disease in sheep. Vet Pathol. 2014;51(5):915-918. 
  10. Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016:194-197.
  11. Weiss DJ, Evanson OA, Souza CD. Mucosal immune response in cattle with subclinical Johne’s disease. Vet Pathol. 2006;43:127-135.
  12. Weiss DJ, Souza CD. Review paper: Modulation of mononuclear phagocyte function by Mycobacterium avium subsp. paratuberculosis. Vet Pathol. 2008;45:829-841.
  13. Sweeney RW. Paratuberculosis (Johne’s disease). In: Smith BP, ed. Large Animal Internal Medicine. 5th ed. St. Louis, MO: Elsevier Mosby; 2015:834-837.
  14. Zachary JF. Mechanisms of microbial infections. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:162-163.


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