JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

September 2017

P-B12

 

Signalment (JPC #1947581):  2‑year‑old mixed breed steer

HISTORY:  This steer was persistently infected with bovine viral diarrhea virus (BVDV). It subsequently became dyspneic and developed diarrhea, dehydration, and anorexia.

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Multifocally, affecting approximately 70% of the lung, alveolar spaces are variably filled with numerous viable and degenerate neutrophils that occasionally have streaming hyperchromatic to smudgy nuclei (oat cells), fewer macrophages, abundant eosinophilic cellular and karyorrhectic debris (necrosis), hemorrhage, fibrin, and edema.  Multifocally bronchiolar lumina are variably filled with an exudate composed of numerous viable and degenerate neutrophils, sloughed/necrotic epithelial cells, foamy macrophages with phagocytized debris, fibrin and hemorrhage. Bronchiolar epithelium is occasionally hypertrophic and hyperplastic, piling up to 3 layers thick. Alveolar septa are thickened up to 5 times normal by similar infiltrate with occasional type II pneumocyte hyperplasia.  In severely affected areas, alveolar septa are fragmented and discontinuous (necrotic).  Diffusely, interlobular septa and the pleura are expanded five to ten times normal by dilated lymphatics (edema), polymerized fibrin, hemorrhage,  and scattered macrophages, lymphocytes, plasma cell and neutrophils.  Multifocally vessels are lined by hypertrophied (reactive) endothelium, with marked perivascular edema.

MORPHOLOGIC DIAGNOSIS:  Lung:  Bronchopneumonia, fibrinosuppurative and necrotizing, multifocal, marked, with oat cell formation, mixed breed, bovine.

ETIOLOGIC DIAGNOSIS:  Pneumonic mannheimiosis

CAUSE:  Mannheimia haemolytica

CONDITION:  Shipping fever; bovine respiratory disease complex (BRDC)

GENERAL DISCUSSION: 

PATHOGENESIS: 

TYPICAL CLINICAL FINDINGS: 

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS: 

 

COMPARATIVE PATHOLOGY: 

REFERENCES:

  1. Aschenbroich S, et al. Mannheimia haemolytica A1-induced fibrinosuppurative meningoencephalitis in a naturally-infected Holstein-Friesian calf. J Comp Pathol. 2013;149(2-3):167-171
  2. Britton AP, et al. Bronchopneumonia associated with Mannheimia granulomatis infection in a Belgian hare (Lepus europaeus). J Vet Diagn Invest. 2017; 29(4):566-569.
  3. Caswell JL. Failure of respiratory defenses in the pathogenesis of bacterial pneumonia of cattle. Vet Pathol. 2014;51(2):393-409.
  4. Caswell JL, et al. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th Philadelphia, PA: Elsevier Saunders; 2016: 543-544, 562-563, 557
  5. Capik SF, et al. Characterization of Mannheimia haemolytica in beef calves via nasopharyngeal culture and pulsed-field gel electrophoresis. J Vet Diagn Invest. 2015;27(5):568-575
  6. Dassanayake RP, et al. Differential susceptibility of bighorn sheep (Ovis canadensis) and domestic dheep (Ovis aries) neutrophils to Mannheimia haemolytica leukotoxin is not due to differential expression of cell surface CD18. J Wildl Dis. 2017; 53(3):625-629.
  7. Ferguson SH,et al. Pathology in practice. Mannheimia haemolytica. J Am Vet Med Assoc. 2011;239(11):1437-1439
  8. Lopez A, et al. Respiratory system, mediastinum and pleurae. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th St. Louis, MO: Mosby Elsevier; 2016:520, 529-531
  9. Murray GM, et al. Pathogens, patterns of pneumonia, and epidemiologic risk factors associated with respiratory disease in recently weaned cattle in Ireland. J Vet Diagn Invest. 2017;29(1):20-34
  10. Omaleki L, et al. Molecular epidemiology of Mannheimia haemolytica and Mannheimia glucosida associated with ovine mastitis. J Vet Diagn Invest. 2012;24(4):730-734
  11. Portis E, et al. A ten-year (2000-2009) study of antimicrobial susceptibility of bacteria that cause bovine respiratory disease complex Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni in the United States and Canada. J Vet Diagn Invest. 2012;24(5):932-44.
  12. Shanthalingam S, et al. PCR assay detects Mannheimia haemolytica in culture-negative pneumonic lung tissues of bighorn sheep (Ovis canadensis) from outbreaks in the western USA, 2009-2010. J Wildl Dis. 2014;50(1):1-10
  13. Singh KJ, et al. Mannheimia haemolytica: bacterial-host interactions in bovine pneumonia. Vet Pathol. 2011;48(2):338-148.
  14. Zachary JF. Mechanisms of microbial infections. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th St. Louis, MO: Mosby Elsevier; 2016:169-170.


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