JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

August 2017

P-B03

 

Signalment (JPC 2019267):  3‑month‑old Yorkshire pig

HISTORY:  This pig went off feed, developed a hacking cough, and eventually died.

HISTOPATHOLOGIC DESCRIPTION:  Lung: Multifocally, surrounding lobular bronchi, bronchioles, and blood vessels, infiltrating adjacent alveoli and expanding adjacent alveolar septa up to 3 times normal, are moderate numbers of lymphocytes, plasma cells, and macrophages, admixed with fibrin. Bronchi and bronchioles have attenuated (or rarely lost), cuboidal epithelium devoid of cilia; lumina often contain an amphophilic material (mucus) admixed with sloughed epithelial cells and degenerate inflammatory cells. Peribronchiolar and peribronchial lymphoid tissue are moderately hyperplastic. Interlobular septa and the overlying pleura are mildly edematous, and infiltrated by low numbers of lymphocytes, plasma cells, and macrophages.

MORPHOLOGIC DIAGNOSIS: Lung:  Bronchointerstitial pneumonia, lymphohistiocytic, moderate, subacute, with lymphoid hyperplasia, Yorkshire, porcine 

ETIOLOGIC DIAGNOSIS:  Pulmonary mycoplasmosis

CAUSE:  Mycoplasma hyopneumoniae

CONDITION:  Porcine enzootic pneumonia (PEN)

CONDITION SYNONYM:  Porcine respiratory disease complex (PRDC); mycoplasmal pneumonia of swine; swine enzootic pneumonia

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

Primary porcine pneumonias:

COMPARATIVE PATHOLOGY:

Swine:

Ruminant:

Rodents:

Avian:

REFERENCES:

  1. Andrada M, et al. Cyclooxygenase-2 expression in pigs infected experimentally with Mycoplasma hyopneumoniae. J Comp Pathol. 2014;151(2-3):271-276.
  2. 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; 2016:403.
  3. Cheville NF. Ultrastructural Pathology: An Introduction to Interpretation. 2nd ed. Ames, IA: Iowa State University Press; 2009:442-443.
  4. Garcia-Morante B, et al. Assessment of Mycoplasma hyopneumoniae-induced pneumonia using different lung lesion scoring systems: a comparative review. J Comp Pathol. 2016;154(2-3):125-134.
  5. Lopez A, et al. Respiratory system, mediastinum and pleurae. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th St. Louis, MO: Mosby Elsevier; 2016:541-542
  6. Pósa R, et al. Use of computed tomography and histopathologic review for lung lesions produced by the interaction between Mycoplasma hyopneumoniae and fumonisin mycotoxins in pigs. Vet Pathol. 2013;50(6):971-979.
  7. Rodríguez F, et al. Relationship between expression of interleukin-5 and interleukin-13 by epithelial cells and bronchiolar changes in pigs infected with Mycoplasma hyopneumoniae. J Comp Pathol. 2016;154(2-3):165-168.
  8. Zachary JF. Mechanisms of microbial infections. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th St. Louis, MO: Mosby Elsevier; 2016:142,174.


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