JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

October 2017

P-V25

 

Signalment (JPC #92-21908):  Piglet.

HISTORY:  This one-week-old crossbred piglet was from a litter that was born weak and within a few days exhibited respiratory distress (“thumping”).  The producer had farrowed six sows thus far in this grouping, and all six had litters with the above problems.  Most sows would eventually have one or two survivors per litter.

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Diffusely alveolar septa are expanded up to 10X normal by numerous macrophages, lymphocytes, fewer viable and degenerate neutrophils and plasma cells, admixed with fibrin and edema.  Multifocally, alveolar lumina are variably expanded by an exudate composed of few previously described inflammatory cells, necrotic cellular debris, fibrin and edema that minimally extends into adjacent terminal bronchiole lumina.  Multifocally there is necrosis and loss of type I pneumocytes with alveoli being lined by cuboidal pneumocytes (type II pneumocyte hyperplasia and hypertrophy). Interlobular septa and perivascular connective tissue are mildly expanded by edema, fibrin and few macrophages, lymphocytes and plasma cells.

MORPHOLOGIC DIAGNOSIS:  Lung:  Pneumonia, interstitial, histiocytic and lymphocytic, diffuse, subacute, moderate, with type II pneumocyte hyperplasia, crossbreed, porcine.

ETIOLOGIC DIAGNOSIS:  Arteriviral pneumonia

CAUSE:  Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)

CONDITION:  Porcine Reproductive and Respiratory Syndrome

SYNONYMS:  Swine infertility and abortion syndrome; Porcine epidemic abortion and respiratory syndrome; Blue ear disease

GENERAL DISCUSSION: 

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

 TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Balka G, Ladinig A, Saalmuller A, et. al. Immunohistochemical characterization of type II pneumocyte proliferation after challenge with type I porcine reproductive and respiratory syndrome virus. J Comp Pathol. 2013;149:322-330.
  2. Breedam WV, Delputte PL, Gorp HV, et al. Porcine reproductive and respiratory syndrome virus entry into the porcine macrophage. J Gen Virol 2010;91:1659-1667.
  3. Cao J, Li B, Fang L, Chen H, Xiao S. Pathogenesis of nonsuppurative encephalitis caused by highly pathogenic Porcine reproductive and respiratory syndrome virus. J Comp Pathol. 2012;24(4):767-771.
  4. Caswell JL, Williams KJ. The respiratory system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer's Pathology of Domestic Animals. 6th ed. Vol 2. Philadelphia, PA: Elsevier Saunders;2016:523-526.
  5. Constable PD, Hinchcliff KW, Done SH, Grünberg W. Veterinary Medicine: A Textbook of the Diseases of Cattle, Sheep, Pigs, Goats and Horses. 11th ed. London, England, UK: WB Saunders Company LTD; 2017:1794-1816,1794-1795.
  6. Choi C, Chae C. Colocalization of porcine reproductive and respiratory syndrome virus and porcine circovirus 2 in porcine dermatitis and nephropathy syndrome by double-labeling technique. Vet Pathol. 2001;38:436-441.
  7. Han K, Seo HW, Oh Y, et al. Pathogenesis of Korean type I (European Genotype) porcine reproductive and respiratory syndrome virus in experimentally infected pregnant gilts. J Comp Pathol. 2013;148:396-404.
  8. Han K, Seo HW, Park C. Comparative virulence of reproductive diseases caused by type I (European-like) and type 2 (North American-like) porcine reproductive and respiratory syndrome virus in experimentally infected pregnant gilts. J Comp Pathol. 2014;150:297-305.
  9. Lopez A, Martinson SA. The respiratory system. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier;2016:210,485,799.
  10. MacLachlan NJ, Dubovi EJ. Fenner’s Veterinary Virology. 4th ed. London, UK: Academic Press; 2017: 54,464,472-474.
  11. Zimmerman JJ, Benfield DA, Dee SA, Murtaugh MP, Stadejek T, Stevenson GW, Torremorrell M. Porcine reproductive and respiratory syndrome (porcine arterivirus). In: Zimmerman JJ, Karriker LA, Ramirez A, Schwartz KJ, Stevenson GW, eds. Diseases of Swine. 10th ed.  Ames, IA: Blackwell Publishing; 2012: 52,461-480.

 

 


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