JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

October 2017

P-V17

 

Signalment (JPC # 2127420):  2‑year‑old ewe

HISTORY:  This ewe had sustained severe weight loss over the winter while receiving a ration adequate for maintenance.

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Diffusely, alveolar septa are expanded up to eight times normal by a cellular infiltrate composed of lymphocytes, macrophages and neutrophils admixed with minimal fibrous connective tissue (fibrosis) and small amounts of fibrin and edema.  Multifocally, there is an increased amount of bronchiolar and alveolar smooth muscle (smooth muscle hypertrophy). Multifocally, the peribronchiolar and perivascular connective tissue is expanded by a similar inflammatory infiltrate, increased clear space and dilated lymphatics (edema) and numerous variably-sized aggregates of lymphocytes forming lymphoid follicles with germinal centers.  Multifocally, bronchi and bronchioles occasionally contain amphophilic fibrillar to flocculent material (mucin) that is admixed with sloughed epithelial cells, cellular and karyorhectic (necrotic) debris and/or pale eosinophilic homogenous (seroproteinaceous) fluid, fibrin and small amounts of hemorrhage. 

MORPHOLOGIC DIAGNOSIS:  Lung:  Pneumonia, interstitial, lymphohistiocytic, chronic, diffuse, marked, with peribronchiolar and perivascular lymphofollicular proliferation (BALT hyperplasia) and bronchiolar smooth muscle hypertrophy, breed unspecified, ovine.

ETIOLOGIC DIAGNOSIS:  Ovine lentiviral pneumonia

CONDITION:  Ovine progressive pneumonia (OPP)

CAUSE: Small ruminant lentivirus

Signalment (JPC #2127420):  2-year-old LaMancha goat

HISTORY:  This LaMancha goat had severe weight loss and clinical signs of respiratory disease.

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Lung:  Multifocally, 70% of bronchioles and blood vessels are surrounded by large aggregates of inflammatory cells that form follicles with prominent germinal cells and are composed predominantly of lymphocytes and macrophages with fewer plasma cells (lymphoid hyperplasia).  Diffusely alveolar septa are expanded to up to 50 um by lymphocytes, alveolar macrophages, fewer plasma cells, and fibrosis, and they are often lined by plump cuboidal pneumocytes (type II pneumocyte hyperplasia).  Alveolar lumina are filled with abundant eosinophilic proteinaceous fluid (surfactant and edema), mucin, macrophages with foamy cytoplasm, few neutrophils, cellular debris, and occasional small areas of hemorrhage and mineral.  Bronchi and broncioles multifocally contain edema and mucin admixed with degenerate and viable neutrophils and sloughed epithelium.  Multifocally, the interlobular septa and pleura are expanded up to two times normal by ectatic lymphatics (edema), moderate amounts of fibrin, low numbers of lymphocytes, macrophages, rare eosinophils, occasional mineral and a focally extensive area of mild hemorrhage.  

MORPHOLOGIC DIAGNOSIS:  Lung:  Pneumonia, interstitial, lymphohistiocytic, chronic, diffuse, severe with lymphoid (BALT) hyperplasia, type II pneumocyte hyperplasia and abundant pulmonary edema, LaMancha, caprine.

ETIOLOGIC DIAGNOSIS:  Lentiviral pneumonia

CAUSE:  Small ruminant lentivirus; caprine arthritis encephalitis virus (CAEV)

SYNONYMS:  Lymphoid interstitial pneumonia, maedi-visna (MVV), Graaff-Reinet (South Africa), Zwoegerziekte (Netherlands) and La bouhite (France)

GENERAL DISCUSSION:

 PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS: 

 TYPICAL LIGHT MICROSCOPIC FINDINGS:

 ULTRASTRUCTURAL FEATURES:

ADDITIONAL DIAGNOSTICS:

DIFFERENTIAL DIAGNOSIS:

 COMPARATIVE PATHOLOGY:

Equine infectious anemia virus  (EIAV)

Horse

Human immunodeficiency virus (HIV)

Human

Bovine immunodeficiency virus (BIV)

Cattle

Jembrana disease (JD)

Cattle

Feline immunodeficiency virus (FIV)

Cat

Simian immunodeficiency virus (SIV)

Nonhuman primate

 

References:

  1. Campbell RSF, Robinson WF. The comparative pathology of the lentiviruses. J Comp Pathol. 1998;119(4):333-395.
  2. Cantile C, Youssef S. Maxie MG, Youssef S. Nervous system. In: Maxie MG, ed. Jubb, Kennedy, Palmer"s Pathology of Domestic Animals. Vol.1. 6th ed. Philadelphia, PA: Elsevier; 2016:378-379.
  3. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy, Palmer"s Pathology of Domestic Animals. Vol. 2. 6th ed. Philadelphia, PA: Elsevier; 2016:558-559.
  4. Dabareiner RM: Diseases of bones, joints, and connective tissue. In: Smith BP, ed. Large Animal Internal Medicine, 4th ed. St. Louis, MO: Mosby Elsevier; 2009:1206-1207.
  5. Gerstner S, Adamovicz JJ, Duncan JV, Laegreid WW, et al. Prevalence of and Risk Associated with Ovine Progressive Pneumonia in Wyoming Sheep Flocks. J Am Vet Med Assoc. 2015 Oct 15;247(8):932-7.
  6. Hermann-Hoesing LM, Noh SM, Snekvik KR, et al. Ovine progressive pneumonia virus capsid antigen as found in CD163- and CD172a-positive alveolar macrophages of persistently infected sheep. Vet Pathol. 2010;47(3):518-528.
  7. Highland MA. Small Animal Lentiviruses: Strain Variation, Viral Tropism, and Genetics Influence Pathogenesis. Vet Pathol. 2017 May; 54(3): 353-354.
  8. Hudachek SF, Kraft SL, Thamm DH, et al. Lung tumor development and spontaneous regression in lambs coinfected with jaagsiekte sheep retrovirus and ovine lentivirus. Vet Pathol. 2010;47(1):148-162.
  9. Jones TC, Hunt RD, King NW. Diseases caused by viruses. In: Jones TC, Hunt RD, King NW, eds. Veterinary Pathology. 6th ed. Baltimore, MD: Williams & Wilkins; 1997:331-334.
  10. Lechner F, Machado J, Bertoni G, et al. Caprine arthritis encephalitis virus dysregulates the expression of cytokines in macrophages. J Virol. 1997 Oct;71(10):7488-97.
  11. Lujan L, Begara I, Collie DDS, Watt NJ. Ovine lentivirus (maedi-visna virus) protein expression in sheep alveolar macrophages. Vet Pathol. 1994;31(6):695-703.
  12. Perez M, Biescas E, Reina R, et al. Small ruminant lentivirus-induced arthritis: clinicopathologic findings in sheep infected by a highly replicative SRLV B2 genotype. Vet Pathol. 2015 Jan 52(1):132-9.
  13. Pinczowski P, Sanjose L, Gimeon M, Crespo H, et al. Small Ruminant Lentiviruses in Sheep: Pathology and Tropism of 2 Strains Using the Bone Marrow route. Vet Pathol. 2017 May:54(3):413-424.
  14. Summers BA, Cummings JF, de Lahunta A. Inflammatory diseases of the central nervous system. In: Summers BA, Cummings JF, de Lahunta A, eds. Veterinary Neuropathology. St. Louis, MO: Mosby-Year Book, Inc.; 1995:128-132.
  15. Varea R, Monleon, E, Pacheco C, et al. Early detection of maedi-visna (ovine progressive pneumonia) virus seroconversion in field sheep samples. J Vet Diagn Invest. 2001;13(4):301-307.
  16. Woodall CJ, MacLaren LJ, Watt NJ. Differential levels of mRNAs for cytokines, the interleukin-2 receptor and class II DR/DQ genes in ovine interstitial pneumonia induced by maedi visna infection. Vet Pathol. 1997;34(3):204-211.
  17. Zachary JF. Mechanisms of microbial infection. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease, 6th ed. St. Louis, MO: Elsevier; 2016:209-210; 537.

 

 


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