JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

October 2017

P-V26

 

Signalment (JPC #2641092):  Adult horse, breed and gender unspecified

HISTORY:  This horse was experimentally inoculated with Hendra virus.  Seven days post-inoculation the horse developed tachycardia, tachypnea, anorexia and lethargy.

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Multifocally, alveolar septa are thickened up to 10X normal by fibrin, edema, increased numbers of macrophages and lymphocytes and small aggregates of brown globular pigment within macrophages (hemosiderin).  Endothelial cells lining small to medium caliber blood vessels and alveolar capillaries often form viral syncytial cells with up to six nuclei.  Occasionally, endothelial cells are shrunken, with bright eosinophilic cytoplasm and a pyknotic nucleus (necrosis).  Remaining endothelial cells are often hypertrophic and the tunica media is infiltrated by low numbers of macrophages and lymphocytes with mild edema. Diffusely, perivascular and peribronchiolar connective tissues, interlobular septa and pleura are markedly expanded by homogenous, pale eosinophilic to clear fluid and ectatic lymphatics (edema), and low numbers of lymphocytes, plasma cells, macrophages, hemosiderin-laden macrophages and fewer neutrophils.  Multifocally, smaller bronchi, bronchioles and alveolar lumina contain variable amounts of edema admixed with a cellular exudate composed of lymphocytes, macrophages and hemorrhage.  Multifocally, alveolar septa are ruptured with blunt clubbed ends forming large confluent airways (emphysema).  Within the interstitium there are aggregates of macrophages which contain a black spiculated pigmented material (anthracosis).

MORPHOLOGIC DIAGNOSIS:  Lung:  Pneumonia, interstitial, multifocal, subacute, moderate, with endothelial viral syncitial cells and perivascular, interlobular and alveolar edema, breed not specified, equine.

HISTOPATHOLOGIC DESCRIPTION: 

Kidney:  Multifocally within renal vessels, the endothelial cells of tunica intima are necrotic or degenerate with syncytial cell formation.  There is myocyte degeneration and fibrin deposition within tunica intermedia, and the tunica adventitia is mildly fibrotic and multifocally surrounded by lymphocytes, with fewer macrophages and plasma cells.  Multifocally the glomeruli are surrounded by moderate amounts of collagen (sclerosis) and glomerular tufts architectures are lost and replaced by thick homogenous eosinophilic material (sclerotic collagen)(glomerular obsolescence).   

MORPHOLOGIC DIAGNOSIS:  1.  Kidney:  Arteriopathy, subacute, multifocal, mild with endothelial degeneration, necrosis and syncytial cell formation, myocyte degeneration and edema, and perivascular lymphoplasmacytic inflammation.

  1. Kidney: Glomerular sclerosis, multifocal, mild.

ETIOLOGIC DIAGNOSIS:  Equine paramyxoviral (Hendraviral) pneumonia

CAUSE:  Hendra virus

GENERAL DISCUSSIOIN: 

PATHOGENESIS: 

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY: 

References:

  1. Barclay AJ, Paton DJ. Hendra (equine morbillivirus). Vet J. 2000;160:169-176.
  2. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA: Elsevier; 2016:569.
  3. Field HE, Mackenzie JS, Daszak P. Henipaviruses: emerging paramyxoviruses associated with fruit bats. Curr Top Microbiol Immunol. 2007;315:133-159.
  4. Hooper PT, Ketterer PJ, Hyatt AD, Russell GM. Lesions of experimental equine morbillivirus pneumonia in horses. Vet Pathol. 1997;34(4):312-322.
  5. Lopez A. Martinson SA Respiratory system, mediastinum, and pleurae. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2016:526.
  6. MacLachlan NJ, Dubovi EJ. Paramyxoviradae. In: MacLachlan NJ, Dubovi EJ, eds. Fenner’s Veterinary Virology. 4th ed. London, UK: Academic Press; 2011:321-323.
  7. Middleton D, Pallister J, Klein R, et al. Hendra virus vaccine, a one health approach to protecting horse, human, and environmental health. Emerg Infect Dis. 2014;20(3)372-379.
  8. Westbury HA. Hendra virus disease in horses. Rev Sci Tech. 2000;19:151-159.
  9. Williamson MM. Hendra virus infection. In: Coetzer JAW, Tustin RC, eds. Infectious Diseases of Livestock. Vol 2. 2nd ed. Cape Town, South Africa: Oxford University Press; 2004:681-686.
  10. Williamson MM, Torres-Velez FJ. Henipavirus: a review of laboratory animal pathology. Vet Pathol. 2010;47(5):871-880.
  11. Wang LF, Yu M, Hansson E, et al. The exceptionally large genome of Hendra virus: support for creation of a new genus within the family Paramyxoviridae. Virol. 2000;74(21):9972-9979.

 

 


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