JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

September 2017

P-P06

 

Signalment (JPC #2133906): Cow

HISTORY:  None

HISTOPATHOLOGIC DESCRIPTION: Lung: Affecting up to 75% of this section, replacing normal pulmonary parenchyma, there are multifocal to coalescing areas of coagulative and lytic necrosis with a center of eosinophilic karryorhectic and cellular debris and fragmented alveolar septa and bronchiolar walls that are surrounded by a dense cellular infiltrate consisting of large numbers of degenerate and non-degenerate neutrophils and macrophages, with few eosinophils, admixed with abundant fibrin, edema, hemorrhage, and additional necrotic debris that fills and expands surrounding alveolar lumina.  Surrounding alveolar septa are thickened up to 3 times normal by macrophages, neutrophils, and fibrous connective tissue (fibrosis).  Also present within the necrotic centers, within alveoli and alveolar septa, are numerous amoebic trophozoites and cysts.  Trophozoites are up to 25um, have vacuolated cytoplasm, a 4-7um karyosome with a single endosome.  Cysts are up to 20um with a clear halo separating an outer ectocyst and inner endocyst.  Bronchiolar epithelium is multifocally hyperplastic and thrown into folds into the airway lumen which is filled with an exudate composed of necrotic debris, viable and degenerate neutrophils, macrophages, hemorrhage and fibrin with additional trophozoites.  Multifocally, the tunica media and adventitia of vessels is expanded and infiltrated by cysts, trophozoites, neutrophils, macrophages, fibrin, hemorrhage, and karyorrhectic debris (necrotizing vasculitis). There is perivascular hemorrhage low to moderate numbers of macrophages, plasma cells and lymphocytes. The pleura is expanded by fibrin and edema.

MORPHOLOGIC DIAGNOSIS:  Lung:  Pneumonia, fibrinous, necrotizing and pyogranulomatous, chronic-active, diffuse, severe, with amoebic trophozoites and cysts, breed unspecified, bovine.

ETIOLOGIC DIAGNOSIS:  Pulmonary amebiasis

CAUSE: Acanthamoeba sp.

CONDITION:  Acanthamebiasis

GENERAL DISCUSSION:

PATHOGENESIS:

LIFE CYCLE:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. Vol 2. St. Louis, MO: Elsevier; 2016:513,574.
  2. Cheville NF. Ultrastructural Pathology: The Comparative Cellular Basis of Disease, 2nd ed. Ames. IA: Wiley-Blackwell;2009:527-528
  3. Gaide N, et al. Necrotizing meningoencephalitis in a captive black and white ruffed lemur (Varecia variegata variegata) caused by Acanthamoeba T4 genotype. J Comp Path. 2015;153(4):231-235.
  4. Gardiner CH, Fayer R, Dubey JP. An Atlas of Protozoan Parasites in Animal Tissues, 2nd ed. Washington, DC: Armed Forces Institute of Pathology;1998;10-11
  5. Gelberg HB. Alimentary system and the peritoneum, omentum, mesentery, and peritoneal cavity. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:381.
  6. Greene CE, Howerth EW, Kent M. Nonenteric amebiasis: acanthamebiasis, hartmannelliasis, and balamuthiasis. In: Greene CE, ed. Infectious Diseases of the Dog and Cat, 4th ed. St. Louis, MO: Elsevier Saunders; 2012:802-806.
  7. Strait K, Else JG, Eberhard ML. Parasitic diseases of nonhuman primates. In: Abee CR, Mansfield K, Tardif S, Morris T, ed. Nonhuman Primates in Biomedical Research: Diseases. Vol 2. London, UK: Academic Press; 2012: 208-209.
  8. Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie MG ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. Vol 2. St. Louis, MO: Elsevier; 2016:242.
  9. Westmorland SV, Rosen J, MacKey J, Romsey C, Xia DL, Visvesvera GS, Mansfield KG. Necrotizing meningoencephalitis and pneumonitis in a simian immunodeficiency virus-infected Rhesus Macaque due to Acanthamoeba. Vet Pathol. 2004;41:398-404.

 


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