JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

SEPTEMBER 2017

P-P01

 

Signalment (JPC #1374690): Cat, age and breed unspecified

HISTORY:  Unknown

HISTOPATHOLOGIC DESCRIPTION:  Lung:  Diffusely, alveolar septa and, to a lesser extent, peribronchial and peribronchiolar interstitium are thickened up to 10 times normal by numerous macrophages, fewer neutrophils and lymphocytes, fibrin, increased clear space (edema), and moderate vascular congestion. Multifocally, alveolar septa are discontinuous with replacement by eosinophilic and karyorrhectic debris, fibrin, edema and similar inflammatory cells (alveolar septal necrosis). There is moderate type II pneumocyte hyperplasia. Alveolar lumina, and to a lesser extent the bronchial and bronchiolar lumina, frequently contain numerous degenerate and nondegenerate neutrophils, macrophages, fewer lymphocytes, erythrocytes (hemorrhage), rare multinucleate giant cell macrophages, eosinophilic cellular and karyorrhectic debris (necrosis), eosinophilic fibrillar beaded material (fibrin), and edema.  Occasionally, alveolar macrophages and type II pneumocytes are distended up to 3 times normal by an intracytoplasmic parasitophorous vacuole containing numerous 2-4 um, round to fusiform, basophilic tachyzoites.  Tachyzoites are rarely free within alveolar lumina adjacent to disrupted alveolar macrophages.  Multifocally, there are perivascular and peribronchial/bronchiolar aggregates of lymphocytes and plasma cells (mild BALT hyperplasia), as well as perivascular edema, and multifocal mesothelial cell hypertrophy (reactive mesothelium).

MORPHOLOGIC DIAGNOSIS:  Lung:  Pneumonia, interstitial, necrotizing, diffuse, severe, with type II pneumocyte hyperplasia, edema, and intrahistiocytic and intraepithelial tachyzoites, etiology consistent with Toxoplasma gondii, breed unspecified, feline.

ETIOLOGIC DIAGNOSIS: Pulmonary toxoplasmosis

CAUSE: Toxoplasma gondii

GENERAL DISCUSSION

LIFE CYCLE

PATHOGENESIS

TYPICAL CLINICAL FINDINGS

TYPICAL GROSS FINDINGS

TYPICAL LIGHT MICROSCOPIC FINDINGS

ULTRASTRUCTURAL FINDINGS

ADDITIONAL DIAGNOSTIC TESTS

DIFFERENTIAL DIAGNOSIS

COMPARATIVE PATHOLOGY

REFERENCES:

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  3. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier Limited; 2016:590.
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  6. Dolgen E. Climate change: As the ice melts. Nature. 2017;543(7647):S54-S55.
  7. Dubey JP and Lappin MR. Toxoplasmosis and neosporosis. In : Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. St. Louis, MO : Elsevier; 2012:806-821.
  8. Fayaad A, Kummerfeld M, Davina I, Wohlsein P, Beineke A, Baumgärtner W, Puff C. Fatal systemic Toxoplasma gondii infection in a red squirrel (Sciurus vulgaris), a Swinhoe's striped squirrel (Tamiops swinhoei) and a New World porcupine (Erethizontidae sp.). J Comp Pathol. 2016;154(2-3):263-7.
  9. Foster RA. Female reproductive system and mammae. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Mosby-Elsevier; 2017:1174, 1183, 1191.
  10. Gardiner CH, Fayer R, Dubey JP. An Atlas of Protozoan Parasites in Animal Tissues. 2nd ed. Washington, DC: Armed Forces Institute of Pathology, American Registry of Pathology; 1998: 53-56.
  11. Lopez A, Martinson SA. Respiratory system, mediastinum, and pleurae. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017: 548.
  12. Sanders JL, Moulton H, Moulton Z, McLeod R, Dubey JP, Weiss LM, Zhou Y, Kent ML. The zebrafish, Dania rerio, as a model for Toxoplasma gondii: an initial description of infection in fish. J Fish Dis. 2015;38(7):675-679.
  13. Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmers Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA: Elsevier; 2016:236-238.
  14. Zachary JF. Mechanisms of microbial infections. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Mosby-Elsevier; 2017:238-239.
  15. Zachary JF. Nervous system. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Mosby-Elsevier; 2017:844-845.


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