JPC SYSTEMIC PATHOLOGY
URINARY SYSTEM
January 2018
U-P06

SINGALMENT (JPC # 1727491): Common loon.

HISTORY:  This common loon (Gavia immer) had been weak, unable to fly, and passed blood-tinged milky droppings two days prior to death.

HISTOPATHOLOGIC DESCRIPTION:  Kidney: The ureteral epithelium is multifocally either ulcerated or hyperplastic with multiple nuclei stacked up to 15 cells layers thick with loss of cellular polarity.  There are numerous coccidia in various stages of development and numerous coccidial oocysts in various stages of sporulation within the hyperplastic ureteral epithelium as well as the lamina propria and underlying interstitium, primarily at foci of ulceration.  Developmental stages present include round macrogametocytes that are 15-20um diameter, thin walled, and filled with 1-4 um diameter, eosinophilic, round macrogametes; fewer microgametocytes that are 15-18um diameter with an indistinguishable cell wall and contain myriad, 1 X 2 um, crescentic, deeply basophilic microgametes; undifferentiated gamonts 4 x 10 um, ovoid, deeply basophilic and homogeneous; and ovoid to spherical oocysts characterized by 1um, undulant, nonrefractile cell that contain either clear cytoplasm or irregularly ovoid aggregates of basophilic material (presumed sporocysts). Within the ureteral lumen are numerous sloughed epithelial cells, degenerate inflammatory cells, and coccidia. The ureteral lamina propria contains moderate numbers of lymphocytes, plasma cells, fewer macrophages, and rare heterophils admixed with the previously described oocysts.  Kidney tubules and collecting ducts are multifocally mildly to moderately ectatic, lined by attenuated or rarely necrotic epithelium, and often contain finely granular, pale eosinophilic flocculant material (urates – urate stasis) and variably contain intraluminal oocysts as previously described, sloughed epithelial cells, hemorrhage, and cellular and nuclear debris (cellular and granular casts).  Renal tubular and collecting duct epithelium multifocally contains coccidial schizonts (meronts) with merozoites that occasionally are associated with ruptured epithelial cells, with merozoites emerging into the lumen.

MORPHOLOGIC DIAGNOSIS: 

  1. Ureter: Ureteritis, ulceroproliferative, lymphoplasmacytic, multifocal, moderate, with luminal and transmural coccidia and oocysts, common loon (Gavia immer), avian.
  2. Kidney: Tubular and collecting duct ectasia with intraluminal urate stasis, minimal tubular hyperplasia and necrosis, and intraepithelial and luminal coccidia and oocysts.

ETIOLOGIC DIAGNOSIS:  Renal coccidiosis

ETIOLOGYEimeria gaviae

GENERAL DISCUSSION: 

PATHOGENESIS: 

LIFE CYCLE:

TYPICAL CLINICAL FINDINGS: 

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

TYPICAL ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS: 

COMPARATIVE PATHOLOGY: 

REFERENCES: 

  1. Bowman DB. Georgis’ Parasitology for Veterinarians.  10th Ed. St. Louis, MO: Elsevier Saunders; 2014:98-103.
  2. Garner MM, Gardiner JF, Wellehan FX, et al. Intranuclear coccidiosis in tortoises: Nine cases.  Vet Pathol. 2006;43(3):311-320.
  3. Gelberg HB. Alimentary system and the peritoneum, omentum, mesentery, and peritoneal cavity. In: Zachary JF, ed. Pathological Basis of Veterinary Disease. 6th ed. Philadelphia, PA: Mosby Elsevier Inc.; 2017:382.
  4. Jankovsky JM, Brand M, Gerhold RW. Identification of a novel renal coccidian (Apocomplexa: Eimeriidae) from the Great-Horned Owl (Bubo virginianus), USA.  J Wildl Dis. 2017;53(2):368-371.
  5. Randall CJ, Reece RL. Color Atlas of Avian Histopathology.  London, England: Mosby-Wolfe; 1996:141.
  6. Uzal FA, Plattner BL, Hostetter JM. Alimentary system.  Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA: Elsevier Saunders; 2016:227-235.
  7. Woolcock, Boulianne M. Diseases of the duck.  In: Boulianne M., ed. Avian Disease Manual. 7th Jacksonville, FL: American Association of Avian Pathologists; 2013:233.
  8. Yamada M, Hatama S, Ishikawa Y, Kadota K. Intranuclear coccidiosis caused by Cyclospora in calves.  Jour Vet Diagn Invest.  2014;26(5):678-682.
  9. Zachary JF. Mechanisms of microbial infection. In: Zachary JF, ed. Pathological Basis of Veterinary Disease. 6th ed. Philadelphia, PA: Mosby Elsevier Inc.; 2017:237.


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