JPC SYSTEMIC PATHOLOGY
SPECIAL SENSES
MAY 2018
S-P01 (NP)

Signalment (JPC #2340404):  A white sucker fish

HISTORY:  Tissue from a white sucker fish taken at the annual Yellowstone Lake survey by gill net.

HISTOPATHOLOGIC DESCRIPTION:  Eye: Circumferentially beneath the lens capsule there is a broad 500 um wide band that has loss of the normal lens fiber structure with replacement by a homogenous bright eosinophilic material (liquefaction of lens fibers) along with several elliptical, trematode larvae (metacercariae) at the posterior aspect of the lens.  In the overlying lens tissue, there are multifocal nodules of enlarged, rounded, foamy, eosinophilic nucleated cells (bladder cells) and rare, rounded, brightly eosinophilic accumulations (Morgagnian globules) of liquefied lens material (cataractous change). Metacercariae are approximately 180 x 360 um long, with an oral sucker, a 5 um thick tegument, no body cavity with a moderately cellular parenchyma surrounded by a layer of regularly palisading epithelial cells beneath a layer of muscle.  Within the choroid and extending into the iris are moderate to high numbers of granulocytes, histiocytes and fewer lymphocytes admixed with an eosinophilic, granular material (protein). Overlying the corneal surface, there is a focally extensive accumulation of erythrocytes, fibrin and necrotic debris.  Focally, in the superficial corneal epithelium near the fornix, there are clusters of 40 um diameter, eosinophilic, glassy cells with irregular nuclei (club cells). Diffusely, within the scleral stroma, there are low numbers of lymphocytes and rare macrophages. 

MORPHOLOGIC DIAGNOSIS:  

  1. Eye, lens:  Cataractous change, subcapsular, multifocal, moderate, with intralenticular trematode metacercariae, white sucker fish (Catostomus commersoni), piscine.
  2. Eye, iris and choroid: Panuveitis, granulocytic, moderate.

ETIOLOGIC DIAGNOSIS:  Lenticular diplostomatosis

CAUSE:  Diplostomum spp.

SYNONYMS:  Diplostomatosis, diplostomiasis, parasitic cataract, eye fluke disease

GENERAL DISCUSSION:

PATHOGENESIS:

LIFE CYCLE:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

DIFFERENTIAL DIAGNOSIS:

Cataracts in freshwater fish

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Bruno DW, Poppe TT. A Colour Atlas of Salmonid Diseases. New York, NY: Academic Press; 1996:90-91.
  2. Davis HS. Culture and Diseases of Game Fishes. Los Angeles, CA: University of California Press; 1967:227-229.
  3. Heckman RA. Parasites of Salmonid Fishes. In: Stoskopf MK, ed. Fish Medicine, Philadelphia, PA: W.B. Saunders; 1993:418-420.
  4. Hoole D, Bucke D, Burgess P, et al. Diseases of Carp and Other Cyprinid Fishes. Malden, MA: Fishing News Books; 2001: 83-84, 88-91.
  5. Roberts RJ. Fish Pathology, 4th West Sussex, UK: Blackwell Publishing Ltd.; 2012:322-323.
  6. Roberts RJ, Shepherd CJ. Handbook of Trout and Salmon Diseases, 3rd ed. Cambridge, MA: Fishing News Books; 1997:30, 47, 49-50, 103.
  7. Smith SA, Noga E. General parasitology. In: Stoskopf MK, ed. Fish Medicine, Philadelphia, PA: W.B. Saunders; 1993:140-141.
  8. Wilcock BP, Dukes TW. The eye. In: Ferguson HW, ed. Systemic Pathology of Fish: A Text and Atlas of Comparative Tissue Responses in Diseases of Teleosts. Ames, IA: Iowa State University Press; 1989:173-176, 185-189.


Click the slide to view.



Click on image for diagnostic series.



Back | Home | Contact Us | Links | Help |