JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

September 2017

P-P17

 

SLIDE A:

Signalment (JPC #1910090):  Juvenile Chinook salmon (Oncorhynchus tshawytscha)

HISTORY:  Several fish had difficulty swimming, decreased growth rate, and increased mortality due to starvation and predation

HISTOPATHOLOGIC DESCRIPTION:  Gill:  Multifocally there is distortion of lamellar architecture with primary lamellae and secondary lamellae  expanded up to 4 times normal by variably-sized, up to 300 um diameter, irregularly round to oval microsporidian xenomas, with a thin eosinophilic wall, and numerous eosinophilic, 2-4 um oval spores.  Multifocally primary and secondary lamellae are mildly expanded by low numbers of macrophages, lymphocytes, and necrotic cellular debris.  There is multifocal atrophy, blunting, fusion and loss of secondary lamellae with branchial epithelial and mucous cell hyperplasia in adjacent lamellae.    

MORPHOLOGIC DIAGNOSIS:  Gill:  Branchitis, granulomatous, subacute, multifocal, mild, with lamellar fusion and atrophy, and many intra-lamellar microsporidian xenomas, Chinook salmon, piscine

ETIOLOGIC DIAGNOSIS:  Branchial microsporidiosis

CAUSE:  Loma salmonae

SYNONYMS:  Microsporidial gill disease

SLIDE B

Signalment (JPC #1901138):  Fingerling channel catfish (Ictalurus punctatus)

HISTORY:  Several fish were gasping at the water surface and succumbed to exertion

HISTOPATHOLGIC DESCRIPTION:  Multifocally, primary lamellae expanded up to 10 times normal width by numerous foamy macrophages, fewer lymphocytes, and scattered hemorrhage and edema admixed with necrotic cellular debris.  Within primary and secondary lamellae, there are few viable and degenerate microsporidian xenomas that are irregularly round, 20-50 um, and contain numerous 2-4 um, eosinophilic oval spores, frequently surrounded by palisading macrophages.  Multifocally, there are intralamellar myxozoan cysts up to 200 um in diameter that contain numerous, 2 x 10 um, fusiform, eosinophilic spores.  There is necrosis and loss of lamellar cartilage.  Adjacent secondary lamellae have moderate epithelial and mucous cell hyperplasia with marked lamellar fusion.  Multifocally separating secondary lamellae are cross sections of 100 um diameter adult trematodes characterized by a 5 um thick tegument, filled with a parenchyma, reproductive organs, vitellaria, and poorly discernible paired caeca (trematodes not present in all slides).

MORPHOLOGIC DIAGNOSIS:  1. Gill:  Branchitis, proliferative and necrotizing, subacute, diffuse, moderate with lamellar blunting, fusion, and atrophy, lamellar cartilage degeneration, and intralamellar myxosporan cysts, channel catfish, piscine

  1. Gill: Branchitis, subacute, multifocal, mild, with intralamellar microsporidian xenomas
  2. Gill: Trematodes, multiple

ETIOLOGIC DIAGNOSIS:  Branchial myxosporidiosis

CAUSE:  Henneguya spp

SYNONYMS:  Proliferative gill disease, hamburger gill disease

GENERAL DISCUSSION:

PATHOGENESIS/LIFE CYCLE:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS: 

Microsporea and Myxosporea grossly produce masses

COMPARATIVE PATHOLOGY:

References:

  1. Cali A, Neafie RC, Takvorian PM. Chapter 14: Microsporidiosis. In: Meyers W, Firpo A, Wear DJ, eds. Topics on the Pathology of Protozoan and Invasive Arthropod Diseases. Washington, DC: Armed Forces Institute of Pathology; 2011: 200-223.
  2. Cavin JM, Donahoe SL, Frasca S, et al. Myxobolus albi infection in cartilage of captive lumpfish (Cyclopterus lumpus). J Vet Diagn Invest. 2012;24(3):516-524.
  3. Eydner M, Donhauser J, Beineke A, et al. Microsporidiosis in four tortoises (Testudo hermanni boettgeri). Vet Pathol. 2017;54(4):704-709.
  4. Gardiner CH, Fayer R, Dubey JP. Microspora and Myxozoa: An Atlas of Protozoan Parasites in Animal Tissues. 2nd ed. Washington, DC: Armed Forces Institute of Pathology, American Registry of Pathology; 1998:12-15.
  5. Hadfield CA, Poynton SL, Clayton LA, et al. Kudoa (Myxozoa: Multivalvulida) in skeletal muscle of captive bullnose eagle rays, Myliobatis freminvillei (Rajiformes: Myliobatidae). J Zoo Wildl Med. 2014;45(4):896-905.
  6. Kent ML, Benda S, St-Hilaire S, et al. Sensitivity and specificity of histology for diagnoses of four common pathogens and detection of nontarget pathogens in adult Chinook salmon (Oncorhynchus tshawytscha) in fresh water. J Vet Diagn Invest. 2013;25(3):341-351.
  7. Noga EJ. Problems 58 through 76: Diagnoses made by necropsy of the viscera and examination of wet mounts or histopathology of internal organs. In: Noga EJ, ed. Fish Disease: Diagnosis and Treatment. Ames, IA: Wiley-Blackwell; 2010: 229-236, 247-253.
  8. Nolan MW, Roberts HE, Zimmerman KL, et al. Pathology in Practice: Myxosporidia. J Amer Vet Med Assoc. 2010; 236(6): 631-633.
  9. Richter B, Csokai J, Graner I, et al. Encephalitozoonosis in two inland bearded dragons (Pogona vitticeps). J Comp Pathol. 2013;143(2-3):278-282.
  10. Richter B, Graner I, Csokai J. Heterosporis anguillarum infection in garter snake (Thamnophis sirtalis). J Comp Pathol. 2014;150(2-3):332-335.

 

 


Click the slide to view.



Click on image for diagnostic series.



Back | Home | Contact Us | Links | Help |