JPC SYSTEMIC PATHOLOGY

INTEGUMENT SYSTEM

November 2016

I-P16

 

Signalment (JPC 1647900): Cardinal tetra (Paracheirodon axelrodi)

HISTORY:  This is one of ten Cardinal tetras obtained from a pet store.  Nine days later, multiple raised, pinpoint to 3 mm white spots appeared.  Within days, all ten tetras were dead.

MICROSCOPIC DESCRIPTION:  Skin, oral cavity, and gills: Multifocally, there are nodular foci up to 500 µm within the epidermis, gill epithelium, and oral mucosa that are composed of hyperplastic epithelium that piles up to 8 cell layers.  Hyperplastic epithelium surrounds up to 150 um diameter, irregularly round, single‑cell protozoal cysts with a 1‑2 µm thick hyaline wall, abundant, finely granular, to vacuolated basophilic cytoplasm that contains numerous host erythrocytes, and a 30 x100 µm, crescent-shaped, deeply basophilic macronucleus (trophont). Multifocally, there is mild hyperplasia of gill epithelium with blunting and fusion of secondary lamellae with numerous previously described intraepithelial protozoa. 

MORPHOLOGIC DIAGNOSIS:  Skin, oral cavity and gills:  Hyperplasia, epithelial, nodular, multifocal, moderate, with numerous protozoal cysts, etiology consistent with Ichthyophthirius multifilis, Cardinal tetra (Paracheirodon axelrodi), piscine.

ETIOLOGY:  Ichthyophthirius multifilis

ETIOLOGIC DIAGNOSIS: Cutaneous, oral, and branchial ichthyophthiriosis

CONDITION:  Ich

CONDITION SYNONYMS:  Freshwater white spot disease

GENERAL: 

LIFE CYCLE:

PATHOGENESIS: 

TYPICAL GROSS FINDINGS: 

TYPICAL MICROSCOPIC FINDINGS: 

DIFFERENTIAL DIAGNOSIS: 

REFERENCES: 

  1. Abdel-Hafez G, Lahnsteiner F, Mansour N, Licek E. Pathophysiology of Ichthyophthirius multifiliis infection in rainbow trout (Oncorhynchus mykiss) and chub (Leuciscus cephalus). J Comp Pathol. 2014; 151(4):394-399.
  2. Gardiner CH, Fayer R, Dubey JP. An Atlas of Protozoal Parasites in Animal Tissues, 2nd ed. Washington, DC: Armed Forces Institute of Pathology; 1998: 16-17.
  3. Noga EJ. Fish Disease Diagnosis and Treatment. 2nd Ames, IA: Wiley-Blackwell; 2010:129-148.
  4. Roberts RJ. Fish Pathology. 4 ed. West Sussex, UK: Wiley-Blackwell; 2012: 84, 159, 309.
  5. Smith SA, Zimmerman K. Fish and chips. Vet Clin Path. 2016; 45(2):213-214.


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