TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 Occurrence Of Systemic Amebiasis In Goldfish (Carassius auratus) Stephen A. Smith, Jeffrey C. Wolf, Robert B. Duncan Jr. And Jenifer L. Cardinale Department of Biomedical Sciences and Pathobiology, VA-MD Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0442 Goldfish (Carassius auratus) from the same aquarium system were presented approximately one year apart for similar signs consisting of severe abdominal distention and chronic intermittent buoyancy problems. At necropsy, multifocal small white nodules were observed in the tissues of the liver, kidney, and larger mesenteric mass suspended in the ceolomic cavity of the fish. Histopatholoy of the liver and mesenteric mass revealed numerous discrete granulomas having an encapsulated central amorphous eosinophilic area with scattered karyorrhectic debris. The central core of each pyogranuloma consisted of either necrotic and degenerating neutrophils or amorpous eosinophilic granular material. Areas of chronic inflammation were occassionally observed within several of the larger macrophages and multinucleated cells surrounding the central core. The pyogranulomas were often encapsulated by a few layers of immature fibrous connective tissue. In addition, many areas of inflammation featured clusters of low to moderate numbers of spherical protozoan organisms that were approximately 2-3 microns in diameter. Organisms were most commonly noted in a narrow zone adjacent to the necrotic core of some pyogranulomas. Special stains did not reveal additional morphological details of the organisms. Severe chronic multifocal pyogranulomatous hepatitis and peritonitis with intralesional protozoa was therefore diagnosed. Previous reports of this type of parasitic infection in goldfish have classified the organism as an amoeba, most likely in the family Hartmannellidae.   Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page