title: Morphologic description of infectious salmon anaemia virus (ISAV)-induced lesions in rainbow trout Oncorhynchus mykiss compared to Atlantic salmon Salmo salar.
abstract: In the present study the pathogenesis of experimental infectious salmon anaemia virus (ISAV) infection in rainbow trout Oncorhynchus mykiss (Walbaum, 1972) and Atlantic salmon Salmo salar was compared. The virus infection in the 2 species demonstrated different mortality patterns and pathology characteristics. Atlantic salmon showed a typical acute mortality pattern peaking at 8 to 16 d post-infection (dpi) depending on virus dose, whereas in rainbow trout, only the highest virus dose (10(7.13-7.8) TCID50/200 microl) showed a similar pattern. The middle (10(4.13) TCID50/200 microl) and lowest virus doses (10(2.13) TCID50/200 microl) in rainbow trout induced only sporadic protracted mortality, lasting up to 46 dpi. Infected rainbow trout that were live-sampled and those that died demonstrated increased erythrophagia, clusters of cellular degeneration in the haematopoietic portion of the kidney, and occasionally epicarditis, endocarditis and myocarditis. These lesions are very different from the typical necrosis in liver and kidney that occur in infected Atlantic salmon, and some of them may be indicative of an antiviral response by a resistant host to the ISAV infection. Virus was detected in the endothelium of the rainbow trout tissues using in situ hybridization, supporting our conclusions of the ISAV-induced lesions in this report.
authors.affiliation: Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: MacWilliams
authors.forename: Gerald
authors.initials: G
authors.lastname: Johnson
authors.forename: David
authors.initials: D
authors.lastname: Groman
authors.forename: Frederick S B
authors.initials: FS
authors.lastname: Kibenge
mesh_terms: D000818:Animals; D017756:Aquaculture; D002432:Cecum / Q000473:pathology / Q000821:virology; D005393:Fish Diseases / Q000473:pathology* / Q000821:virology*; D006321:Heart / Q000821:virology; D006400:Hematocrit / Q000662:veterinary; D006651:Histocytochemistry / Q000662:veterinary; D017403:In Situ Hybridization / Q000662:veterinary; D046829:Isavirus / Q000235:genetics / Q000254:growth & development*; D053208:Kaplan-Meier Estimate; D007668:Kidney / Q000473:pathology / Q000821:virology; D008099:Liver / Q000473:pathology / Q000821:virology; D017686:Oncorhynchus mykiss; D009976:Orthomyxoviridae Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D020317:Salmo salar
chemical_list: D012367:RNA, Viral