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Atlantic Salmon Swim Bladder Sarcoma Virus,
Management Of A Newly Reported Virus In Imperiled Feral Stocks John A. Coll1, P. R. Bowser2, J. W. Casey2, R. C.
Cipriano3, L. Lofton4, and T. King5 1U.S. Fish and Wildlife Service, Fish Health Center, Lamar,
PA 16848; 2Department of Microbiology and Immunology, College of
Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401; 3U.S.
Geological Survey, National Fish Health research Laboratory, 1700 Leetown Road,
Kearneysville, WV 25430; 4U.S. Fish and Wildlife Service, National
Fish Hatchery, North Attleboro, MA 02760; 5U.S. Fish and Wildlife
Service, National Fish Hatchery, East Orland, ME 04431 A population of adult Atlantic salmon (Salmo salar) held a North Attleboro National Fish Hatchery as part of an Atlantic Salmon Recovery Program, first demonstrated degrees of lethargy and poor growth, then experienced chronic mortalities which later progressed to the expression of external signs including multifocal hemorrhage on the body and fins along with swollen abdomens. Upon necropsy, these fish had multinodular masses of the swim bladder which histologically were made up of well-differentiated fibroblastic cells arranged in interlacing bundles, similar to a report in cage-cultured Atlantic salmon in Scotland in 1976. The presence of a retrovirus was identified through the use of degenerate RT-PCR and gene sequencing techniques. The specific role of this retrovirus in the development of Salmon Swim Bladder Sarcoma Virus (SSSV) is still unknown. Subsequently, seven other captive feral populations of Atlantic salmon held at Craig Brook National Fish Hatchery were similarly screened, with six testing positive for proviral DNA of SSSV in blood samples. A limited number of fish were placed in an isolation facility for monitoring on a seasonal basis. Factors affecting the management of this virus and its host, including limited screening capability, unknown virulence and transmission, completion of isolation facilities and the listing of these Atlantic salmon stocks as endangered species will be discussed. |