DAO 46:7-14 (2001)  -  doi:10.3354/dao046007

Infectious hematopoietic necrosis virus antibody profiles in naturally and experimentally infected Atlantic salmon Salmo salar

Sophie St-Hilaire1,2,*, Carl S. Ribble1, Scott E. LaPatra3, Stacy Chartrand2, Michael L. Kent2,**

1Department of Population Medicine, University of Guelph, Guelph, Ontario N1G 2W1, Canada
2Pacific Biological Station, Department of Fisheries and Oceans, Nanaimo, British Columbia V9T 1E1, Canada
3Clear Springs Foods, Buhl, Idaho 83316, USA
*E-mail: **Present address: Department of Microbiology, 220 Nash Hall, Center for Salmon Disease Research, Oregon State University, Corvallis, Oregon 97331-3804, USA

ABSTRACT: Atlantic salmon Salmo salar naturally and experimentally exposed to infectious hematopoietic necrosis virus (IHNV) in British Columbia, Canada, developed antibodies against the virus. More than 50% of the fish exposed to IHNV remained seropositive for several months after the IHN epizootic had subsided. The virus itself could not be detected in asymptomatic fish once the fish had recovered from IHN. The persistence of IHNV-specific antibodies in a large percentage of Atlantic salmon, from 4 different populations that survived an outbreak of IHN, and the lack of IHNV-specific antibodies in fish with no history of the disease, suggests that serology may be a useful tool for determining previous exposure to the virus. It may be important to determine whether Atlantic salmon have been infected with IHNV because, although the virus is difficult to detect in asymptomatic fish, an incidental finding suggests it may persist in a small number of fish after the outbreak has subsided. Furthermore, the presence of seropositive fish would be an indication that the virus may be enzootic at a farm, and such information would thus aid producers with stocking decisions.

KEY WORDS: IHNV · IHNV-specific antibodies · Surveillance · Convalescent carrier state · Atlantic salmon

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