DAO 49:99-105 (2002)  -  doi:10.3354/dao049099

First report of piscine nodavirus infecting wild winter flounder Pleuronectes americanus in Passamaquoddy Bay, New Brunswick, Canada

Duane E. Barker1,*, Ann-Margaret MacKinnon2, Linda Boston2, Michael D. B. Burt3, David K. Cone4, David J. Speare5, Steve Griffiths6, Marcia Cook6, Rachael Ritchie6, Gilles Olivier2

1School of Fisheries, Marine Institute of Memorial University, St. John¹s, Newfoundland A1C 5R3, Canada
2Fish Health Unit, Department of Fisheries & Oceans, PO Box 5030, Moncton, New Brunswick E1C 9B6, Canada
3Huntsman Marine Science Centre, St. Andrews, New Brunswick E5B 2L7, Canada
4Department of Biology, Saint Mary¹s University, Halifax, Nova Scotia B3H 3C3, Canada
5Atlantic Veterinary College, Charlottetown, Prince Edward Island C1A 4P3, Canada
6Molecular Biology Group, Research Productivity Council, Fredericton, New Brunswick E3B 6Z9, Canada

ABSTRACT: Piscine nodaviruses (Betanodaviridae) are frequently reported from a variety of cultured and wild finfishes. These non-enveloped, single-stranded RNA virions cause viral encephalopathy and retinopathy (VER), also known as viral nervous necrosis (VNN) or fish encephalitis. Recently, nodavirus infections have posed serious problems for larval and juvenile cultured halibut Hippoglossus hippoglossus in Norway and Scotland. To date, no such viruses have been described from any cultured or wild pleuronectid in Atlantic Canada. Obviously, there exists a need to survey wild populations of pleuronectids to assess the risk of potential transfer of nodavirus from wild to caged fishes. This paper presents the results of monthly surveys (April 2000 to March 2001) of viruses from wild winter flounder Pleuronectes americanus collected from Passamaquoddy Bay, New Brunswick, Canada. Tissue samples from wild flounder were screened initially on commercial cell lines (EPC, SSN-1, SHK and CHSE-214) for any evidence of cytopathic effect (CPE). After confirmation of CPE, nodavirus identification was achieved using reverse transcription polymerase chain reaction (RT-PCR) analysis. We detected nodavirus from only 1 out of 440 flounder (0.23%) examined. This is the first report of piscine nodavirus isolated from wild winter flounder in Atlantic Canada, and although this prevalence may seem low, we discuss the implications of this finding for Canada¹s emerging halibut aquaculture industry.


KEY WORDS: Nodavirus · Betanodavirus · Winter flounder · Pleuronectes americanus · Halibut aquaculture · RT-PCR · Passamaquoddy Bay · New Brunswick · Atlantic Canada


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