First report of piscine nodavirus, (Betanodaviridae) infecting wild winter flounder, Pleuronectes americanus, from Passamaquoddy Bay, New Brunswick

Piscine nodaviruses are frequently being reported from a variety of cultured and wild finfish. These pathogens are responsible for 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 pleuronectids in Atlantic Canada, however, surveys of wild populations of pleuronectids are required to accurately assess the risk of potential transfer of nodavirus from wild to caged halibut. This paper presents the results of monthly surveys (April 2000 - March 2001) of viruses from wild winter flounder, Pleuronectes americanus, collected from Passamaquoddy Bay, New Brunswick, Canada. We detected nodavirus from only one 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 our emerging 'alternative species' aquaculture industry..