Endangered wild salmon infected by newly discovered viruses

Mordecai, Gideon J; Miller, Kristina M; Di Cicco, Emiliano; Schulze, Angela D; Kaukinen, Karia H; Ming, Tobi J; Li, Shaorong; Tabata, Amy; Teffer, Amy; Patterson, David A; Ferguson, Hugh W; Suttle, Curtis A

Before the discovery of these viruses clinical signs of disease and histopathological lesions were assessed for approximately 230 farmed Chinook salmon sampled in the Audit program. Consequently, gills, skeletal muscle, spleen, liver, heart, anterior and posterior kidney, pyloric caeca and brain from eleven samples of Chinook (eight wild fish and three farmed fish) and ten sockeye (all wild fish) positive for SPAV were histopathologically analysed to assess the presence of lesions. All tissues were fixed in 10% neutral buffered formalin, dehydrated through an ascending gradient of alcohol solutions, embedded in paraffin wax, cut at 3.5 mm thickness, and stained with routine hematoxylin and eosin (H and E) for morphological evaluation by light microscope.