Experimental infection of Atlantic halibut, Hippoglossus hippoglossus L.; yolk-sac larvae with infectious pancreatic necrosis virus: detection of virus by immunohistochemistry and in situ hybridization.

摘要

Three different concentrations (107, 105 and 103 TCID50/ml) of pancreatic necrosis virus (PNV) serotype Sp isolated from Atlantic halibut were used to bath-challenge Atlantic halibut yolk-sac larvae. The larvae challenged with 107 TCID50/ml sufferedsignificantly higher cumulative mortality than the other challenged groups and the control group, and affected individuals displayed necrosis of the intestine, liver and kidney. In larvae from the groups challenged with 107 and 105 TCID50/ml, PNV was detected by immunohistochemistry and in situ RNA/DNA hybridization in the intestine, liver and kidney. In addition, some individuals stained PNV-positive in the heart and eye/brain region. Detection by in situ hybridization did not appear to be more sensitive than immunohistochemistry. However, background staining was virtually absent in comparison with immunohistochemistry, and the staining seemed to be more distinctly localized to the cytoplasm of infected cells. It is concluded that farmed halibut yolk-sac larvae can be infected by PNV immediately after hatching, with resulting high mortality.