DAO 57:35-41 (2003)  -  doi:10.3354/dao057035

Acute and persistent experimental nodavirus infection in spotted wolffish Anarhichas minor

R. Johansen1,*, M. Amundsen2, B. H. Dannevig1, A. I. Sommer2

1National Veterinary Institute, PO Box 8156, 0033 Oslo, Norway
2Norwegian Institute of Fisheries and Aquaculture Research, 9291 Tromsø, Norway

ABSTRACT: Spotted wolffish Anarhichas minor (approx. 0.7 g) were found to be susceptible to infection with a nodavirus isolated from Atlantic halibut (AHNV) by bath-challenge. During the acute stage of infection, 4 to 8 wk post-challenge, viral encephalopathy and retinopathy (VER) were diagnosed by histopathology, immunohistochemistry (IHC) and reverse transcriptase-polymerase chain reaction (RT-PCR). Accumulated mortality was 52% in the challenged group. The surviving fish were sampled 16 wk post-challenge, by which time they had grown to approximately 17 g. No clinical signs of VER were observed in these fish. RT-PCR examination revealed the presence of nodavirus in several organs of the survivors, but no immunopositive cells were detected by IHC. Nodavirus was reisolated from fish at the last sampling in SSN-1 cells, showing that nodavirus retains virulence in persistently infected wolffish for at least 16 wk post-bath-challenge.


KEY WORDS: Nodavirus · Viral encephalopathy and retinopathy · VER · Viral nervous necrosis · VNN · Spotted wolffish · Anarhichas minor


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