Back to Search Start Over

Characterization of nodavirus and viral encephalopathy and retinopathy in farmed turbot, Scophthalmus maximus (L.).

Characterization of nodavirus and viral encephalopathy and retinopathy in farmed turbot, Scophthalmus maximus (L.).

Authors :
Johansen R
Sommerset I
Tørud B
Korsnes K
Hjortaas MJ
Nilsen F
Nerland AH
Dannevig BH
Source :
Journal of fish diseases [J Fish Dis] 2004 Oct; Vol. 27 (10), pp. 591-601.
Publication Year :
2004

Abstract

An outbreak of nodavirus infection in turbot larvae is described with respect to histopathology, immunohistochemistry, cell culture cultivation, RT-PCR amplification and sequence analysis of the capsid protein gene RNA2. Affected turbot developed classical signs of viral encephalopathy and retinopathy (VER) with abnormal swimming behaviour and high mortality levels. In the acute stage of infection, light microscopy revealed vacuolation of the central nervous system (CNS), with positive immunohistochemical staining for nodavirus. Later in the infection, CNS lesions appeared more chronic and contained clusters of cells immunopositive for nodavirus. Bacterial overgrowth in the intestines of the fish may have provoked or influenced the course of the nodavirus infection. We were unable to propagate the virus in cell culture. While RT-PCR using primers designed to detect Atlantic halibut nodavirus gave negative results, further testing with primers complementary to a more conserved region of RNA2 resulted in amplification of a product of the expected size. The entire RNA2 segment was cloned and sequenced. Sequence alignment showed that the turbot nodavirus (TNV) was different from previously described fish nodaviruses. In addition, phylogenetic analysis based on an 823 nt region of the sequence indicated that TNV clustered outside the four established fish nodavirus genotypes, suggesting a fifth genotype within the betanodaviruses.

Details

Language :
English
ISSN :
0140-7775
Volume :
27
Issue :
10
Database :
MEDLINE
Journal :
Journal of fish diseases
Publication Type :
Academic Journal
Accession number :
15482424
Full Text :
https://doi.org/10.1111/j.1365-2761.2004.00581.x