Pathological changes in juvenile Atlantic halibut Hippoglossus hippoglossus persistently infected with nodavirus

Diseases of Aquatic Organisms

T. Taksdal¹  M. K. Hansen¹  T. Ranheim¹  G. K. Totland¹  R. Johansen¹ 

关键词: Atlantic halibut;    Fish;    Nodavirus;    Persistent infection;    Subclinical infection;    Immunohistochemistry;    Ultrastructure;    Viral encephalopathy and retinopathy;    VER;   

DOI  :  10.3354/dao050161

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: This is the first description of a persistent subclinical nodavirus infection in the Atlantic halibut Hippoglossus hippoglossus. Juvenile fish (1 to 5 g) were sampled at 4, 5 and 8 mo of age at a fish farm in Norway during and afterweaning. None showed clinical signs of viral encephalopathy and retinopathy (VER) or other disease. Pathological changes and/or nodavirus were detected by light microscopy, immunohistochemistry, reverse transcriptase polymerase chain reaction (RT-PCR) andtransmission electron microscopy in all fish examined. High numbers of virus particles were found in macrophage-like cells in the central nervous system, including brain and retina (CNS). The virus particles displayed the icosahedral shape and size(approximately 25 nm) characteristic of nodaviruses. The virus-infected cells formed focal cell aggregates and were seen in all regions of the brain and all nuclear cell layers of the retina. The cytoplasm of the infected cells was filled withmembrane-enclosed inclusions packed with virus particles. Some virus particles lay along membranes and formed membrane-bound necklace-like arrangements. The virus-infected cells of the retina also contained pigment granula located generally inside virusinclusions and sometimes forming a coating around the virus particles. All frontal parts with the eyes and brain and 50% of the mid-parts, which included the abdominal organs, were found positive for nodavirus with RT-PCR. Pathological changes in thesepersistently nodavirus-infected fish differ from earlier descriptions in Atlantic halibut during outbreaks of VER. Vertical transmission from infected spawners is believed to be a major route for nodavirus infection. Detection of nodavirus in subclinicalinfected fish and a better understanding of its pathogenesis are important in order to prevent the spread of nodavirus in the fish-farming industry.

【 授权许可】

Unknown