The first isolation of a rhabdovirus from perch (Perca fluviatilis) in Norway

A rhabdovirus was isolated from perch (Perca fluviatilis) harvested from lake Arungen in the South-Eastern part of Norway. The fish were placed in indoor tanks for reproduction studies. A few days after the introduction, fish showed swimming disturbancies and lethargy, and a low mortality was observed during a period of several months. No gross or histopathological changes were observed. The virus was isolated from moribund fish in BF-2 cells. An extensive cytopathic effect (CPE) was observed, and examination of infected cell cultures by electron microscopy demonstrated virus particles with a morphology consistent with that of rhabdoviruses. The viral genome consists of RNA as shown by using specific metabolic inhibitors. The virus was further characterized by immunofluorescence (IF) and a plaque neutralization test using a panel of different antisera against several fish rhabdoviruses. The virus was stained in IF with rabbit antisera against perch rhabdovirus, pike rhabdovirus and lake trout rhabdovirus and neutralised by anti perch rhabdovirus indicating that the Norwegian perch virus is closely related to these viruses belonging to the Vesiculovirus genus of the family Rhabdoviridae. This is the first time a rhabdovirus has been detected in perch in Norway, and it indicates that viruses belonging to this group might be more widespread in nature than previously assumed.