Isolation of viral haemorrhagic septicaemia virus from Atlantic herring Clupea harengus from the English Channel

Viral haemorrhagic septicaemia virus (VHSV) was isolated from apparently healthy Atlantic herring Clupea harengus from the English Channel. The virus was isolated in bluegill fibroblast (BF-2) cells but not epithelioma papulosum cyprini (EPC) cells; however, the virus was passaged from BF-2 to EPC cells. The identity of the virus was confirmed by an enzyme-linked immunosorbent assay and by a reverse transcriptase-polymerase chain reaction (RT-PCR). The virus was classified as a member of genogroup III of VHSV, which comprises many European freshwater and marine VHSV isolates. Sequence comparisons of the RT-PCR products showed that the herring isolate was closely related (99.1% nucleotide similarity) to a VHSV isolate from Atlantic cod Gadus morhua; both of those isolates were avirulent for rainbow trout Oncorhynchus mykiss by bath infection. Circumstantial evidence is presented which suggests that VHSV from herring could have been the source of VHS disease in rainbow trout in Denmark.