Characteristics of a new birnavirus associated with a warm-water fish cell line

Abstract

A warm-water fish cell line developed from blotched snakehead caudal peduncle (BSN) was found to have persistent birnavirus infection. Purified virus particles were of icosahedral shape and had 57±1·6 nm diameter. The BSN virus was resistant to 5-iodo-2′-deoxyuridine and induced yellowish-green cytoplasmic inclusions when stained with acridine orange. The virus was resistant to chloroform, acid and alkaline pH and heat treatment at 56 °C for 2 h. Purified virions had a buoyant density of 1·33 g/ml in CsCl and contained two genomic segments with molecular masses of 2·56×106 and 2·00×106 Da and four structural polypeptides of 112 (polyprotein, PP), 91 (VP1), 44 (VP2) and 37 (VP3) kDa. Reciprocal β cross-neutralization tests incorporating four classical strains of infectious pancreatic necrosis virus (IPNV) (WB, Sp, Ab and TV-1) and the BSN virus established the complete serological distinctness of the virus from IPNV. Considering the uniqueness of the virus, the name blotched snakehead virus is proposed for this agent.