Isolation and characterisation of rhabdovirus from wild common bream Abramis brama, roach Rutilus rutilus, farmed brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss in Northern Ireland.

Abstract

Rhabdovirus was isolated from wild common bream Abramis brama during a disease outbreak with high mortality in Northern Ireland during May 1998. Rhabdovirus was also isolated at the same time from healthy farmed rainbow Oncorhynchus mykiss and brown trout Salmo trutta on the same stretch of river and 11 mo later from healthy wild bream and roach Rutilus rutilus in the same river system. Experimental intra-peritoneal infection of bream and mirror carp Cyprinus carpio var specularis with 2 of these isolates produced low mortality rates of < or = 12%. Serological testing of these isolates by virus neutralisation indicated that they were antigenically closely related to pike fry rhabdovirus (PFRV) but not to spring viraemia of carp virus (SVCV), while testing by enzyme-linked immunosorbent assay indicated them to be antigenically different from both. Comparison of nucleotide sequence data of a 550 base pair segment of the viral glycoprotein generated by reverse transcription-polymerase chain reaction indicated a high (> or = 96.6%) degree of similarity between these isolates and a previous Northern Ireland isolate made in 1984, a 1997 isolate from bream in the Republic of Ireland and an earlier Dutch isolate from roach. In contrast, similarity between these isolates and PFRV was < 82.4%, indicating that these viruses belong to 2 distinct genogroups, while similarity to SVCV was even lower (< 67.4%).