Comparison of the haemagglutinin genotype with the antigenic type of infectious salmon anaemia virus

Infectious salmon anaemia (ISA) has been recognized as affecting salt-water farmed Atlantic salmon, Salmo salar, in Norway since 1984. The first disease outbreak outside of Norway occurred in the Bay of Fundy, New Brunswick, Canada, in 1996 and has since occurred in Scotland, the USA and Denmark. The goal of this study was to further investigate the haemagglutinin (HA) genotype of infectious salmon anaemia virus (ISAV) in relation to its antigenic type. It was hypothesized that (a) ISAV, being an orthomyxovirus-like virus, may have similar characteristics to other members of Orthomyxoviridae ; (b) genetic variation in the HA gene of ISAV has led to two antigenically distinct isolates and may be responsible for pathogenic differences; and (c) the CHSE-214 cell line may give a better assessment of virus neutralization than the TO cell line. This study supports the original observation that the two HA genotypes of ISAV do differ antigenically. (Abstract shortened by UMI.).