Anti-Infectious Hematopoietic Necrosis Virus (IHNV) polyclonal antibody

Infectious hematopoietic necrosis (IHN) leads to periodic epidemics among certain wild and farmed fish species of the Northeast (NE) Pacific. The source of the IHN virus (IHNV) that initiates these outbreaks remains unknown; however, a leading hypothesis involves viral persistence in marine host species such as Pacific herring Clupea pallasii. Under laboratory conditions we exposed specific pathogen-free (SPF) larval and juvenile Pacific herring to 10(3) to 10(4) plaque-forming units (pfu) of IHNV ml(-1) by waterborne immersion. Cumulative mortalities among exposed groups were not significantly different from those of negative control groups. After waterborne exposure, IHNV was transiently recovered from the tissues of larvae but absent in tissues of juveniles. Additionally, no evidence of viral shedding was detected in the tank water containing exposed juveniles. After intraperitoneal (IP) injection of IHNV in juvenile herring with 10(3) pfu, IHNV was recovered from the tissues of sub-sampled individuals for only the first 5 d post-exposure. The lack of susceptibility to overt disease and transient levels of IHNV in the tissues of exposed fish indicate that Pacific herring do not likely serve a major epizootiological role in perpetuation of IHNV among free-ranging sock-eye salmon Oncorhynchus nerka and farmed Atlantic salmon Salmo salar in the NE Pacific.

The continuous appearance of new virus isolations from aquacultured fish makes it important to have efficient and reliable methods available, not only for identification of these viruses, but also for further typing in order to allow epidemiological analysis. Recent immunological and genetic assays for detection and typing of the rhabdoviruses infectious haematopoietic necrosis virus (IHNV), viral haemorrhagic septicaemia virus (VHSV), spring viraemia of carp virus (SVCV) and European perch rhabdoviruses were presented and discussed during this workshop, Also, the need to standardise as well as validate these molecular techniques with traditional techniques as reference regarding sensitivity and specificity were discussed.