Pathogenesis of Infectious Hematopoietic Necrosis Virus in Adult Sockeye Salmon (Oncorhynchus nerka)

Abstract

The concentration of infectious hematopoietic necrosis (IHN) virus was determined in eight organs and two body fluids from each of 60 adult sockeye salmon (Oncorhynchus nerka). Included in the sample were 4 males and 56 prespawning, spawning, or spent female fish. All fish were infected, and virus was present in nearly all organs. There was an overall tendency for the mean concentration to increase in many of the organs over time as the fish progressed in ripeness. In prespawning females, IHN virus could be detected in all organs and in ovarian fluid but not in serum; the incidences were highest in the gills, spleen, and pyloric ceca, and the titers were highest in the pyloric ceca and liver. Incidences of infection in the organs were higher in spawning than in prespawning females and higher still in spent females in which the incidence of virus was 100% in all organs except brains (78%) and sera (67%). Virus concentrations in organs or fluids ranged from 5 to 4.0 × 109 plaque-forming units per millilitre. In males, the highest incidences of virus were found in gills, pyloric ceca, and liver. The gills were the only organ in which the virus concentration in males exceeded that of females.Key words: infectious hematopoietic necrosis, IHN, fish virus, viral pathogenesis, sockeye salmon

Occurrence and genetic typing of infectious hematopoietic necrosis virus in Kamchatka, Russia

“…IHNV can be isolated most easily during epidemics among young fish or at the end of the fish life cycle during spawning (Mulcahy et al 1982). For this reason, adult fish were caught on their natural spawning grounds for sampling.…”

“…IHNV can be isolated most easily during epidemics among young fish or at the end of the fish life cycle during spawning (Mulcahy et al 1982 Vahtang River, Domashniy stream, Lake Nachikinskoe, and Plotnikova River. Wild fish were also sampled from 2 other independent watersheds: Avacha River and Paratunka River (including Bolshoy Viljuy Lake).…”

Detection of infectious hematopoietic necrosis virus in fish mucus.

“…The gill has been assumed to be the primary portal of entry of the virus (MULCAHY et al, 1982). YAMAMOTO et al (1988) used immunohistochemical stains to detect viral antigen in juvenile rainbow trout exposed to waterborne IHNV.…”

Isolation of infectious hematopoietic necrosis virus from a leech (Piscicola salmositica) and a copepod (Salmincola sp.), ectoparasites of sockeye salmon Oncorhynchus nerka

“…Copepods from each fish were processed in groups of up to 12, but leeches were homogenized individual1.y. Tissues and body fluids were processed as described by Mulcahy et al (1982). Detection and quantitation of IHN virus was performed using the plaque assay (Burke & Mulcahy 1980) as modified by Mulcahy et al (1982), using the epithelioma papulosum cyprini cell line (Fijan et al 1983).…”

“…Tissues and body fluids were processed as described by Mulcahy et al (1982). Detection and quantitation of IHN virus was performed using the plaque assay (Burke & Mulcahy 1980) as modified by Mulcahy et al (1982), using the epithelioma papulosum cyprini cell line (Fijan et al 1983). The mean virus titer and the standard error of the mean were calculated as pfu ml-' or pfu g-' following log,, transformation of the individual titers.…”