Infectious Hematopoietic Necrosis Virus Detected by Separation and Incubation of Cells from Salmonid Cavity Fluid

1987 ◽  
Vol 44 (5) ◽  
pp. 1071-1075 ◽  
Author(s):  
D. Mulcahy ◽  
W. N. Batts
Keyword(s):  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Culture Medium ◽  
Cultured Cells ◽  
Virus Titer ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Ovarian Fluid ◽  
Necrosis Virus ◽  
Infectious Hematopoietic Necrosis

Infectious hematopoietic necrosis (IHN) virus is usually detected by inoculating susceptible cell cultures with cavity ("ovarian") fluid (CF) from spawning females. We identified additional adult carriers of virus in spawning populations of steelhead trout (Salmo gairdneri) and sockeye salmon (Oncorhynchus nerka) by collecting nonerythrocytic cells from CF samples by low-speed centrifugation, culturing the cells for at least 7 d at 15 °C, and then testing the culture medium for virus. Virus appeared in the cultured cells from some samples of CF that remained negative during incubation. In additional samples of CF from these species, the virus titer increased in cultured cells compared with the titer in the original CF sample. With chinook salmon (O. tshawytscha), no negative samples converted to positive during incubation, but the virus titer was retained in incubated CF cells, but not in cell-free CF.

Testing of Male Sockeye Salmon (Oncorhynchus nerka) and Steel head Trout (Salmo gairdneri) for Infectious Hematopoietic Necrosis Virus

1987 ◽  
Vol 44 (5) ◽  
pp. 1075-1078 ◽  
Author(s):  
D. Mulcahy ◽  
R. J. Pascho ◽  
W. N. Batts
Keyword(s):  
Sockeye Salmon ◽  
Virus Isolation ◽  
Oncorhynchus Nerka ◽  
Infectious Hematopoietic Necrosis Virus ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Necrosis Virus ◽  
Spleen Sample ◽  
Infectious Hematopoietic Necrosis

Infectious hematopoietic necrosis (IHN) virus has been isolated only rarely from whole milt samples of male sockeye salmon (Oncorhynchus nerka). In 3 yr of testing, virus incidences in males ranged from 0 to 13% when milt was sampled but were 60–100% with spleen or kidney. When IHN virus was isolated from sockeye salmon milt at titers less than 3.00 log10 plaque-forming units (pfu)/mL, the level of virus in the kidney or spleen exceeded 7.00 log10 pfu/g. Higher rates of IHN virus isolation from kidney or spleen than from milt were also generally found in steelhead trout (Salmo gairdneri), although the differences were less pronounced than in sockeye salmon. Furthermore, virus was sometimes isolated from steelhead trout milt when the level of virus in kidney or spleen samples was very low, and was recovered from some milt samples when none was isolated from the corresponding spleen sample. When male salmonids are tested for IHN virus, kidney or spleen samples are superior to whole milt, but milt should be included for critical examinations.

Sequential Tests for Infectious Hematopoietic Necrosis Virus in Individuals and Populations of Sockeye Salmon (Oncorhynchus nerka)

1986 ◽  
Vol 43 (12) ◽  
pp. 2515-2519 ◽  
Author(s):  
Dan M. Mulcahy ◽  
Ron J. Pascho
Keyword(s):  
Quantitative Data ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Virus Titer ◽  
Infectious Hematopoietic Necrosis Virus ◽  
Necrosis Virus ◽  
High Virus Titer ◽  
Sequential Tests ◽  
Infectious Hematopoietic Necrosis ◽  
High Virus

The incidence and titer distribution of infectious hematopoietic necrosis virus in cavity fluid from spent female sockeye salmon (Oncorhynchus nerka) varied little when fish from a naturally spawning population were sampled three times on alternate days. However, when prespawning female sockeye salmon from a second population were individually tagged, penned, and sampled daily, the incidence and proportion of fish with high virus titer rose over a 6-d period. In 10 instances, consecutive cavity fluid samples from the same fish reverted from virus-positive to virus-negative. We suggest that spent fish should be sampled when accurate and quantitative data on the incidence and level of the virus are required.

Occurrence of the eyefluke, Diplostomum (Diplostomum) baeri bucculentum Dubois et Rausch, 1948, in salmonid fishes of northern British Columbia

1985 ◽  
Vol 63 (2) ◽  
pp. 396-399 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
Rainbow Trout ◽  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Lake Trout ◽  
Infected Fish ◽  
Salmo Gairdneri ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Dolly Varden Salvelinus Malma ◽  
Prosopium Williamsoni

As a result of experimental infections in chicks, diplostomula found in the retina of chinook salmon from the Nechako River were identified as Diplostomum (Diplostomum) baeri bucculentum. Eyeflukes in other salmonids were considered to be the same species based on similar measurements and site in the eyes. These eyeflukes varied in prevalence and mean intensity in seven salmonid species surveyed in nine localities in 1979–1981. The following fish were sampled: rainbow trout (Salmo gairdneri), 505; mountain whitefish (Prosopium williamsoni), 334; lake whitefish (Coregonus clupeaformis), 32; Dolly Varden (Salvelinus malma), 66; lake trout (S. namaycush), 13; kokanee or sockeye salmon (Oncorhynchus nerka), 323; and chinook salmon (O. tshawytscha), 164. Eyeflukes had prevalences ranging from 84 to 100% in six lakes, 64% in the river, 53% in one reservoir site, and a prevalence of 15% in the other reservoir site. Mountain and lake whitefishes had high mean intensities while kokanee had low mean intensities. Correlation of increased intensity with increased fish size was significant for 6 of 27 samples. Four samples of lake whitefish, mountain whitefish, rainbow trout, and chinook salmon showed significant asymmetry when numbers of diplostomula were compared between eyes. More of the heavily infected fish showed asymmetry than did the lightly infected fish.

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

1982 ◽  
Vol 39 (8) ◽  
pp. 1144-1149 ◽  
Author(s):  
Dan Mulcahy ◽  
John Burke ◽  
Ron Pascho ◽  
C. K. Jenes
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Virus Concentration ◽  
Ovarian Fluid ◽  
Female Fish ◽  
Fish Virus ◽  
Infectious Hematopoietic Necrosis ◽  
The Mean ◽  
Mean Concentration ◽  
Pyloric Ceca

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

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