scholarly journals Infectious Hematopoietic necrosis Virus Transmission and Disease Among Juvenile Chinook Salmon Exposed in culture Compared to Environmentally Relevant Conditions

Author(s):  
J. Scott Foot ◽  
Dan Free ◽  
Terry McDowell ◽  
Kristen D. Arkush ◽  
Ronald P. Hedrick
Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 701
Author(s):  
Daniel G. Hernandez ◽  
William Brown ◽  
Kerry A. Naish ◽  
Gael Kurath

Infectious Hematopoietic Necrosis Virus (IHNV) infects juvenile salmonid fish in conservation hatcheries and aquaculture facilities, and in some cases, causes lethal disease. This study assesses intra-specific variation in the IHNV susceptibility of Chinook salmon (Oncorhynchus tshawytscha) in the Columbia River Basin (CRB), in the northwestern United States. The virulence and infectivity of IHNV strains from three divergent virus genogroups are measured in four Chinook salmon populations, including spring-run and fall-run fish from the lower or upper regions of the CRB. Following controlled laboratory exposures, our results show that the positive control L strain had significantly higher virulence, and the UC and MD strains that predominate in the CRB had equivalently low virulence, consistent with field observations. By several experimental measures, there was little variation in host susceptibility to infection or disease. However, a small number of exceptions suggested that the lower CRB spring-run Chinook salmon population may be less susceptible than other populations tested. The UC and MD viruses did not differ in infectivity, indicating that the observed asymmetric field prevalence in which IHNV detected in CRB Chinook salmon is 83% UC and 17% MD is not due to the UC virus being more infectious. Overall, we report little intra-species variation in CRB Chinook salmon susceptibility to UC or MD IHNV infection or disease, and suggest that other factors may instead influence the ecology of IHNV in the CRB.


1978 ◽  
Vol 35 (7) ◽  
pp. 1009-1011 ◽  
Author(s):  
R. K. Kelly ◽  
B. W. Souter ◽  
H. R. Miller

The rainbow trout, Salmo gairdneri, gonad (RTG-2) cell line was more sensitive to lytic infection by infectious pancreatic necrosis virus (IPNV) than was the fathead minnow, Pimephales promelas, (FHM) cell line in laboratory and field studies. Laboratory investigations with known strains of IPNV (VR 299 and Buhl) also indicated that the cytopathic response in IPNV-infected chinook salmon, Oncorhynchus tshawytscha, embryo (CHSE-214) cells was greater than in infected FHM cells. In contrast, titration experiments with standard infectious hematopoietic necrosis virus (IHNV) isolates (Oregon and Cedar River) showed that the FHM cells were more sensitive to destructive infection by IHNV than was either of the salmonid cell lines (RTG-2, CHSE-214). Key words: fish cell culture, infectious pancreatic necrosis virus, infectious hematopoietic necrosis virus, chinook salmon embryo cells, fathead minnow cells, rainbow trout cells, salmonid viruses


2020 ◽  
Vol 655 ◽  
pp. 185-198
Author(s):  
J Weil ◽  
WDP Duguid ◽  
F Juanes

Variation in the energy content of prey can drive the diet choice, growth and ultimate survival of consumers. In Pacific salmon species, obtaining sufficient energy for rapid growth during early marine residence is hypothesized to reduce the risk of size-selective mortality. In order to determine the energetic benefit of feeding choices for individuals, accurate estimates of energy density (ED) across prey groups are required. Frequently, a single species is assumed to be representative of a larger taxonomic group or related species. Further, single-point estimates are often assumed to be representative of a group across seasons, despite temporal variability. To test the validity of these practices, we sampled zooplankton prey of juvenile Chinook salmon to investigate fine-scale taxonomic and temporal differences in ED. Using a recently developed model to estimate the ED of organisms using percent ash-free dry weight, we compared energy content of several groups that are typically grouped together in growth studies. Decapod megalopae were more energy rich than zoeae and showed family-level variability in ED. Amphipods showed significant species-level variability in ED. Temporal differences were observed, but patterns were not consistent among groups. Bioenergetic model simulations showed that growth rate of juvenile Chinook salmon was almost identical when prey ED values were calculated on a fine scale or on a taxon-averaged coarse scale. However, single-species representative calculations of prey ED yielded highly variable output in growth depending on the representative species used. These results suggest that the latter approach may yield significantly biased results.


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