scholarly journals Susceptibility and Pathology in Juvenile Atlantic Cod Gadus morhua to a Marine Viral Haemorrhagic Septicaemia Virus Isolated from Diseased Rainbow Trout Oncorhynchus mykiss

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3523
Author(s):  
Nina Sandlund ◽  
Renate Johansen ◽  
Ingrid U. Fiksdal ◽  
Ann Cathrine B. Einen ◽  
Ingebjørg Modahl ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Pcr Analysis ◽  
Hematopoietic Tissue ◽  
Haemorrhagic Septicaemia ◽  
Genotype Iii ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Positive Immunostaining ◽  
Viral Haemorrhagic Septicaemia Virus

The first known outbreak caused by a viral haemorrhagic septicaemia virus (VHSV) strain of genotype III in rainbow trout occurred in 2007 at a marine farm in Storfjorden, Norway. The source of the virus is unknown, and cod and other marine fish around the farms are suspected as a possible reservoir. The main objective of this study was to test the susceptibility of juvenile Atlantic cod to the VHSV isolate from Storfjorden. As the pathology of VHS in cod is sparsely described, an additional aim of the study was to give a histopathological description of the disease. Two separate challenge experiments were carried out, using both intra peritoneal (ip) injection and cohabitation as challenge methods. Mortality in the ip injection experiment leveled at approximately 50% three weeks post challenge. Both immunohistochemical and rRT-PCR analysis of organs sampled from diseased and surviving fish confirmed VHSV infection. No VHSV was detected in the cohabitants. The results indicate that Atlantic cod has a low natural susceptibility to this VHSV genotype III strain. One of the most extensive pathological changes was degeneration of cardiac myocytes. Immunohistochemistry confirmed that the lesions were related to VHSV. In some fish, the hematopoietic tissue of spleen and kidney showed degeneration and immunostaining, classical signs of VHS, as described in rainbow trout. Positive immunostaining of the capillaries of the gills, suggests this organ as a useful alternative when screening for VHSV.

Organization of Microsatellites Differs between Mammals and Cold-water Teleost Fishes

1994 ◽  
Vol 51 (9) ◽  
pp. 1959-1966 ◽  
Author(s):  
Amanda L. Brooker ◽  
Doug Cook ◽  
Paul Bentzen ◽  
Jonathan M. Wright ◽  
Roger W. Doyle
Keyword(s):  
Rainbow Trout ◽  
Gadus Morhua ◽  
Cold Water ◽  
Atlantic Cod ◽  
Pcr Amplification ◽  
Sample Population ◽  
Teleost Fishes ◽  
Dinucleotide Repeats ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Significant Difference

Microsatellites, in particular (dG-dT)n and (dG-dA)n dinucleotide repeats, are abundant and display a high degree of length polymorphism and heterozygosity in eukaryotic genomes. Here, we report the cloning and characterization of 64 microsatellite sequences from Atlantic cod, Gadus morhua. The microsatellites were classified as perfect, imperfect, and compound repeats. The length and integrity of these repeats were compared with microsatellites characterized from two other teleosts, rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar), and from three mammalian genomes, human, porcine, and canine. Differences were found in the proportions of the repeat classes; however, the most significant difference between microsatellites from teleost fishes and mammals was the propensity of the former to be of greater length: some cod and rainbow trout microsatellites were more than twice the size of the longest microsatellite repeats reported for any mammalian genome. Primers for PCR amplification were constructed for seven of the cod microsatellites. Allele frequencies, degree of polymorphism, and heterozygosity were estimated for a sample population. Amplification with these cod primers was also carried out on a number of related gadids. These polymorphic microsatellite loci have enormous potential utility as genetic markers for use in population, breeding, and evolutionary studies.

Tissue Response of Fish to Invasion by Larval Pseudoterranova decipiens (Nematoda; Ascaridoidea)

1991 ◽  
Vol 48 (9) ◽  
pp. 1623-1628 ◽  
Author(s):  
N. R. Ramakrishna ◽  
M. D. B. Burt
Keyword(s):  
Rainbow Trout ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Giant Cells ◽  
Tissue Response ◽  
Polymorphonuclear Neutrophils ◽  
Epithelioid Cells ◽  
Collagen Fibres ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Pseudoterranova Decipiens

The histopathology of Pseudoterranova decipiens (L3) in experimentally infected rainbow trout (Oncorhynchus mykiss) and naturally infected Atlantic cod (Gadus morhua) was similar. The chronic granulomatous inflammatory reaction included polymorphonuclear neutrophils, macrophages, lymphocytes, epithelioid cells, and fibroblasts. Giant cells were also found but only in the experimentally infected rainbow trout. Mature capsules around the larvae consisted of an inner layer, composed of macrophages which underwent epithelioid transformation and later gradually degenerated, and an outer layer, composed of fibroblasts and collagen fibres. A layer of lipofuscin was adjacent to the parasite in older cod infections but this was absent in all of the newly formed capsules in the experimentally infected rainbow trout.

Sign in / Sign up

Export Citation Format

Share Document