Hemorrhagic Septicemia, Viral: A systemic infection of various salmonid and a few nonsalmonid fishes caused by Viral hemorrhagic septicemia virus (see NOVIRHABDOVIRUS),Novirhabdovirus: A genus in the family RHABDOVIRIDAE, infecting numerous species of fish with broad geographic distribution. The type species is INFECTIOUS HEMATOPOIETIC NECROSIS VIRUS.Hemorrhagic Septicemia: Any of several bacterial diseases, usually caused by PASTEURELLA MULTOCIDA, marked by the presence of hemorrhagic areas in the subcutaneous tissues, serous membranes, muscles, lymph glands, and throughout the internal organs. The diseases primarily affect animals and rarely humans.Rhabdoviridae Infections: Virus diseases caused by RHABDOVIRIDAE. Important infections include RABIES; EPHEMERAL FEVER; and vesicular stomatitis.Rhabdoviridae: A family of bullet-shaped viruses of the order MONONEGAVIRALES, infecting vertebrates, arthropods, protozoa, and plants. Genera include VESICULOVIRUS; LYSSAVIRUS; EPHEMEROVIRUS; NOVIRHABDOVIRUS; Cytorhabdovirus; and Nucleorhabdovirus.Fish Diseases: Diseases of freshwater, marine, hatchery or aquarium fish. This term includes diseases of both teleosts (true fish) and elasmobranchs (sharks, rays and skates).Oncorhynchus mykiss: A large stout-bodied, sometimes anadromous, TROUT found in still and flowing waters of the Pacific coast from southern California to Alaska. It has a greenish back, a whitish belly, and pink, red, or lavender stripes on the sides, with usually a sprinkling of black dots. It is highly regarded as a sport and food fish. Its former name was Salmo gairdneri. The sea-run rainbow trouts are often called steelheads. Redband trouts refer to interior populations of rainbows.Flatfishes: Common name for the order Pleuronectiformes. A very distinctive group in that during development they become asymmetrical, i.e., one eye migrates to lie adjacent to the other. They swim on the eyeless side. FLOUNDER, sole, and turbot, along with several others, are included in this order.Great Lakes Region: The geographic area of the Great Lakes in general and when the specific state or states are not indicated. It usually includes Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin.Fishes: A group of cold-blooded, aquatic vertebrates having gills, fins, a cartilaginous or bony endoskeleton, and elongated bodies covered with scales.Aquaculture: Cultivation of natural faunal resources of water. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Salmonidae: A family of anadromous fish comprising SALMON; TROUT; whitefish; and graylings. They are the most important food and game fishes. Their habitat is the northern Atlantic and Pacific, both marine and inland, and the Great Lakes. (Nelson: Fishes of the World, 1976, p97)Infectious hematopoietic necrosis virus: The type species of NOVIRHABDOVIRUS, in the family RHABDOVIRIDAE. It is a major pathogen of TROUT and SALMON.Pasteurella Infections: Infections with bacteria of the genus PASTEURELLA.Flounder: Common name for two families of FLATFISHES belonging to the order Pleuronectiformes: left-eye flounders (Bothidae) and right-eye flounders (Pleuronectidae). The latter is more commonly used in research.Fisheries: Places for cultivation and harvesting of fish, particularly in sea waters. (from McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Animal Fins: Membranous appendage of fish and other aquatic organisms used for locomotion or balance.Edwardsiella tarda: A species of EDWARDSIELLA distinguished by its hydrogen sulfide production. (From Bergey's Manual of Determinative Bacteriology, 9th ed)Pasteurella multocida: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria normally found in the flora of the mouth and respiratory tract of animals and birds. It causes shipping fever (see PASTEURELLOSIS, PNEUMONIC); HEMORRHAGIC BACTEREMIA; and intestinal disease in animals. In humans, disease usually arises from a wound infection following a bite or scratch from domesticated animals.Pasteurella: The oldest recognized genus of the family PASTEURELLACEAE. It consists of several species. Its organisms occur most frequently as coccobacillus or rod-shaped and are gram-negative, nonmotile, facultative anaerobes. Species of this genus are found in both animals and humans.Salmon: Fish of the genera ONCORHYNCHUS and Salmo in the family SALMONIDAE. They are anadromous game fish, frequenting the coastal waters of both the North Atlantic and Pacific. They are known for their gameness as a sport fish and for the quality of their flesh as a table fish. (Webster, 3d ed).3-Phosphoshikimate 1-Carboxyvinyltransferase: An enzyme of the shikimate pathway of AROMATIC AMINO ACID biosynthesis, it generates 5-enolpyruvylshikimate 3-phosphate and ORTHOPHOSPHATE from PHOSPHOENOLPYRUVATE and shikimate-3-phosphate. The shikimate pathway is present in BACTERIA and PLANTS but not in MAMMALS.Sepsis: Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by HYPOTENSION despite adequate fluid infusion, it is called SEPTIC SHOCK.Cyprinidae: A family of freshwater fish comprising the minnows or CARPS.Gills: Paired respiratory organs of fishes and some amphibians that are analogous to lungs. They are richly supplied with blood vessels by which oxygen and carbon dioxide are exchanged directly with the environment.Infectious pancreatic necrosis virus: The type species of AQUABIRNAVIRUS, causing infectious pancreatic necrosis in salmonid fish and other freshwater and marine animals including mollusks.Perciformes: The most diversified of all fish orders and the largest vertebrate order. It includes many of the commonly known fish such as porgies, croakers, sunfishes, dolphin fish, mackerels, TUNA, etc.Trout: Various fish of the family SALMONIDAE, usually smaller than salmon. They are mostly restricted to cool clear freshwater. Some are anadromous. They are highly regarded for their handsome colors, rich well-flavored flesh, and gameness as an angling fish. The genera Salvelinus, Salmo, and ONCORHYNCHUS have been introduced virtually throughout the world.Immersion: The placing of a body or a part thereof into a liquid.Animals, Wild: Animals considered to be wild or feral or not adapted for domestic use. It does not include wild animals in zoos for which ANIMALS, ZOO is available.North AmericaMolecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Fresh Water: Water containing no significant amounts of salts, such as water from RIVERS and LAKES.Viral Envelope Proteins: Layers of protein which surround the capsid in animal viruses with tubular nucleocapsids. The envelope consists of an inner layer of lipids and virus specified proteins also called membrane or matrix proteins. The outer layer consists of one or more types of morphological subunits called peplomers which project from the viral envelope; this layer always consists of glycoproteins.Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Seawater: The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Viral Proteins: Proteins found in any species of virus.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Bacteremia: The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion.Disease Outbreaks: Sudden increase in the incidence of a disease. The concept includes EPIDEMICS and PANDEMICS.RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.Enzyme-Linked Immunosorbent Assay: An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.Cell Line: Established cell cultures that have the potential to propagate indefinitely.
Hemorrhagic septicemia: Hemorrhagic septicemia is an acute pasteurellosis, which occurs notably in cattle and water buffalo, and to lesser degrees in other ruminants as well as other animals. It is caused by Pasteurella multocida bacteria, and can be rapidly fatal.Sigma viruses: Sigma viruses are a clade of viruses in the family Rhabdoviridae that naturally infect dipterans, and have recently been proposed to represent a new genus of rhabdoviruses.Longdon B and Walker PJ (2011) Sigma virus genus proposal for the International Committee on Taxonomy of Viruses.European Community Reference Laboratory for Fish Diseases: The European Community Reference Laboratory for Fish DiseasesCommunity Reference Laboratory for Fish Diseases is located in Frederiksberg in Denmark at the National Veterinary Institute (a part of Technical University of Denmark).Southern California Steelhead DPS: The Southern California Steelhead Distinct Population Segment (DPS) occurs from the Santa Maria River to the Tijuana River at the United States and Mexican Border in seasonally accessible rivers and streams.*NOAA.Thomas Dover: Thomas Dover, M.D.Great Lakes BasinBaltic sculpin: The Baltic sculpinBaltic sculpin (Cottus microstomus) at EOL (Cottus microstomus) is a species of sculpin, a European freshwater fish in the Cottidae family. It is widespread in the Dniester drainage (Black Sea basin), Odra and Vistula drainages (southern Baltic basin), most likely extending further east to Gulf of Finland.Aquaculture of sea sponges: Sea sponge aquaculture is the process of farming sea sponges under controlled conditions. It has been conducted in the world's oceans for centuries using a number of aquaculture techniques.Thymallus yaluensis: Thymallus yaluensis is a putative species of freshwater fish, a grayling in the salmon family Salmonidae. It is endemic to the upper Yalu River in Korea, on the Chinese border.Infectious hematopoietic necrosis virus: Infectious hematopoietic necrosis virus (IHNV), is a negative-sense single-stranded, bullet-shaped RNA virus that is a member of the Rhabdoviridae family, and from the genus Novirhabdovirus. It causes the disease known as infectious hematopoietic necrosis in salmonid fish such as trout and salmon.Blackfin flounder: The blackfin flounder, Glyptocephalus stelleri, is a flatfish of the family Pleuronectidae. It is a demersal fish that lives in temperate waters at depths of between , though it is most commonly found between .Sustainable Fisheries Act of 1996: The Sustainable Fisheries Act of 1996 is an amendment to the Magnuson-Stevens Fishery Conservation and Management Act, a law governing the management of marine fisheries in the United States. Another major amendment to this legislation was later made under the Magnuson-Stevens Fishery Conservation and Management Reauthorization Act of 2006.Fin rotEdwardsiella tarda: Edwardsiella tarda is a member of the Enterobacteriaceae family. The bacterium is a facultatively anaerobic, small, motile, gram negative, straight rod with flagella.Pasteurella multocida: Pasteurella multocida is a Gram-negative, nonmotile, penicillin-sensitive coccobacillus belonging to the Pasteurellaceae family. Strains belonging to the species are currently classified into five serogroups (A, B, D, E, F) based on capsular composition and 16 somatic serovars (1-16).Pasteurella dagmatis: Pasteurella dagmatis is a Gram-negative, nonmotile, penicillin-sensitive coccobacillus belonging to the Pasteurellaceae family. Bacteria from this family cause zoonotic infections in humans.Diseases and parasites in salmonEPSP synthaseSepsis Alliance: Sepsis Alliance is a voluntary health organization dedicated to raising awareness of sepsis by educating patients, families, and healthcare professionals to treat sepsis as a medical emergency.http://www.Notropis: Notropis is a genus of fish in the family Cyprinidae, the carps and minnows. They are known commonly as eastern shiners.Fish gill: Most fish exchange gases using gills on either side of the pharynx (throat). Gills are tissues which consist of cloth and fabric structures called filaments.Infectious pancreatic necrosis: Infectious pancreatic necrosis (IPN) is a severe viral disease of salmonid fish. It is caused by infectious pancreatic necrosis virus, which is a member of the Birnaviridae family.Pink skunk clownfish: Amphiprion perideraion also known as the pink skunk clownfish or pink anemonefish, is a species of anemonefish from the skunk complex that is widespread from northern Australia through the Malay Archipelago and Melanesia. Like all anemonefishes it forms a symbiotic mutualism with sea anemones and is unaffected by the stinging tentacles of the host anemone.Prittle Brook: The Prittle Brook is a minor watercourse in Essex, England. A short tributary of the River Roach, the brook rises near Thundersley and discharges into the Roach at Rochford.Oil immersionAmerican Medical Student AssociationColes PhillipsBulloo-Bancannia drainage basin: The Bulloo-Bancannia drainage basin is a drainage basin that covers part of western Queensland and New South Wales. It is adjacent to the much larger Lake Eyre basin.Pseudotyping: Pseudotyping is the process of producing viruses or viral vectors in combination with foreign viral envelope proteins. The result is a pseudotyped virus particle.Virulence: Virulence is, by MeSH definition, the degree of pathogenicity within a group or species of parasites as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism - its ability to cause disease - is determined by its virulence factors.Deep chlorophyll maximum: A deep chlorophyll maximum (DCM) is a subsurface maximum in the concentration of chlorophyll in the ocean or a lake. A DCM is not always present--sometimes there is more chlorophyll at the surface than at any greater depth--but it is a common feature of most aquatic ecosystems.Branching order of bacterial phyla (Gupta, 2001): There are several models of the Branching order of bacterial phyla, one of these was proposed in 2001 by Gupta based on conserved indels or protein, termed "protein signatures", an alternative approach to molecular phylogeny. Some problematic exceptions and conflicts are present to these conserved indels, however, they are in agreement with several groupings of classes and phyla.Bacteremia: (NOS) |National Outbreak Reporting System: ==The National Outbreak Reporting System (NORS)==Symmetry element: A symmetry element is a point of reference about which symmetry operations can take place. In particular, symmetry elements can be centers of inversion, axes of rotation and mirror planes.Tumor-associated glycoprotein: Tumor-associated glycoproteins (TAGs) are glycoproteins found on the surface of many cancer cells. They are mucin-like molecules with a molar mass of over 1000 kDa.Protein primary structure: The primary structure of a peptide or protein is the linear sequence of its amino acid structural units, and partly comprises its overall biomolecular structure. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end.Eva Engvall: Eva Engvall, born 1940, is one of the scientists who invented ELISA in 1971.Eva Engvall, The Scientist 1995, 9(18):8
(1/29) Studies on pathogenesis following single and double infection with viral hemorrhagic septicemia virus and infectious hematopoietic necrosis virus in rainbow trout (Oncorhynchus mykiss).
Rainbow trout (Oncorhynchus mykiss) were bath challenged with viral hemorrhagic septicemia (VHS) virus or infectious hematopoietic necrosis (IHN) virus or with both viruses simultaneously. The viral distribution and development of histologic lesions were examined using immunohistochemistry, while virus titer in kidney was determined by viral titration in cell culture. Single infections with VHS virus and IHN virus showed similar distributions of virus in internal organs. The early identification of virus in gill epithelium, 1 and 2 days postinfection (PI) for VHS virus and IHN virus, respectively, indicates that this organ is the point of entry for both viruses. The detection of VHS virus at 1 day PI and 3 days PI for IHN virus is indicative of kidney and spleen being the target organs for these viruses. A simultaneous infection of VHS virus and IHN virus resulted in both viruses establishing an infection. Further double infection did not result in a statistically significant lower titer of both viruses in kidney but a more restricted distribution of IHN virus in internal organs compared with the single infected group. The most striking finding is that, for IHN virus, virus was not detected in the brain in situ in the double-infected group. This study provides support for the conclusion that simultaneous infection with two piscine rhabdoviruses in a susceptible host results in some degree of interaction at the cell level, leading to a reduced systemic distribution of IHN virus. (+info)
(2/29) Four years of monitoring for viral haemorrhagic septicaemia virus in marine waters around the United Kingdom.
Between 1995 and 1998, marine fish from around the coast of the UK were collected and samples analysed for viral haemorrhagic septicaemia virus (VHSV) using cell culture isolation methods. In 1997 and 1998 the samples were also analysed for VHSV by reverse transcription PCR (RT-PCR). A total of 1867 fish of 11 species were tested, but VHSV was isolated on only 1 occasion, from herring Clupea harengus, in 1996. However, despite VHSV not being isolated in 1997 and 1998, in both years samples of herring from the west and south coasts of England produced positive signals in the RT-PCR, and in 1997 cod from the east coast of England also produced positive signals in the RT-PCR. These results are believed to be true indications of the presence of VHSV nucleic acid in the fish. In 1997, birnaviruses from Serogroup B1 were isolated from herring (a previously unrecorded host for the virus) and cod Gadus morhua, and a birnavirus from Serogroup A2 was also isolated from cod. In 1998, an aquareovirus was isolated from haddock Melanogrammus aeglefinus, a previously unrecorded host for the virus. (+info)
(3/29) Haematological analyses in rainbow trout Oncorhynchus mykiss affected by viral haemorrhagic septicaemia (VHS).
Rainbow trout Oncorhynchus mykiss weighing 87 +/- 15 g (mean +/- SD) were infected with viral haemorrhagic septicaemia virus (VHSV) and the haematological and biochemical profiles of peripheral blood examined. Depending on the clinical signs and gross pathology, the fish were divided into 2 groups: Group A included fish in the acute stage, Group B comprised fish in the chronic stage. Red blood cells were subjected to 6 haematological tests and blood plasma to 14 biochemical tests, which provided findings on changed substrate concentrations and enzyme activities. Diseased fish, compared to healthy fish, had a significantly lower red blood cell count, and lower haematocrit and haemoglobin levels. As for the biochemical parameters, the fish had less total protein, creatinine, glucose, triacylglycerol, inorganic phosphate, total calcium and sodium, and more blood urea, nitrogen and potassium. Uric acid levels remained unchanged. Increases were recorded in the catalytic concentration of alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase. A decrease was recorded in the catalytic concentration of alkaline phosphatase. Fish with VHS in the chronic stage, compared with healthy fish, were in worse condition, with a significantly reduced Fulton coefficient and Clark coefficient, and a higher hepatosomatic index and visceral somatic index. (+info)
(4/29) Effect of intraperitoneally administered IL-1beta-derived peptides on resistance to viral haemorrhagic septicaemia in rainbow trout Oncorhynchus mykiss.
The present work provides the first information concerning the immunostimulatory activity of trout interleukin (IL)-1beta-derived peptides in vivo. Previous studies have demonstrated the ability of 2 such peptides, referred to as P1 and P3, to up-regulate a range of important immune parameters in vitro. P1 corresponds to fragment 146-157 (YVTPVPIETEAR) of the trout sequence and is analogous to a biologically active mammalian IL-1beta-derived peptide, whilst P3 was synthesised to complex with the IL-1 receptor and corresponds to fragment 197-206 (YRRNTGVDIS) of the trout sequence. Optimal migration of peritoneal leucocytes, peptide induced phagocytosis and intracellular respiratory burst activity occurred following intraperitoneal injection of 3.0 micromol of P3. Furthermore, resistance to viral haemorrhagic septicaemia virus (VHSV) was soon augmented (2 d) post-injection of P3. (+info)
(5/29) Reversible inhibition of spreading of in vitro infection and imbalance of viral protein accumulation at low pH in viral hemorrhagic septicemia rhabdovirus, a salmonid rhabdovirus.
The inhibition of viral hemorrhagic septicemia rhabdovirus (VHSV) in vitro infection by pHs of <7 (low pH) has been previously reported. Nevertheless, the details of the mechanism underlying this effect remain obscure. We present evidence showing that low-pH inhibition occurs during a viral postadsorption step. Thus, while VHSV bound, replicated within single cells, and presented its G protein on the membranes of infected cells at both low and physiological pHs, both cell-to-cell spreading of infection (as estimated by the appearance of foci of infected cells) and fusion (as estimated by a syncytium assay) were inhibited by this low pH. The decreased VHSV titers and the inhibition of both cell-to-cell spreading of infection and fusion could be reversed by adjusting the pH to 7.5 at any time during infection. This effect should be taken into account to avoid false negatives in the diagnosis of VHSV by cell culture. On the other hand, the cell-to-cell spreading of infection at pH 7.5 could be stopped at any time by reducing the pH to 6.5. Since at low pH there were changes in the protein G conformation and smaller and imbalanced amounts of N with respect to M1, M2, and G viral proteins, alterations of the assembly and/or budding of VHSV are most probably involved in the absence of newly released infective virions. (+info)
(6/29) Experimental infection of rainbow trout Oncorhynchus mykiss with viral haemorrhagic septicaemia virus isolates from European marine and farmed fishes.
The susceptibility of rainbow trout Oncorhynchus mykiss to infection with various isolates of viral haemorrhagic septicaemia virus (VHSV) was examined. A total of 8 experiments with rainbow trout ranging from 0.6 to 6.2 g was conducted for 139 isolates originating from wild marine fishes in European waters (115 isolates), farmed turbot from Scotland and Ireland (2 isolates), and farmed rainbow trout (22 isolates). The isolates were tested by immersion and/or intraperitoneal injection either as pooled or single isolates. The isolates from wild marine fishes did not cause mortality by immersion while some of the isolates caused mortality when injected. All VHSV isolates from farmed rainbow trout caused significant mortality by immersion. Currently, pathogenicity trials are the only way to differentiate VHSV isolates from wild marine fishes and farmed rainbow trout. The 2 farmed turbot isolates did not cause mortality by immersion, supporting the view that they originated from the marine environment. (+info)
(7/29) Experimental horizontal transmission of viral hemorrhagic septicemia virus (VHSV) in Japanese flounder Paralichthys olivaceus.
Infection by viral hemorrhagic septicemia virus (VHSV) has recently occurred among wild and farmed Japanese flounder Paralichthys olivaceus in Japan. In the present study, horizontal transmission of VHSV among Japanese flounder was experimentally demonstrated by immersion challenge. Exposure to a flounder isolate (Obama25) of VHSV revealed a dose-response, with higher mortality (81 and 70%) at the 2 higher exposure levels (6.0 and 4.0 log10 TCID50 ml(-1)). In a second experiment, high titers of VHSV were expressed from moribund and dead flounder based on virus detection in holding-tank waters 2 to 3 d prior to death of the fish and 1 d after death. The virus could not be detected in tank waters 2 d after death. Finally, a third cohabitation experiment in small tanks demonstrated horizontal transmission of VHSV from experimentally infected to uninfected fish. (+info)
(8/29) Sequential pathology after experimental infection with marine viral hemorrhagic septicemia virus isolates of low and high virulence in turbot (Scophthalmus maximus L).
Three marine viral hemorrhagic septicemia virus isolates were used to bath challenge turbot with the purpose of studying mortality and the pathology and antigen distribution over time. Two high-virulence isolates, 860/94, 4p168 and a low-virulence isolate 1p3 from a Baltic Sea herring were used. Organ samples were collected sequentially at 2, 4, 7, 10, 15, 20, 25, and 45 days postinfection. Specimens were processed for virology, histopathology, and immunohistochemistry. Organs during the early stages of infection (from 2 to 7 days) had virus isolation from all three groups only on day 7. Virus titer in kidney and heart sampled at day 25 was higher for the two virulent isolates compared with the low-virulence isolate. The viral distribution in situ of the two more virulent isolates from turbot (860/94) and herring (4p168) resembled viral hemorrhagic septicemia in rainbow trout with regard to the target organs. Early infection of endothelial cells in both kidney and heart was observed. Accumulated mean mortality was 41.5% for the turbot isolate 860/94, 48% for the herring isolate 4p168, and 3.5% for the herring isolate 1p3. This study revealed that the isolates from turbot (860/94) and herring (4p168) induced significantly higher mortality compared with the virus-free control and the herring isolate (1p3). The onset of mortality is markedly later in turbot compared with what is seen in rainbow trout. (+info)