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Paul R Bowser - One of the best experts on this subject based on the ideXlab platform.
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pathogenesis of experimental Viral Hemorrhagic Septicemia virus ivb infection in adult sea lamprey petromyzon marinus
Journal of Great Lakes Research, 2017Co-Authors: L L Coffee, Rodman G Getchell, Geoffrey H Groocock, Emily R Cornwell, G A Wooster, J S Lumsden, Paul R BowserAbstract:Abstract In 2008, Viral Hemorrhagic Septicemia virus (VHSV) genotype IVb, the causative agent of Viral Hemorrhagic Septicemia (VHS) in a wide range of fish, was isolated from sea lamprey (Petromyzon marinus) in the Great Lakes Basin. To better understand the implications of the reported isolation, we utilized four virus detection methods to follow the pathogenesis on an experimental infection of VHSV IVb in 60 wild, adult lamprey. Thirty lamprey were infected by intracoelomic cavity injections with 106 plaque forming units (pfu) of the VHSV IVb MI03 isolate, and 30 control lamprey were injected with sterile culture media. All media-injected controls tested negative by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and cell culture. Twenty-six of the 30 infected lamprey were positive for VHSV by qRT-PCR, and nine were positive by cell culture. In-vivo replication was demonstrated by a significant temporal increase in the mean concentration of VHS Viral RNA copy number equivalents in pooled viscera measured by qRT-PCR from day 7 to day 28 and an increase in cell culture positive pools at day 28. Microscopically, infected lamprey did not develop lesions typical of virulent VHSV. Despite this, the virus was identified by immunohistochemistry in multiple organs, most readily in the kidney, where localization progressed from the interstitium to the tubular lumens. The combined results from qRT-PCR, cell culture, histopathology, and immunohistochemistry suggest that VHSV causes a sublethal infection in lamprey characterized by depletion of renal interstitial cells and in-vivo Viral replication with maintenance in the brain at later stages of infection.
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goldfish carassius auratus susceptibility to Viral Hemorrhagic Septicemia virus genotype ivb depends on exposure route
Diseases of Aquatic Organisms, 2015Co-Authors: Rodman G Getchell, Toni Erkinharju, Anna O Johnson, Benjamin W Davis, Emily E Hatch, Emily R Cornwell, Paul R Bowser, Rodman G Getchell, Emily R Cornwell, Paul R BowserAbstract:We assessed the susceptibility of goldfish Carassius auratus to infection by genotype IVb of the Viral Hemorrhagic Septicemia virus. Goldfish were infected by intraperitoneal injections of 106 plaque-forming units (pfu) fish-1, single bath exposure of 105 pfu ml-1 for 24 h, or consumption of 0.4 g of commercial fish feed soaked in 107 pfu per 8 fish. The mortality rate of intraperitoneal-infected goldfish was 10 to 32%, although the virus was detected by quantitative RT-PCR in 77% (65/84) of the survivors at the end of the 42 d trial, suggesting a carrier state. Severe gross lesions were observed in many of the moribund and dead goldfish such as hemorrhaging in the skin, fin, liver, kidney, brain, intestine, and eye as well as abdominal distension, bilateral exophthalmia, and splenomegaly. There was minimal morbidity or mortality in the immersion, feeding, or control groups.
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Fin and gill biopsies are effective nonlethal samples for detection of Viral Hemorrhagic Septicemia virus genotype IVb
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2013Co-Authors: Emily R Cornwell, Rodman G Getchell, Geoffrey H Groocock, Chelsea A. Bellmund, Po Ting Wong, Katherine L. Hambury, Paul R BowserAbstract:Nonlethal sampling is becoming a common method to diagnose fish diseases, especially with the availability of molecular testing. Viral Hemorrhagic Septicemia virus (VHSV) is a Viral pathogen of finfish distributed worldwide. Although VHSV has been known to occur in some parts of the world for decades, a new genotype, IVb, recently emerged in the Laurentian Great Lakes of northeastern North America. Golden shiners (Notemigonus crysoleucas; Mitchill, 1814) and fathead minnows (Pimephales promelas; Rafinesque, 1820) were exposed to VHSV-IVb doses between 102 and 106 plaque forming units per fish by intraperitoneal injection at 10°C. Both species experienced significant mortality after exposure, ranging from 38% to 52% in golden shiners and from 35% to 95% in fathead minnows. In golden shiners, a fin or gill sample was somewhat less sensitive at detecting VHSV-IVb by quantitative reverse transcription polymerase chain reaction (qRT-PCR) than a pooled organ sample (consisting of liver, anterior and posterior k...
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iodophor disinfection of walleye eggs exposed to Viral Hemorrhagic Septicemia virus type ivb
North American Journal of Aquaculture, 2013Co-Authors: Geoffrey H Groocock, Rodman G Getchell, Emily R Cornwell, G A Wooster, Paul R Bowser, Stephen A Frattini, Steven R LapanAbstract:Abstract Two experiments were performed to determine the persistence of Viral Hemorrhagic Septicemia virus (VHSV) genotype IVb on Walleye Sander vitreus eggs. Fertilized Walleye eggs were exposed for 30 min to 105 plaque-forming units/mL VHSV genotype IVb, and control eggs were exposed to phosphate-buffered saline. In the first experiment, the eggs were treated with 0 and 50 mg/L iodophor and incubated at 12±1°C until the first fry emerged. In the second experiment, a treatment of 100 mg/L iodophor was also tested. Periodic samples were taken during embryo development and tested for VHSV by Viral isolation and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The effect of tannic acid, an inhibitor of qRT-PCR testing, was evaluated in the second experiment. In both experiments no virus was detected in any control eggs by either test. In the first experiment, virus was isolated in 0-mg/L iodophor-treated eggs up to 3 d postinfection (DPI). Virus was also isolated in the 50-mg/L iodoph...
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Experimental Infection of Koi Carp with Viral Hemorrhagic Septicemia Virus Type IVb
Journal of aquatic animal health, 2013Co-Authors: Emily R Cornwell, Rodman G Getchell, Geoffrey H Groocock, Sandra L. Labuda, Paul R BowserAbstract:Abstract Viral Hemorrhagic Septicemia virus (VHSV) type IVb has a wide host range that includes at least three cyprinid species: Fathead Minnow Pimephales promelas, Emerald Shiner Notropis atherinoides, and Bluntnose Minnow P. notatus. To date, VHSV IVb has only been found in wild fish. However, the possibility of infection in culture facilities remains. Koi Carp Cyprinus carpio are a major ornamental aquaculture species in the United States; however, their potential to become infected with VHSV IVb has not yet been examined. In this study, we exposed Koi to 3 × 106 PFU VHSV Great Lakes isolate MI03 by intraperitoneal injection. While we observed low mortality (0–5%), VHSV was isolated in cell culture from the majority of fish up to 28 d postexposure (DPE) and was detected by a quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay up to 90 DPE, when the trial was terminated. The results of this study strongly suggest that Koi are at risk for VHSV infection, although their susceptibi...
Geoffrey H Groocock - One of the best experts on this subject based on the ideXlab platform.
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pathogenesis of experimental Viral Hemorrhagic Septicemia virus ivb infection in adult sea lamprey petromyzon marinus
Journal of Great Lakes Research, 2017Co-Authors: L L Coffee, Rodman G Getchell, Geoffrey H Groocock, Emily R Cornwell, G A Wooster, J S Lumsden, Paul R BowserAbstract:Abstract In 2008, Viral Hemorrhagic Septicemia virus (VHSV) genotype IVb, the causative agent of Viral Hemorrhagic Septicemia (VHS) in a wide range of fish, was isolated from sea lamprey (Petromyzon marinus) in the Great Lakes Basin. To better understand the implications of the reported isolation, we utilized four virus detection methods to follow the pathogenesis on an experimental infection of VHSV IVb in 60 wild, adult lamprey. Thirty lamprey were infected by intracoelomic cavity injections with 106 plaque forming units (pfu) of the VHSV IVb MI03 isolate, and 30 control lamprey were injected with sterile culture media. All media-injected controls tested negative by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and cell culture. Twenty-six of the 30 infected lamprey were positive for VHSV by qRT-PCR, and nine were positive by cell culture. In-vivo replication was demonstrated by a significant temporal increase in the mean concentration of VHS Viral RNA copy number equivalents in pooled viscera measured by qRT-PCR from day 7 to day 28 and an increase in cell culture positive pools at day 28. Microscopically, infected lamprey did not develop lesions typical of virulent VHSV. Despite this, the virus was identified by immunohistochemistry in multiple organs, most readily in the kidney, where localization progressed from the interstitium to the tubular lumens. The combined results from qRT-PCR, cell culture, histopathology, and immunohistochemistry suggest that VHSV causes a sublethal infection in lamprey characterized by depletion of renal interstitial cells and in-vivo Viral replication with maintenance in the brain at later stages of infection.
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detection and surveillance of Viral Hemorrhagic Septicemia virus using real time rt pcr ii diagnostic evaluation of two protocols
Diseases of Aquatic Organisms, 2014Co-Authors: Janet V Warg, Mohamed Faisal, Rodman G Getchell, Geoffrey H Groocock, Emily R Cornwell, Travis Clement, Angela Cruz, Cem Giray, Andrew E Goodwin, Robert KimAbstract:Two real-time reverse transcription polymerase chain reaction (rRT-PCR) assays under consideration for deployment to multiple testing laboratories across the USA were evalu- ated for diagnostic sensitivity and specificity on tissue homogenates obtained from natural and experimental Viral Hemorrhagic Septicemia (VHS)-infected fish. Estimates for diagnostic speci- ficity using virus isolation as the reference method were similar between laboratories regardless of the assay. Diagnostic sensitivity estimates of 0.96 (95% CI: 0.95, 0.97) for Jonstrup et al. (2013)'s assay (J Fish Dis 36:9�23) exceeded the diagnostic sensitivity of 0.85 (95% CI: 0.83, 0.87) for Phelps et al. (2012)'s assay (J Aquat Anim Health 24:238�243). The Jonstrup rRT-PCR assay is robust as demonstrated by high sensitivity and specificity estimates across laboratories and can be used as a valuable tool for targeted surveillance and for testing of suspect VHSV samples.
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detection and surveillance of Viral Hemorrhagic Septicemia virus using real time rt pcr i initial comparison of four protocols
Diseases of Aquatic Organisms, 2014Co-Authors: Janet V Warg, Mohamed Faisal, Rodman G Getchell, Geoffrey H Groocock, Emily R Cornwell, Travis Clement, Angela Cruz, Cem Giray, Andrew E Goodwin, Robert KimAbstract:Eight laboratories worked collectively to evaluate 4 real-time RT-PCR (rRT-PCR) protocols targeting Viral Hemorrhagic Septicemia virus (VHSV) being considered for deployment to a USA laboratory testing network. The protocols utilized previously published primers and probe sets developed for detection and surveillance of VHSV. All participating laboratories received and followed a standard operating protocol for extraction and for each of the rRT-PCR assays. Performance measures specifically evaluated included limit of detection (defined as the smallest amount of analyte in which 95% of the samples are classified as positive), analytical specificity, assay efficiency across genotype representatives, within- and between-plate variation within a laboratory, and variation between laboratories using the same platform, between platforms, and between software versions. This evaluation clearly demonstrated that the TaqMan®-based assay developed by Jonstrup et al. (2013; J Fish Dis 36:9-23) produced the most consistent analytical performance characteristics for detecting all genotypes of VHSV across the 8 participating laboratories.
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Fin and gill biopsies are effective nonlethal samples for detection of Viral Hemorrhagic Septicemia virus genotype IVb
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2013Co-Authors: Emily R Cornwell, Rodman G Getchell, Geoffrey H Groocock, Chelsea A. Bellmund, Po Ting Wong, Katherine L. Hambury, Paul R BowserAbstract:Nonlethal sampling is becoming a common method to diagnose fish diseases, especially with the availability of molecular testing. Viral Hemorrhagic Septicemia virus (VHSV) is a Viral pathogen of finfish distributed worldwide. Although VHSV has been known to occur in some parts of the world for decades, a new genotype, IVb, recently emerged in the Laurentian Great Lakes of northeastern North America. Golden shiners (Notemigonus crysoleucas; Mitchill, 1814) and fathead minnows (Pimephales promelas; Rafinesque, 1820) were exposed to VHSV-IVb doses between 102 and 106 plaque forming units per fish by intraperitoneal injection at 10°C. Both species experienced significant mortality after exposure, ranging from 38% to 52% in golden shiners and from 35% to 95% in fathead minnows. In golden shiners, a fin or gill sample was somewhat less sensitive at detecting VHSV-IVb by quantitative reverse transcription polymerase chain reaction (qRT-PCR) than a pooled organ sample (consisting of liver, anterior and posterior k...
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iodophor disinfection of walleye eggs exposed to Viral Hemorrhagic Septicemia virus type ivb
North American Journal of Aquaculture, 2013Co-Authors: Geoffrey H Groocock, Rodman G Getchell, Emily R Cornwell, G A Wooster, Paul R Bowser, Stephen A Frattini, Steven R LapanAbstract:Abstract Two experiments were performed to determine the persistence of Viral Hemorrhagic Septicemia virus (VHSV) genotype IVb on Walleye Sander vitreus eggs. Fertilized Walleye eggs were exposed for 30 min to 105 plaque-forming units/mL VHSV genotype IVb, and control eggs were exposed to phosphate-buffered saline. In the first experiment, the eggs were treated with 0 and 50 mg/L iodophor and incubated at 12±1°C until the first fry emerged. In the second experiment, a treatment of 100 mg/L iodophor was also tested. Periodic samples were taken during embryo development and tested for VHSV by Viral isolation and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The effect of tannic acid, an inhibitor of qRT-PCR testing, was evaluated in the second experiment. In both experiments no virus was detected in any control eggs by either test. In the first experiment, virus was isolated in 0-mg/L iodophor-treated eggs up to 3 d postinfection (DPI). Virus was also isolated in the 50-mg/L iodoph...
James R. Winton - One of the best experts on this subject based on the ideXlab platform.
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Principles Underlying the Epizootiology of Viral Hemorrhagic Septicemia in Pacific Herring and other Fishes throughout the North Pacific Ocean
Canadian Journal of Fisheries and Aquatic Sciences, 2016Co-Authors: Paul K. Hershberger, Kyle A. Garver, James R. WintonAbstract:Although Viral Hemorrhagic Septicemia virus (VHSV) typically occurs at low prevalence and intensity in natural populations of Pacific herring (Clupea pallasii) and other marine fishes in the Northeast Pacific Ocean, epizootics of the resulting disease (VHS) periodically occur, often in association with observed fish kills. Here we identify a list of principles, based on a combination of field studies, controlled laboratory experiments, and previously unpublished observations, that govern the epizootiology of VHS in Pacific herring. A thorough understanding of these principles provides the basis for identifying risk factors that predispose certain marine fish populations to VHS epizootics, including the lack of population resistance, presence of chronic Viral carriers in a population, copious Viral shedding by infected individuals, cool water temperatures, limited water circulation patterns, and gregarious host behavioral patterns. Further, these principles are used to define the epizootiological stages of...
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Influence of temperature on Viral Hemorrhagic Septicemia (Genogroup IVa) in Pacific herring, Clupea pallasii Valenciennes☆
Journal of Experimental Marine Biology and Ecology, 2013Co-Authors: Paul K. Hershberger, J. L. Gregg, Maureen K. Purcell, Lucas M. Hart, Rachel L. Thompson, Kyle A. Garver, James R. WintonAbstract:Abstract An inverse relationship between water temperature and susceptibility of Pacific herring ( Clupea pallasii ) to Viral Hemorrhagic Septicemia, genogroup IVa (VHS) was indicated by controlled exposure studies where cumulative mortalities, Viral shedding rates, and Viral persistence in survivors were greatest at the coolest exposure temperatures. Among groups of specific pathogen-free (SPF) Pacific herring maintained at 8, 11, and 15 °C, cumulative mortalities after waterborne exposure to Viral Hemorrhagic Septicemia virus (VHSV) were 78%, 40%, and 13%, respectively. The prevalence of survivors with VHSV-positive tissues 25 d post-exposure was 64%, 16%, and 0% (at 8, 11 and 15 °C, respectively) with Viral prevalence typically higher in brain tissues than in kidney/spleen tissue pools at each temperature. Similarly, geometric mean Viral titers in brain tissues and kidney/spleen tissue pools decreased at higher temperatures, and kidney/spleen titers were generally 10-fold lower than those in brain tissues at each temperature. This inverse relationship between temperature and VHS severity was likely mediated by an enhanced immune response at the warmer temperatures, where a robust type I interferon response was indicated by rapid and significant upregulation of the herring Mx gene. The effect of relatively small temperature differences on the susceptibility of a natural host to VHS provides insights into conditions that preface periodic VHSV epizootics in wild populations throughout the NE Pacific.
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Susceptibility of pacific herring to Viral Hemorrhagic Septicemia is influenced by diet
Journal of aquatic animal health, 2012Co-Authors: J. Beaulaurier, J. L. Gregg, C. A. Grady, James R. Winton, Nathaniel A Bickford, A. L. Gannam, Paul K. HershbergerAbstract:Abstract Groups of specific-pathogen-free Pacific herring Clupea pallasii were highly susceptible to infection by Viral Hemorrhagic Septicemia virus (VHSV); however, the level of mortality was influenced by diet during the 40–71 d before, during, and after the first exposure to the virus. Cumulative mortality was highest among the herring maintained on an experimental soy-based pellet, intermediate among those maintained on a commercially available fish-meal-based pellet, and lowest among those maintained on a second commercially available fish-meal-based pellet containing β-glucans. Additionally, the herring maintained on the experimental soy-based feed demonstrated less growth than those on the commercially available feeds. The results indicate the importance of standardizing diet during empirical determinations of disease susceptibility and provide insights into the risk factors affecting VHS susceptibility in wild populations. Received August 26, 2011; accepted November 4, 2011
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Predictive factors and Viral genetic diversity for Viral Hemorrhagic Septicemia virus infection in Lake Ontario and the St. Lawrence River
Journal of Great Lakes Research, 2012Co-Authors: Emily R Cornwell, James R. Winton, Rodman G Getchell, Geoffrey H Groocock, Geofrey E. Eckerlin, Tarin M. Thompson, William N. Batts, Gael Kurath, Rufina N. Casey, James W. CaseyAbstract:Abstract Viral Hemorrhagic Septicemia virus (VHSV) is the causative agent of a devastating disease in fish, Viral Hemorrhagic Septicemia (VHS), which has recently spread to the Laurentian Great Lakes. In this paper, we report the results of infection surveillance conducted during 2009 for VHSV with a focus on yellow perch ( Perca flavescens ) and round goby ( Neogobius melanostomus ). We collected 1928 fish representing eight species at nine sites in Lake Ontario and the St. Lawrence River and found fish positive for VHSV by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) at every site. Prevalence of virus-positive fish at individual sites ranged from 0.7% to 27.5%. Yellow perch were significantly less likely to test positive than round goby in this study. In logistic regression models, maturity was a significant predictor of testing positive in yellow perch, but no evaluated factor was a significant predictor of testing positive in round goby. Virus isolation in cell culture was successful in seven out of 37 high titer fish samples, and partial glycoprotein gene sequences obtained from these virus isolates showed an increase in genetic diversity relative to the previously known diversity of Laurentian Great Lakes VHSV genotype IVb. These results highlight the importance of continued movement restrictions and surveillance for VHSV in wild fish in the Laurentian Great Lakes as well as suggest future work to further elucidate the infection dynamics of this virus in wild fish populations.
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Passive Immunization of Pacific Herring against Viral Hemorrhagic Septicemia
Journal of aquatic animal health, 2011Co-Authors: Paul K. Hershberger, J. L. Gregg, C. A. Grady, Scott E. Lapatra, James R. WintonAbstract:Abstract The plasma of Pacific herring Clupea pallasii that survived laboratory-induced Viral Hemorrhagic Septicemia (VHS) epizootics contained humoral substances that, when injected into naive animals, conferred passive immunity against the disease. Among groups exposed to Viral Hemorrhagic Septicemia virus (VHSV), injection of donor plasma from VHS survivors resulted in significantly greater survival (50%) and significantly lower tissue titers (1.5 × 105 plaque-forming units [PFU]/g) than the injection of plasma from VHSV-naive donors (6% survival; 3.7 × 106 PFU/g). Additionally, the magnitude of the protective immune response increased during the postexposure period; plasma that was collected from survivors at 123 d postexposure (931 degree-days) provided greater protection than plasma collected from survivors at 60 d postexposure (409 degree-days). These results provide proof of concept that the VHSV exposure history of Pacific herring populations can be determined post hoc; furthermore, the results c...
Øystein Evensen - One of the best experts on this subject based on the ideXlab platform.
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Stability and efficacy of the 3'-UTR A4G-G5A variant of Viral Hemorrhagic Septicemia virus (VHSV) as a live attenuated immersion VHSV vaccine in olive flounder (Paralichthys olivaceus).
Vaccine, 2016Co-Authors: Sung-hyun Kim, Jung-ha Kang, Øystein Evensen, Meesun Kim, Go-eun Choi, Lee Jeongho, Woo-jai LeeAbstract:Viral Hemorrhagic Septicemia virus (VHSV) is the causative agent of Viral Hemorrhagic Septicemia in fish, a disease that affects a number of teleost fish species including olive flounder (Paralichthys olivaceus). In this study, we assessed the safety and efficacy of two recombinant attenuated VHSV strains, termed A4G-G5A and ΔNV, with the purpose to select the most suitable vaccine strain. The virus strains were passaged in two commercially available cell lines, EPC and RTG-2, and the strains were also tested for residual virulence in zebrafish (Danio rerio). The A4G-G5A strain showed an attenuated growth profile in both the EPC and RTG-2 cell lines compared to wild-type (WT) VHSV (JF-09, genotype IVa), whereas the growth profile of ΔNV was comparable to the WT strains in RTG-2 cells in contrast to EPC cells. Moreover, ΔNV had higher residual virulence compared to A4G-G5A and was highly pathogenic to zebrafish. The A4G-G5A strain was chosen as vaccine candidate and tested for efficacy in in vivo fish studies in the target species, olive flounder, using an immersion vaccine scheme. Groups of fish were immunized with 10(2.5), 10(3.5), 10(4.5), and 10(5.5) TCID50/ml of A4G-G5A giving 5-13.3 cumulative percent mortality (CPM) post immunization. Immunization was followed by a challenge experiment using VHSV-WT. The relative percent survival (RPS) in immunized groups ranged from 81.6% to 100%, correlating with vaccination dose. This study demonstrates that while strain A4G-G5A has retained some residual virulence it confers high level of protection in immunized olive flounder.
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Use of Poly(I:C) Stabilized with Chitosan As a Vaccine-Adjuvant Against Viral Hemorrhagic Septicemia Virus Infection in Zebrafish.
Zebrafish, 2015Co-Authors: Arturas Kavaliauskis, Sung-hyun Kim, Øystein Evensen, Beatriz Novoa, Marianne Arnemo, Lilia S. Ulanova, Martin Speth, S. Dios, Gareth Griffiths, Tor GjøenAbstract:Abstract There is an urgent need for more efficient Viral vaccines in finfish aquaculture worldwide. Here, we report the use of poly(I:C) stabilized with chitosan as an adjuvant for development of better finfish vaccines. The adjuvant was co-injected with inactivated Viral Hemorrhagic Septicemia virus (VHSV) (CSpIC+iV vaccine) in adult zebrafish and its efficiency in protection against VHSV infection was compared to a live, attenuated VHS virus vaccine (aV). Both free and stabilized poly(I:C) were strong inducers of an antiViral state, measured by transcriptional activation of the genes of Viral sensors: toll-like receptors, interferons, and interferon-stimulated genes, such as MXa within 48 h after injection. Both the CSpIC+iV and the aV formulations provided a significant protection against VHSV-induced mortality. However, when plasma from survivors was tested for neutralizing antibodies in an in vitro protection assay, we could not demonstrate any protective effect. On the contrary, plasma from aV vacc...
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Interchange of L polymerase protein between two strains of Viral Hemorrhagic Septicemia virus (VHSV) genotype IV alters temperature sensitivities in vitro.
Virus research, 2014Co-Authors: Sung-hyun Kim, Shamila Yusuff, Vikram N. Vakharia, Øystein EvensenAbstract:Abstract Viral Hemorrhagic Septicemia virus (VHSV) has four genotypes (I–IV) and sub-lineages within genotype I and IV. Using a reverse genetics approach, we explored the importance of the L gene for growth characteristics at different temperatures following interchange of the L gene within genotype IV (IVa and IVb) strains. VHSV strains harboring heterologous L gene were recovered and we show that the L gene determines growth characteristics at different temperatures in permissive cell lines.
Rodman G Getchell - One of the best experts on this subject based on the ideXlab platform.
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pathogenesis of experimental Viral Hemorrhagic Septicemia virus ivb infection in adult sea lamprey petromyzon marinus
Journal of Great Lakes Research, 2017Co-Authors: L L Coffee, Rodman G Getchell, Geoffrey H Groocock, Emily R Cornwell, G A Wooster, J S Lumsden, Paul R BowserAbstract:Abstract In 2008, Viral Hemorrhagic Septicemia virus (VHSV) genotype IVb, the causative agent of Viral Hemorrhagic Septicemia (VHS) in a wide range of fish, was isolated from sea lamprey (Petromyzon marinus) in the Great Lakes Basin. To better understand the implications of the reported isolation, we utilized four virus detection methods to follow the pathogenesis on an experimental infection of VHSV IVb in 60 wild, adult lamprey. Thirty lamprey were infected by intracoelomic cavity injections with 106 plaque forming units (pfu) of the VHSV IVb MI03 isolate, and 30 control lamprey were injected with sterile culture media. All media-injected controls tested negative by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and cell culture. Twenty-six of the 30 infected lamprey were positive for VHSV by qRT-PCR, and nine were positive by cell culture. In-vivo replication was demonstrated by a significant temporal increase in the mean concentration of VHS Viral RNA copy number equivalents in pooled viscera measured by qRT-PCR from day 7 to day 28 and an increase in cell culture positive pools at day 28. Microscopically, infected lamprey did not develop lesions typical of virulent VHSV. Despite this, the virus was identified by immunohistochemistry in multiple organs, most readily in the kidney, where localization progressed from the interstitium to the tubular lumens. The combined results from qRT-PCR, cell culture, histopathology, and immunohistochemistry suggest that VHSV causes a sublethal infection in lamprey characterized by depletion of renal interstitial cells and in-vivo Viral replication with maintenance in the brain at later stages of infection.
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goldfish carassius auratus susceptibility to Viral Hemorrhagic Septicemia virus genotype ivb depends on exposure route
Diseases of Aquatic Organisms, 2015Co-Authors: Rodman G Getchell, Toni Erkinharju, Anna O Johnson, Benjamin W Davis, Emily E Hatch, Emily R Cornwell, Paul R Bowser, Rodman G Getchell, Emily R Cornwell, Paul R BowserAbstract:We assessed the susceptibility of goldfish Carassius auratus to infection by genotype IVb of the Viral Hemorrhagic Septicemia virus. Goldfish were infected by intraperitoneal injections of 106 plaque-forming units (pfu) fish-1, single bath exposure of 105 pfu ml-1 for 24 h, or consumption of 0.4 g of commercial fish feed soaked in 107 pfu per 8 fish. The mortality rate of intraperitoneal-infected goldfish was 10 to 32%, although the virus was detected by quantitative RT-PCR in 77% (65/84) of the survivors at the end of the 42 d trial, suggesting a carrier state. Severe gross lesions were observed in many of the moribund and dead goldfish such as hemorrhaging in the skin, fin, liver, kidney, brain, intestine, and eye as well as abdominal distension, bilateral exophthalmia, and splenomegaly. There was minimal morbidity or mortality in the immersion, feeding, or control groups.
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detection and surveillance of Viral Hemorrhagic Septicemia virus using real time rt pcr ii diagnostic evaluation of two protocols
Diseases of Aquatic Organisms, 2014Co-Authors: Janet V Warg, Mohamed Faisal, Rodman G Getchell, Geoffrey H Groocock, Emily R Cornwell, Travis Clement, Angela Cruz, Cem Giray, Andrew E Goodwin, Robert KimAbstract:Two real-time reverse transcription polymerase chain reaction (rRT-PCR) assays under consideration for deployment to multiple testing laboratories across the USA were evalu- ated for diagnostic sensitivity and specificity on tissue homogenates obtained from natural and experimental Viral Hemorrhagic Septicemia (VHS)-infected fish. Estimates for diagnostic speci- ficity using virus isolation as the reference method were similar between laboratories regardless of the assay. Diagnostic sensitivity estimates of 0.96 (95% CI: 0.95, 0.97) for Jonstrup et al. (2013)'s assay (J Fish Dis 36:9�23) exceeded the diagnostic sensitivity of 0.85 (95% CI: 0.83, 0.87) for Phelps et al. (2012)'s assay (J Aquat Anim Health 24:238�243). The Jonstrup rRT-PCR assay is robust as demonstrated by high sensitivity and specificity estimates across laboratories and can be used as a valuable tool for targeted surveillance and for testing of suspect VHSV samples.
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detection and surveillance of Viral Hemorrhagic Septicemia virus using real time rt pcr i initial comparison of four protocols
Diseases of Aquatic Organisms, 2014Co-Authors: Janet V Warg, Mohamed Faisal, Rodman G Getchell, Geoffrey H Groocock, Emily R Cornwell, Travis Clement, Angela Cruz, Cem Giray, Andrew E Goodwin, Robert KimAbstract:Eight laboratories worked collectively to evaluate 4 real-time RT-PCR (rRT-PCR) protocols targeting Viral Hemorrhagic Septicemia virus (VHSV) being considered for deployment to a USA laboratory testing network. The protocols utilized previously published primers and probe sets developed for detection and surveillance of VHSV. All participating laboratories received and followed a standard operating protocol for extraction and for each of the rRT-PCR assays. Performance measures specifically evaluated included limit of detection (defined as the smallest amount of analyte in which 95% of the samples are classified as positive), analytical specificity, assay efficiency across genotype representatives, within- and between-plate variation within a laboratory, and variation between laboratories using the same platform, between platforms, and between software versions. This evaluation clearly demonstrated that the TaqMan®-based assay developed by Jonstrup et al. (2013; J Fish Dis 36:9-23) produced the most consistent analytical performance characteristics for detecting all genotypes of VHSV across the 8 participating laboratories.
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Fin and gill biopsies are effective nonlethal samples for detection of Viral Hemorrhagic Septicemia virus genotype IVb
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2013Co-Authors: Emily R Cornwell, Rodman G Getchell, Geoffrey H Groocock, Chelsea A. Bellmund, Po Ting Wong, Katherine L. Hambury, Paul R BowserAbstract:Nonlethal sampling is becoming a common method to diagnose fish diseases, especially with the availability of molecular testing. Viral Hemorrhagic Septicemia virus (VHSV) is a Viral pathogen of finfish distributed worldwide. Although VHSV has been known to occur in some parts of the world for decades, a new genotype, IVb, recently emerged in the Laurentian Great Lakes of northeastern North America. Golden shiners (Notemigonus crysoleucas; Mitchill, 1814) and fathead minnows (Pimephales promelas; Rafinesque, 1820) were exposed to VHSV-IVb doses between 102 and 106 plaque forming units per fish by intraperitoneal injection at 10°C. Both species experienced significant mortality after exposure, ranging from 38% to 52% in golden shiners and from 35% to 95% in fathead minnows. In golden shiners, a fin or gill sample was somewhat less sensitive at detecting VHSV-IVb by quantitative reverse transcription polymerase chain reaction (qRT-PCR) than a pooled organ sample (consisting of liver, anterior and posterior k...
