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Gael Kurath, Ph.D.

Viruses and infectious diseases are natural components of every ecosystem. In aquatic ecosystems of the Pacific Northwest infectious hematopoietic necrosis virus (IHNV) is a significant viral pathogen of many salmonid fish populations. Studies of IHNV molecular biology, pathogenesis, field ecology, and evolution contribute to understanding and management of viral disease in salmon and trout.

Research Interests:                        

Our research involves viral diseases in finfish, with an emphasis on the rhabdovirus IHNV in Pacific salmon and trout of Pacific Northwest ecosystems. We conduct landscape-scale genetic typing of IHNV as it occurs across Western North America and use phylogenetic analyses and molecular epidemiology to identify patterns of virus occurrence, transmission, and disease impacts across large geographic regions, and over many years.  This has revealed divergence of IHNV into three major genetic groups (U, M, or L) with distinct host specificities and geographic ranges in North America. There is also clear evidence for viral host jumps, displacement events, and evolution of both specialist and generalist virus lineages. Potential drivers of these evolutionary events are tested in controlled wet laboratory challenge studies in salmonid fish, providing sound scientific data on the biological basis of patterns observed in the field. In a recent project we demonstrated evolution of increasing virulence as a driver of viral genotype displacements in steelhead trout of the Columbia River Basin and worked with collaborators to develop the first landscape-scale transmission model for IHNV.  We also explore the biological basis of specialist (adapted to single host species) and generalist (adapted to multiple host species) viruses, using naturally evolved subgroups of IHNV. This has potential to explain changes in virus types and disease impacts observed in the Columbia River Basin, and it also serves as a tractable research model for empirical testing of predictions of basic specialist-generalist theory for pathogens.  Finally, we collaborate with other researchers to investigate the evolution of IHNV virulence after a historical host jump from sockeye salmon to farmed rainbow trout using a historical panel of over 60 IHNV isolates collected over the last 50 years. Long-term interests include understanding drivers of viral evolution and ecology, host and virus factors that define virus transmission and transmission models, and how human activities can be modified to avoid unintended disease consequences.

Professional Experience

  • 1992 to Present - Research Microbiologist, U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA

  • 1989 - 1992 - Postdoctoral researcher, Plant Virology, University of California, Riverside, CA

  • 1985 - 1988 - Postdoctoral researcher, Plant Virology, Cornell University, Ithaca, NY

Education and Certifications

  • Ph.D. 1985. Virology, Oregon State University, Corvallis, OR

  • M.S. 1980. Marine Microbiology, Oregon State University, Corvallis, OR

  • B.A. 1978. Microbiology, Miami University, Oxford, OH

Affiliations and Memberships*

  • University of Washington, affiliate faculty in Pathobiology with graduate faculty status. 1994 to Present (full professor since 2017).

  • University of Washington, affiliate faculty in the School of Aquatic and Fisheries Sciences with graduate faculty status (2007 to Present).

  • International Committee on Taxonomy of Viruses, member of study groups Rhabdovirus family (1997 to Present), Paramyxovirus Family (2008 to present), and Mononegavirales Super-family (2008 to Present).

  • International Committee on Taxonomy of Viruses, member of study groups Rhabdovirus family (1997 to Present), Paramyxovirus Family (2008 to present), and Mononegavirales Super-family (2008 to Present).

  • Scientific Journal Editorial Board: Virology (1995-1998); Journal of Aquatic Animal Health (2002-2005); Diseases of Aquatic Organisms (2011-2015); Journal of General Virology (2011-2016).

  • Ad hoc reviewer for numerous journals.

  • Grant review panel member or panel chair: USDA Biotechnology Risk Assessment (1996, 1997); USDA NRI Virology (1999, 2000); USDA-NIFA AFRI Diseases of Agricultural Animals program (2020).

  • American Fisheries Society, Fish Health Section, member since 1994, nominating/balloting committee member 2002-2003; chair 2004.

  • American Fisheries Society, Fish Health Section, elected vice-president 2006, executive committee 2006-2010, president 2008.

  • American Society for Virology member since 1983.

Honors and Awards

  • Special Achievement Award, American Fisheries, Society Fish Health Section, 1999

  • U.S. Department of the Interior Star Awards, 2000, 2003, 2004, 2008

  • Snieszko Distinguished Service Award, Fish Health Section, American Fisheries Society, 2020

Science and Products

Filter Total Items: 145

Characterization of maternal immunity following vaccination of broodstock against IHNV or Flavobacterium psychrophilum in rainbow trout (Oncorhynchus mykiss)

Infectious hematopoietic necrosis (IHN) is a significant viral disease affecting salmonids, whereas Flavobacterium psychrophilum (Fp), the causative agent of bacterial coldwater disease (BCWD), remains one of the most significant bacterial pathogens of salmonids. We explored maternal immunity in the context of IHN and BCWD management in rainbow trout (Oncorhynchus mykiss) aquaculture. Two experime
Authors
Jie Ma, Jesse T. Trushenski, Evan M. Jones, Timothy J. Bruce, Doug G. McKenney, Gael Kurath, Kenneth D. Cain
By
Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)

Coproduction and modeling spatial contact networks prevent bias about infectious hematopoietic necrosis virus transmission for Snake River Basin salmonids

Much remains unknown about variation in pathogen transmission across the geographic range of a free-ranging fish or animal species and about the influence of movement (associated with husbandry practices or animal behavior) on pathogen transmission. Salmonid hatcheries are an ideal system in which to study these processes. Salmonid hatcheries are managed for endangered species recovery, supplement
Authors
Jeffrey P. Mattheiss, Rachel Breyta, Gael Kurath, Shannon L. LaDeau, David James Páez, Paige F. B. Ferguson
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)

Comparative susceptibilities of selected California Chinook salmon and steelhead populations to isolates of L Genogroup Infectious Hematopoietic Necrosis Virus (IHNV)

Salmonid species demonstrate varied susceptibility to the viral pathogen infectious hematopoietic necrosis virus (IHNV). In California conservation hatcheries, juvenile Chinook salmon (Oncorhynchus tshawytscha) have experienced disease outbreaks due to L genogroup IHNV since the 1940s, while indigenous steelhead (anadromous O. mykiss) appear relatively resistant. To characterize factors contributi
Authors
Christin M. Bendorf, Susan C. Yun, Gael Kurath, Ronald P. Hedrick
By
Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)

Variation in within-host replication kinetics among virus genotypes provides evidence of specialist and generalist infection strategies across three salmonid host species

Theory of the evolution of pathogen specialization suggests that a specialist pathogen gains high fitness in one host, but this comes with fitness loss in other hosts. By contrast, a generalist pathogen does not achieve high fitness in any host, but gains ecological fitness by exploiting different hosts, and has higher fitness than specialists in nonspecialized hosts. As a result, specialist patho
Authors
David James Páez, Douglas G. McKenney, Maureen K. Purcell, Kerry A. Naish, Gael Kurath
By
Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)

Genetics reveal long-distance virus transmission links in Pacific salmon

In the coastal region of Washington State, a major pathogen emergence event occurred between 2007 and 2011 in which steelhead trout (Oncorhynchus mykiss) experienced a high incidence of infection and disease outbreaks due to the rhabdovirus infectious hematopoietic necrosis virus (IHNV). Genetic typing showed that the introduced viruses were in the steelhead-specific MD subgroup of IHNV and indica
Authors
Rachel Breyta, William N. Batts, Gael Kurath
By
Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)

Shedding kinetics of Infectious Hematopoietic Necrosis Virus (IHNV) in juvenile spring- and fall-run Chinook salmon of the Columbia River Basin

This investigation sought to characterize the shedding of infectious hematopoietic necrosis virus (IHNV) in two populations of Columbia River Basin (CRB) Chinook salmon (Oncorhynchus tshawytscha). Juvenile spring- and fall-run Chinook salmon were exposed by immersion to each of three IHN virus strains from the UC, MD, and L subgroups, and then monitored for viral shedding from individual fish for
Authors
Daniel G. Hernandez, Gael Kurath
By
Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)

Revised taxonomy of rhabdoviruses infecting fish and marine mammals

Rhabdoviridae is a large family of negative-sense (-) RNA viruses that includes important pathogens of ray-finned fish and marine mammals. As for all viruses, the taxonomic assignment of rhabdoviruses occurs through a process implemented by the International Committee on Taxonomy of Viruses (ICTV). A recent revision of taxonomy conducted in conjunction with the ICTV Rhabdoviridae Study Group has r
Authors
Peter J. Walker, Laurent Bigarré, Gael Kurath, Laurent Dacheux, Laurane Pallandre
By
Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)

Effects of stocking density on stress response and susceptibility to infectious hematopoietic necrosis virus in rainbow trout

The goals of this study were to examine the effect of stocking density on the stress response and disease susceptibility in juvenile rainbow trout (Oncorhynchus mykiss). Fish were sorted into one of 2 stocking densities (high density "HD", 20-40 kg/m3) or (low density, "LD", 4-8 kg/m3) and 3 stress indices (cortisol levels in serum and water, and neutrophil: lymphocyte (N:L) ratios from blood smea
Authors
Jenna J Klug, Piper M Treuting, George E. Sanders, James Winton, Gael Kurath
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Ecosystems Mission Area, Species Management Research Program, Western Fisheries Research Center, Fish Health Program (FHP)

Temperature variation and host immunity regulate viral persistence in a salmonid host

Environmental variation has important effects on host–pathogen interactions, affecting large-scale ecological processes such as the severity and frequency of epidemics. However, less is known about how the environment interacts with host immunity to modulate virus fitness within hosts. Here, we studied the interaction between host immune responses and water temperature on the long-term persistence

Authors
David J. Páez, Rachel L. Powers, Peng Jia, Natalia Ballesteros, Gael Kurath, Kerry A. Naish, Maureen K. Purcell
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Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Species Management Research Program, Western Fisheries Research Center, Fish Health Program (FHP)

Virus shedding kinetics and unconventional virulence tradeoffs

Tradeoff theory, which postulates that virulence provides both transmission costs and benefits for pathogens, has become widely adopted by the scientific community. Although theoretical literature exploring virulence-tradeoffs is vast, empirical studies validating various assumptions still remain sparse. In particular, truncation of transmission duration as a cost of virulence has been difficult t
Authors
Andrew R. Wargo, Gael Kurath, Robert J. Scott, Benjamin Kerr
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Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Species Management Research Program, Western Fisheries Research Center, Fish Health Program (FHP)

Virulence and infectivity of UC, MD and L strains of infectious hematopoietic necrosis virus (IHNV) in four populations of Columbia River Basin Chinook salmon

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
Authors
Daniel G. Hernandez, William E. Brown, Kerry A. Naish, Gael Kurath
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Species Management Research Program, Western Fisheries Research Center, Fish Health Program (FHP)

Fish Rhabdoviruses (Rhabdoviridae)

The family Rhabdoviridae currently has 18 genera accepted by the International Committee for Virus Taxonomy (ICTV), and three of those genera contain fish rhabdoviruses. In the genera Novirhabdovirus, Sprivivirus, and Perhabdovirus all viruses infect fish hosts, and there are no fish viruses in any of the other 15 rhabdovirus genera. In the overall phylogeny of the Rhabdoviridae the three fish vir
Authors
Gael Kurath, David B. Stone
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Species Management Research Program, Western Fisheries Research Center, Fish Health Program (FHP)

Non-USGS Publications**

Kurath, G., and C. Robaglia. 1995. Genetic variation and evolution of satellite viruses and satellite RNAs. Pages 385-403 in A. Gibbs, C. Calisher, and F. Garcia-Arenal (eds.), Molecular Basis of Virus Evolution. Cambridge Press, Cambridge, U.K.
Kurath, G., and J.A. Dodds. 1995. Mutation analyses of molecularly cloned satellite tobacco mosaic virus during serial passage in plants: evidence for hotspots of genetic change. RNA 1: 491-500.
Kurath, G., and J.A. Dodds. 1994. Satellite tobacco mosaic virus sequence variants with only five nucleotide differences can interfere with each other in a cross protection-like phenomenon in plants. Virology 202(2): 1065-1069. DOI: https://doi.org/10.1006/viro.1994.1441.
Rodriguez-Alvarado, G., G. Kurath, and J.A. Dodds. 1994. Symptom modification by satellite tobacco mosaic virus in pepper types and cultivars infected with helper tobamoviruses. Phytopathology 84(6): 617-621. DOI: 10.1094/Phyto-84-617.
Kurath, G., M.E. C. Rey, and J.A. Dodds. 1993. Tobamovirus helper specificity of satellite tobacco mosaic virus involves a domain near the 5' end of the satellite genome. Journal of General Virology 74(7): 1233-1243. DOI: 10.1099/0022-1317-74-7-1233.
Kurath, G., M.E. C. Rey, and J.A. Dodds. 1992. Analysis of genetic heterogeneity within the type strain of satellite tobacco mosaic virus reveals several variants and a strong bias for G to A substitution mutations. Virology 189(1): 233-244. DOI: https://doi.org/10.1016/0042-6822(92)90699-P.
Kurath, G., and P. Palukaitis. 1990. Serial passage of infectious transcripts of a cucumber mosaic virus satellite RNA clone results in sequence heterogeneity. Virology 176(1): 8-15. DOI: https://doi.org/10.1016/0042-6822(90)90224-F.
Kurath, G., and P. Palukaitis. 1989. RNA sequence heterogeneity in natural populations of three satellite RNAs of cucumber mosaic virus. Virology 173(1): 231-240. DOI: https://doi.org/10.1016/0042-6822(89)90239-0.
Kurath, G., and P. Palukaitis. 1987. Biological activity of T7 transcripts of a prototype clone and a sequence variant clone of a satellite RNA of cucumber mosaic virus. Virology 159(2):199-208. DOI: https://doi.org/10.1016/0042-6822(87)90456-9.
Kurath, G., and J.C. Leong. 1985. Characterization of IHN virus mRNA species reveals a non-virion rhabdovirus protein. Journal of Virology 53(2):462-468.
Kurath, G., K.G. Ahern, G.D. Pearson, and J.C. Leong. 1985. Molecular cloning of six mRNA species of IHNV, a fish rhabdovirus: Gene order determined by R-loop mapping. Journal of Virology 53(2): 469-476.
Kurath, G., and R.Y. Morita. 1983. Some physiological studies on starvation survival of a marine Pseudomonas sp. Applied and Environmental Microbiology 45(4):1206-1211.

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

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Koi infected with spring viremia of carp virus

Investigation and Disease Prevention of Spring Viremia of Carp Virus (SVCV)

There has been long history of disease outbreaks and economic losses in wild and farmed carp species due to SVCV. Formerly thought to be restricted to Europe and Asia, SVCV was detected for the first time in North America from diseased koi at a North Carolina fish farm in 2002, and there were extensive eradication efforts with 135,000 fish euthanized in addition to the ~15,000 that died from the...
By
Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Investigation and Disease Prevention of Spring Viremia of Carp Virus (SVCV)

There has been long history of disease outbreaks and economic losses in wild and farmed carp species due to SVCV. Formerly thought to be restricted to Europe and Asia, SVCV was detected for the first time in North America from diseased koi at a North Carolina fish farm in 2002, and there were extensive eradication efforts with 135,000 fish euthanized in addition to the ~15,000 that died from the...
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Scientist examines a cell cuture

Reference Laboratory Service - FHP

The Fish Health Section provides reference laboratory services to identify viral pathogens submitted by staff from the Northwest Indian Fisheries Commission (NWIFC) fish health laboratory.
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Reference Laboratory Service - FHP

The Fish Health Section provides reference laboratory services to identify viral pathogens submitted by staff from the Northwest Indian Fisheries Commission (NWIFC) fish health laboratory.
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Cutthroat trout

Emerging Viruses - FHP

Fish Diseases - Emerging Viruses
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Emerging Viruses - FHP

Fish Diseases - Emerging Viruses
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Photo of yellow perch

Viral Hemorrhagic Septicemia (VHS) - FHP

Fish Diseases - Viral Hemorrhagic Septicemia (VHS)
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Viral Hemorrhagic Septicemia (VHS) - FHP

Fish Diseases - Viral Hemorrhagic Septicemia (VHS)
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Photo of Rainbow trout with IHN

Infectious Hematopoietic Necrosis (IHN) - FHP

Fish Diseases - Infectious Hematopoietic Necrosis (IHN)
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Infectious Hematopoietic Necrosis (IHN) - FHP

Fish Diseases - Infectious Hematopoietic Necrosis (IHN)
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Photo of fathead minnow

Spring Viremia of Carp (SVC) - FHP

Fish Diseases - Spring Viremia of Carp (SVC)
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Spring Viremia of Carp (SVC) - FHP

Fish Diseases - Spring Viremia of Carp (SVC)
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Koi (Cyprinus carpio koi) infected with SVCV

Koi (Cyprinus carpio koi) - FHP

Species Studied - Koi (Cyprinus carpio koi)
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Koi (Cyprinus carpio koi) - FHP

Species Studied - Koi (Cyprinus carpio koi)
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Yellow perch (Perca flavescens) fry

Yellow Perch (Perca flavescens) - FHP

Species Studied - Yellow Perch (Perca flavescens)
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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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Yellow Perch (Perca flavescens) - FHP

Species Studied - Yellow Perch (Perca flavescens)
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Entry and spread of specialist and generalist infectious hematopoietic necrosis virus (IHNV) genotypes in Chinook salmon, steelhead and sockeye salmon

Infectious hematopoietic necrosis virus (IHNV) represents one of the most critical challenges for salmonids in the Pacific Northwest. There are three genogroups of IHNV, designated U, M, and L; the U is further delineated into two subgroups, UC and UP, and the M is further delineated into four subgroups (MA – MD). The UP, UC and MD subgroups co-occur in the Columbia River Basin where the host spec
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Western Fisheries Research Center, Fish Health Program (FHP), Marrowstone Marine Field Station (MMFS)

Survival and viral load of chinook salmon, sockeye salmon, and steelhead trout exposed to 4 genogroups of infectious hematopoietic necrosis virus (IHNV)

Theory of the evolution of pathogen specialization suggests that a specialist pathogen gains high fitness in one host, but this comes with fitness loss in other hosts. By contrast, a generalist pathogen does not achieve high fitness in any host, but gains ecological fitness by exploiting different hosts, and has higher fitness than specialists in non-specialized hosts. As a result, specialist path
By
Biological Threats and Invasive Species Research Program, Western Fisheries Research Center, Fish Health Program (FHP)
Researchers processing fish samples in MMFS wet laboratory
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Researchers condition chinook in swim flume
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Fish swimming in swim flume
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Researcher preparing to sample fish from swim flume
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Collecting tissues from fish
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Measuring virus for a Chinook salmon infection experiment
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Working in the WFRC wet lab
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An Online Database for IHN Virus in Pacific Salmonid Fish: MEAP-IHNV

The Molecular Epidemiology of Aquatic Pathogens (MEAP)-IHNV Database

The MEAP-IHNV database provides access to detailed data for anyone interested in IHNV molecular epidemiology, such as fish health professionals, fish culture facility managers, and academic researchers.

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Ecosystems Mission Area, Species Management Research Program, Western Fisheries Research Center, Fish Health Program (FHP)

AquaPathogen X: A Template Database for Tracking Field Isolates of Aquatic Pathogens

Aquatic Pathogen Template Database (AquaPathogen X)

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Ecosystems Mission Area, Western Fisheries Research Center, Fish Health Program (FHP)
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If You Build It, They Will Swim—New Swim Flume Gives Insight into Fish Disease, Swimming Performance, and Fitness

Scientists at the Western Fisheries Research Center, Marrowstone Marine Field Station have designed a fish swim flume to investigate the effects of...

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Western Fisheries Science News, December 2015 | Issue 3.12

How Infectious Hematopoietic Necrosis (IHN) Got its Name

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Western Fisheries Science News, February 2015 | Issue 3.2

IHN Research at the WFRC

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Science and Products

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government