I am a laboratory technician in the Fish Health Section at the Western Fisheries Research Center in Seattle, WA. I have worked on a variety of projects using molecular biology-based methods to study parasites, bacteria, and viruses that infect wild and hatchery populations of salmon and trout in the Pacific Northwest.
Professional Experience
2010-present: Biological Science Technician, USGS Western Fisheries Research Center, Seattle, WA
Education and Certifications
B.S. 2010. Aquatic and Fishery Sciences, University of Washington, Seattle, WA
Honors and Awards
2021- Department of the Interior, Unit Award for Excellence of Service awarded to the Quality Management System Work Group
2012 – U.S. Geological Survey, Western States Diversity Award group award to Fish Health Section
Science and Products
Filter Total Items: 18
A phylogeny based on cytochrome-c oxidase gene sequences identifies sympatric Ichthyophonus genotypes in the NE Pacific Ocean
ABSTRACT: In recent decades, evidence has accumulated to suggest that the widespread and highly variable parasite Ichthyophonus hoferi is actually a species complex. Highly plastic morphology and a general lack of defining structures has contributed to the likely underestimate of biodiversity within this group. Molecular methods are a logical next step in the description of these parasites, but ma
Authors
Jacob L. Gregg, Paul Hershberger, Abigail S. Neat, Hiruni T. Jayasekera, Jayde A. Ferguson, Rachel L. Powers, Maureen K. Purcell
Rapid diagnostic test to detect and discriminate infectious hematopoietic necrosis virus (IHNV) genogroups U and M to aid management of Pacific Northwest salmonid populations
Infectious hematopoietic necrosis virus (IHNV) is an acute pathogen of salmonids in North America, Europe, and Asia that is phylogenetically classified into five major virus genogroups (U, M, L, E, and J). The geographic range of the U and M genogroup isolates overlap in the North American Columbia River Basin and Washington Coast region, where these genogroups pose different risks depending on th
Authors
William N. Batts, Tony R. Capps, Lisa M. Crosson, Rachel L. Powers, Rachel Breyta, Maureen K. Purcell
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
Long-term shedding from fully convalesced individuals indicates that Pacific herring are a reservoir for viral hemorrhagic septicemia virus
Processes that allow viral hemorrhagic septicemia (VHS) virus to persist in the marine environment remain enigmatic, owing largely to the presence of covert and cryptic infections in marine fishes during typical sub-epizootic periods. As such, marine host reservoirs for VHS virus have not been fully demonstrated, nor have the mechanism(s) by which infected hosts contribute to virus perpetuation an
Authors
Paul Hershberger, Ashley Mackenzie, Jacob L. Gregg, M. D. Wilmot, Rachel L. Powers, Maureen K. Purcell
Effect of temperature on survival of Lost River Suckers with a natural infection of Ichthyobodo spp.
To compensate for low natural survival of endangered Lost River Suckers Deltistes luxatus, the U.S. Fish and Wildlife Service and the Klamath Tribes have initiated captive rearing programs. We conducted laboratory experiments intended to determine the temperature for optimum growth of juvenile Lost River Suckers; however, due to an unanticipated infection with Ichthyobodo spp., we instead estimate
Authors
Barbara A. Martin, Summer M. Burdick, Maureen K. Purcell, Rachel L. Powers
Consequences of Piscine orthoreovirus genotype 1 (PRV‐1) infections in Chinook salmon (Oncorhynchus tshawytscha ), coho salmon (O. kisutch ) and rainbow trout (O. mykiss )
Piscine orthoreovirus genotype 1 (PRV‐1) is the causative agent of heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar L.). The virus has also been found in Pacific salmonids in western North America, raising concerns about the risk to native salmon and trout. Here, we report the results of laboratory challenges using juvenile Chinook salmon, coho salmon and rainbo
Authors
Maureen K. Purcell, Rachel L. Powers, Torunn Taksdal, Douglas Mckenney, Carla M. Conway, Diane G. Elliott, Mark Polinski, Kyle A. Garver, James Winton
Mortality of endangered juvenile Lost River Suckers associated with cyanobacteria blooms in mesocosms in Upper Klamath Lake, Oregon
Unsustainably high mortality within the first 2 years of life prevents endangered Lost River Suckers Deltistes luxatus in Upper Klamath Lake, Oregon, from recruiting to spawning populations. Massive blooms of the cyanobacterium Aphanizomenon flos‐aquae and their subsequent death and decay in the lake (bloom‐crashes) are associated with high pH, low percent oxygen saturation, high total ammonia con
Authors
Summer M. Burdick, Danielle M Hereford, Carla M. Conway, Nathan V Banet, Rachel L. Powers, Barbara A. Martin, Diane G. Elliott
Complete genome sequences of the index isolates of two genotypes of Pacific salmon paramyxovirus
We report here the genome sequences of two index strains of Pacific salmon paramyxovirus isolated in 1982 and 1983 from adult salmon in Oregon. The isolates are most closely related to Atlantic salmon paramyxovirus, the type species of the genus Aquaparamyxovirus, but are sufficiently distinct to be considered two genotypes of a novel species.
Authors
James Winton, William N. Batts, Rachel L. Powers, Maureen K. Purcell
Broad-spectrum antiviral JL122 blocks infection and inhibits transmission of aquatic rhabdoviruses
The aquaculture industry is growing rapidly to meet the needs for global protein consumption. Viral diseases in aquaculture are quite challenging due to lack of treatment options as well as limited injection-delivery vaccines, which are costly. Thus, water-immersion antiviral treatments are highly desirable. This study focused on broad-spectrum, light-activated antivirals that target the viral mem
Authors
Bethany F. Balmer, Rodman G. Getchell, Rachel L. Powers, Jihye Lee, Tinghu Zhang, Michael E. Jung, Maureen K. Purcell, Kevin Snekvik, Hector C. Aguilar
Molecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus in Alaska and Washington
This research was initiated in conjunction with a systematic, multiagency surveillance effort in the United States (U.S.) in response to reported findings of infectious salmon anaemia virus (ISAV) RNA in British Columbia, Canada. In the systematic surveillance study reported in a companion paper, tissues from various salmonids taken from Washington and Alaska were surveyed for ISAV RNA using the U
Authors
Maureen K. Purcell, Rachel L. Thompson, Joy Evered, John Kerwin, Ted R. Meyers, Bruce Stewart, James Winton
Detection of Nanophyetus salmincola in water, snails, and fish tissues by quantitative polymerase chain reaction
We report the development and validation of two quantitative PCR (qPCR) assays to detect Nanophyetus salmincola DNA in water samples and in fish and snail tissues. Analytical and diagnostic validation demonstrated good sensitivity, specificity, and repeatability of both qPCR assays. The N. salmincola DNA copy number in kidney tissue was significantly correlated with metacercaria counts based on mi
Authors
Maureen K. Purcell, Rachel L. Powers, Bonnie Besijn, Paul K. Hershberger
Optimization of a Plaque Neutralization Test (PNT) to identify the exposure history of Pacific Herring to viral hemorrhagic septicemia virus (VHSV)
Methods for a plaque neutralization test (PNT) were optimized for the detection and quantification of viral hemorrhagic septicemia virus (VHSV) neutralizing activity in the plasma of Pacific Herring Clupea pallasii. The PNT was complement dependent, as neutralizing activity was attenuated by heat inactivation; further, neutralizing activity was mostly restored by the addition of exogenous compleme
Authors
Lucas Hart, Ashley Mackenzie, Maureen K. Purcell, Rachel L. Thompson, Paul Hershberger
Analytical and diagnostic validation of a molecular test to detect and discriminate IHNV genogroups U and M
Infectious hematopoietic necrosis virus (IHNV) is an acute pathogen of salmonids in North America, Europe and Asia that is phylogenetically classified into five major virus genogroups (U, M, L, E and J). The geographic range of the U and M genogroup isolates overlap in the North American Columbia River Basin and Washington Coast region, where these genogroups pose different risks depending on the
Histological and molecular testing of nuclear inclusion X in Pacific Razor clams from select locations in Washington, USA
Nuclear inclusion X (NIX), the etiological agent of bacterial gill disease in Pacific razor clams (Siliqua patula) was associated with host mortality events in coastal Washington, USA during the mid-1980s. Ongoing observations of truncated razor clam size distributions in Kalaloch Beach, Washington raised concerns that NIX continues to impact populations. We conducted a series of spatial and longi
Survival, viral load and neutralizing antibodies in steelhead trout and cell cultures exposed to infectious hematopoietic necrosis virus (IHNV) at 3 temperatures
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 modulates viral fitness traits and within host infection processes. Viral genetic variation, fish host immune response and environmental parameters such as temperature have been repo
Data from 2018 Experiment on Effects of Temperature on Survival and Growth of Juvenile Lost River Suckers (Deltistes luxatus) naturally exposed to Ichthyobodo spp
Data included in this data set are for an experiment conducted in 2018. Data were collected on survival, growth, food consumption, and Ichthyobodo copy numbers of Lost River suckers exposed to five different temperature groups. There are five levels of data. Temperature data contains 1,178 records and the data file is 35 KB, survival data contains 150 records and the data file is 3 KB, food consum
Final Dataset: Molecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus (PRV) in Alaska and Washington
Dataset for the publication 'Molecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus (PRV) in Alaska and Washington'. This research was initiated in conjunction with a systematic, multi-agency surveillance effort in the United States (U.S.) in response to reported findings of infectious salmon ane
Science and Products
- Publications
Filter Total Items: 18
A phylogeny based on cytochrome-c oxidase gene sequences identifies sympatric Ichthyophonus genotypes in the NE Pacific Ocean
ABSTRACT: In recent decades, evidence has accumulated to suggest that the widespread and highly variable parasite Ichthyophonus hoferi is actually a species complex. Highly plastic morphology and a general lack of defining structures has contributed to the likely underestimate of biodiversity within this group. Molecular methods are a logical next step in the description of these parasites, but maAuthorsJacob L. Gregg, Paul Hershberger, Abigail S. Neat, Hiruni T. Jayasekera, Jayde A. Ferguson, Rachel L. Powers, Maureen K. PurcellRapid diagnostic test to detect and discriminate infectious hematopoietic necrosis virus (IHNV) genogroups U and M to aid management of Pacific Northwest salmonid populations
Infectious hematopoietic necrosis virus (IHNV) is an acute pathogen of salmonids in North America, Europe, and Asia that is phylogenetically classified into five major virus genogroups (U, M, L, E, and J). The geographic range of the U and M genogroup isolates overlap in the North American Columbia River Basin and Washington Coast region, where these genogroups pose different risks depending on thAuthorsWilliam N. Batts, Tony R. Capps, Lisa M. Crosson, Rachel L. Powers, Rachel Breyta, Maureen K. PurcellTemperature 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
AuthorsDavid J. Páez, Rachel L. Powers, Peng Jia, Natalia Ballesteros, Gael Kurath, Kerry A. Naish, Maureen K. PurcellLong-term shedding from fully convalesced individuals indicates that Pacific herring are a reservoir for viral hemorrhagic septicemia virus
Processes that allow viral hemorrhagic septicemia (VHS) virus to persist in the marine environment remain enigmatic, owing largely to the presence of covert and cryptic infections in marine fishes during typical sub-epizootic periods. As such, marine host reservoirs for VHS virus have not been fully demonstrated, nor have the mechanism(s) by which infected hosts contribute to virus perpetuation anAuthorsPaul Hershberger, Ashley Mackenzie, Jacob L. Gregg, M. D. Wilmot, Rachel L. Powers, Maureen K. PurcellEffect of temperature on survival of Lost River Suckers with a natural infection of Ichthyobodo spp.
To compensate for low natural survival of endangered Lost River Suckers Deltistes luxatus, the U.S. Fish and Wildlife Service and the Klamath Tribes have initiated captive rearing programs. We conducted laboratory experiments intended to determine the temperature for optimum growth of juvenile Lost River Suckers; however, due to an unanticipated infection with Ichthyobodo spp., we instead estimateAuthorsBarbara A. Martin, Summer M. Burdick, Maureen K. Purcell, Rachel L. PowersConsequences of Piscine orthoreovirus genotype 1 (PRV‐1) infections in Chinook salmon (Oncorhynchus tshawytscha ), coho salmon (O. kisutch ) and rainbow trout (O. mykiss )
Piscine orthoreovirus genotype 1 (PRV‐1) is the causative agent of heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar L.). The virus has also been found in Pacific salmonids in western North America, raising concerns about the risk to native salmon and trout. Here, we report the results of laboratory challenges using juvenile Chinook salmon, coho salmon and rainboAuthorsMaureen K. Purcell, Rachel L. Powers, Torunn Taksdal, Douglas Mckenney, Carla M. Conway, Diane G. Elliott, Mark Polinski, Kyle A. Garver, James WintonMortality of endangered juvenile Lost River Suckers associated with cyanobacteria blooms in mesocosms in Upper Klamath Lake, Oregon
Unsustainably high mortality within the first 2 years of life prevents endangered Lost River Suckers Deltistes luxatus in Upper Klamath Lake, Oregon, from recruiting to spawning populations. Massive blooms of the cyanobacterium Aphanizomenon flos‐aquae and their subsequent death and decay in the lake (bloom‐crashes) are associated with high pH, low percent oxygen saturation, high total ammonia conAuthorsSummer M. Burdick, Danielle M Hereford, Carla M. Conway, Nathan V Banet, Rachel L. Powers, Barbara A. Martin, Diane G. ElliottComplete genome sequences of the index isolates of two genotypes of Pacific salmon paramyxovirus
We report here the genome sequences of two index strains of Pacific salmon paramyxovirus isolated in 1982 and 1983 from adult salmon in Oregon. The isolates are most closely related to Atlantic salmon paramyxovirus, the type species of the genus Aquaparamyxovirus, but are sufficiently distinct to be considered two genotypes of a novel species.AuthorsJames Winton, William N. Batts, Rachel L. Powers, Maureen K. PurcellBroad-spectrum antiviral JL122 blocks infection and inhibits transmission of aquatic rhabdoviruses
The aquaculture industry is growing rapidly to meet the needs for global protein consumption. Viral diseases in aquaculture are quite challenging due to lack of treatment options as well as limited injection-delivery vaccines, which are costly. Thus, water-immersion antiviral treatments are highly desirable. This study focused on broad-spectrum, light-activated antivirals that target the viral memAuthorsBethany F. Balmer, Rodman G. Getchell, Rachel L. Powers, Jihye Lee, Tinghu Zhang, Michael E. Jung, Maureen K. Purcell, Kevin Snekvik, Hector C. AguilarMolecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus in Alaska and Washington
This research was initiated in conjunction with a systematic, multiagency surveillance effort in the United States (U.S.) in response to reported findings of infectious salmon anaemia virus (ISAV) RNA in British Columbia, Canada. In the systematic surveillance study reported in a companion paper, tissues from various salmonids taken from Washington and Alaska were surveyed for ISAV RNA using the UAuthorsMaureen K. Purcell, Rachel L. Thompson, Joy Evered, John Kerwin, Ted R. Meyers, Bruce Stewart, James WintonDetection of Nanophyetus salmincola in water, snails, and fish tissues by quantitative polymerase chain reaction
We report the development and validation of two quantitative PCR (qPCR) assays to detect Nanophyetus salmincola DNA in water samples and in fish and snail tissues. Analytical and diagnostic validation demonstrated good sensitivity, specificity, and repeatability of both qPCR assays. The N. salmincola DNA copy number in kidney tissue was significantly correlated with metacercaria counts based on miAuthorsMaureen K. Purcell, Rachel L. Powers, Bonnie Besijn, Paul K. HershbergerOptimization of a Plaque Neutralization Test (PNT) to identify the exposure history of Pacific Herring to viral hemorrhagic septicemia virus (VHSV)
Methods for a plaque neutralization test (PNT) were optimized for the detection and quantification of viral hemorrhagic septicemia virus (VHSV) neutralizing activity in the plasma of Pacific Herring Clupea pallasii. The PNT was complement dependent, as neutralizing activity was attenuated by heat inactivation; further, neutralizing activity was mostly restored by the addition of exogenous complemeAuthorsLucas Hart, Ashley Mackenzie, Maureen K. Purcell, Rachel L. Thompson, Paul Hershberger - Data
Analytical and diagnostic validation of a molecular test to detect and discriminate IHNV genogroups U and M
Infectious hematopoietic necrosis virus (IHNV) is an acute pathogen of salmonids in North America, Europe and Asia that is phylogenetically classified into five major virus genogroups (U, M, L, E and J). The geographic range of the U and M genogroup isolates overlap in the North American Columbia River Basin and Washington Coast region, where these genogroups pose different risks depending on theHistological and molecular testing of nuclear inclusion X in Pacific Razor clams from select locations in Washington, USA
Nuclear inclusion X (NIX), the etiological agent of bacterial gill disease in Pacific razor clams (Siliqua patula) was associated with host mortality events in coastal Washington, USA during the mid-1980s. Ongoing observations of truncated razor clam size distributions in Kalaloch Beach, Washington raised concerns that NIX continues to impact populations. We conducted a series of spatial and longiSurvival, viral load and neutralizing antibodies in steelhead trout and cell cultures exposed to infectious hematopoietic necrosis virus (IHNV) at 3 temperatures
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 modulates viral fitness traits and within host infection processes. Viral genetic variation, fish host immune response and environmental parameters such as temperature have been repoData from 2018 Experiment on Effects of Temperature on Survival and Growth of Juvenile Lost River Suckers (Deltistes luxatus) naturally exposed to Ichthyobodo spp
Data included in this data set are for an experiment conducted in 2018. Data were collected on survival, growth, food consumption, and Ichthyobodo copy numbers of Lost River suckers exposed to five different temperature groups. There are five levels of data. Temperature data contains 1,178 records and the data file is 35 KB, survival data contains 150 records and the data file is 3 KB, food consumFinal Dataset: Molecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus (PRV) in Alaska and Washington
Dataset for the publication 'Molecular testing of adult Pacific salmon and trout (Oncorhynchus spp.) for several RNA viruses demonstrates widespread distribution of piscine orthoreovirus (PRV) in Alaska and Washington'. This research was initiated in conjunction with a systematic, multi-agency surveillance effort in the United States (U.S.) in response to reported findings of infectious salmon ane