USGS Eastern Ecological Science Center - Fish Health Lab
USGS Eastern Ecological Science Center - Fish Health Lab
Dr. Vicki Blazer and Dr. Heather Walsh
Best presentation award winner
1,2Cheyenne R. Smith, 2Christopher A. Ottinger, 2Heather L. Walsh, 3Justin B. Greer, 4Patricia M. Mazik, and 2Vicki S. Blazer
1West Virginia University, Division of Forestry and Natural Resources, 333 Evansdale Drive, Morgantown, WV 26506; 2United States Geological Survey, Eastern Ecological Science Center at Leetown Research Laboratory, 11649 Leetown Road, Kearneysville, WV 25430; 3United States Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, Washington 98115; 4United States Geological Survey, West Virginia Cooperative Fish and Wildlife Research Unit, West Virginia University, 1145 Evansdale Drive, Morgantown, WV 26506
Over recent decades, researchers and biologists have observed a disconcerting trend – a decline in the health and stability of smallmouth bass (Micropterus dolomieu) populations across the Chesapeake Bay watershed with growing economic and ecological implications. Disease, declines, and death have been observed in multiple locations, particularly in the Susquehanna and Potomac drainages with the adults disproportionately affected in the Potomac River basin and young-of-year in the Susquehanna River basin. There has not been a single or consistent cause to the declines or mortality events. More likely, it is believed immunosuppression relating to a complex mixture of stressors has been occurring. To investigate immunosuppression as a mechanism behind disease and death of wild smallmouth bass, three immune function in vitro assays were developed and utilized in comprehensive fish health assessments at a total of eight sites over multiple years. The immune function assays measured both innate and adaptive immunity and consisted of bactericidal activity, respiratory burst activity, and lymphocyte mitogenesis with the capability to independently assess background immunity from the stimulated response. Most studies do not report the background response, but we have found it to be as important (or more) than the lab-stimulated responses, especially for wild fish. Our data shows when background responses were high, indicating an ongoing cellular response to pathogens, parasites, contaminants, or even water quality issues, there may be a limitation in the capacity for further stimulation. This suggests that cells already engaged in responding to existing stressors might face challenges in mounting effective responses to new threats, potentially increasing vulnerability to disease. At some of the sites, our data also shows a decrease in background over time and a simultaneous increase in stimulated responses. To discern any potential associations with the overall health status of the fish over time, our investigation into background responses considers their correlation with factors such as contaminants, transcript abundance of immune- and contaminant-related genes, health assessment index, and parasite/macrophage aggregate densities. Analyzing this large dataset of over 400 fish is an ongoing project where now the challenge is bringing all the results together in a comprehensible framework or picture of understanding. Future work includes controlled laboratory studies, pathways analyses of important immune transcripts, and the development of more advanced statistical modeling for analyses.
Clayton Raines1,2 Cynthia Adams1,3, Zanethia Barnett4, Morgan Biggs1, Vicki Blazer1, Drew Carter5, John Coll6, Scott Cornman7, Carly Fenstermacher5, Justin Greer8, Cynthia Holt9, Luke Iwanowicz1,10, Tom Jones11, Brandon Keplinger5, Jan Lovy8,12, Pat Mazik2, Blayk Michaels13, Sunil Mor14, Brent Murry15, Terry Fei Fan Ng16, John Odenkirk17, Nicolas Phelps18, Wade Schaeffer19, Sean Simmons20, Cheyenne Smith1,2, Geoffrey Smith21, Paul Venturelli19, Heather Walsh1, Amy Welsh15, Kelsey Young22
1U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, 2West Virginia USGS Cooperative Fish and Wildlife Research Unit, 3University of Pittsburgh, Department of Medicine, 4U.S. Forest Service, Southern Research Station, 5West Virginia Division of Natural Resources, 6US Fish and Wildlife Service, Lamar Fish Health Center, 7U.S. Geological Survey, Fort Collins Science Center, 8U.S. Geological Survey, Western Fisheries Research Center, 9Texas Parks and Wildlife Department, 10USDA-ARS, National Center for Cool and Cold Water Aquaculture, 11Vermont Fish & Wildlife Department, 12New Jersey Division of Fish & Wildlife, 13Bass Pro Shops, 14Minnesota Veterinary Diagnostic Laboratory, University of Minnesota, 15West Virginia University, Davis College of Agriculture, Natural Resources & Design, 16Division of Viral Diseases, Centers for Disease Control and Prevention, 17Virginia Department of Wildlife Resources, 18Minnesota Aquatic Invasive Species Research Center, University of Minnesota, 19Ball State University, Department of Fish and Wildlife, 20Angler’s Atlas MyCatch, 21Pennsylvania Fish and Boat Commission, 22University of Georgia, College of Veterinary Medicine
Wild fish health management often relies on identification and understanding of primary and secondary pathogens. For many significant fish species such as river herring (Alosa spp.), black basses (Micropterus spp.), and white sucker (Catostomus commersonii) numerous bacterial pathogens have been described, yet there is a paucity of viral research. However, this likely reflects the black-box containing the universe of uncharacterized viruses of these hosts rather than an indication of a scarcity of primary viral pathogens. Advances in discovery and diagnostic capabilities using “next generation sequencing (NGS)”, coupled with de novo assembly approaches, have augmented surveillance efforts. Subsequently this has led to the discovery of numerous novel viruses which may be present in fish without any clinical signs. PCR methods or conventional culture methods are extremely effective for post hoc detection of known pathogens, but no consistent methodology has been ascribed for detection of novel pathogens or in cases of mixed infections. Furthermore, few commercially available cell lines are permissive to viruses of non-model organisms. Accepting massively-parallel sequencing approaches as standard workflows can provide a contemporary approach to discover the diverse and otherwise unculturable viruses that affect fish species of management interest. It can also serve as a foundational catalyst to supplement more established virus detection methods. This presentation will focus on a few specific applications of molecular virology to evaluate potentially emerging pathogens which are generally understudied and of unknown significance to fish health. We will detail methodology used to identify and detect a novel hepadnavirus from clinically normal alewives (A. pseudoharengus), novel adomaviruses and a nackednavirus from largemouth bass (M. salmoides), as well as assessments of hepadnavirus and hepacivirus of white sucker. Additionally, results from less traditional approaches including gene expression analysis, multivariate statistical analysis, and crowd-sourced data collection will be presented. Staying ahead of the cutting edge of disease research creates an opportunity to explore a new frontier of host-pathogen relationships and microbes associated with changing environments.
Lindsey N. Hartzell1*, Heather L. Walsh2, Vicki S. Blazer2, and Patricia M. Mazik3
1West Virginia University, Division of Forestry and Natural Resources, Morgantown, WV 26506 lnh0011@mix.wvu.edu; 2U.S. Geological Survey, Eastern Ecological Science Center, Leetown Research Laboratory, Kearneysville, WV 25430 hwalsh@usgs.gov; vblazer@usgs.gov; 3West Virginia Cooperative Fish and Wildlife Unit, West Virginia University, Morgantown, WV 25606 pmazik@wvu.edu
In the early 2000s, fish kills of different species, including Smallmouth Bass Micropterus dolomieu, were reported in areas of the Potomac River drainage, including the Shenandoah River in Virginia. Since the first reports of fish kills and lesions affecting Smallmouth Bass, they have continued to show signs of adverse health effects. Additionally, in some areas of the Potomac River drainage population declines have occurred, and lethal sampling is disparaged. To test the usefulness of non-lethal sampling, Smallmouth Bass were collected and sampled with both lethal and non-lethal techniques at three sites within the Shenandoah River drainage and one out-of-basin site along the Maury River (located within the James River drainage). Lethal sampling allows for a comprehensive assessment and includes a health assessment index (HAI), organosomatic indices, blood/plasma collection for numerous endpoints, tissue preservation for histopathology and gene expression. For non-lethal methodology development, a skin and gill health assessment index (HAI) was conducted, gill snips were taken in RNAlater for immune-function gene expression, whole blood was collected for contaminant analysis, immune-function gene expression, and blood smears, plasma was extracted for enzyme, protein, and lysozyme analysis, and portions of the dorsal and anal fin from each fish were sampled for aging. Blood smears will be analyzed for white blood cell type and counts as well as micronuclei and red blood cell nuclear abnormalities. The results of this study will not only be applicable for future Smallmouth Bass studies but will provide relevant health assessment techniques for other species experiencing population declines or under a conserved status.