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Batts WN, Capps TR, Crosson LM, Powers RL, Breyta R, Purcell MK. Rapid Diagnostic Test to Detect and Discriminate Infectious Hematopoietic Necrosis Virus (IHNV) Genogroups U and M to Aid Management of Pacific Northwest Salmonid Populations. Animals (Basel) 2022; 12:ani12141761. [PMID: 35883308 PMCID: PMC9311590 DOI: 10.3390/ani12141761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 11/16/2022] Open
Abstract
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 species of Pacific salmon (Oncorhynchus spp.). For certain management decisions, there is a need to both test for IHNV presence and rapidly determine the genogroup. Herein, we report the development and validation of a U/M multiplex reverse transcription, real-time PCR (RT-rPCR) assay targeting the IHNV nucleocapsid (N) protein gene. The new U/M RT-rPCR is a rapid, sensitive, and repeatable assay capable of specifically discriminating between North American U and M genogroup IHNV isolates. However, one M genogroup isolate obtained from commercially cultured Idaho rainbow trout (O. mykiss) showed reduced sensitivity with the RT-rPCR test, suggesting caution may be warranted before applying RT-rPCR as the sole surveillance test in areas associated with the Idaho trout industry. The new U/M assay had high diagnostic sensitivity (DSe > 94%) and specificity (DSp > 97%) in free-ranging adult Pacific salmon, when assessed relative to cell culture, the widely accepted reference standard, as well as the previously validated universal N RT-rPCR test. The high diagnostic performance of the new U/M assay indicates the test is suitable for surveillance, diagnosis, and confirmation of IHNV in Pacific salmon from the Pacific Northwest regions where the U and M genogroups overlap.
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Affiliation(s)
- William N. Batts
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA 98115, USA; (W.N.B.); (R.L.P.)
| | - Tony R. Capps
- Washington Department of Fish and Wildlife, Olympia, WA 98501, USA; (T.R.C.); (L.M.C.)
| | - Lisa M. Crosson
- Washington Department of Fish and Wildlife, Olympia, WA 98501, USA; (T.R.C.); (L.M.C.)
| | - Rachel L. Powers
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA 98115, USA; (W.N.B.); (R.L.P.)
| | - Rachel Breyta
- School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA 98195, USA;
| | - Maureen K. Purcell
- U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA 98115, USA; (W.N.B.); (R.L.P.)
- Correspondence:
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Teffer AK, Miller KM. A Comparison of Nonlethal and Destructive Methods for Broad-Based Infectious Agent Screening of Chinook Salmon Using High-Throughput qPCR. JOURNAL OF AQUATIC ANIMAL HEALTH 2019; 31:274-289. [PMID: 31343778 DOI: 10.1002/aah.10079] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/20/2019] [Indexed: 06/10/2023]
Abstract
Molecular tools, such as high-throughput quantitative polymerase chain reaction (HT-qPCR), are useful for monitoring multiple infectious agents in wild animal populations (i.e., broad-based screening). If destructive tissue samples cannot be obtained due to experimental design requirements (e.g., bio-telemetry; holding with repeated biopsy) or the conservation status of host species, then nonlethally sampled tissues can be substituted. However, infection profiles have been found to differ between nonlethally and destructively sampled tissues. We present a comparative analysis of nonlethal (gill and blood) and destructive (pool of internal and external tissue) approaches for broad-based infectious agent screening of adult Chinook Salmon Oncorhynchus tshawytscha. Of a possible 47 agents, 16 were detected overall by nonlethal and destructive methods. Our results indicated moderate differences in infection profiles among tissues, with limitations of each tissue type dependent on the ecology of each agent. The gill was the most comprehensive screening tissue, as more infectious agents were detected overall in gill (n = 16) than in blood (n = 12) or multi-tissue pools (n = 15). The agreement in the estimated agent prevalence between tissue types ranged from poor to excellent, while overall agent community structure (the combined prevalence of all agents) showed low agreement between tissue types. Two agents occurred at 100% prevalence in all tissue types. Nine agents, including types of bacteria and gill parasites, were more prevalent in gill than in blood, while five agents, including one virus and several microparasites, were more prevalent in blood. Future studies should pair microscopy and histopathology with HT-qPCR to better characterize host health and disease development relative to molecular detection of agents across tissue types.
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Affiliation(s)
- Amy K Teffer
- Department of Biology, University of Victoria, Post Office Box 1700, Station CSC, Victoria, British Columbia, V8W 2Y2, Canada
| | - Kristina M Miller
- Fisheries and Oceans Canada, Molecular Genetics Section, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, V9T 6N7, Canada
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Yong CY, Ong HK, Tang HC, Yeap SK, Omar AR, Ho KL, Tan WS. Infectious hematopoietic necrosis virus: advances in diagnosis and vaccine development. PeerJ 2019; 7:e7151. [PMID: 31341728 PMCID: PMC6640626 DOI: 10.7717/peerj.7151] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/20/2019] [Indexed: 12/16/2022] Open
Abstract
The aquaculture of salmonid fishes is a multi-billion dollar industry with production over 3 million tons annually. However, infectious hematopoietic necrosis virus (IHNV), which infects and kills salmon and trout, significantly reduces the revenue of the salmon farming industry. Currently, there is no effective treatment for IHNV infected fishes; therefore, early detection and depopulation of the infected fishes remain the most common practices to contain the spread of IHNV. Apart from hygiene practices in aquaculture and isolation of infected fishes, loss of fishes due to IHNV infection can also be significantly reduced through vaccination programs. In the current review, some of the diagnostic methods for IHNV, spanning from clinical diagnosis to cell culture, serological and molecular methods are discussed in detail. In addition, some of the most significant candidate vaccines for IHNV are also extensively discussed, particularly the DNA vaccines.
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Affiliation(s)
- Chean Yeah Yong
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.,Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Hui Kian Ong
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Hooi Chia Tang
- Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Swee Keong Yeap
- China ASEAN College of Marine Sciences, Xiamen University Malaysia, Sepang, Selangor, Malaysia
| | - Abdul Rahman Omar
- Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Kok Lian Ho
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Wen Siang Tan
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.,Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
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Chiaramonte LV, Burbank D, Scott R, Trushenski JT. Comparison of Sampling and Detection Methods for Chinook Salmon and Steelhead Naturally Infected with Myxobolus cerebralis. JOURNAL OF AQUATIC ANIMAL HEALTH 2018; 30:57-64. [PMID: 29595883 DOI: 10.1002/aah.10008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 12/10/2017] [Indexed: 06/08/2023]
Abstract
Myxobolus cerebralis (Mc) is a myxozoan parasite causing whirling disease in hatchery- and natural-origin salmonids. To minimize spread of this parasite and the incidence of its associated disease, fish health professionals routinely screen fish for Mc before stocking or moving the fish to Mc-free waters. Sample collection for Mc traditionally entails lethal sampling of cranial tissue followed by pepsin-trypsin digest (PTD) and screening of the sample for mature myxobolid myxospores (PTD method); however, nonlethal sampling methods would be advantageous in some circumstances, such as when dealing with rare or otherwise valuable fish. Accordingly, we compared Mc detections in cranial cartilage by using the PTD method with PCR assays of fin biopsies collected from juvenile Chinook Salmon Oncorhynchus tshawytscha and adult steelhead O. mykiss. Cranial samples were also analyzed using PCR methods for comparative purposes. Results indicated that Mc could be detected by PCR in fin clips, but the results generated by this approach differed significantly from those associated with PTD- and/or PCR-based analysis of cranial cartilage samples. Polymerase chain reaction-based analysis-of individual head samples and head digest pools in both species as well as fins in steelhead-yielded more positive detections than PTD analysis alone. The PCR-based analysis of head and fin tissues yielded different Mc detection rates in both species, but the nature of the detection disparity varied depending on the species and/or life stage of the fish. We conclude that for lethal cranial samples, neither PTD nor PCR should be used alone, but using these techniques in concert may provide the most complete and accurate estimation of Mc presence in a group of salmonids. If imperiled or highly valuable fish are in question, nonlethal fin samples may be used to generate some information regarding Mc status, with the understanding that parasite DNA detections do not necessarily signify mature infections or disease.
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Affiliation(s)
- Luciano V Chiaramonte
- Idaho Department of Fish and Game, Nampa Research Office, 1414 East Locust Lane, Nampa, Idaho, 83686, USA
| | - David Burbank
- Pacific States Marine Fisheries Commission, Eagle Fish Health Laboratory, 1800 Trout Road, Eagle, Idaho, 83616, USA
| | - Roberta Scott
- Idaho Department of Fish and Game, Eagle Fish Health Laboratory, 1800 Trout Road, Eagle, Idaho, 83616, USA
| | - Jesse T Trushenski
- Idaho Department of Fish and Game, Eagle Fish Health Laboratory, 1800 Trout Road, Eagle, Idaho, 83616, USA
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