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Liao J, Kang S, Zhang L, Zhang D, Xu Z, Qin Q, Wei J. Isolation and identification of a megalocytivirus strain (SKIV-TJ) from cultured spotted knifejaw (Oplegnathus punctatus) in China and its pathogenicity analysis. FISH & SHELLFISH IMMUNOLOGY 2023; 141:109034. [PMID: 37640124 DOI: 10.1016/j.fsi.2023.109034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/26/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
The spotted knifejaw (Oplegnathus punctatus) has recently emerged as a highly economically significant farmed fish in China. However, due to increasing environmental pollution and breeding density, a range of infectious diseases, including the iridovirus pathogen, have begun to spread widely. In this study, we isolated and identified a strain of Megalocytivirus, SKIV-TJ, from cultured spotted knifejaw in Tianjin, China. We observed significant cytopathic effects (CPE) in SKIV-TJ-infected spotted knifejaw brain (SKB) cells, and electron microscopy showed numerous virus particles in the cytoplasm of SKB cells 6 days post-infection. The annotated complete genome of SKIV-TJ (GenBank accession number ON075463) contained 112,489 bp and 132 open reading frames. Based on the multigene association evolutionary tree using 26 iridovirus core genes, SKIV-TJ was found to be most closely related to Rock bream iridovirus (RBIV). Cumulative mortality of spotted knifejaw infected with SKIV-TJ reached 100% by day 9. A transcriptomic analysis were conducted and a total of 5517 differentially expressed genes were identified, including 2757 upregulated genes and 2760 downregulated genes. The upregulated genes were associated with viral infection and immune signaling pathways. Our findings provide a valuable genetic resource and a deeper understanding of the immune response to SKIV infection in spotted knifejaw.
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Affiliation(s)
- Jiaming Liao
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Shaozhu Kang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Luhao Zhang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Dongzhuo Zhang
- Guangdong Winsun Biological Pharmaceutical Co., Ltd., Guangzhou, 511356, China
| | - Zhuqing Xu
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266000, China.
| | - Jingguang Wei
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.
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Koda SA, Subramaniam K, Groff JM, Yanong RP, Pouder DB, Pedersen M, Pelton C, Garner MM, Phelps NBD, Armien AG, Hyatt MW, Hick PM, Becker JA, Stidworthy MF, Waltzek TB. Genetic characterization of infectious spleen and kidney necrosis virus in Banggai cardinalfish Pterapogon kauderni identified from eight separate cases between 2000 and 2017. JOURNAL OF FISH DISEASES 2023. [PMID: 37057714 DOI: 10.1111/jfd.13788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 05/07/2023]
Affiliation(s)
- Samantha A Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Joseph M Groff
- Retired, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Roy P Yanong
- Tropical Aquaculture Laboratory, School of Forest, Fisheries, and Geomatics Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, Florida, USA
| | - Deborah B Pouder
- Tropical Aquaculture Laboratory, School of Forest, Fisheries, and Geomatics Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, Florida, USA
| | - Matt Pedersen
- Reef to Rainforest Media, LLC, Shelburne, Vermont, USA
- MiniWaters LLC, Duluth, Minnesota, USA
| | - Craig Pelton
- Sea Life Aquarium, Orlando, Florida, USA
- OdySea Aquarium, Scottsdale, Arizona, USA
| | | | - Nicholas B D Phelps
- Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, St. Paul, Minnesota, USA
| | - Anibal G Armien
- California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California Davis, California, USA
| | | | - Paul M Hick
- The University of Sydney, School of Veterinary Science, Camden, New South Wales, Australia
| | - Joy A Becker
- The University of Sydney, School of Life and Environmental Sciences, Camden, New South Wales, Australia
| | | | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
- Sea Life Aquarium, Orlando, Florida, USA
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Koda SA, Subramaniam K, Hick PM, Hall E, Waltzek TB, Becker JA. Partial validation of a TaqMan quantitative polymerase chain reaction for the detection of the three genotypes of Infectious spleen and kidney necrosis virus. PLoS One 2023; 18:e0281292. [PMID: 36735738 PMCID: PMC9897559 DOI: 10.1371/journal.pone.0281292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/19/2023] [Indexed: 02/04/2023] Open
Abstract
Megalocytiviruses (MCVs) are double-stranded DNA viruses known to infect important freshwater and marine fish species in the aquaculture, food, and ornamental fish industries worldwide. Infectious spleen and kidney necrosis virus (ISKNV) is the type species within the genus Megalocytivirus that causes red seabream iridoviral disease (RSIVD) which is a reportable disease to the World Animal Health Organization (WOAH). To better control the transboundary spread of this virus and support WOAH reporting requirements, we developed and partially validated a TaqMan real-time qPCR assay (ISKNV104R) to detect all three genotypes of ISKNV, including the two genotypes that cause RSIVD. Parameters averaged across 48 experiments used a 10-fold dilution series of linearized plasmid DNA (107-101 copies), carrying a fragment of the three-spot gourami iridovirus (TSGIV) hypothetical protein revealed that the assay was linear over 7 orders of magnitude (107-101), a mean efficiency of 99.97 ± 2.92%, a mean correlation coefficient of 1.000 ± 0.001, and a limit of detection (analytical sensitivity) of ≤10 copies of TSGIV DNA. The diagnostic sensitivity and specificity for the ISKNV104R qPCR assay was evaluated and compared to other published assays using a panel of 397 samples from 21 source populations with different prevalence of ISKNV infection (0-100%). The diagnostic sensitivity and specificity for the ISKNV104R qPCR assay was 91.99% (87.28-95.6; 95% CI) and 89.8% (83.53-94.84). The latent class analysis showed that the ISKNV104R qPCR assay had similar diagnostic sensitivities and specificities with overlapping confidence limits compared to a second TaqMan qPCR assay and a SYBR green assay. This newly developed TaqMan assay represents a partially validated qPCR assay for the detection of the three genotypes of the species ISKNV. The ISKNV104R qPCR assay once fully validated, will serve as an improved diagnostic tool that can be used for ISKNV surveillance efforts and diagnosis in subclinical fish to prevent further spread of MCVs throughout the aquaculture and ornamental fish industries.
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Affiliation(s)
- Samantha A. Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Paul M. Hick
- Sydney School of Veterinary Science, The University of Sydney, Camden, New South Wales, Australia
| | - Evelyn Hall
- Sydney School of Veterinary Science, The University of Sydney, Camden, New South Wales, Australia
| | - Thomas B. Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
- * E-mail: (JAB); (TBW)
| | - Joy A. Becker
- School of Life and Environmental Sciences, The University of Sydney, Camden, New South Wales, Australia
- * E-mail: (JAB); (TBW)
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Kumaratunga V, Adams VJ, Donaldson D, Pont RT, Stidworthy MF. Ocular pathology in aquarium fish with a focus on the Syngnathidae and Apogonidae families. J Comp Pathol 2023; 200:1-11. [PMID: 36587440 DOI: 10.1016/j.jcpa.2022.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/12/2022] [Accepted: 11/09/2022] [Indexed: 12/31/2022]
Abstract
This study catalogued ocular pathology in fish histopathology submissions to a specialist diagnostic service and investigated associations with species and systemic disease, with a focus on species of conservation interest. Cross-tabulations and Fisher's exact tests were used to identify associations among the variables and results are reported as prevalence ratios (PRs) with 95% confidence intervals (CI). Of 12,488 reports reviewed, ocular histology examination was available for 4,572 submissions, in which histopathological ocular lesions were identified in 18% (813/4572). Most diagnoses (701/813; 87%) were in marine fish. Inflammatory conditions were most common (608/813; 75%), with identification of a bacterial aetiology in 42% (255/608) and a parasitic aetiology in 30% (183/608). Most bacterial infections were due to mycobacteriosis (153/255; 60%) and most parasitic infections were due to scuticociliatosis (114/184; 62%). The Syngnathidae, Centriscidae and Cichlidae families were each more likely than all other families combined to be diagnosed with ocular manifestations of mycobacteriosis (PRs = 2.6, 4.4 and 2.9, respectively, P <0.0001 for each). The Syngnathidae were also more likely to be diagnosed with ocular scuticociliatosis (PR = 1.9, P <0.0001). Fifty-four percent (39/72) of ocular mycobacteriosis and 38% (9/24) of gas bubble disease cases affected threatened or near threatened Syngnathidae species. The Apogonidae were more likely than any other family to have ocular iridovirus (PR = 10.3, 95% CI = 5.5-19.4, P <0.0001) and neoplasia (PR = 8.2, 95% CI = 4.2-16.3, P <0.0001). The endangered Banggai cardinalfish (Pterapogon kauderni) accounted for 13/15 ocular iridovirus and 16/18 mycobacteriosis cases in this family. All cases of neoplasia in the Apogonidae occurred in pajama cardinalfish (Sphaeramia nematoptera). These results should inform clinical diagnosis of ocular disease in aquarium fish and influence training for aquarists, highlighting ocular pathology as a potential early warning of systemic disease. The findings also have direct/indirect consequences for the welfare and conservation of some of these popular flagship fish species.
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Affiliation(s)
- Vim Kumaratunga
- Department of Clinical Science and Services, The Royal Veterinary College, University of London, London, UK.
| | | | - David Donaldson
- Department of Clinical Science and Services, The Royal Veterinary College, University of London, London, UK
| | - Roser T Pont
- Department of Clinical Science and Services, The Royal Veterinary College, University of London, London, UK
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Fonseca AA, Laguardia-Nascimento M, Scotá Ferreira AP, Pinto CA, Pereira Freitas TR, Rivetti Júnior AV, Ferreira Homem VS, Camargos MF. Detection of megalocytivirus in Oreochromis niloticus and Pseudoplatystoma corruscans in Brazil. DISEASES OF AQUATIC ORGANISMS 2022; 149:25-32. [PMID: 35510818 DOI: 10.3354/dao03657] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The infectious spleen and kidney necrosis virus (ISKNV) belongs to the genus Megalocytivirus (MCV), a group of double-stranded DNA genome viruses. The aim of this study was to retrospectively analyze samples from suspected foci of MCV infection in freshwater fish in Brazil. Samples were collected from infected fish between 2017 and 2021. Phylogenetic analysis revealed 2 groups of MCV circulating in the country. A genetically homogeneous group formed a clade with ISKNV samples from different parts of the world. Only 2 of the sequences from the state of Goiás showed a small genetic distance when compared to the larger group in the same clade. This study describes the validation of 3 qPCR methods and the presence of MCV in Brazil since 2017, including a genotype not previously described.
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Affiliation(s)
- Antônio Augusto Fonseca
- Ministério da Agricultura, Pecuária e Abastecimento, LFDA-MG/MAPA, 33600-000 Pedro Leopoldo, MG, Brazil
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Shahin K, Subramaniam K, Camus AC, Yazdi Z, Yun S, Koda SA, Waltzek TB, Pierezan F, Hu R, Soto E. Isolation, Identification and Characterization of a Novel Megalocytivirus from Cultured Tilapia ( Oreochromis spp.) from Southern California, USA. Animals (Basel) 2021; 11:3524. [PMID: 34944299 PMCID: PMC8697977 DOI: 10.3390/ani11123524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 11/17/2022] Open
Abstract
In spring 2019, diseased four-month-old tilapia (Oreochromis spp.) from an aquaculture farm in Southern California, USA were received for diagnostic evaluation with signs of lethargy, anorexia, abnormal swimming, and low-level mortalities. At necropsy, non-specific external lesions were noted including fin erosion, cutaneous melanosis, gill pallor, and coelomic distension. Internal changes included ascites, hepatomegaly, renomegaly, splenomegaly, and multifocal yellow-white nodules in the spleen and kidney. Cultures of spleen and kidney produced bacterial colonies identified as Francisella orientalis. Homogenized samples of gill, brain, liver, spleen, and kidney inoculated onto Mozambique tilapia brain cells (OmB) developed cytopathic effects, characterized by rounding of cells and detaching from the monolayer 6-10 days post-inoculation at 25 °C. Transmission electron microscopy revealed 115.4 ± 5.8 nm icosahedral virions with dense central cores in the cytoplasm of OmB cells. A consensus PCR, targeting the DNA polymerase gene of large double-stranded DNA viruses, performed on cell culture supernatant yielded a sequence consistent with an iridovirus. Phylogenetic analyses based on the concatenated full length major capsid protein and DNA polymerase gene sequences supported the tilapia virus as a novel species within the genus Megalocytivirus, most closely related to scale drop disease virus and European chub iridovirus. An intracoelomic injection challenge in Nile tilapia (O. niloticus) fingerlings resulted in 39% mortality after 16 days. Histopathology revealed necrosis of head kidney and splenic hematopoietic tissues.
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Affiliation(s)
- Khalid Shahin
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; or (Z.Y.); (S.Y.); (R.H.)
- Aquatic Animal Diseases Laboratory, Aquaculture Department, National Institute of Oceanography and Fisheries, Suez P.O. Box 43511, Egypt
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA; (K.S.); (S.A.K.); (T.B.W.)
| | - Alvin C. Camus
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA;
| | - Zeinab Yazdi
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; or (Z.Y.); (S.Y.); (R.H.)
| | - Susan Yun
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; or (Z.Y.); (S.Y.); (R.H.)
| | - Samantha A. Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA; (K.S.); (S.A.K.); (T.B.W.)
| | - Thomas B. Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA; (K.S.); (S.A.K.); (T.B.W.)
| | - Felipe Pierezan
- School of Veterinary Medicine, Federal University of Minas Gerais, Belo Horizonte 31270-010, Brazil;
| | - Ruixue Hu
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; or (Z.Y.); (S.Y.); (R.H.)
| | - Esteban Soto
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; or (Z.Y.); (S.Y.); (R.H.)
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Swaminathan TR, Raj NS, Preena PG, Pradhan PK, Sood N, Kumar RG, Sudhagar A, Sood NK. Infectious spleen and kidney necrosis virus-associated large-scale mortality in farmed giant gourami, Osphronemus goramy, in India. JOURNAL OF FISH DISEASES 2021; 44:2043-2053. [PMID: 34449899 DOI: 10.1111/jfd.13519] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Megalocytivirus cause diseases that have serious economic impacts on aquaculture, mainly in East and South-East Asia. Five primary genotypes are known: infectious spleen and kidney necrosis virus (ISKNV), red sea bream iridovirus (RSIV), turbot reddish body iridovirus (TRBIV), threespine stickleback iridovirus (TSIV) and scale drop disease virus (SDDV). ISKNV-mediated infectious spleen and kidney necrosis disease (ISKND) is a major viral disease in both freshwater and marine fish species. In this study, we report the isolation of ISKNV from diseased giant gourami, Osphronemus goramy, in India. Transmission electron microscopy of ultrathin sections of kidney and spleen revealed the presence of numerous polygonal naked viral particles having an outer nucleocapsid layer within the cytoplasm of enlarged cells (115-125 nm). Molecular and phylogenetic analyses confirmed the presence of ISKNV and the major capsid protein (MCP) (1,362 bp) gene in the infected fish had a high similarity to the other ISKNV-I isolates. Moreover, ISKNV was propagated in the Astronotus ocellatus fin (AOF) cell line and further confirmed genotypically. A high mortality rate (60%) was observed in gourami fish injected with ISKNV-positive tissue homogenate through challenge studies. Considering the lethal nature of ISKNV, the present study spotlights the implementation of stringent biosecurity practices for the proper control of the disease in the country.
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Affiliation(s)
- Thangaraj Raja Swaminathan
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Nithianantham Sundar Raj
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Prasannan Geetha Preena
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | | | - Neeraj Sood
- ICAR- National Bureau of Fish Genetic Resources, Lucknow, India
| | - Rahul Girish Kumar
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Arun Sudhagar
- Peninsular and Marine Fish Genetic Resources Centre, ICAR-National Bureau of Fish Genetic Resources, CMFRI Campus, Kochi, India
| | - Naresh Kumar Sood
- Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, India
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Kerddee P, Dinh-Hung N, Dong HT, Hirono I, Soontara C, Areechon N, Srisapoome P, Kayansamruaj P. Molecular evidence for homologous strains of infectious spleen and kidney necrosis virus (ISKNV) genotype I infecting inland freshwater cultured Asian sea bass (Lates calcarifer) in Thailand. Arch Virol 2021; 166:3061-3074. [PMID: 34462803 DOI: 10.1007/s00705-021-05207-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022]
Abstract
Infectious spleen and kidney necrosis virus (ISKNV) is a fish-pathogenic virus belonging to the genus Megalocytivirus of the family Iridoviridae. In 2018, disease occurrences (40-50% cumulative mortality) associated with ISKNV infection were reported in grown-out Asian sea bass (Lates calcarifer) cultured in an inland freshwater system in Thailand. Clinical samples were collected from seven distinct farms located in the eastern and central regions of Thailand. The moribund fish showed various abnormal signs, including lethargy, pale gills, darkened body, and skin hemorrhage, while hypertrophied basophilic cells were observed microscopically in gill, liver, and kidney tissue. ISKNV infection was confirmed on six out of seven farms using virus-specific semi-nested PCR. The MCP and ATPase genes showed 100% sequence identity among the virus isolates, and the virus was found to belong to the ISKNV genotype I clade. Koch's postulates were later confirmed by challenge assay, and the mortality of the experimentally infected fish at 21 days post-challenge was 50-90%, depending on the challenge dose. The complete genome of two ISKNV isolates, namely KU1 and KU2, was recovered directly from the infected specimens using a shotgun metagenomics approach. The genome length of ISKNV KU1 and KU2 was 111,487 and 111,610 bp, respectively. In comparison to closely related ISKNV strains, KU1 and KU2 contained nine unique genes, including a caspase-recruitment-domain-containing protein that is potentially involved in inhibition of apoptosis. Collectively, this study indicated that inland cultured Asian sea bass are infected by homologous ISKNV strains. This indicates that ISKNV genotype I should be prioritized for future vaccine research.
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Affiliation(s)
- Pattarawit Kerddee
- Center for Agricultural Biotechnology, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, 73140, Thailand.,Center of Excellence on Agricultural Biotechnology: (AG-BIO/PERDO-CHE), Bangkok, 10900, Thailand
| | - Nguyen Dinh-Hung
- Fish Infectious Diseases Research Unit (FID RU), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Ha Thanh Dong
- Department of Food, Agriculture and Bioresources, School of Environment, Resources and Development, Asian Institute of Technology, Pathum Thani, 12120, Thailand
| | - Ikuo Hirono
- Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Konan, Minato, 4-5-7, Tokyo, 108-8477, Japan
| | - Chayanit Soontara
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand
| | - Nontawith Areechon
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand
| | - Prapansak Srisapoome
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand.,Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand
| | - Pattanapon Kayansamruaj
- Department of Aquaculture, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand. .,Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Bangkok, 10900, Thailand.
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Koda SA, Subramaniam K, Pouder DB, Yanong RP, Frasca S, Popov VL, Waltzek TB. Complete genome sequences of infectious spleen and kidney necrosis virus isolated from farmed albino rainbow sharks Epalzeorhynchos frenatum in the United States. Virus Genes 2021; 57:448-452. [PMID: 34272657 DOI: 10.1007/s11262-021-01857-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 06/17/2021] [Indexed: 10/20/2022]
Abstract
The genus Megalocytivirus includes viruses known to cause significant disease in aquacultured fish stocks. Herein, we report the complete genome sequences of two megalocytiviruses (MCVs) isolated from diseased albino rainbow sharks Epalzeorhynchos frenatum reared on farms in the United States in 2018 and 2019. Histopathological examination revealed typical megalocytivirus microscopic lesions (i.e., basophilic cytoplasmic inclusions) that were most commonly observed in the spleen and kidney. Transmission electron microscopic examination of spleen and kidney tissues from specimens of the 2018 case revealed hexagonally shaped virus particles with a mean diameter of 153 ± 6 nm (n = 20) from opposite vertices and 131 ± 5 nm (n = 20) from opposite faces. Two MCV-specific conventional PCR assays confirmed the presence of MCV DNA in the collected samples. Full genome sequencing of both 2018 and 2019 Epalzeorhynchos frenatus iridoviruses (EFIV) was accomplished using a next-generation sequencing approach. Phylogenomic analyses revealed that both EFIV isolates belong to the infectious spleen and kidney necrosis virus (ISKNV) genotype within the genus Megalocytivirus. This study is the first report of ISKNV in albino rainbow sharks.
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Affiliation(s)
- Samantha A Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Deborah B Pouder
- Tropical Aquaculture Laboratory, School of Forest, Fisheries, and Geomatics Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, FL, 33570, USA
| | - Roy P Yanong
- Tropical Aquaculture Laboratory, School of Forest, Fisheries, and Geomatics Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, FL, 33570, USA
| | - Salvatore Frasca
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA.,Connecticut Veterinary Medical Diagnostic Laboratory, Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, Connecticut, 06269, USA
| | - Vsevolod L Popov
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA.
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10
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Johan CAC, Zainathan SC. Megalocytiviruses in ornamental fish: A review. Vet World 2020; 13:2565-2577. [PMID: 33363355 PMCID: PMC7750215 DOI: 10.14202/vetworld.2020.2565-2577] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022] Open
Abstract
Iridoviruses, especially megalocytiviruses, are related to severe disease resulting in high economic losses in the aquaculture industry worldwide. The ornamental fish industry has been affected severely due to Megalocytivirus infections. Megalocytivirus is a DNA virus that has three genera; including red sea bream iridovirus, infectious spleen and kidney necrosis virus, and turbot reddish body iridovirus. Megalocytivirus causes non-specific clinical signs in ornamental fish. Cell culture, histology, immunofluorescence test, polymerase chain reaction (PCR) assay, and loop-mediated isothermal amplification assay have been used to diagnose megalocytiviruses. Risk factors such as temperature, transportation (export and import), and life stages of ornamental fish have been reported for the previous cases due to Megalocytivirus infections. In addition, other prevention and control methods also have been practiced in farms to prevent Megalocytivirus outbreaks. This is the first review of megalocytiviruses in ornamental fish since its first detection in 1989. This review discusses the occurrences of Megalocytivirus in ornamental fish, including the history, clinical signs, detection method, risk factors, and prevention measures.
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Affiliation(s)
- Che Azarulzaman Che Johan
- Department of Fisheries and Aquaculture, Faculty of Fisheries and Food Science, University Malaysia Terengganu, Terengganu, Malaysia
| | - Sandra Catherine Zainathan
- Department of Fisheries and Aquaculture, Faculty of Fisheries and Food Science, University Malaysia Terengganu, Terengganu, Malaysia
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11
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Kawato Y, Mohr PG, Crane MSJ, Williams LM, Neave MJ, Cummins DM, Dearnley M, Crameri S, Holmes C, Hoad J, Moody NJG. Isolation and characterisation of an ISKNV-genotype megalocytivirus from imported angelfish Pterophyllum scalare. DISEASES OF AQUATIC ORGANISMS 2020; 140:129-141. [PMID: 32759471 DOI: 10.3354/dao03499] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Using cultures of the SKF-9 cell line, megalocytivirus AFIV-16 was isolated from imported angelfish Pterophyllum scalare held in quarantine at the Australian border. The cytopathic effect caused by isolate AFIV-16 presented as cell rounding and enlargement, but complete destruction of the infected cell cultures did not occur. The infected cells demonstrated immunocytochemical reactivity with monoclonal antibody M10, which is used for diagnosis of OIE-listed red sea bream iridoviral disease. Using electron microscopy, the virus particles, consisting of hexagonal nucleocapsids, were observed in the cytoplasm of SKF-9 cells. The replication of AFIV-16 in cultured SKF-9 cells was significantly greater at 28°C incubation than at 22 and 25°C incubation, whereas no difference in growth characteristics was observed for red sea bream iridovirus (RSIV) isolate KagYT-96 across this temperature range. Whole genome sequencing demonstrated that AFIV-16 has a 99.96% similarity to infectious spleen and kidney necrosis virus (ISKNV), the type species in the genus Megalocytivirus. AFIV-16 was classified into ISKNV genotype Clade 1 by phylogenetic analysis of the major capsid protein gene nucleotide sequence. This is the first report of whole genome sequencing of an ISKNV genotype megalocytivirus isolated from ornamental fish.
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Affiliation(s)
- Yasuhiko Kawato
- Nansei Main Station, National Research Institute of Aquaculture, Japan Fisheries Research and Education Agency, Minami-Ise, Mie 516-0193, Japan
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12
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Prevalence of Infectious Spleen and Kidney Necrosis Virus (ISKNV), Nervous Necrosis Virus (NNV) and Ectoparasites in Juvenile Epinephelus spp. Farmed in Aceh, Indonesia. Pathogens 2020; 9:pathogens9070578. [PMID: 32708765 PMCID: PMC7400217 DOI: 10.3390/pathogens9070578] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 11/26/2022] Open
Abstract
A cross-sectional survey was used to estimate the prevalence of infections with the Infectious spleen and kidney necrosis virus (ISKNV, Megalocytivirus), nervous necrosis virus (NNV, Betanodavirus), and infestations with ectoparasites during the rainy season in juvenile grouper (Epinephelus spp.) farmed in Aceh, Indonesia. The survey was intended to detect aquatic pathogens present at 10% prevalence with 95% confidence, assuming 100% sensitivity and specificity using a sample size of 30 for each diagnostic test. Eight populations of grouper from seven farms were sampled. Additional targeted sampling was conducted for populations experiencing high mortality. Infection with NNV was detected at all farms with seven of the eight populations being positive. The apparent prevalence for NNV ranged from 0% (95% CI: 0–12) to 73% (95% CI: 54–88). All of the fish tested from the targeted samples (Populations 9 and 10) were positive for NNV and all had vacuolation of the brain and retina consistent with viral nervous necrosis (VNN). Coinfections with ISKNV were detected in five populations, with the highest apparent prevalence being 13% (95% CI: 4–31%). Trichodina sp., Cryptocaryonirritans and Gyrodactylus sp. were detected at three farms, with 66% to 100% of fish being infested. Hybrid grouper sourced from a hatchery were 5.4 and 24.9 times more likely to have a NNV infection and a higher parasite load compared to orange-spotted grouper collected from the wild (p < 0.001). This study found that VNN remains a high-impact disease in grouper nurseries in Aceh, Indonesia.
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13
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Koda SA, Subramaniam K, Francis-Floyd R, Yanong RP, Frasca S, Groff JM, Popov VL, Fraser WA, Yan A, Mohan S, Waltzek TB. Phylogenomic characterization of two novel members of the genus Megalocytivirus from archived ornamental fish samples. DISEASES OF AQUATIC ORGANISMS 2018; 130:11-24. [PMID: 30154268 DOI: 10.3354/dao03250] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The genus Megalocytivirus is the most recently described member of the family Iridoviridae; as such, little is known about the genetic diversity of this genus of globally emerging viral fish pathogens. We sequenced the genomes of 2 megalocytiviruses (MCVs) isolated from epizootics involving South American cichlids (oscar Astronotus ocellatus and keyhole cichlid Cleithracara maronii) and three spot gourami Trichopodus trichopterus sourced through the ornamental fish trade during the early 1990s. Phylogenomic analyses revealed the South American cichlid iridovirus (SACIV) and three spot gourami iridovirus (TSGIV) possess 116 open reading frames each, and form a novel clade within the turbot reddish body iridovirus genotype (TRBIV Clade 2). Both genomes displayed a unique truncated paralog of the major capsid protein gene located immediately upstream of the full-length parent gene. Histopathological examination of archived oscar tissue sections that were PCR-positive for SACIV revealed numerous cytomegalic cells characterized by basophilic intracytoplasmic inclusions within various organs, particularly the anterior kidney, spleen, intestinal lamina propria and submucosa. TSGIV-infected grunt fin (GF) cells grown in vitro displayed cytopathic effects (e.g. cytomegaly, rounding, and refractility) as early as 96 h post-infection. Ultrastructural examination of infected GF cells revealed unenveloped viral particles possessing hexagonal nucleocapsids (120 to 144 nm in diameter) and electron-dense cores within the cytoplasm, consistent with the ultrastructural morphology of a MCV. Sequencing of SACIV and TSGIV provides the first complete TRBIV Clade 2 genome sequences and expands the known host and geographic range of the TRBIV genotype to include freshwater ornamental fishes traded in North America.
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Affiliation(s)
- Samantha A Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32611, USA
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14
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Bermúdez R, Losada AP, de Azevedo AM, Guerra-Varela J, Pérez-Fernández D, Sánchez L, Padrós F, Nowak B, Quiroga MI. First description of a natural infection with spleen and kidney necrosis virus in zebrafish. JOURNAL OF FISH DISEASES 2018; 41:1283-1294. [PMID: 29882280 DOI: 10.1111/jfd.12822] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 05/04/2023]
Abstract
Zebrafish has become a popular research model in the last years, and several diseases affecting zebrafish research facilities have been reported. However, only one case of naturally occurring viral infections was described for this species. In 2015, infectious spleen and kidney necrosis virus (ISKNV) was detected in zebrafish from a research facility in Spain. Affected fish showed lethargy, loss of appetite, abnormal swimming, distention of the coelomic cavity and, in the most severe cases, respiratory distress, pale gills and petechial haemorrhages at the base of fins. Cytomegaly was the most relevant histopathological finding in organs and tissues, sometimes associated to degenerative and necrotic changes. ISKNV belongs to the relatively newly defined genus Megalocytivirus, family Iridoviridae, comprising large, icosahedral cytoplasmic DNA viruses. This is the first case of naturally occurring Megalocytivirus infection in zebrafish research facilities, associated with morbidity. The virus has been identified based on both pathologic and genetic evidence, to better understand the pathogenesis of the infection in zebrafish and the phylogenetic relationship with other iridoviruses. Given the ability of megalocytiviruses to cross-species boundaries, it seems necessary to implement stringent biosecurity practices as these infections may invalidate experimental data and have major impact on laboratory and cultured fish.
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Affiliation(s)
- Roberto Bermúdez
- Department of Anatomy, Animal Production and Veterinary Clinical Sciences, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain
| | - Ana Paula Losada
- Department of Anatomy, Animal Production and Veterinary Clinical Sciences, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain
| | - Ana Manuela de Azevedo
- Department of Anatomy, Animal Production and Veterinary Clinical Sciences, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain
| | - Jorge Guerra-Varela
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain
| | - David Pérez-Fernández
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain
| | - Laura Sánchez
- Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain
| | - Francesc Padrós
- Department of Animal Biology, Vegetal Biology and Ecology, Autonomous University of Barcelona, Barcelona, Spain
| | - Barbara Nowak
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania
| | - María Isabel Quiroga
- Department of Anatomy, Animal Production and Veterinary Clinical Sciences, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain
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15
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Molecular detection and phylogenetic analysis of megalocytivirus in Brazilian ornamental fish. Arch Virol 2018; 163:2225-2231. [DOI: 10.1007/s00705-018-3834-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 03/30/2018] [Indexed: 10/17/2022]
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16
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Mishra A, Nam GH, Gim JA, Lee HE, Jo A, Yoon D, Oh S, Kim S, Kim A, Kim DH, Kim YC, Jeong HD, Cha HJ, Choi YH, Kim HS. Comparative evaluation of MCP gene in worldwide strains of Megalocytivirus (Iridoviridae family) for early diagnostic marker. JOURNAL OF FISH DISEASES 2018; 41:105-116. [PMID: 28914452 DOI: 10.1111/jfd.12685] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/18/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Members of the Iridoviridae family have been considered as aetiological agents of iridovirus diseases, causing fish mortalities and economic losses all over the world. Virus identification based on candidate gene sequencing is faster, more accurate and more reliable than other traditional phenotype methodologies. Iridoviridae viruses are covered by a protein shell (capsid) encoded by the important candidate gene, major capsid protein (MCP). In this study, we investigated the potential of the MCP gene for use in the diagnosis and identification of infections caused Megalocytivirus of the Iridoviridae family. We selected data of 66 Iridoviridae family isolates (53 strains of Megalocytivirus, eight strains of iridoviruses and five strains of Ranavirus) infecting various species of fish distributed all over the world. A total of 53 strains of Megalocytivirus were used for designing the complete primer sets for identifying the most hypervariable region of the MCP gene. Further, our in silico analysis of 102 sequences of related and unrelated viruses reconfirms that primer sets could identify strains more specifically and offers a useful and fast alternative for routine clinical laboratory testing. Our findings suggest that phenotype observation along with diagnosis using universal primer sets can help detect infection or carriers at an early stage.
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Affiliation(s)
- A Mishra
- Genetic Engineering Institute, Pusan National University, Busan, Korea
| | - G-H Nam
- Genetic Engineering Institute, Pusan National University, Busan, Korea
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, Korea
| | - J-A Gim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, Korea
| | - H-E Lee
- Genetic Engineering Institute, Pusan National University, Busan, Korea
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, Korea
| | - A Jo
- Genetic Engineering Institute, Pusan National University, Busan, Korea
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, Korea
| | - D Yoon
- Department of Chemistry, College of Natural Sciences, Pusan National University, Busan, Korea
| | - S Oh
- Department of Chemistry, College of Natural Sciences, Pusan National University, Busan, Korea
| | - S Kim
- Department of Chemistry, College of Natural Sciences, Pusan National University, Busan, Korea
| | - A Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
| | - D-H Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
| | - Y C Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
| | - H D Jeong
- Department of Aquatic Life Medicine, Pukyong National University, Busan, Korea
| | - H-J Cha
- Departments of Parasitology and Genetics, College of Medicine, Kosin University, Busan, Korea
| | - Y H Choi
- Department of Biochemistry, College of Korean Medicine, Dongeui University, Busan, Korea
| | - H-S Kim
- Genetic Engineering Institute, Pusan National University, Busan, Korea
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan, Korea
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17
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Development of cross-priming amplification coupled with vertical flow visualization for rapid detection of infectious spleen and kidney necrosis virus (ISKNV) in mandarin fish, Siniperca chuatsi. J Virol Methods 2017; 253:38-42. [PMID: 29288074 DOI: 10.1016/j.jviromet.2017.12.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/11/2017] [Accepted: 12/24/2017] [Indexed: 01/30/2023]
Abstract
Infectious spleen and kidney necrosis virus (ISKNV) has been recognized as the causative agent of the most serious disease in cultured mandarin fish, Siniperca chuatsi, in China. Disease outbreaks have resulted in substantial losses to the aquaculture industry. Currently, reliable laboratory detection and identification methods are available for this virus. However, rapid detection methods applicable for on-site diagnosis of this infectious agent are unavailable. To address this need, a nearly instrument-free, cost-effective and simple detection method was developed and optimized and incorporates cross priming amplification coupled with vertical flow visualization for rapid identification of ISKNV (ISKNV-CPA-VF). Results show that cross circulation amplification targeting the conserved region of the major capsid protein (MCP) regiment of the ISKNV genome had a sensitivity 10 times greater than traditional PCR at 64 °C within 60 min. The optimized concentration of dNTPs and the concentration for Mg2+ were 1.0 mmol/L and 10 mmol/L, respectively. No cross-reactions with other viruses or bacteria were observed. When combined with the nucleic acid strip detection technology, visual detection of ISKNV amplified products was realized within 3-5 min following amplification. The simplicity and nearly instrument-free method for this ISKNV-CPA-VF assay shows great potential for on-site diagnostics of ISKNV infection in Siniperca chuatsi.
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18
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Sivasankar P, John KR, George MR, Mageshkumar P, Manzoor MM, Jeyaseelan MJP. Characterization of a virulent ranavirus isolated from marine ornamental fish in India. Virusdisease 2017; 28:373-382. [PMID: 29291228 DOI: 10.1007/s13337-017-0408-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 11/08/2017] [Indexed: 11/24/2022] Open
Abstract
A viral agent implicated in the mortality of marine ornamental "Similar Damselfish" (Pomacentrus similis Allen, 1991) was isolated and characterized. The virus grew well in marine and freshwater fish cell lines from seabass and snakehead. The virus was sensitive to chloroform, acidic pH (3.0) and heat treatment at 56 °C. Biochemical characterisation indicated that the virus had double stranded DNA genome. Transmission electron microscopic analysis of ultrathin sections of infected cell pellets showed iridovirus-like icosahedral virus particles of 120-130 nm. Purified virus had six structural protein bands that ranged from of 44 to 132 kDa. PCR analysis confirmed the presence of viral DNA in infected cell cultures and sequence analysis of the major capsid protein gene showed an identity of 99.82% to that of largemouth bass virus. Serum neutralization studies involving the viral agent and koi ranavirus (KIRV) indicated partial homogeneity between the two isolates. Experimental infection of seabass (Lates calcarifer) and similar damselfish (P. similis) fingerlings with the similar damselfish virus showed cumulative mortalities of 68.75 and 93.33%. The biophysical and biochemical properties of the viral agent isolated, serological characteristics, size of major capsid proteins and the sequence similarity of the MCP gene proved that the virus belongs to the genus Ranavirus of the family Iridoviridae. Ability of the virus to grow in marine and freshwater fish cell lines and its pathogenicity to one of the cultivable marine fish shows the wide host range of the virus. This is the first report of ranavirus induced mortality in marine fish in India.
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Affiliation(s)
- P Sivasankar
- Department of Fish Pathology and Health Management, Fisheries College and Research Institute, Tamil Nadu Fisheries University, Thoothukudi, 628008 India
| | - K Riji John
- Department of Fish Pathology and Health Management, Fisheries College and Research Institute, Tamil Nadu Fisheries University, Thoothukudi, 628008 India
| | - M Rosalind George
- Department of Fish Pathology and Health Management, Fisheries College and Research Institute, Tamil Nadu Fisheries University, Thoothukudi, 628008 India
| | - P Mageshkumar
- Department of Fish Pathology and Health Management, Fisheries College and Research Institute, Tamil Nadu Fisheries University, Thoothukudi, 628008 India
| | - M Mohamed Manzoor
- Department of Fish Pathology and Health Management, Fisheries College and Research Institute, Tamil Nadu Fisheries University, Thoothukudi, 628008 India
| | - M J Prince Jeyaseelan
- Department of Fish Pathology and Health Management, Fisheries College and Research Institute, Tamil Nadu Fisheries University, Thoothukudi, 628008 India
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19
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Rimmer AE, Whittington RJ, Tweedie A, Becker JA. Susceptibility of a number of Australian freshwater fishes to dwarf gourami iridovirus (Infectious spleen and kidney necrosis virus). JOURNAL OF FISH DISEASES 2017; 40:293-310. [PMID: 27334576 DOI: 10.1111/jfd.12510] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/27/2016] [Accepted: 04/28/2016] [Indexed: 06/06/2023]
Abstract
Megalocytiviruses cause high mortality diseases that have seriously impacted aquaculture, with the most frequent outbreaks occurring in East and South-East Asia. The international trade of juvenile fish for food and ornamental aquaculture has aided the spread of these viruses, which have spread to Europe and Australia and other regions. Australian freshwater fishes were examined for susceptibility to infection with the exotic megalocytivirus, dwarf gourami iridovirus (DGIV), which belongs to a group with the type species, Infectious spleen and kidney necrosis virus (ISKNV). Fish were held at 23 ± 1 °C and challenged by intraperitoneal (IP) injection or by cohabitation with Murray cod, Maccullochella peelii (Mitchell) infected with DGIV. A species was deemed to be susceptible to DGIV based on evidence of viral replication, as determined by qPCR, and megalocytic inclusion bodies observed histologically. Horizontal transmission occurred between infected Murray cod and golden perch, Macquaria ambigua (Richardson), Macquarie perch, Macquaria australasica (Cuvier) and Murray cod. This indicated that DGIV shed from infected fish held at 23 °C can survive in fresh water and subsequently infect these naïve fish. Further, DGIV administered IP was highly pathogenic to golden perch, Macquarie perch and Murray cod. Compared to these species, the susceptibility of southern pygmy perch, Nannoperca australis (Gunther) was lower. Freshwater catfish (dewfish), Tandanus tandanus (Mitchell), were not susceptible under the experimental conditions based on the absence of clinical disease, mortality and virus replication. This study showed the potential risks associated with naïve and DGIV-infected fish sharing a common water source.
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Affiliation(s)
- A E Rimmer
- Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia
| | - R J Whittington
- Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia
| | - A Tweedie
- Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia
| | - J A Becker
- Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia
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20
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Go J, Waltzek TB, Subramaniam K, Yun SC, Groff JM, Anderson IG, Chong R, Shirley I, Schuh JCL, Handlinger JH, Tweedie A, Whittington RJ. Detection of infectious spleen and kidney necrosis virus (ISKNV) and turbot reddish body iridovirus (TRBIV) from archival ornamental fish samples. DISEASES OF AQUATIC ORGANISMS 2016; 122:105-123. [PMID: 28000602 DOI: 10.3354/dao03068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Although infections caused by megalocytiviruses have been reported from a wide range of finfish species for several decades, molecular characterisation of the viruses involved has been undertaken only on more recent cases. Sequence analysis of the major capsid protein and adenosine triphosphatase genes is reported here from formalin-fixed, paraffin-embedded material from 2 archival ornamental fish cases from 1986 and 1988 in conjunction with data for a range of genes from fresh frozen tissues from 5 cases obtained from 1991 through to 2010. Turbot reddish body iridovirus (TRBIV) genotype megalocytiviruses, previously not documented in ornamental fish, were detected in samples from 1986, 1988 and 1991. In contrast, megalocytiviruses from 1996 onwards, including those characterised from 2002, 2006 and 2010 in this study, were almost indistinguishable from infectious spleen and kidney necrosis virus (ISKNV). Three of the species infected with TRBIV-like megalocytiviruses from 1986 to 1991, viz. dwarf gourami Trichogaster lalius (formerly Colisa lalia), freshwater angelfish Pterophyllum scalare and oscar Astronotus ocellatus, were infected with ISKNV genotype megalocytiviruses from 2002 to 2010. The detection of a TRBIV genotype isolate in ornamental fish from 1986 represents the index case, confirmed by molecular sequence data, for the genus Megalocytivirus.
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Affiliation(s)
- J Go
- Faculty of Veterinary Science, University of Sydney, NSW 2570, Australia
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21
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Hine PM, Wakefield SJ, Mackereth G, Morrison R. Ultrastructural morphogenesis of a virus associated with lymphocystis-like lesions in parore Girella tricuspidata (Kyphosidae: Perciformes). DISEASES OF AQUATIC ORGANISMS 2016; 121:129-139. [PMID: 27667810 DOI: 10.3354/dao03050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The morphogenesis of large icosahedral viruses associated with lymphocystis-like lesions in the skin of parore Girella tricuspidata is described. The electron-lucent perinuclear viromatrix comprised putative DNA with open capsids at the periphery, very large arrays of smooth endoplasmic reticulum (sER), much of it with a reticulated appearance (rsER) or occurring as rows of vesicles. Lysosomes, degenerating mitochondria and virions in various stages of assembly, and paracrystalline arrays were also present. Long electron-dense inclusions (EDIs) with 15 nm repeating units split terminally and curled to form tubular structures internalising the 15 nm repeating structures. These tubular structures appeared to form the virion capsids. Large parallel arrays of sER sometimes alternated with aligned arrays of crinkled cisternae along which passed a uniformly wide (20 nm) thread-like structure. Strings of small vesicles near open capsids may also have been involved in formation of an inner lipid layer. Granules with a fine fibrillar appearance also occurred in the viromatrix, and from the presence of a halo around mature virions it appeared that the fibrils may form a layer around the capsid. The general features of virogenesis of large icosahedral dsDNA viruses, the large amount of ER, particularly rsER and the EDIs, are features of nucleo-cytoplasmic large DNA viruses, rather than features of 1 genus or family.
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Affiliation(s)
- P M Hine
- National Centre for Disease Investigation, MAF Operations, Ministry of Agriculture and Forestry, PO Box 40-742, Upper Hutt, New Zealand
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22
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Subramaniam K, Gotesman M, Smith CE, Steckler NK, Kelley KL, Groff JM, Waltzek TB. Megalocytivirus infection in cultured Nile tilapia Oreochromis niloticus. DISEASES OF AQUATIC ORGANISMS 2016; 119:253-258. [PMID: 27225209 DOI: 10.3354/dao02985] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Megalocytiviruses, such as infectious spleen and kidney necrosis virus (ISKNV), induce lethal systemic diseases in both ornamental and food fish species. In this study, we investigated an epizootic affecting Nile tilapia Oreochromis niloticus cultured in the US Midwest. Diseased fish displayed lethargy, gill pallor, and distension of the coelomic cavity due to ascites. Histopathological examination revealed a severe systemic abundance of intravascular megalocytes that were especially prominent in the gills, kidney, spleen, liver, and intestinal submucosa. Transmission electron microscopic examination revealed abundant intracytoplasmic polygonal virions consistent with iridovirus infection. Comparison of the full-length major capsid protein nucleotide sequences from a recent outbreak with a remarkably similar case that occurred at the same facility many years earlier revealed that both epizootics were caused by ISKNV. A comparison of this case with previous reports suggests that ISKNV may represent a greater threat to tilapia aquaculture than previously realized.
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Affiliation(s)
- Kuttichantran Subramaniam
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32611, USA
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23
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Mohr PG, Moody NJG, Williams LM, Hoad J, Cummins DM, Davies KR, StJ Crane M. Molecular confirmation of infectious spleen and kidney necrosis virus (ISKNV) in farmed and imported ornamental fish in Australia. DISEASES OF AQUATIC ORGANISMS 2015; 116:103-110. [PMID: 26480913 DOI: 10.3354/dao02896] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Viruses of the genus Megalocytivirus have not been detected in wild populations of fish in Australia but circulate in imported ornamental fish. In 2012, detection of a megalocytivirus in healthy platys Xiphophorus maculatus was reported from a farm in Australia during surveillance testing as part of a research project undertaken at the University of Sydney. Confirmatory testing of the original samples at the AAHL Fish Diseases Laboratory verified the presence of an infectious spleen and kidney necrosis virus (ISKNV)-like virus. Additional sampling at the positive farm confirmed the persistence of the virus in the platys, with 39 of 265 (14.7%) samples testing positive. Comparison of 3 separate gene regions of the virus with those of ISKNV confirmed the detection of a virus indistinguishable from ISKNV. Subsequently, ISKNV was also detected in a range of imported ornamental fish from several countries between 2013 and 2014, by screening with real-time PCR and confirmation by conventional PCR and sequence analysis. Accordingly, the current importation of live ornamental fish acts as a potential perpetual source for the establishment of ISKNV viruses within Australia. The testing of the farmed and imported ornamental fish verified the utility of the probe-based real-time PCR assay for screening of ornamental fish for Megalocytivirus.
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Affiliation(s)
- Peter G Mohr
- CSIRO Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia
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