1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Nie M, Zou C, Peng L, Wu Z, You F. Establishment and application of four long-term culture cell lines of the olive flounder Paralichthys olivaceus blastocysts. Comp Biochem Physiol C Toxicol Pharmacol 2023; 265:109536. [PMID: 36584834 DOI: 10.1016/j.cbpc.2022.109536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/25/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022]
Abstract
Four new embryonic cell lines derived from blastocysts of the olive flounder Paralichthys olivaceus, an important commercial marine fish, were established and characterized. They were designated as PoEFCI, PoEFCII, PoEFCIII, and PoEFCIV and were all fibroblastic cells. The cells were cultured in DMEM/F-12 medium supplemented with antibiotics, FBS, and growth factors at temperature of 25 °C and subcultured for >100 passages over 18 months. The origin of the cell lines was confirmed by examining the partial sequences of the cytochrome oxidase c subunit I (COI) gene of the flounder mitochondrial DNA (mtDNA). The four cell lines showed different growth curve patterns. According to the results of gene and protein expression and enzyme activity, the cell lines PoEFCI, PoEFCII, and PoEFC III could be pluripotent. The cells of all four cell lines were also successfully transfected with the green fluorescent protein (GFP) reporter gene, suggesting that they could be used to study gene function in the flounder or other fish. More importantly, PoEFCI-III were sensitive to chromium (Cr) and red sea bream Pagrus major iridovirus (RSIV), so they could be used as a powerful tool for the study of the toxicological investigation of heavy metals and RSIV in fish. Therefore, these cell lines would be useful for biotechnological and toxicological research on marine fish as an in vitro biological system.
Collapse
Affiliation(s)
- Miaomiao Nie
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China; State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, 251 Ningda Road, Xining 810016, PR China
| | - Congcong Zou
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, PR China
| | - Limin Peng
- Shandong Open University, Jinan 250014, PR China
| | - Zhihao Wu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, PR China
| | - Feng You
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, PR China.
| |
Collapse
|
3
|
Fonseca AA, Laguardia-Nascimento M, Ferreira APS, Pinto CDA, da Silva Gonçalves VL, Barbosa AAS, Rivetti Junior AV, Camargos MF. Genetic differentiation of Megalocytivirus by real time PCR and sequencing. Mol Biol Rep 2023; 50:3439-3450. [PMID: 36757549 DOI: 10.1007/s11033-023-08282-y] [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: 07/21/2022] [Accepted: 01/13/2023] [Indexed: 02/10/2023]
Abstract
BACKGROUND Megalocytiviruses (MCV) are double-stranded DNA viruses that infect fish. Two species within the genus are epidemiologically important for fish farming: red sea bream iridovirus (RSIV) and infectious spleen and kidney necrosis virus (ISKNV). The objective of this work was to study regions that allow the differentiation and correct diagnosis of RSIV and ISKNV. METHODS The regions ORF450L, ORF342L, ORF077, and the intergenic region between ORF37 and ORF42R were sequenced and compared with samples from the database. RESULTS The tree constructed using the sequencing of the PCR product Megalocytivirus. ORF077 separated the three major clades of MCV. RISV genotypes were well divided, but not ISKNV. All qPCRs tests showed acceptable repeatability values, that is, less than 5%. CONCLUSION Two qPCRs for ISKNV detection and two for RSIV were considered suitable for use in the diagnosis and typing of MCV. The results of this study demonstrate the importance of an accurate evaluation of methodologies for the differentiation of MCV.
Collapse
Affiliation(s)
- Antônio Augusto Fonseca
- Laboratório Federal de Defesa Agropecuária de Minas Gerais, Pedro Leopoldo, Brazil. .,UNIFEMM - Centro Universitário, Sete Lagoas, Brazil.
| | | | | | | | | | | | | | | |
Collapse
|
4
|
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.
Collapse
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)
| |
Collapse
|
5
|
Isolation, Characterization, and Transcriptome Analysis of an ISKNV-Like Virus from Largemouth Bass. Viruses 2023; 15:v15020398. [PMID: 36851612 PMCID: PMC9959643 DOI: 10.3390/v15020398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 01/19/2023] [Accepted: 01/28/2023] [Indexed: 02/03/2023] Open
Abstract
Largemouth bass (Micropterus salmoides) is an important commercial fish farmed in China. Challenges related to diseases caused by pathogens, such as iridovirus, have become increasingly serious. In 2017, we detected iridovirus-infected diseased largemouth bass in Zunyi, Guizhou Province. The isolated virus was identified as an infectious spleen and kidney necrosis virus (ISKNV)-like virus (ISKNV-ZY). ISKNV-ZY induces a cytopathic effect after infecting mandarin fish brain (MFB) cells. Abundant hexagonal virus particles were observed in the cytoplasm of ISKNV-ZY-infected MFB cells, using electron microscopy. The whole genome of ISKNV-ZY contained 112,248 bp and 122 open reading frames. Phylogenetic tree analysis showed that ISKNV-ZY was most closely related to BCIV, indicating that it is an ISKNV-like megalocytivirus. ISKNV-ZY-infected largemouth bass started to die on day six and reached a death peak on days 7-8. Cumulative mortality reached 100% on day 10. Using RNA sequencing-based transcriptome analysis after ISKNV-ZY infection, 6254 differentially expressed unigenes (DEGs) were identified, of which 3518 were upregulated and 2673 downregulated. The DEGs were associated with endocytosis, thermogenesis, oxidative phosphorylation, the JAK-STAT signaling pathway, the MAPK signaling pathway, etc. These results contribute to understanding the molecular regulation mechanism of ISKNV infection and provide a basis for ISKNV prevention.
Collapse
|
6
|
Ishihara H, Harakawa S, Kawakami H, Yoshii K, Murase N, Yamada H, Fukuda Y, Nozaki R, Kawato S, Koiwai K, Hirono I, Kondo H. Whole-genome analysis of red sea bream iridovirus spread in 2021 in Japan provided epidemiological and viral traits insight. JOURNAL OF FISH DISEASES 2022; 45:1593-1597. [PMID: 35862188 DOI: 10.1111/jfd.13690] [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: 05/19/2022] [Revised: 07/03/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Red sea bream iridovirus (RSIV) is the pathogen that causes red sea bream iridoviral disease. It causes a huge loss to the Japanese aquaculture industry. In 2021, outbreaks of red sea bream iridovirus occurred in South Japan. This study analysed nine whole-genome sequences of RSIV isolated in Oita and Ehime Prefectures in 2021 using a short-read next-generation sequencer. Nine isolates had highly uniform sequences, and there was no variant depending on locations or host species. Phylogenetic analyses with other reported megalocytivirus isolates showed that RSIV isolated in 2021 was genetically different from RSIV previously isolated in Oita and Ehime Prefectures in 2017-2019. These results suggest that RSIV isolated in Oita and Ehime Prefectures in 2021 might spread from a common ancestor different from the recent one. Additionally, it was found that RSIV isolated in 2021 had sequence mutations on protein-coding sequences that may be involved in viral pathogenicity and infectivity.
Collapse
Affiliation(s)
- Hikaru Ishihara
- Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Shogo Harakawa
- Ehime Fisheries Research Center, Ehime Research Institute of Agriculture, Forestry and Fisheries, Ehime, Japan
| | - Hidemasa Kawakami
- Ehime Fisheries Research Center, Ehime Research Institute of Agriculture, Forestry and Fisheries, Ehime, Japan
| | - Keisuke Yoshii
- Fisheries Research Division, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Oita, Japan
| | - Naoya Murase
- Fisheries Research Division, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Oita, Japan
| | - Hidetoshi Yamada
- Fisheries Research Division, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Oita, Japan
| | - Yutaka Fukuda
- Fisheries Research Division, Oita Prefectural Agriculture, Forestry and Fisheries Research Center, Oita, Japan
| | - Reiko Nozaki
- Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Satoshi Kawato
- Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Keiichiro Koiwai
- Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Ikuo Hirono
- Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Hidehiro Kondo
- Laboratory of Genome Science, Tokyo University of Marine Science and Technology, Tokyo, Japan
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Girisha SK, Kushala KB, Nithin MS, Puneeth TG, Naveen Kumar BT, Vinay TN, Suresh T, Ajay SK, Venugopal MN, Ramesh KS. First report of the infectious spleen and kidney necrosis virus (ISKNV) infection in ornamental fishes in India. Transbound Emerg Dis 2020; 68:964-972. [PMID: 33448668 DOI: 10.1111/tbed.13793] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 11/29/2022]
Abstract
Infectious spleen and kidney necrosis virus (ISKNV), a member of family iridoviridae, reported for the first time in a wide range of ornamental fish species in India. Significant mortalities during the year 2018-19 were reported from a number of retailers in the region with various clinical signs. The samples of moribund, dead and apparently healthy ornamental fishes were collected from retailers, located in three districts of Karnataka, India. Out of 140 fish samples, 16 samples (11.42%) representing 10 different fish species were found positive to ISKNV by OIE listed primers and same samples were reported to amplify the major capsid protein (MCP) gene of ISKNV. Further, sequence analysis of MCP gene showed that all strains detected in this study were closely related to other documented isolates from different countries with an identity ranging from 98.76% to 100%. Further, they clustered in the clade of ISKNV, during the phylogenetic analysis. The sequence similarity was high (99.94%) to ISKNV strains from Japan, Australia and Malaysia. This is the first report of an ISKNV infection in India. Moreover, out of 10 ISKNV-positive fish species, three species were reported positive to ISKNV for the first time in the world. Further, the in vitro experiment showed the growth of virus in Asian sea bass cell line, which is a natural host of ISKNV. Therefore, considering the lethal nature of megalocytiviruses to infect a vast range of species, proper biosecurity measures need to be taken to control these emerging pathogens.
Collapse
Affiliation(s)
- S K Girisha
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| | - K B Kushala
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| | - M S Nithin
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| | - T G Puneeth
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| | - B T Naveen Kumar
- Department of Aquatic Environment, College of Fisheries, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, India
| | - T N Vinay
- Indian Council of Agricultural Research - Central Institute of Brackishwater Aquaculture, Chennai, India
| | - T Suresh
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| | - S K Ajay
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| | - M N Venugopal
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| | - K S Ramesh
- College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Matsyanagar, India
| |
Collapse
|
9
|
Tsai JM, Huang SL, Yang CD. PCR Detection and Phylogenetic Analysis of Megalocytivirus Isolates in Farmed Giant Sea Perch Lates calcarifer in Southern Taiwan. Viruses 2020; 12:v12060681. [PMID: 32599850 PMCID: PMC7354458 DOI: 10.3390/v12060681] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 01/12/2023] Open
Abstract
The Megalocytivirus genus includes three genotypes, red sea bream iridovirus (RSIV), infectious spleen and kidney necrosis virus (ISKNV), and turbot reddish body iridovirus (TRBIV), and has caused mass mortalities in various marine and freshwater fish species in East and Southeast Asia. Of the three genotypes, TRBIV-like megalocytivirus is not included in the World Organization for Animal Health (OIE)-reportable virus list because of its geographic restriction and narrow host range. In 2017, 39 cases of suspected iridovirus infection were isolated from fingerlings of giant sea perch (Lates calcarifer) cultured in southern Taiwan during megalocytivirus epizootics. Polymerase chain reaction (PCR) with different specific primer sets was undertaken to identify the causative agent. Our results revealed that 35 out of the 39 giant sea perch iridovirus (GSPIV) isolates were TRBIV-like megalocytiviruses. To further evaluate the genetic variation, the nucleotide sequences of major capsid protein (MCP) gene (1348 bp) from 12 of the 35 TRBIV-like megalocytivirus isolates were compared to those of other known. High nucleotide sequence identity showed that these 12 TRBIV-like GSPIV isolates are the same species. Phylogenetic analysis based on the MCP gene demonstrated that these 12 isolates belong to the clade II of TRBIV megalocytiviruses, and are distinct from RSIV and ISKNV. In conclusion, the GSPIV isolates belonging to TRBIV clade II megalocytiviruses have been introduced into Taiwan and caused a severe impact on the giant sea perch aquaculture industry.
Collapse
Affiliation(s)
- Jia-Ming Tsai
- Graduate Institute of Animal Vaccine Technology, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan;
| | - Song-Lang Huang
- Pingtung County Animal Disease Control Center, Pingtung 90001, Taiwan;
| | - Chung-Da Yang
- Graduate Institute of Animal Vaccine Technology, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan;
- International Degree Program of Animal Vaccine Technology, International College, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
- Correspondence: ; Tel.: +886-8-7703-202 (ext. 5334)
| |
Collapse
|
10
|
Koda SA, Subramaniam K, Pouder DB, Yanong RP, Waltzek TB. Phylogenomic characterization of red seabream iridovirus from Florida pompano Trachinotus carolinus maricultured in the Caribbean Sea. Arch Virol 2019; 164:1209-1212. [PMID: 30741339 DOI: 10.1007/s00705-019-04155-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 12/28/2018] [Indexed: 11/30/2022]
Abstract
Between 2010 and 2016, six mortality events were observed in Florida pompano (Trachinotus carolinus) maricultured in the Dominican Republic. Histopathological examination and conventional PCR confirmed a megalocytivirus (MCV) infection in each case. Subsequently, next-generation sequencing and phylogenomic analyses confirmed that MCV DNA was present in the infected pompano tissue samples from 2010, 2014, and 2016, and each was determined to be red seabream iridovirus (RSIV). Annotation of the RSIV genome sequences identified 121 open reading frames, and BLASTN analysis revealed the highest nucleotide sequence identity (> 99%) to a RSIV clade 1 MCV isolated from a moribund red seabream (Pagrus major) maricultured in Japan. These cases represent the first fully sequenced RSIV genomes detected outside of Asia and are the earliest reports of MCV infections in Florida pompano. This recent geographical expansion of RSIV warrants further attention to determine its potential economic and ecological impact.
Collapse
Affiliation(s)
- Samantha A Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Bldg. 1379, Mowry Road, Gainesville, FL, 32611, USA
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Bldg. 1379, Mowry Road, Gainesville, FL, 32611, USA
| | - Deborah B Pouder
- Tropical Aquaculture Laboratory, Program in Fisheries and Aquatic Sciences, School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, FL, 33570, USA
| | - Roy P Yanong
- Tropical Aquaculture Laboratory, Program in Fisheries and Aquatic Sciences, School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, FL, 33570, USA
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Bldg. 1379, Mowry Road, Gainesville, FL, 32611, USA.
| |
Collapse
|
11
|
Lopez-Porras A, Morales JA, Alvarado G, Koda SA, Camus A, Subramaniam K, Waltzek TB, Soto E. Red seabream iridovirus associated with cultured Florida pompano Trachinotus carolinus mortality in Central America. DISEASES OF AQUATIC ORGANISMS 2018; 130:109-115. [PMID: 30198486 DOI: 10.3354/dao03267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Mariculture of Florida pompano Trachinotus carolinus in Central America has increased over the last few decades and it is now a highly valued food fish. High feed costs and infectious diseases are significant impediments to the expansion of mariculture. Members of the genus Megalocytivirus (MCV), subfamily Alphairidovirinae, within the family Iridoviridae, are emerging pathogens that negatively impact Asian mariculture. A significant mortality event in Florida pompano fingerlings cultured in Central America occurred in October 2014. Affected fish presented with abdominal distension, darkening of the skin, and periocular hemorrhages. Microscopic lesions included cytomegalic 'inclusion body-bearing cells' characterized by basophilic granular cytoplasmic inclusions in multiple organs. Transmission electron microscopy revealed arrays of hexagonal virions (155-180 nm in diameter) with electron-dense cores within the cytoplasm of cytomegalic cells. Pathological findings were suggestive of an MCV infection, and the diagnosis was later confirmed by partial PCR amplification and sequencing of the viral gene encoding the myristylated membrane protein. The viral sequence revealed that the fingerlings were infected with an MCV genotype, red seabream iridovirus (RSIV), previously reported only from epizootics in Asian mariculture. This case underscores the threat RSIV poses to global mariculture, including the production of Florida pompano in Central America.
Collapse
Affiliation(s)
- Adrian Lopez-Porras
- Servicio de Patologia Veterinaria, Universidad Nacional de Costa Rica, Heredia, Costa Rica
| | | | | | | | | | | | | | | |
Collapse
|
12
|
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.
Collapse
Affiliation(s)
- Samantha A Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32611, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Invertebrate Iridoviruses: A Glance over the Last Decade. Viruses 2018; 10:v10040161. [PMID: 29601483 PMCID: PMC5923455 DOI: 10.3390/v10040161] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 02/06/2023] Open
Abstract
Members of the family Iridoviridae (iridovirids) are large dsDNA viruses that infect both invertebrate and vertebrate ectotherms and whose symptoms range in severity from minor reductions in host fitness to systemic disease and large-scale mortality. Several characteristics have been useful for classifying iridoviruses; however, novel strains are continuously being discovered and, in many cases, reliable classification has been challenging. Further impeding classification, invertebrate iridoviruses (IIVs) can occasionally infect vertebrates; thus, host range is often not a useful criterion for classification. In this review, we discuss the current classification of iridovirids, focusing on genomic and structural features that distinguish vertebrate and invertebrate iridovirids and viral factors linked to host interactions in IIV6 (Invertebrate iridescent virus 6). In addition, we show for the first time how complete genome sequences of viral isolates can be leveraged to improve classification of new iridovirid isolates and resolve ambiguous relations. Improved classification of the iridoviruses may facilitate the identification of genus-specific virulence factors linked with diverse host phenotypes and host interactions.
Collapse
|
14
|
Establishment of rock bream Oplegnathus fasciatus embryo (RoBE-4) cells with cytolytic infection of red seabream iridovirus (RSIV). J Virol Methods 2016; 238:1-5. [DOI: 10.1016/j.jviromet.2016.09.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 09/26/2016] [Accepted: 09/26/2016] [Indexed: 11/17/2022]
|
15
|
Nolan D, Stephens F, Crockford M, Jones JB, Snow M. Detection and characterization of viruses of the genus Megalocytivirus in ornamental fish imported into an Australian border quarantine premises: an emerging risk to national biosecurity. JOURNAL OF FISH DISEASES 2015; 38:187-195. [PMID: 24475941 DOI: 10.1111/jfd.12222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/21/2013] [Accepted: 11/29/2013] [Indexed: 06/03/2023]
Abstract
This report documents an emerging trend of identification of Megalocytivirus-like inclusions in a range of ornamental fish species intercepted during quarantine detention at the Australian border. From September 2012 to February 2013, 5 species of fish that had suffered mortality levels in excess of 25% whilst in the post-entry quarantine and had Megalocytivirus-like inclusion bodies in histological sections were examined by PCR. The fish had been imported from Singapore, Malaysia and Sri Lanka. Ninety-seven of 111 individual fish from affected tanks of fish tested were positive for the presence of Megalocytivirus by PCR. Sequence analysis of representative PCR products revealed an identical sequence of 621 bp in all cases which was identical to a previously characterized Megalocytivirus (Sabah/RAA1/2012 strain BMGIV48). Phylogenetic analysis of available Megalocytivirus major capsid protein (MCP) sequences confirmed the existence of 3 major clades of Megalocytivirus. The virus detected in this study was identified as a member of Genotype II. The broad host range and pathogenicity of megalocytiviruses, coupled to the documented spread of ornamental fish into the environment, render this a significant and emerging biosecurity threat to Australia.
Collapse
Affiliation(s)
- D Nolan
- Department of Fisheries, Government of Western Australia, Perth, WA, Australia
| | | | | | | | | |
Collapse
|
16
|
Subramaniam K, Shariff M, Omar AR, Hair-Bejo M, Ong BL. Detection and molecular characterization of infectious spleen and kidney necrosis virus from major ornamental fish breeding states in Peninsular Malaysia. JOURNAL OF FISH DISEASES 2014; 37:609-618. [PMID: 23952914 DOI: 10.1111/jfd.12152] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/15/2013] [Accepted: 06/17/2013] [Indexed: 06/02/2023]
Abstract
'Gold standard' OIE reference PCR assay was utilized to detect the presence of infectious spleen and kidney necrosis virus (ISKNV) in freshwater ornamental fish from Malaysia. From total of 210 ornamental fish samples representing 14 species, ISKNV was detected in 36 samples representing 5 fish species. All positive cases did not show any clinical signs of ISKNV. Three restriction enzymes analyses showed that the fish were infected by identical strains of the same virus species within Megalocytivirus genus. Major capsid protein (MCP) genes of 10 ISKNV strains were sequenced and compared with 9 other reference nucleotide sequences acquired from GenBank. Sequence analysis of MCP gene showed that all strains detected in this study were closely related to the reference ISKNV with nucleotide sequence identity that was ranging from 99.8% to 100%. In addition, phylogenetic analysis of MCP gene revealed that viruses from genus Megalocytivirus can be divided into three genotypes: genotype 1 include reference ISKNV and all other strains that were detected in this study, genotype 2 include viruses closely related to red sea bream iridovirus (RSIV), and genotype 3 include viruses closely related turbot reddish body iridovirus (TRBIV).
Collapse
Affiliation(s)
- K Subramaniam
- Faculty of Veterinary Medicine, Universiti Putra Malaysia, Selangor, Malaysia
| | | | | | | | | |
Collapse
|
17
|
Dong Y, Weng S, He J, Dong C. Field trial tests of FKC vaccines against RSIV genotype Megalocytivirus in cage-cultured mandarin fish (Siniperca chuatsi) in an inland reservoir. FISH & SHELLFISH IMMUNOLOGY 2013; 35:1598-1603. [PMID: 24035751 DOI: 10.1016/j.fsi.2013.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/28/2013] [Accepted: 09/02/2013] [Indexed: 06/02/2023]
Abstract
Megalocytiviruses are one of the most important causative agents in finfish industry in China, Japan and South East Asia. The viruses are mainly composed of ISKNV, RSIV and TRBIV genotypes. Among them, ISKNV genotype isolate is the most important causative agent in mandarin fish industry in South China. Since its first occurrence in mid-1990s in China, no effective drug has been developed to prevent and control this virus until our recent work. In this study, unusual RSIV genotype Megalocytivirus was validated as the causative agent in natural mass mortality of cage-cultured mandarin fish in an inland reservoir. One isolate was obtained using MFF-1 cells from natural mass mortality of mandarin fish and designated as Megalocyti-LJ2012. Based on two previous megalocytiviral isolates, formalin-killed cell (FKC) vaccines were prepared to immunize 2000 and 9000 cage-cultured mandarin in October 2011 and August 2012, respectively. As results, greater than 70% protective effects were observed in vaccination group in both individual field tests. Adjuvant-emulsified FKC vaccine provided even greater than 99% protective effect (N = 1000). In contrast, almost all fish died in non-vaccination group (N = 1000). Immuno-protection test under laboratory condition showed that 100% relative percent survival was obtained in surviving fish from vaccination group after challenge with Megalocyti-LJ2012 at 4 months post vaccination. Taken together, the present study shows that FKC vaccine is also efficient in preventing RSIV genotype Megalocytivirus in cage-cultured mandarin fish in two field tests.
Collapse
Affiliation(s)
- Youyong Dong
- MOE Key Laboratory of Aquatic Food Safety/State Key Laboratory for Bio-control, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, People's Republic of China
| | | | | | | |
Collapse
|
18
|
Wen CM, Ku CC, Wang CS. Viral susceptibility, transfection and growth of SPB--a fish neural progenitor cell line from the brain of snubnose pompano, Trachinotus blochii (Lacépède). JOURNAL OF FISH DISEASES 2013; 36:657-667. [PMID: 23305502 DOI: 10.1111/jfd.12067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 11/08/2012] [Accepted: 11/11/2012] [Indexed: 06/01/2023]
Abstract
This study investigates the susceptibilities of the SPB cell line to fish viruses including giant seaperch iridovirus (GSIV-K1), red sea bream iridovirus (RSIV-Ku), grouper nervous necrosis virus (GNNV-K1), chum salmon reovirus (CSV) and eel herpesvirus (HVA). GSIV-K1, RSIV-Ku and CSV replicated well in SPB cells, with a significant cytopathic effect and virus production. However, the cells were HVA and GNNV refractory. To examine the ability of SPB cells to stably express foreign protein, expression vectors encoding GNNV B1 and B2 fused to enhanced green fluorescent protein (EGFP) and GSIV ORF35L fused to DsRed were constructed and introduced by transfection into SPB cells. Stable transfectants displayed different morphologies compared with SPB and with each other. EGFP-B1 was predominantly localized in the nuclei, EFPF-B2 was distributed throughout the cytoplasm and nucleus, and granular 35L-DsRed was localized with secreted vesicles. The expression of EFPF-B2 in SPB cells produced blebs on the surface, but the cells showing stable expression of EGFP, EGFP-B1 or 35L-DsRed showed normal morphologies. Results show the SPB cells and the transfected cells grow well at temperatures between 20 and 35 °C and with serum-dependent growth. SPB cells are suitable for studies on foreign protein expression and virology.
Collapse
Affiliation(s)
- C-M Wen
- Department of Life Sciences, National University of Kaohsiung, Kaohsiung, Nan-Tzu District, Taiwan.
| | | | | |
Collapse
|
19
|
Dong C, Xiong X, Luo Y, Weng S, Wang Q, He J. Efficacy of a formalin-killed cell vaccine against infectious spleen and kidney necrosis virus (ISKNV) and immunoproteomic analysis of its major immunogenic proteins. Vet Microbiol 2013. [DOI: 10.1016/j.vetmic.2012.10.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
20
|
Abstract
The genus Megalocytivirus, represented by red sea bream iridovirus (RSIV), the first identified and one of the best characterized megalocytiviruses, Infectious spleen and kidney necrosis virus (ISKNV), the type species of the genus, and numerous other isolates, is the newest genus within the family Iridoviridae. Viruses within this genus are causative agents of severe disease accompanied by high mortality in multiple species of marine and freshwater fish. To date outbreaks of megalocytivirus-induced disease have occurred primarily in south-east Asia and Japan, but infections have been detected in Australia and North America following the importation of infected ornamental fish. The first outbreak of megalocytiviral disease was recorded in cultured red sea bream (Pagrus major) in Japan in 1990 and was designated red sea bream iridovirus disease (RSIVD). Following infection fish became lethargic and exhibited severe anemia, petechiae of the gills, and enlargement of the spleen. Although RSIV was identified as an iridovirus, sequence analyses of RSIV genes revealed that the virus did not belong to any of the four known genera within the family Iridoviridae. Thus a new, fifth genus was established and designated Megalocytivirus to reflect the characteristic presence of enlarged basophilic cells within infected organs. Indirect immunofluorescence tests employing recently generated monoclonal antibodies and PCR assays are currently used in the rapid diagnosis of RSIVD. For disease control, a formalin-killed vaccine was developed and is now commercially available in Japan for several fish species. Following the identification of RSIV, markedly similar viruses such as infectious spleen and kidney necrosis virus (ISKNV), dwarf gourami iridovirus (DGIV), turbot reddish body iridovirus (TRBIV), Taiwan grouper iridovirus (TGIV), and rock bream iridovirus (RBIV) were isolated in East and Southeast Asia. Phylogenetic analyses of the major capsid protein (MCP) and ATPase genes indicated that although these viruses shared considerable sequence identity, they could be divided into three tentative species, represented by RSIV, ISKNV and TRBIV, respectively. Whole genome analyses have been reported for several of these viruses. Sequence analysis detected a characteristic difference in the genetic composition of megalocytiviruses and other members of the family in reference to the large and small subunits of ribonucleotide reductase (RR-1, RR‑2). Megalocytiviruses contain only the RR-2 gene, which is of eukaryotic origin; whereas the other genera encode both the RR-1 and RR-2 genes which are thought to originate from Rickettsia-like α-proteobacteria.
Collapse
|
21
|
Waltzek TB, Marty GD, Alfaro ME, Bennett WR, Garver KA, Haulena M, Weber ES, Hedrick RP. Systemic iridovirus from threespine stickleback Gasterosteus aculeatus represents a new megalocytivirus species (family Iridoviridae). DISEASES OF AQUATIC ORGANISMS 2012; 98:41-56. [PMID: 22422128 DOI: 10.3354/dao02415] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Megalocytiviruses have been associated with epizootics resulting in significant economic losses in public aquaria and food-fish and ornamental fish industries, as well as threatening wild fish stocks. The present report describes characteristics of the first megalocytivirus from a wild temperate North American fish, the threespine stickleback Gasterosteus aculeatus. Moribund and dead fish sampled after transfer to quarantine for an aquarium exhibit had amphophilic to basophilic intracytoplasmic inclusions (histopathology) and icosahedral virions (transmission electron microscopy) consistent with an iridovirus infection. Phylogenetic analyses of the major capsid, ATPase, and DNA polymerase genes confirmed the virus as the first known member of the genus Megalocytivirus (family Iridoviridae) from a gasterosteid fish. The unique biologic and genetic properties of this virus are sufficient to establish a new Megalocytivirus species to be formally known as the threespine stickleback iridovirus (TSIV). The threespine stickleback is widely distributed throughout the northern hemisphere in both freshwater and estuarine environments. The presence of megalocytiviruses with broad host specificity and detrimental economic and ecologic impacts among such a widely dispersed fish species indicates the need for sampling of other stickleback populations as well as other North American sympatric marine and freshwater ichthyofauna.
Collapse
Affiliation(s)
- Thomas B Waltzek
- Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Fu X, Li N, Liu L, Lin Q, Wang F, Lai Y, Jiang H, Pan H, Shi C, Wu S. Genotype and host range analysis of infectious spleen and kidney necrosis virus (ISKNV). Virus Genes 2010; 42:97-109. [DOI: 10.1007/s11262-010-0552-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 11/08/2010] [Indexed: 12/01/2022]
|
23
|
Weber ES, Waltzek TB, Young DA, Twitchell EL, Gates AE, Vagelli A, Risatti GR, Hedrick RP, Frasca S. Systemic iridovirus infection in the Banggai cardinalfish (Pterapogon kauderni Koumans 1933). J Vet Diagn Invest 2009; 21:306-20. [PMID: 19407082 DOI: 10.1177/104063870902100302] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Iridoviruses infect food and ornamental fish species from a wide range of freshwater to marine habitats across the globe. The objective of the current study was to characterize an iridovirus causing systemic infection of wild-caught Pterapogon kauderni Koumans 1933 (Banggai cardinalfish). Freshly frozen and fixed specimens were processed for histopathologic evaluation, transmission electron microscopic examination, virus culture, molecular virologic testing, microbiology, and in situ hybridization (ISH) using riboprobes. Basophilic granular cytoplasmic inclusions were identified in cytomegalic cells often found beneath endothelium, and hexagonal virus particles typical of iridovirus were identified in the cytoplasm of enlarged cells by transmission electron microscopy. Attempts at virus isolation in cell culture were unsuccessful; however, polymerase chain reaction (PCR)-based molecular testing resulted in amplification and sequencing of regions of the DNA polymerase and major capsid protein genes, along with the full-length ATPase gene of the putative iridovirus. Virus gene sequences were then used to infer phylogenetic relationships of the P. kauderni agent to other known systemic iridoviruses from fishes. Riboprobes, which were transcribed from a cloned PCR amplification product from the viral genome generated hybridization signals from inclusions within cytomegalic cells in histologic sections tested in ISH experiments. To the authors' knowledge, this is the first report of a systemic iridovirus from P. kauderni. The pathologic changes induced and the genomic sequence data confirm placement of the Banggai cardinalfish iridovirus in the genus Megalocytivirus family Iridoviridae. The ISH provides an additional molecular diagnostic technique for confirmation of presumptive infections detected in histologic sections from infected fish.
Collapse
|
24
|
Abstract
Members of the family Iridoviridae infect a diverse array of invertebrate and cold-blooded vertebrate hosts and are currently viewed as emerging pathogens of fish and amphibians. Iridovirid replication is unique and involves both nuclear and cytoplasmic compartments, a circularly permuted, terminally redundant genome that, in the case of vertebrate iridoviruses, is also highly methylated, and the efficient shutoff of host macromolecular synthesis. Although initially neglected largely due to the perceived lack of health, environmental, and economic concerns, members of the genus Ranavirus, and the newly recognized genus Megalocytivirus, are rapidly attracting growing interest due to their involvement in amphibian population declines and their adverse impacts on aquaculture. Herein we describe the molecular and genetic basis of viral replication, pathogenesis, and immunity, and discuss viral ecology with reference to members from each of the invertebrate and vertebrate genera.
Collapse
|
25
|
Dong C, Weng S, Shi X, Xu X, Shi N, He J. Development of a mandarin fish Siniperca chuatsi fry cell line suitable for the study of infectious spleen and kidney necrosis virus (ISKNV). Virus Res 2008; 135:273-81. [DOI: 10.1016/j.virusres.2008.04.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2008] [Revised: 04/01/2008] [Accepted: 04/01/2008] [Indexed: 11/24/2022]
|
26
|
Song JY, Kitamura SI, Jung SJ, Miyadai T, Tanaka S, Fukuda Y, Kim SR, Oh MJ. Genetic variation and geographic distribution of megalocytiviruses. J Microbiol 2008; 46:29-33. [DOI: 10.1007/s12275-007-0184-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
27
|
Imajoh M, Ikawa T, Oshima SI. Characterization of a new fibroblast cell line from a tail fin of red sea bream, Pagrus major, and phylogenetic relationships of a recent RSIV isolate in Japan. Virus Res 2007; 126:45-52. [PMID: 17335926 DOI: 10.1016/j.virusres.2006.12.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 12/05/2006] [Accepted: 12/05/2006] [Indexed: 11/18/2022]
Abstract
Red sea bream iridovirus (RSIV) is a causative agent of red sea bream iridoviral disease (RSIVD) in marine fish species in Japan. Fibroblast cells were developed from a tail fin of red sea bream, Pagrus major, and then underwent single cell cloning. The successful cloned cells were named CRF-1 cells. Most CRF-1 cells had a normal diploid karyotype with 2n=48 by chromosomal analysis. RSIV-infected CRF-1 cells showed typical morphological changes that were associated with apoptosis by EGFP-annexin V staining. The serial viral passages were successful in CRF-1 cells but failed in BF-2 cells as judged by MTT assay. The expression of three genes obviously decreased in BF-2 cells compared with CRF-1 cells and finally was below detectable level. Because the expression of 591R gene showed the fastest decrease among three transcripts, the suppression of IE transcript may be responsible for the restricted replication in BF-2 cells. MCP and ATPase phylogenetic trees showed that RSIV strain U-1 belongs to a distinct group from RSIV strain ehime-1. Therefore, possibly recent epizootics of RSIVD in Japan do not originate directly from RSIV strain ehime-1. Taken together, this study confirmed that RSIV strain U-1 is more closely related to Korean RSIV isolates.
Collapse
Affiliation(s)
- Masayuki Imajoh
- Laboratory of Cell Structure and Function, Division of Marine Bioresource Science, Graduate School of Kuroshio Science, Kochi University, Nankoku, Kochi 783-8502, Japan
| | | | | |
Collapse
|