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Chacón RD, Sánchez-Llatas CJ, L Pajuelo S, Diaz Forero AJ, Jimenez-Vasquez V, Médico JA, Soto-Ugaldi LF, Astolfi-Ferreira CS, Piantino Ferreira AJ. Molecular characterization of the meq oncogene of Marek's disease virus in vaccinated Brazilian poultry farms reveals selective pressure on prevalent strains. Vet Q 2024; 44:1-13. [PMID: 38465827 DOI: 10.1080/01652176.2024.2318198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 02/05/2024] [Indexed: 03/12/2024] Open
Abstract
Marek's disease virus (MDV) has become an increasingly virulent pathogen in the poultry industry despite vaccination efforts to control it. Brazil has experienced a significant rise of Marek's disease (MD) outbreaks in recent years. Our study aimed to analyze the complete meq gene sequences to understand the molecular epidemiological basis of MD outbreaks in Brazilian vaccinated layer farms. We detected a high incidence rate of visceral MD (67.74%) and multiple circulating MDV strains. The most prevalent and geographically widespread genotype presented several clinical and molecular characteristics of a highly virulent strain and evolving under positive selective pressure. Phylogenetic and phylogeographic analysis revealed a closer relationship with strains from the USA and Japan. This study sheds light on the circulation of MDV strains capable of infecting vaccinated birds. We emphasize the urgency of adopting preventive measures to manage MDV outbreaks threatening the poultry farming industry.
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Affiliation(s)
- Ruy D Chacón
- Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo, Brazil
| | - Christian J Sánchez-Llatas
- Department of Genetics, Physiology, and Microbiology, Faculty of Biology, Complutense University of Madrid, Madrid, Spain
| | | | - Andrea J Diaz Forero
- Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo, Brazil
| | | | - Jack A Médico
- Vertebrate Genome Laboratory, The Rockefeller University, New York, NY, USA
| | - Luis F Soto-Ugaldi
- Tri-Institutional Program in Computational Biology and Medicine, New York, NY, USA
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2
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Ortigas-Vasquez A, Pandey U, Renner DW, Bowen CD, Baigent SJ, Dunn J, Cheng H, Yao Y, Read AF, Nair V, Kennedy DA, Szpara ML. Comparative analysis of multiple consensus genomes of the same strain of Marek's disease virus reveals intrastrain variation. Virus Evol 2024; 10:veae047. [PMID: 39036034 PMCID: PMC11259760 DOI: 10.1093/ve/veae047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/24/2024] [Accepted: 06/17/2024] [Indexed: 07/23/2024] Open
Abstract
Current strategies to understand the molecular basis of Marek's disease virus (MDV) virulence primarily consist of cataloging divergent nucleotides between strains with different phenotypes. However, most comparative genomic studies of MDV rely on previously published consensus genomes despite the confirmed existence of MDV strains as mixed viral populations. To assess the reliability of interstrain genomic comparisons relying on published consensus genomes of MDV, we obtained two additional consensus genomes of vaccine strain CVI988 (Rispens) and two additional consensus genomes of the very virulent strain Md5 by sequencing viral stocks and cultured field isolates. In conjunction with the published genomes of CVI988 and Md5, this allowed us to perform three-way comparisons between multiple consensus genomes of the same strain. We found that consensus genomes of CVI988 can vary in as many as 236 positions involving 13 open reading frames (ORFs). By contrast, we found that Md5 genomes varied only in 11 positions involving a single ORF. Notably, we were able to identify 3 single-nucleotide polymorphisms (SNPs) in the unique long region and 16 SNPs in the unique short (US) region of CVI988GenBank.BAC that were not present in either CVI988Pirbright.lab or CVI988USDA.PA.field. Recombination analyses of field strains previously described as natural recombinants of CVI988 yielded no evidence of crossover events in the US region when either CVI988Pirbright.lab or CVI988USDA.PA.field were used to represent CVI988 instead of CVI988GenBank.BAC. We were also able to confirm that both CVI988 and Md5 populations were mixed, exhibiting a total of 29 and 27 high-confidence minor variant positions, respectively. However, we did not find any evidence of minor variants in the positions corresponding to the 19 SNPs in the unique regions of CVI988GenBank.BAC. Taken together, our findings suggest that continued reliance on the same published consensus genome of CVI988 may have led to an overestimation of genomic divergence between CVI988 and virulent strains and that multiple consensus genomes per strain may be necessary to ensure the accuracy of interstrain genomic comparisons.
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Affiliation(s)
- Alejandro Ortigas-Vasquez
- Department of Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Utsav Pandey
- Department of Biochemistry and Molecular Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Daniel W Renner
- Department of Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Chris D Bowen
- Department of Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Susan J Baigent
- Viral Oncogenesis Group, The Pirbright Institute, Woking GU24 0NF, UK
| | - John Dunn
- United States Department of Agriculture, Agricultural Research Service, US National Poultry Research Center, Southeast Poultry Research Laboratory, Athens, GA 30605, USA
| | - Hans Cheng
- United States Department of Agriculture, Agricultural Research Service, US National Poultry Research Center, Avian Disease and Oncology Laboratory, East Lansing, MI 48823, USA
| | - Yongxiu Yao
- Viral Oncogenesis Group, The Pirbright Institute, Woking GU24 0NF, UK
| | - Andrew F Read
- Department of Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Venugopal Nair
- Viral Oncogenesis Group, The Pirbright Institute, Woking GU24 0NF, UK
| | - Dave A Kennedy
- Department of Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Moriah L Szpara
- Department of Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
- Department of Biochemistry and Molecular Biology, Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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3
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Cheng MC, Lai GH, Tsai YL, Lien YY. Circulating hypervirulent Marek's disease viruses in vaccinated chicken flocks in Taiwan by genetic analysis of meq oncogene. PLoS One 2024; 19:e0303371. [PMID: 38728352 PMCID: PMC11086920 DOI: 10.1371/journal.pone.0303371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/23/2024] [Indexed: 05/12/2024] Open
Abstract
Marek's disease (MD) is an important neoplastic disease caused by serotype 1 Marek's disease virus (MDV-1), which results in severe economic losses worldwide. Despite vaccination practices that have controlled the MD epidemic, current increasing MD-suspected cases indicate the persistent viral infections circulating among vaccinated chicken farms in many countries. However, the lack of available information about phylogeny and molecular characterization of circulating MDV-1 field strains in Taiwan reveals a potential risk in MD outbreaks. This study investigated the genetic characteristics of 18 MDV-1 strains obtained from 17 vaccinated chicken flocks in Taiwan between 2018 and 2020. Based on the sequences of the meq oncogene, the phylogenetic analysis demonstrated that the circulating Taiwanese MDV-1 field strains were predominantly in a single cluster that showed high similarity with strains from countries of the East Asian region. Because the strains were obtained from CVI988/Rispens vaccinated chicken flocks and the molecular characteristics of the Meq oncoprotein showed features like vvMDV and vv+MDV strains, the circulating Taiwanese MDV-1 field strains may have higher virulence compared with vvMDV pathotype. In conclusion, the data presented demonstrates the circulation of hypervirulent MDV-1 strains in Taiwan and highlights the importance of routine surveillance and precaution strategies in response to the emergence of enhanced virulent MDV-1.
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Affiliation(s)
- Ming-Chu Cheng
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Animal Disease Diagnostic Center, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Center of Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Guan-Hua Lai
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Animal Disease Diagnostic Center, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Center of Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Yi-Lun Tsai
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Yi-Yang Lien
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Animal Disease Diagnostic Center, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Research Center of Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan
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4
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Davidson I, Lupini C, Catelli E, Quaglia G, Maddaloni L, Mescolini G. Virulence evaluation of Israeli Marek's disease virus isolates from commercial poultry using their meq gene sequence. Virus Genes 2024; 60:32-43. [PMID: 38184501 DOI: 10.1007/s11262-023-02042-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/17/2023] [Indexed: 01/08/2024]
Abstract
Fifty-seven Gallid alphaherpesvirus 2 (GaHV-2) isolates, collected during a 30-year period (1990-2019) from commercial poultry flocks affected by Marek's disease (MD), were molecularly characterised. The GaHV-2 meq gene was amplified and sequenced to evaluate the virus virulence, based on the number of PPPPs within the proline-rich repeats (PRRs) of its transactivation domain. The present illustration of virus virulence evaluation on a large scale of field virus isolates by molecular analysis exemplifies the practical benefit and usefulness of the molecular marker in commercial GaVH-2 isolates. The alternative assay of GaVH-2 virulence pathotyping is the classical Gold Standard ADOL method, which is difficult and impossible to employ on a large scale using the Specific Pathogen Free (SPF) chicks of the ADOL strains kept in isolators for two months. The phylogenetic analysis performed in the present study showed that the meq gene amino acid sequences of the 57 Israeli strains divide into 16 phylogenetic branches. The virulence evaluation was performed in comparison with 36 GaHV-2 prototype strains, previously characterised by the in vivo Gold Standard ADOL assay. The results obtained revealed that the GaHV-2 strains circulating in Israel have evolved into a higher virulence potential during the years, as the four-proline stretches number in the meq gene decreased over the investigated period, typically of very virulent virus prototypes. The present study supports the meq gene molecular markers for the assessment of field GaVH-2 strains virulence.
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Affiliation(s)
| | - Caterina Lupini
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Bologna, Italy
| | - Elena Catelli
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Bologna, Italy
| | - Giulia Quaglia
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Bologna, Italy
| | - Luca Maddaloni
- Department of Public Health and Infectious Diseases, Sapienza, University of Rome, Rome, Italy
| | - Giulia Mescolini
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Bologna, Italy
- Operating Unit of Animal Health and Hygiene of Livestock Production, Department of Public Health, AUSL della Romagna, Forlì, FC, Italy
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5
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Motai Y, Murata S, Sato J, Nishi A, Maekawa N, Okagawa T, Konnai S, Ohashi K. Characterization of a Very Short Meq Protein Isoform in a Marek's Disease Virus Strain in Japan. Vet Sci 2024; 11:43. [PMID: 38275925 PMCID: PMC10818563 DOI: 10.3390/vetsci11010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/27/2024] Open
Abstract
Marek's disease virus (MDV) causes malignant lymphoma (Marek's disease; MD) in chickens. The Meq protein is essential for tumorigenesis since it regulates the expression of host and viral genes. Previously, we reported that the deletion of the short isoform of Meq (S-Meq) decreases the pathogenicity of MDV. Recently, we identified a further short isoform of Meq (very short isoform of Meq, VS-Meq) in chickens with MD in Japan. A 64-amino-acid deletion was confirmed at the C-terminus of VS-Meq. We measured the transcriptional regulation by VS-Meq in three gene promoters to investigate the effect of VS-Meq on protein function. Wild-type VS-Meq decreased the transrepression of the pp38 promoter but did not alter the transactivation activity of the Meq and Bcl-2 promoters. The deletion in VS-Meq did not affect the activity of the pp38 promoter but enhanced the transactivation activities of the Meq and Bcl-2 promoters. Collectively, the deletion of VS-Meq potentially enhanced the activity of the Meq promoter, while other amino acid sequences in wild-type VS-Meq seemed to affect the weak transrepression of the pp38 promoter. Further investigation is required to clarify the effects of these changes on pathogenicity.
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Affiliation(s)
- Yoshinosuke Motai
- Laboratory of Infectious Diseases, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
| | - Shiro Murata
- Laboratory of Infectious Diseases, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
| | - Jumpei Sato
- Laboratory of Infectious Diseases, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
| | - Akihito Nishi
- Chuo Livestock Hygiene Service Center, Agriculture Promotion Department, Kochi Prefecture, 3229 Otsu, Takaoka-cho, Tosa 781-1102, Japan
| | - Naoya Maekawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
| | - Tomohiro Okagawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
| | - Satoru Konnai
- Laboratory of Infectious Diseases, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
- Institute for Vaccine Research and Development (HU-IVReD), Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
| | - Kazuhiko Ohashi
- Laboratory of Infectious Diseases, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
- International Affairs Office, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
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6
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Ortigas-Vasquez A, Pandey U, Renner D, Bowen C, Baigent SJ, Dunn J, Cheng H, Yao Y, Read AF, Nair V, Kennedy DA, Szpara ML. Comparative Analysis of Multiple Consensus Genomes of the Same Strain of Marek's Disease Virus Reveals Intrastrain Variation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.04.556264. [PMID: 37732198 PMCID: PMC10508761 DOI: 10.1101/2023.09.04.556264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Current strategies to understand the molecular basis of Marek's disease virus (MDV) virulence primarily consist of cataloguing divergent nucleotides between strains with different phenotypes. However, each MDV strain is typically represented by a single consensus genome despite the confirmed existence of mixed viral populations. To assess the reliability of single-consensus interstrain genomic comparisons, we obtained two additional consensus genomes of vaccine strain CVI988 (Rispens) and two additional consensus genomes of the very virulent strain Md5 by sequencing viral stocks and cultured field isolates. In conjunction with the published genomes of CVI988 and Md5, this allowed us to perform 3-way comparisons between consensus genomes of the same strain. We found that consensus genomes of CVI988 can vary in as many as 236 positions involving 13 open reading frames (ORFs). In contrast, we found that Md5 genomes varied only in 11 positions involving a single ORF. Phylogenomic analyses showed all three Md5 consensus genomes clustered closely together, while also showing that CVI988 GenBank.BAC diverged from CVI988 Pirbright.lab and CVI988 USDA.PA.field . Comparison of CVI988 consensus genomes revealed 19 SNPs in the unique regions of CVI988 GenBank.BAC that were not present in either CVI988 Pirbright.lab or CVI988 USDA.PA.field . Finally, we evaluated the genomic heterogeneity of CVI988 and Md5 populations by identifying positions with >2% read support for alternative alleles in two ultra-deeply sequenced samples. We were able to confirm that both populations of CVI988 and Md5 were mixed, exhibiting a total of 29 and 27 high-confidence minor variant positions, respectively. We did not find any evidence of minor variants in the positions corresponding to the 19 SNPs in the unique regions of CVI988 GenBank.BAC . Taken together, our findings confirm that consensus genomes of the same strain of MDV can vary and suggest that multiple consensus genomes per strain are needed in order to maximize the accuracy of interstrain genomic comparisons.
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7
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Žlabravec Z, Slavec B, Rožmanec E, Koprivec S, Dovč A, Zorman Rojs O. First Report of Marek's Disease Virus in Commercial Turkeys in Slovenia. Animals (Basel) 2024; 14:250. [PMID: 38254418 PMCID: PMC10812425 DOI: 10.3390/ani14020250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/09/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Marek's disease (MD), caused by Mardivirus gallidalpha 2 (GaAHV-2), also known as MD virus (MDV), is a lymphoproliferative disease that primarily affects chickens. Recently, MDV has been detected in lymphomatous tumors in turkeys in various countries. Between 2021 and 2023, three cases ranging from no to severe clinical disorders (depression, lameness, and increased mortality) occurred in commercial turkey flocks in Slovenia. In all cases, MDV was detected by PCR in DNA samples extracted from organs developing tumor infiltrations. Sequencing and phylogenetic analysis of the meq gene revealed that the GaAHV-2 detected has molecular features of a very virulent pathotype and genetic similarity with GaAHV-2 detected in chickens in Tunisia. This is the first report of MDV in commercial turkeys in Slovenia.
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Affiliation(s)
- Zoran Žlabravec
- Institute of Poultry, Birds, Small Mammals, and Reptiles, Faculty of Veterinary Medicine, University of Ljubljana, Gerbičeva ulica 60, 1000 Ljubljana, Slovenia; (Z.Ž.)
| | - Brigita Slavec
- Institute of Poultry, Birds, Small Mammals, and Reptiles, Faculty of Veterinary Medicine, University of Ljubljana, Gerbičeva ulica 60, 1000 Ljubljana, Slovenia; (Z.Ž.)
| | - Ema Rožmanec
- Veterinarska Ambulanta PP, d.o.o., Potrčeva cesta 10, 2250 Ptuj, Slovenia
| | - Saša Koprivec
- Institute of Preclinical Sciences, Faculty of Veterinary Medicine, University of Ljubljana, Gerbičeva ulica 60, 1000 Ljubljana, Slovenia
| | - Alenka Dovč
- Institute of Poultry, Birds, Small Mammals, and Reptiles, Faculty of Veterinary Medicine, University of Ljubljana, Gerbičeva ulica 60, 1000 Ljubljana, Slovenia; (Z.Ž.)
| | - Olga Zorman Rojs
- Institute of Poultry, Birds, Small Mammals, and Reptiles, Faculty of Veterinary Medicine, University of Ljubljana, Gerbičeva ulica 60, 1000 Ljubljana, Slovenia; (Z.Ž.)
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8
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Fiddaman SR, Dimopoulos EA, Lebrasseur O, du Plessis L, Vrancken B, Charlton S, Haruda AF, Tabbada K, Flammer PG, Dascalu S, Marković N, Li H, Franklin G, Symmons R, Baron H, Daróczi-Szabó L, Shaymuratova DN, Askeyev IV, Putelat O, Sana M, Davoudi H, Fathi H, Mucheshi AS, Vahdati AA, Zhang L, Foster A, Sykes N, Baumberg GC, Bulatović J, Askeyev AO, Askeyev OV, Mashkour M, Pybus OG, Nair V, Larson G, Smith AL, Frantz LAF. Ancient chicken remains reveal the origins of virulence in Marek's disease virus. Science 2023; 382:1276-1281. [PMID: 38096384 DOI: 10.1126/science.adg2238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 10/25/2023] [Indexed: 12/18/2023]
Abstract
The pronounced growth in livestock populations since the 1950s has altered the epidemiological and evolutionary trajectory of their associated pathogens. For example, Marek's disease virus (MDV), which causes lymphoid tumors in chickens, has experienced a marked increase in virulence over the past century. Today, MDV infections kill >90% of unvaccinated birds, and controlling it costs more than US$1 billion annually. By sequencing MDV genomes derived from archeological chickens, we demonstrate that it has been circulating for at least 1000 years. We functionally tested the Meq oncogene, one of 49 viral genes positively selected in modern strains, demonstrating that ancient MDV was likely incapable of driving tumor formation. Our results demonstrate the power of ancient DNA approaches to trace the molecular basis of virulence in economically relevant pathogens.
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Affiliation(s)
| | - Evangelos A Dimopoulos
- The Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Ophélie Lebrasseur
- Centre d'Anthropobiologie et de Génomique de Toulouse, CNRS/Université Toulouse III Paul Sabatier, Toulouse, France
- Instituto Nacional de Antropología y Pensamiento Latinoamericano, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Louis du Plessis
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Bram Vrancken
- Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Leuven, Belgium
- Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, Brussels, Belgium
| | - Sophy Charlton
- The Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, UK
- BioArCh, Department of Archaeology, University of York, York, UK
| | - Ashleigh F Haruda
- The Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, UK
| | - Kristina Tabbada
- The Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, UK
| | | | | | | | - Hannah Li
- Institute of Immunity and Transplantation, University College London, London, UK
| | | | | | | | | | - Dilyara N Shaymuratova
- Laboratory of Biomonitoring, The Institute of Problems in Ecology and Mineral Wealth, Tatarstan Academy of Sciences, Kazan, Russia
| | - Igor V Askeyev
- Laboratory of Biomonitoring, The Institute of Problems in Ecology and Mineral Wealth, Tatarstan Academy of Sciences, Kazan, Russia
| | | | - Maria Sana
- Departament de Prehistòria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Hossein Davoudi
- Bioarchaeology Laboratory, Central Laboratory, University of Tehran, Tehran, Iran
| | - Homa Fathi
- Bioarchaeology Laboratory, Central Laboratory, University of Tehran, Tehran, Iran
| | - Amir Saed Mucheshi
- Department of Art and Architecture, Payame Noor University (PNU), Tehran, Iran
| | - Ali Akbar Vahdati
- Iranian Ministry of Cultural Heritage, Tourism, and Handicrafts, North Khorasan Office, Iran
| | - Liangren Zhang
- Department of Archaeology, School of History, Nanjing University, China
| | | | - Naomi Sykes
- Department of Archaeology, University of Exeter, Exeter, UK
| | - Gabrielle Cass Baumberg
- The Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, UK
| | - Jelena Bulatović
- Department of Historical Studies, University of Gothenburg, Gothenburg, Sweden
| | - Arthur O Askeyev
- Laboratory of Biomonitoring, The Institute of Problems in Ecology and Mineral Wealth, Tatarstan Academy of Sciences, Kazan, Russia
| | - Oleg V Askeyev
- Laboratory of Biomonitoring, The Institute of Problems in Ecology and Mineral Wealth, Tatarstan Academy of Sciences, Kazan, Russia
| | - Marjan Mashkour
- Bioarchaeology Laboratory, Central Laboratory, University of Tehran, Tehran, Iran
- CNRS, National Museum Natural History Paris, Paris, France
| | - Oliver G Pybus
- Department of Biology, University of Oxford, Oxford, UK
- Department of Pathobiology and Population Sciences, Royal Veterinary College, London, UK
| | - Venugopal Nair
- Department of Biology, University of Oxford, Oxford, UK
- Viral Oncogenesis Group, Pirbright Institute, Woking, UK
| | - Greger Larson
- The Palaeogenomics and Bio-Archaeology Research Network, Research Laboratory for Archaeology and History of Art, University of Oxford, Oxford, UK
| | | | - Laurent A F Frantz
- Palaeogenomics Group, Institute of Palaeoanatomy, Domestication Research and the History of Veterinary Medicine, Ludwig-Maximilians-Universitat, Munich, Germany
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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9
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Kim T, Hearn CJ, Mays J, Velez-Irizarry D, Reddy SM, Spatz SJ, Cheng HH, Dunn JR. Phenotypic Characterization of Recombinant Marek's Disease Virus in Live Birds Validates Polymorphisms Associated with Virulence. Viruses 2023; 15:2263. [PMID: 38005939 PMCID: PMC10674313 DOI: 10.3390/v15112263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
Marek's disease (MD) is a highly infectious lymphoproliferative disease in chickens with a significant economic impact. Mardivirus gallidalpha 2, also known as Marek's disease virus (MDV), is the causative pathogen and has been categorized based on its virulence rank into four pathotypes: mild (m), virulent (v), very virulent (vv), and very virulent plus (vv+). A prior comparative genomics study suggested that several single-nucleotide polymorphisms (SNPs) and genes in the MDV genome are associated with virulence, including nonsynonymous (ns) SNPs in eight open reading frames (ORF): UL22, UL36, UL37, UL41, UL43, R-LORF8, R-LORF7, and ICP4. To validate the contribution of these nsSNPs to virulence, the vv+MDV strain 686 genome was modified by replacing nucleotides with those observed in the vMDV strains. Pathogenicity studies indicated that these substitutions reduced the MD incidence and increased the survival of challenged birds. Furthermore, using the best-fit pathotyping method to rank the virulence, the modified vv+MDV 686 viruses resulted in a pathotype similar to the vvMDV Md5 strain. Thus, these results support our hypothesis that SNPs in one or more of these ORFs are associated with virulence but, as a group, are not sufficient to result in a vMDV pathotype, suggesting that there are additional variants in the MDV genome associated with virulence, which is not surprising given this complex phenotype and our previous finding of additional variants and SNPs associated with virulence.
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Affiliation(s)
- Taejoong Kim
- Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA; (S.J.S.); (J.R.D.)
| | - Cari J. Hearn
- Avian Diseases and Oncology Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI 48823, USA; (C.J.H.); (J.M.); (D.V.-I.); (H.H.C.)
| | - Jody Mays
- Avian Diseases and Oncology Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI 48823, USA; (C.J.H.); (J.M.); (D.V.-I.); (H.H.C.)
| | - Deborah Velez-Irizarry
- Avian Diseases and Oncology Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI 48823, USA; (C.J.H.); (J.M.); (D.V.-I.); (H.H.C.)
| | - Sanjay M. Reddy
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843, USA;
| | - Stephen J. Spatz
- Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA; (S.J.S.); (J.R.D.)
| | - Hans H. Cheng
- Avian Diseases and Oncology Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI 48823, USA; (C.J.H.); (J.M.); (D.V.-I.); (H.H.C.)
| | - John R. Dunn
- Southeast Poultry Research Laboratory, U.S. National Poultry Research Center, Agricultural Research Service, U.S. Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA; (S.J.S.); (J.R.D.)
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10
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Davidson I. Avian Oncogenic and Immunosuppressive Viruses. Infect Dis (Lond) 2023. [DOI: 10.1007/978-1-0716-2463-0_1091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
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11
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Wannaratana S, Tunterak W, Prakairungnamthip D, Sasipreeyajan J, Thontiravong A. Genetic characterization of Marek's disease virus in chickens in Thailand reveals a high genetic diversity of circulating strains. Transbound Emerg Dis 2022; 69:3771-3779. [PMID: 36315934 DOI: 10.1111/tbed.14748] [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: 08/12/2022] [Revised: 10/09/2022] [Accepted: 10/27/2022] [Indexed: 11/13/2022]
Abstract
Marek's disease (MD) is a highly contagious lymphoproliferative disease of chickens caused by Gallid alphaherpesvirus 2, commonly known as serotype 1 Marek's disease virus (MDV-1). Despite widespread vaccination, MD-related cases have been frequently observed worldwide, including in Thailand. However, no information is available on the genetic characteristics of MDV-1 field strains circulating in chickens in Thailand. This study investigated the geographic distribution and genetic characteristics of MDV-1 field strains circulating in chickens in Thailand between 2013 and 2021 by analysing the Meq and pp38 genes. Out of a total of the 286 clinical samples obtained from 70 chicken farms located in major chicken raising areas of Thailand, 138 samples (48.25%) from 46 chicken farms (65.71%) tested positive for MDV-1 field strains. Results demonstrated that MDV-1 field strains were extensively distributed in major chicken raising areas. Phylogenetic analyses based on the Meq gene revealed that four clusters of MDV-1 circulated in chickens in Thailand between 2013 and 2021. Among these clusters, cluster 1 was the predominant cluster circulating in chickens in Thailand. Additionally, our findings based on molecular characteristics of Meq and pp38 gene/protein suggested that most of the Thai MDV-1 field strains were potentially highly virulent. In conclusion, our data demonstrated the circulation of different clusters of MDV-1 with virulence characteristics in chickens in Thailand, indicating high genetic diversity of MDV-1 in Thailand. This study highlights the importance of more effective vaccine development and routine MDV-1 surveillance for early detection and control of highly virulent MDV-1.
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Affiliation(s)
- Suwarak Wannaratana
- Faculty of Veterinary Medicine, Rajamangala University of Technology Tawan-Ok, Bang Phra, Chonburi, Thailand
| | - Wikanda Tunterak
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Duangduean Prakairungnamthip
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Jiroj Sasipreeyajan
- Avian Health Research Unit, Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Aunyaratana Thontiravong
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.,Center of Excellence for Emerging and Re-emerging Infectious Diseases in Animals (CUEIDAs), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.,Animal Vector-Borne Disease Research Unit, Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.,Research Unit of Systems Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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12
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Ghalyanchilangeroudi A, Hosseini H, Nazarpak HH, Molouki A, Dezfoulian O, Morshed R. Molecular Characterization and Phylogenetic Analysis of Marek's Disease Virus in Iran. Avian Dis 2022; 66:1-5. [PMID: 36106908 DOI: 10.1637/aviandiseases-d-22-00018] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/24/2022] [Indexed: 12/14/2022]
Abstract
Marek's disease (MD) is a highly contagious, lymphoproliferative poultry disease caused by the oncogenic herpesvirus, serotype 1 Marek's disease virus (MDV-1), or Gallid herpesvirus 2 (GaHV-2). MDV strains have shown a continued evolution of virulence leading to immune failure, and MD cases continue to occur or surge. Meq, the major MDV-1 oncoprotein, induces T-cell neoplastic transformation through several mechanisms including inhibition of apoptosis, cell cycle regulation, and serum-anchorage independent growth. There is no current information on the MDV serotypes and pathotypes circulating in vaccinated commercial farms in Iran, where the birds are vaccinated at the hatchery with GaHV-2 and Meleagrid herpesvirus 1 (MeHV-1) vaccines. This study reports the molecular characterization of a GaHV-2 strain detected in 19 flocks of Iranian layer farms exhibiting MDV-1-like clinical signs and visceral lymphomas. Based on sequencing and phylogenetic analysis of the Meq gene, the Iranian GaHV-2 isolates could be divided into two separate clades regarding molecular features. The clade containing strains was closely related to Italian, Indian, and Hungarian virulent isolates, and the clade was related to American very virulent plus (vv+) isolates. For the first time, the MDV-1 virus was characterized by an outbreak in poultry flocks in Iran. Although MDV-1 strains obtained in Iran's present outbreak are presumably related to virulent (v) and vv+ pathotypes based on nucleotide, amino acid, and phylogenetic analysis of the viruses, they are not confirmed so far. Thus, it is highly recommended to perform further analyses to demonstrate the pathotype characteristics in vivo.
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Affiliation(s)
- Arash Ghalyanchilangeroudi
- Department of Microbiology and Immunology, University of Tehran, Faculty of Veterinary Medicine, Tehran, Iran 1419963111
| | - Hossein Hosseini
- Department of Clinical Sciences, Karaj Branch, Islamic Azad University, Karaj, Iran 3149968111,
| | - Hadi Haghbin Nazarpak
- Department of Clinical Sciences, Garmsar Branch, Islamic Azad University, Semnan, Iran 3581631167
| | - Aidin Molouki
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran 3197619751
| | - Omid Dezfoulian
- Department of Pathobiology, School of Veterinary Medicine, Lorestan University, Khorramabad, Iran 6815144316
| | - Rima Morshed
- Department of Basic Sciences, Faculty of Encyclopedia, Tehran, Iran 1997743881
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13
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Phylogenetic analyses on Marek's disease virus circulating in Iranian backyard and commercial poultry indicate viruses of different origin. Braz J Microbiol 2022; 53:1683-1689. [PMID: 35484378 PMCID: PMC9433632 DOI: 10.1007/s42770-022-00738-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/19/2022] [Indexed: 11/02/2022] Open
Abstract
As neoplastic viruses have been affecting Iranian chicken farms more frequently in recent years, the first step in prevention may therefore be to genetically characterize and systematically identify their source and origin. Recently, we published a phylogenetic analysis based on the meq gene of Gallid alphaherpesvirus 2, commonly known as serotype 1 Marek's disease virus (MDV-1), that circulated in Iranian backyard and commercial chickens. In the current study, we are reporting for the first time the identification of a 298 aa meq protein containing only two PPPP motifs from an MDV-1-infected unvaccinated backyard turkey. This protein length has never been reported from any turkey species before. According to phylogenetic analysis, a close genetic relationship (0.68%) to several chicken-origin isolates such as the American vv + 648A strain was found. In addition, we identified a standard meq protein from a MDV-1-infected commercial chicken farm. In corroboration with our previous finding from other Iranian provinces, it is likely that the highly identical MDV-1 viruses currently circulating in Iranian chicken farms, which may be indicative of human role in the spread of the virus, have similar Eurasian origin. Our data suggest that regardless of the meq size, MDV-1 circulating in Iran are from different origins. On the other hand, meq sequences from bird species other than chicken have been reported but are very few. Our investigation suggests MDV-1 circulating in turkey do not have species-specific sequences.
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14
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Sato J, Murata S, Yang Z, Kaufer BB, Fujisawa S, Seo H, Maekawa N, Okagawa T, Konnai S, Osterrieder N, Parcells MS, Ohashi K. Effect of Insertion and Deletion in the Meq Protein Encoded by Highly Oncogenic Marek’s Disease Virus on Transactivation Activity and Virulence. Viruses 2022; 14:v14020382. [PMID: 35215975 PMCID: PMC8876991 DOI: 10.3390/v14020382] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 02/04/2023] Open
Abstract
Marek’s disease virus (MDV) causes malignant lymphoma in chickens (Marek’s disease, MD). Although MD is currently controlled by vaccination, MDV strains have continuously increased in virulence over the recent decades. Polymorphisms in Meq, an MDV-encoded oncoprotein that serves as a transcription factor, have been associated with the enhanced virulence of the virus. In addition, insertions and deletions in Meq have been observed in MDV strains of higher virulence, but their contribution to said virulence remains elusive. In this study, we investigated the contribution of an insertion (L-Meq) and a deletion in the Meq gene (S-Meq) to its functions and MDV pathogenicity. Reporter assays revealed that both insertion and deletion enhanced the transactivation potential of Meq. Additionally, we generated RB-1B-based recombinant MDVs (rMDVs) encoding each Meq isoform and analyzed their pathogenic potential. rMDV encoding L-Meq indueced the highest mortality and tumor incidence in infected animals, whereas the rMDV encoding S-Meq exhibited the lowest pathogenicity. Thus, insertion enhanced the transactivation activity of Meq and MDV pathogenicity, whereas deletion reduced pathogenicity despite having increased transactivation activity. These data suggest that other functions of Meq affect MDV virulence. These data improve our understanding of the mechanisms underlying the evolution of MDV virulence.
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Affiliation(s)
- Jumpei Sato
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (J.S.); (Z.Y.); (S.F.); (H.S.); (S.K.); (K.O.)
| | - Shiro Murata
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (J.S.); (Z.Y.); (S.F.); (H.S.); (S.K.); (K.O.)
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (N.M.); (T.O.)
- Correspondence: ; Tel.: +81-11-706-5274; Fax: +81-11-706-5217
| | - Zhiyuan Yang
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (J.S.); (Z.Y.); (S.F.); (H.S.); (S.K.); (K.O.)
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Benedikt B. Kaufer
- Institut für Virologie, Freie Universität Berlin, 14163 Berlin, Germany; (B.B.K.); (N.O.)
| | - Sotaro Fujisawa
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (J.S.); (Z.Y.); (S.F.); (H.S.); (S.K.); (K.O.)
| | - Hikari Seo
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (J.S.); (Z.Y.); (S.F.); (H.S.); (S.K.); (K.O.)
| | - Naoya Maekawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (N.M.); (T.O.)
| | - Tomohiro Okagawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (N.M.); (T.O.)
| | - Satoru Konnai
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (J.S.); (Z.Y.); (S.F.); (H.S.); (S.K.); (K.O.)
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (N.M.); (T.O.)
| | - Nikolaus Osterrieder
- Institut für Virologie, Freie Universität Berlin, 14163 Berlin, Germany; (B.B.K.); (N.O.)
- Department of Infectious Diseases and Public Health, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Mark S. Parcells
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716, USA;
| | - Kazuhiko Ohashi
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (J.S.); (Z.Y.); (S.F.); (H.S.); (S.K.); (K.O.)
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan; (N.M.); (T.O.)
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15
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Ongor H, Timurkaan N, Abayli H, Karabulut B, Kalender H, Tonbak S, Eroksuz H, Çetinkaya B. First report of Serotype-1 Marek's disease virus (MDV-1) with oncogenic form in backyard turkeys in Turkey: a molecular analysis study. BMC Vet Res 2022; 18:30. [PMID: 35016700 PMCID: PMC8753842 DOI: 10.1186/s12917-021-03130-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/27/2021] [Indexed: 12/03/2022] Open
Abstract
Background Marek’s disease (MD) is a lymphoproliferative disease caused by Gallid alphaherpesvirus 2 (GaHV-2, MDV-1), which primarily affects chickens. However, the virus is also able to induce tumors and polyneuritis in turkeys, albeit less frequently than in chickens. Results This is the first study in Turkey reporting the molecular characterization of a MDV-1 strain detected in a flock of backyard turkeys exhibiting visceral lymphoma. Here, MEQ, vIL-8, pp38 and 132-bp tandem repeat regions, which are frequently preferred in the pathotyping of MDV-1, were examined. It was determined that the MEQ gene of MDV-1/TR-21/turkey strain obtained in the present study encoded 339 amino acids (1020 nt) and had four proline-rich repeat regions (PPPP). Based on the nucleotide sequence of the MEQ gene of the MDV-1/TR-21/turkey strain, a phylogenetic tree was created using the MEGA-X software with the Maximum Likelihood Method (in 1000 replicates). Our strain was highly identical (> 99.8) to the Italian/Ck/625/16, Polish (Polen5) and some Turkish (Layer-GaHV-2-02-TR-2017, Tr/MDV-1/19) MDV-1 strains. Also, nt and aa sequences of the MEQ gene of our strain were 99.1 and 99.41% identical to another Turkish strain (MDV/Tur/2019) originated from chickens. Sequence analysis of pp38 and vIL-8 genes also supported the above finding. The identity ratios of nucleotide and amino acid sequences of vIL-8 and pp38 genes of MDV-1/TR-21/turkey strain were 99.64–100% and 99.79–100%, respectively, when compared with those of the Polish strain. According to 132-bp tandem repeat PCR results, the MDV-1/TR-21/turkey strain had five copies. Conclusions These results suggested that the MDV-1/TR-21/turkey strain obtained from backyard turkeys can be either very virulent or very virulent plus pathotype, though experimental inoculation is required for precise pathotyping.
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Affiliation(s)
- Hasan Ongor
- Department of Microbiology, Faculty of Veterinary Medicine, Firat University, 23110, Elazig, Turkey.
| | - Necati Timurkaan
- Department of Pathology, Faculty of Veterinary Medicine, Firat University, Elazig, Turkey
| | - Hasan Abayli
- Department of Virology, Faculty of Veterinary Medicine, Firat University, Elazig, Turkey
| | - Burak Karabulut
- Department of Pathology, Faculty of Veterinary Medicine, Firat University, Elazig, Turkey
| | - Hakan Kalender
- Department of Microbiology, Faculty of Veterinary Medicine, Firat University, 23110, Elazig, Turkey
| | - Sukru Tonbak
- Department of Virology, Faculty of Veterinary Medicine, Firat University, Elazig, Turkey
| | - Hatice Eroksuz
- Department of Pathology, Faculty of Veterinary Medicine, Firat University, Elazig, Turkey
| | - Burhan Çetinkaya
- Department of Microbiology, Faculty of Veterinary Medicine, Firat University, 23110, Elazig, Turkey
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16
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Yimer YM, Asfaw Ali D, Getachew Ayalew B, Bitew Asires M, Gelaye E. Pathogenicity of Field Marek’s Disease Virus Serotype-1 and Vaccine Efficacy Test in Chicken in Eastern Shewa Ethiopia. Vet Med (Auckl) 2021; 12:347-357. [PMID: 35223432 PMCID: PMC8866982 DOI: 10.2147/vmrr.s332737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/02/2021] [Indexed: 11/23/2022]
Abstract
Background Marek’s disease is a chicken lymphoproliferative viral illness. As new viruses emerge, vaccination immunity is being broken and hence pathogenecity assessment and vaccine evaluation related to the pathogen is critical for developing vaccine immunity in the field. Methods An experimental investigation was conducted to determine the pathogenicity of field isolates against Marek’s disease in antibody-free chicks and to assess the protective efficacy of the Marek’s disease vaccination. The viral isolates in question were discovered during an outbreak investigation for a previous study. The pathogenicity and effectiveness trial used a complete random design. Results In the pathogenicity trial, chickens inoculated with Bishoftu and Mojo field isolate had lower body weight 77.7±3.757 and 78.15±1.95 g at 10 dpi, respectively, when compared to un-inoculated controls, 89.85±3.838 g at 10 dpi. Incidence of early mortality syndrome (35% and 25%), lymphoma (53.8% and 40%), and overall mortality (50% and 45%) between Bishoftu and Mojo isolates, respectively, was discovered. Vaccinations with Herpes virus of turkey challenged chickens were provided complete protection against Marek’s disease. Conclusion Based on the findings in pathogenecity assessment experimental trials, Bishoftu and Mojo isolates were designated as virulent Marek’s disease viruses. Regular vaccinations with Herpes virus of turkey vaccine and supported by biosecurity measures in poultry farms are important to prevent the disease.
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Affiliation(s)
| | - Destaw Asfaw Ali
- College of Veterinary Medicine and Animal Sciences, University of Gondar, Gondar, Ethiopia
- Correspondence: Destaw Asfaw Ali College of Veterinary Medicine and Animal Science, University of Gondar, P.O. Box 196, Gondar, Ethiopia Email
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17
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Murata S, Yamamoto E, Sakashita N, Maekawa N, Okagawa T, Konnai S, Ohashi K. Research Note: Characterization of S-Meq containing the deletion in Meq protein's transactivation domain in a Marek's disease virus strain in Japan. Poult Sci 2021; 100:101461. [PMID: 34601441 PMCID: PMC8531842 DOI: 10.1016/j.psj.2021.101461] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/18/2021] [Accepted: 08/26/2021] [Indexed: 11/28/2022] Open
Abstract
Marek's disease virus (MDV) causes malignant lymphomas in chickens (Marek's disease; MD). Although MD has caused significant economic losses to the poultry industry, currently, its occurrence in the field is effectively controlled by vaccination. However, the genetic characteristics of MDV strains have changed, and the poultry industry has experienced MD outbreaks in vaccinated chickens because of enhanced virulence. Meq, an oncoprotein of MDV, is a key transcription factor correlated with the tumorigenesis in MD. Animal experiments using recombinant MDV revealed that distinct polymorphisms in Meq affect the virulence of MDV strains. Meq containing an insertion or deletion is present in some MDV strains. In the 2010s, field strains that encode Meq containing the deletion (S-Meq) were reported. In this study, we characterized the genetic features of S-Meq detected in a Japanese MDV strain and analyzed its transactivation activity to investigate S-Meq's protein function. S-Meq lacked 41 amino acids, and the deletion was at the same position as those observed in other countries. In addition, S-Meq exhibited higher transactivation activity than Meq from other MDV strains circulating in Japan. These results suggest that the deletion in the transactivation domain may enhance the Meq protein's function. Further investigation is needed to clarify whether the deletion in the transactivation domain of Meq affects MDV's virulence.
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Affiliation(s)
- Shiro Murata
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan; Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
| | - Eiji Yamamoto
- Western Livestock Hygiene Service Center, Kagawa Prefectural Government, Zentsuji, Japan
| | | | - Naoya Maekawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Tomohiro Okagawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Satoru Konnai
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan; Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Kazuhiko Ohashi
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan; Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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18
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Molouki A, Ghalyanchilangeroudi A, Abdoshah M, Shoushtari A, Abtin A, Eshtartabadi F, Mahmoudzadeh Akhijahani M, Ziafatikafi Z, Babaeimarzango SS, Allahyari E, Ahmadzadeh L, Fallah Mehrabadi MH, Lim SHE, Rouhani K, Hosseini H, Nair V. Report of a new meq gene size: The first study on genetic characterisation of Marek's disease viruses circulating in Iranian commercial layer and backyard chicken. Br Poult Sci 2021; 63:142-149. [PMID: 34423692 DOI: 10.1080/00071668.2021.1963677] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
1. In recent months, several outbreaks with clinical signs of MDV-1 were reported in Iranian parent and laying hen farms, in addition to backyard chickens. Several meq gene sequences from these outbreaks were amplified and molecularly characterised.2. The meq protein sequences revealed three different sizes, namely the standard 339 aa, a shorter form of 338 aa lacking a proline residue at position 191, and a very short (vs) size of 265 aa. Based on sequence and size, the 265 aa meq has never been reported from international research groups before. The protein has only one PPPP repeat motif suggesting it belongs to a highly virulent strain.3. The standard meq sequences showed 100% BLAST identity to the vv+ isolate Polen5. However, the 338 aa form clustered to the clade usually reported from North America.4. This is the first report on genetic analysis of MDV-1 from Iran, but further study is required to obtain a better picture of the diversity and prevalence of different MDV-1 strains circulating in the country's farms, backyard poultry and other bird species.
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Affiliation(s)
- A Molouki
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - A Ghalyanchilangeroudi
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - M Abdoshah
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - A Shoushtari
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - A Abtin
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - F Eshtartabadi
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - M Mahmoudzadeh Akhijahani
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Z Ziafatikafi
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | | | - E Allahyari
- Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
| | - L Ahmadzadeh
- Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
| | - M H Fallah Mehrabadi
- Department of Avian Diseases Research and Diagnostics, Razi Vaccine and Serum Research, Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - S H E Lim
- Health Sciences Division, Abu Dhabi Women's College, Higher Colleges of Technology, Abu Dhabi, United Arab Emirates
| | - K Rouhani
- Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - H Hosseini
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Islamic Azad University, Karaj, Iran
| | - V Nair
- Viral Oncogenesis Group & OIE Marek's Disease Virus Reference Laboratory, Pirbright Institute, Surrey, UK
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19
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Kannaki TR, Priyanka E, Nishitha Y, Krishna SV, Haunshi S, Subbiah M. Molecular detection and phylogenetic analysis of Marek's disease virus virulence-associated genes from vaccinated flocks in southern India reveals circulation of virulent MDV genotype. Transbound Emerg Dis 2021; 69:e244-e253. [PMID: 34403565 DOI: 10.1111/tbed.14289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 11/30/2022]
Abstract
Marek's disease (MD) is a re-emerging viral disease of chickens and a serious economic threat to the poultry industry worldwide. Continuous surveillance with molecular investigation is essential to monitor the emergence of virulent Marek's disease virus (MDV) strains and to devise any appropriate vaccination strategy and implement bio-security programmes. In the present study, we investigated the cases of MD outbreaks in vaccinated poultry flocks. The MD outbreak was confirmed through necropsy (mainly visceral tumours), histopathology and viral gene specific PCR. The pathotypes of the field MDV strains were assessed by molecular analysis of three virulence-associated genes, meq, pp38 and vIL-8. The Meq sequence of the field strains analyzed in this study lacked the 59 aa unique to mild strains, indicating that they are potentially virulent strains. Mutation at position 71 and the presence of five proline rich repeats in the transactivation domain, both associated with virulence were observed in these strains; however, the signature sequences specific to very virulent plus strains were absent. Phylogenetic analysis of meq oncogene sequences revealed clustering of the field strains with North Indian strains and with a very virulent plus ATE 2539 strain from Hungary. Analyses of pp38 protein at positions 107 and 109 and vIL-8 protein at positions 4 and 31 showed signatures of virulence. Sequence and phylogenetic analysis of oncogene and virulence-associated genes of field MDVs from vaccinated flock indicated that these strains possessed molecular features of virulent strains.
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Affiliation(s)
- T R Kannaki
- ICAR-Directorate of Poultry Research, Hyderabad, Telangana, India
| | - E Priyanka
- ICAR-Directorate of Poultry Research, Hyderabad, Telangana, India
| | - Y Nishitha
- Department of Veterinary Microbiology, P. V. Narasimha Rao Telangana Veterinary University, Hyderabad, Telangana, India
| | - S Vamshi Krishna
- Department of Veterinary Microbiology, P. V. Narasimha Rao Telangana Veterinary University, Hyderabad, Telangana, India
| | - Santosh Haunshi
- ICAR-Directorate of Poultry Research, Hyderabad, Telangana, India
| | - Madhuri Subbiah
- National Institute of Animal Biotechnology, Hyderabad, Telangana, India
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20
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Bayoumi M, El-Saied M, Ahmed B, El-Mahdy M, Amer H. Gallid Alphaherpesvirus 2 in the Egyptian Turkeys: Molecular Characterization and Establishment of a Universal System for Phylogenetic Classification. Intervirology 2021; 64:156-164. [PMID: 34023833 DOI: 10.1159/000515904] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 03/16/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Gallid alphaherpesvirus 2 (GaHV-2) is a highly contagious oncogenic virus that causes Marek's disease in chickens and occasionally in turkeys. Among 100 genes identified in GaHV-2 genome, the Meq gene appears to involve viral virulence, oncogenicity, and genetic diversity. Despite the use of Meq gene sequences in phylogenetic classification of GaHV-2 strains circulating in many countries worldwide, no integrated system exists yet. METHODS Turkeys from 2 commercial Egyptian farms were presented with signs of dullness, dehydration, and emaciation. Samples prepared from the internal organs were examined by histopathology and immunohistochemistry. Pools of the internal organs were analyzed by PCR for identification of GaHV-2, avian leucosis virus, and reticuloendotheliosis virus. The Meq gene of an Egyptian strain was sequenced and analyzed in comparison to 40 reference strains for generation of a universal system for phylogenetic classification of GaHV-2 strains. RESULTS Gross and histopathological examination revealed grayish-white soft masses in the internal organs characterized by diffuse infiltration of pleomorphic neoplastic cells. All lymphoma cells were identified as T-lymphocytes of CD3+ phenotype. Samples of both farms were only positive for GaHV-2 by PCR. Sequence analysis of the Meq gene has classified the current turkey strain as related to the Egyptian strains identified in chicken in 2012. A universal phylogenetic system for classification of GaHV-2 strains into 4 clusters was proposed. The vaccine strains were all grouped in cluster 2, and most of the classical American strains belonged to cluster 4. Cluster 1 was further divided into 3 subclusters (1.1-1.3). CONCLUSION GaHV-2 was identified in turkeys for the first time in Africa and the Middle East. Sequence analysis of the Meq gene of the Egyptian strain along with a wide array of the global strains has enabled the construction of a novel phylogenetic classification system.
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Affiliation(s)
- Mahmoud Bayoumi
- Virology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.,Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
| | - Mohamed El-Saied
- Pathology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Basem Ahmed
- Virology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Magdy El-Mahdy
- Pathology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Haitham Amer
- Virology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
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21
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In Vivo Inhibition of Marek's Disease Virus in Transgenic Chickens Expressing Cas9 and gRNA against ICP4. Microorganisms 2021; 9:microorganisms9010164. [PMID: 33450980 PMCID: PMC7828426 DOI: 10.3390/microorganisms9010164] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 12/28/2022] Open
Abstract
Marek’s disease (MD), caused by MD herpesvirus (MDV), is an economically important disease in chickens. The efficacy of the existing vaccines against evolving virulent stains may become limited and necessitates the development of novel antiviral strategies to protect poultry from MDV strains with increased virulence. The CRISPR/Cas9 system has emerged as a powerful genome editing tool providing an opportunity to develop antiviral strategies for the control of MDV infection. Here, we characterized Tol2 transposon constructs encoding Cas9 and guide RNAs (gRNAs) specific to the immediate early infected-cell polypeptide-4 (ICP4) of MDV. We generated transgenic chickens that constitutively express Cas9 and ICP4-gRNAs (gICP4) and challenged them via intraabdominal injection of MDV-1 Woodlands strain passage-19 (p19). Transgenic chickens expressing both gRNA/Cas9 had a significantly reduced replication of MDV in comparison to either transgenic Cas9-only or the wild-type (WT) chickens. We further confirmed that the designed gRNAs exhibited sequence-specific virus interference in transgenic chicken embryo fibroblast (CEF) expressing Cas9/gICP4 when infected with MDV but not with herpesvirus of turkeys (HVT). These results suggest that CRISPR/Cas9 can be used as an antiviral approach to control MDV infection in chickens, allowing HVT to be used as a vector for recombinant vaccines.
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22
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Ozan E, Muftuoglu B, Sahindokuyucu I, Kurucay HN, Inal S, Kuruca N, Elhag AE, Karaca E, Tamer C, Gumusova S, Albayrak H, Barry G, Gulbahar MY, Yazici Z. Marek's disease virus in vaccinated poultry flocks in Turkey: its first isolation with molecular characterization. Arch Virol 2021; 166:559-569. [PMID: 33409548 DOI: 10.1007/s00705-020-04943-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/15/2020] [Indexed: 12/28/2022]
Abstract
Marek's disease (MD) is an important disease of avian species and a potential threat to the poultry industry worldwide. In this study, 16 dead commercial chickens from flocks with suspected MD were necropsied immediately after death. Pathological findings were compatible with MD, and gallid alphaherpesvirus 2 was identified in PCR of spleen samples. Virus isolation was performed in primary cell culture, and partial sequencing of the meq gene of the isolate revealed >99% nucleotide sequence identity to virulent and very virulent plus strains from a number of European countries, placing it in the same subclade of clade III as two virulent Italian strains and a very virulent plus Polish strain as well as virulent strains of geese and ducks. The data reported here indicate that a virulent strain of Marek's disease virus is circulating in Turkey and has not been stopped by the current national vaccination programme.
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Affiliation(s)
- Emre Ozan
- Department of Veterinary Experimental Animals, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey.
| | - Bahadir Muftuoglu
- Department of Veterinary Experimental Animals, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Ismail Sahindokuyucu
- Bornova Veterinary Control Institute, Veterinary Control Institute Directorates, Ministry of Agriculture and Forestry, 35010, Izmir, Turkey
| | - Hanne Nur Kurucay
- Department of Veterinary Virology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Sinem Inal
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Nilufer Kuruca
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Ahmed Eisa Elhag
- Department of Veterinary Virology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Efe Karaca
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Cuneyt Tamer
- Department of Veterinary Virology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Semra Gumusova
- Department of Veterinary Virology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Harun Albayrak
- Department of Veterinary Virology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Gerald Barry
- Veterinary Science Centre, School of Veterinary Medicine, University College of Dublin, Belfield, Dublin 4, Ireland
| | - Mustafa Yavuz Gulbahar
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
| | - Zafer Yazici
- Department of Veterinary Virology, Faculty of Veterinary Medicine, Ondokuz Mayis University, 55139, Atakum, Samsun, Turkey
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23
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Deng Q, Shi M, Li Q, Wang P, Li M, Wang W, Gao Y, Li H, Lin L, Huang T, Wei P. Analysis of the evolution and transmission dynamics of the field MDV in China during the years 1995-2020, indicating the emergence of a unique cluster with the molecular characteristics of vv+ MDV that has become endemic in southern China. Transbound Emerg Dis 2020; 68:3574-3587. [PMID: 33354907 DOI: 10.1111/tbed.13965] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/19/2020] [Accepted: 12/20/2020] [Indexed: 01/23/2023]
Abstract
Marek's disease (MD) continues to threaten the sustainability of the world poultry industry. In this study, the sequences of the meq gene of 220 MDV strains isolated during the years 1964-2020 were analysed, including 50 from our group plus 170 isolates from the GenBank. Analyses, using phylogenetic trees, amino acid (aa)-mutation screening, evolutionary studies and transmission dynamics were all performed. All strains were divided into two clusters (Clusters 1 and 2), and Cluster 1 includes the mild strains, the vaccine strains and the foreign virulent strains, while Cluster 2 was dominated by the Chinese field strains. Our study identified that the Chinese field strains in Cluster 2 during the years 1995-2020 likely originated in the 1980s from abroad, and the estimated genetic diversity of these strains experienced two growth phases in the years 2005-2007.5 and 2015-2017. Viral phylogeography identified 3 major geographic provincial regions for the Chinese field strains of Cluster 2: the Northeastern Region (Jilin, Liaoning and Heilongjiang), the East-central Region (Henan, Shandong and Jiangsu) and the Southern Region (Guangxi, Guangdong and Yunnan). The spread of Northeastern strains to East-central chicken flocks and the further spread from Guangxi to Guangdong are strongly indicated. The emergence of the mutations A88T and Q93R together in the Southern strains during the years 2017-2020 with molecular characteristics of vv+ MDV were also found later than those in the Northern strains. Overall, the Chinese field strains in Cluster 2 in southern China in recent years have been rapidly evolving. Guangxi Province has become an epicentre for these viruses and the chicken flocks in the Southern region have been facing the adverse effects of the emerging vv+ MDV.
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Affiliation(s)
- Qiaomu Deng
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Mengya Shi
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Qiuhong Li
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Peikun Wang
- Institute of Microbe and Host Health, Linyi University, Linyi, China
| | - Min Li
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Weiwei Wang
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Yanli Gao
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Haijuan Li
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Lulu Lin
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Teng Huang
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
| | - Ping Wei
- Institute for Poultry Science and Health, Guangxi University, Nanning, China
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24
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Murata S, Machida Y, Isezaki M, Maekawa N, Okagawa T, Konnai S, Ohashi K. Genetic characterization of a Marek's disease virus strain isolated in Japan. Virol J 2020; 17:186. [PMID: 33228722 PMCID: PMC7684920 DOI: 10.1186/s12985-020-01456-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/15/2020] [Indexed: 01/29/2023] Open
Abstract
Background Marek’s disease virus (MDV) causes malignant lymphomas in chickens (Marek’s disease, MD). MD is currently controlled by vaccination; however, MDV strains have a tendency to develop increased virulence. Distinct diversity and point mutations are present in the Meq proteins, the oncoproteins of MDV, suggesting that changes in protein function induced by amino acid substitutions might affect MDV virulence. We previously reported that recent MDV isolates in Japan display distinct mutations in Meq proteins from those observed in traditional MDV isolates in Japan, but similar to those in MDV strains isolated from other countries. Methods To further investigate the genetic characteristics in Japanese field strains, we sequenced the whole genome of an MDV strain that was successfully isolated from a chicken with MD in Japan. A phylogenetic analysis of the meq gene was also performed. Results Phylogenetic analysis revealed that the Meq proteins in most of the Japanese isolates were similar to those of Chinese and European strains, and the genomic sequence of the Japanese strain was classified into the Eurasian cluster. Comparison of coding region sequences among the Japanese strain and MDV strains from other countries revealed that the genetic characteristics of the Japanese strain were similar to those of Chinese and European strains. Conclusions The MDV strains distributed in Asian and European countries including Japan seem to be genetically closer to each other than to MDV strains from North America. These findings indicate that the genetic diversities of MDV strains that emerged may have been dependent on the different vaccination-based control approaches.
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Affiliation(s)
- Shiro Murata
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan. .,Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan.
| | - Yuka Machida
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan
| | - Masayoshi Isezaki
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan
| | - Naoya Maekawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan
| | - Tomohiro Okagawa
- Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan
| | - Satoru Konnai
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan.,Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan
| | - Kazuhiko Ohashi
- Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan.,Department of Advanced Pharmaceutics, Faculty of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo, 060-0818, Japan
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25
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An outbreak in three-yellow chickens with clinical tumors of high mortality caused by the coinfection of reticuloendotheliosis virus and Marek's disease virus: a speculated reticuloendotheliosis virus contamination plays an important role in the case. Poult Sci 2020; 100:19-25. [PMID: 33357681 PMCID: PMC7772669 DOI: 10.1016/j.psj.2020.09.034] [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: 03/10/2020] [Revised: 08/14/2020] [Accepted: 09/11/2020] [Indexed: 12/19/2022] Open
Abstract
Both reticuloendotheliosis and Marek's disease are neoplastic diseases of chickens caused by reticuloendotheliosis virus (REV) and Marek's disease virus (MDV), respectively. The infection of REV or MDV may lead to clinical tumors and also result in immunosuppression and easily allow secondary infection by other pathogens. Here, we investigated a breeder flock of three-yellow chickens in southern China that had been vaccinated with CVI988/Rispens at hatching and had experienced depression, weakness, reduction in weight gain, and an increased death rate after 120 d of age. The morbidity and mortality were 20% and 10%, respectively, at 140 d of age when this infection was diagnosed. The necropsy of the birds revealed significant tumor-like lesions in the heart, liver, spleen, and ceca. Peripheral blood lymphocytes and tumor-like tissues were sampled for PCR detection and for histopathological observation, for virus isolation and the subsequent immunofluorescent assay on the cell cultures and for gene sequencing of the isolated viruses. A REV isolate GX18NNR1 and a MDV isolate GX18NNM5 were both recovered from the sampled bird. Further phylogenetic analysis based on the env gene of REV and the meq gene of MDV demonstrated that GX18NNR1 was closely related to the reference REV strain MD-2, which was isolated from a contaminated commercial turkey herpesvirus vaccine. In addition, the GX18NNM5 was found to belong to the Chinese very virulent MDV strains' cluster. The coinfection of REV and MDV may contribute to tumor outbreaks with high morbidity and mortality in three-yellow chicken flocks.
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26
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Lachheb J, Mastour H, Nsiri J, Kaboudi K, Choura I, Ammouna F, Amara A, Ghram A. Newly detected mutations in the Meq oncogene and molecular pathotyping of very virulent Marek's disease herpesvirus in Tunisia. Arch Virol 2020; 165:2589-2597. [PMID: 32876794 PMCID: PMC7547972 DOI: 10.1007/s00705-020-04790-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 07/27/2020] [Indexed: 11/25/2022]
Abstract
Marek's disease (MD) is a contagious avian viral disease that is responsible for large economic losses to farmers. The disease is caused by Marek's disease virus (species Gallid alphaherpesvirus 2), which causes neurological lesions, immune suppression, and tumor proliferation of lymphoid cells that invade a large number of organs and tissues. Despite widespread vaccination, Marek's disease virus (MDV), has shown a continuous increase in its virulence and has acquired the ability to overcome immune responses induced by vaccines. In the present study, the oncogenic serotype MDV-1 was detected by real-time PCR in DNA samples extracted from organs developing tumor infiltrations. Identification of the pathotype based on a 132-bp tandem repeat and sequencing and phylogenetic analysis of the Meq gene and its encoded protein allowed classification of the isolated viruses as "very virulent", with two new and unique mutations in the Meq gene resulting in amino acid substitutions. Sequencing of pp38, vIl-8, UL1 and UL44 genes did not reveal any new mutations that were characteristic of the Tunisian isolates or correlated with virulence. These results raised concerns about the ability of HVT and CVI988 vaccines, which are currently used in Tunisia and other countries, to protect chickens against highly virulent virus strains.
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Affiliation(s)
- Jihene Lachheb
- Laboratory of Epidemiology and Veterinary Microbiology, LR 11 IPT 03, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia.
| | - Houssem Mastour
- Laboratory of Epidemiology and Veterinary Microbiology, LR 11 IPT 03, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Jihene Nsiri
- Laboratory of Epidemiology and Veterinary Microbiology, LR 11 IPT 03, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Khaled Kaboudi
- Department of Poultry Farming and Pathology, National School of Veterinary Medicine, University of Carthage, Sidi Thabet, Tunis, Tunisia
| | - Imed Choura
- Society of Animal Nutrition (SNA), Tunis, Tunisia
| | - Faten Ammouna
- Laboratory of Epidemiology and Veterinary Microbiology, LR 11 IPT 03, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Abdelkader Amara
- Department of Poultry Farming and Pathology, National School of Veterinary Medicine, University of Carthage, Sidi Thabet, Tunis, Tunisia
| | - Abdeljelil Ghram
- Laboratory of Epidemiology and Veterinary Microbiology, LR 11 IPT 03, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
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27
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Davidson I. Out of Sight, but Not Out of Mind: Aspects of the Avian Oncogenic Herpesvirus, Marek's Disease Virus. Animals (Basel) 2020; 10:E1319. [PMID: 32751762 PMCID: PMC7459476 DOI: 10.3390/ani10081319] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 02/08/2023] Open
Abstract
Marek's disease virus is an economically important avian herpesvirus that causes tumors and immunosuppression in chickens and turkeys. The virus, disease, and vaccines have been known for more than 50 years, but as knowledge gaps still exists, intensive research is still ongoing. The understanding of MDV complexity can provide scientific insight in topics that cannot be experimented in humans, providing a unique model that is dually useful for the benefit of the poultry industry and for studying general herpesvirology. The present review presents the following topics: the MDV biology, the vaccine's and virulent virus' peculiar presence in feathers, protection by vaccination. In addition, two relatively behind the scenes topics are reviewed; first, the meq MDV oncogene and its recent implication in molecular epidemiology and in the MDV virulence determination, and second, the functionality of conformational epitopes of the MDV immunodominant protein, glycoprotein B. Our studies were particular, as they were the only ones describing three-dimensional MDV gB oligomers. MDV gB (glycoprotein B) continuous and discontinuous epitopes were shown to possess distinctive neutralization activities. In contrast, the significance of oligomerization of the viral membrane proteins for the creation of discontinuous epitopes in other herpesviruses was explored extensively.
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Affiliation(s)
- Irit Davidson
- Division of Avian Diseases, Kimron Veterinary Institute, Bet Dagan 50250, Israel
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28
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Kannaki TR, Gowthaman V. Marek’s disease: time to review the emerging threat in Indian poultry. WORLD POULTRY SCI J 2020. [DOI: 10.1080/00439339.2020.1729674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- T. R. Kannaki
- ICAR-Directorate of Poultry Research, Hyderabad, India
| | - Vasudevan Gowthaman
- Poultry Disease Diagnosis and Surveillance Laboratory, Veterinary College and Research Institute Campus, Namakkal, India
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29
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Mescolini G, Lupini C, Davidson I, Massi P, Tosi G, Fiorentini L, Catelli E. Molecular characterization of a Marek's disease virus strain detected in tumour-bearing turkeys. Avian Pathol 2019; 49:202-207. [PMID: 31702386 DOI: 10.1080/03079457.2019.1691715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Marek's disease (MD) is a lymphoproliferative disease caused by Gallid alphaherpesvirus 2 (GaHV-2), which primarily affects chickens. However, the virus is also able to induce tumours in turkeys, albeit less frequently than in chickens. This study reports the molecular characterization of a GaHV-2 strain detected in a flock of Italian meat-type turkeys exhibiting visceral lymphomas. Sequencing and phylogenetic analysis of the meq gene revealed that the turkey GaHV-2 has molecular features of high virulence and genetic similarity with GaHV-2 strains recently detected in Italian commercial and backyard chickens. GaHV-2 is ubiquitous among chickens despite vaccination, and chicken-to-turkey transmission is hypothesized due to the presence of broilers in neighbouring pens.RESEARCH HIGHLIGHTS A GaHV-2 strain from Italian turkeys was molecularly characterized.The turkey strain presented molecular characteristics of high virulence in its meq gene.The turkey strain was closely related to previously detected chicken strains.
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Affiliation(s)
- Giulia Mescolini
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, BO, Italy
| | - Caterina Lupini
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, BO, Italy
| | - Irit Davidson
- Division of Avian Diseases, Kimron Veterinary Institute, Bet Dagan, Israel
| | - Paola Massi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Sezione Diagnostica di Forlì, Forlì, FC, Italy
| | - Giovanni Tosi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Sezione Diagnostica di Forlì, Forlì, FC, Italy
| | - Laura Fiorentini
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Sezione Diagnostica di Forlì, Forlì, FC, Italy
| | - Elena Catelli
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, BO, Italy
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Zeng F, Wu M, Ma L, Han Z, Shi Y, Zhang Y, Liu C, Zhang S, Cong F, Liu S. Rapid and sensitive real-time recombinase polymerase amplification for detection of Marek's disease virus. Mol Cell Probes 2019; 48:101468. [PMID: 31580913 DOI: 10.1016/j.mcp.2019.101468] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/24/2019] [Accepted: 09/30/2019] [Indexed: 12/18/2022]
Abstract
Marek's disease (MD) is one of the most devastating diseases of poultry. It's caused by the highly infectious alphaherpesvirus MD virus serotype 1 (MDV-1). In this study, a rapid and easy-to-use assay based on recombinase polymerase amplification (RPA) was developed for MDV detection. Primer-probe sets targeting the highly conserved region of Meq gene were designed and applied to the RPA assay. The assay was carried out on a real-time thermostatic fluorescence detector at 39 °C for 20 min. As revealed by the results, no cross-reactions were found with the Newcastle disease virus (NDV), chicken infectious anemia virus (CAV), infectious bursal disease virus (IBDV), avian infectious bronchitis virus (IBV), infectious laryngotracheitis virus (ILTV), avain influenza virus (AIV), avian leucosis virus (ALV), avian reovirus (ARV), Marek's disease virus serotype 2 (MDV-2) and turkey herpes virus (HVT), indicating appropriate specificity of the assay. Plasmid DNA standards were used to determine the sensitivity of the assay and the detection limit was 102copies/μL. To further evaluate the clinical performance, 94 clinical samples were subjected to the RPA assay and 28 samples were tested MDV positive, suggesting that the real-time RPA assay was sufficient enough for clinical sample detection. Thus, a highly specific and sensitive real-time RPA assay was established and validated as a candidate for MDV diagnosis. Additionally, the portability of real-time RPA assay makes it suitable to be potentially applied in clinical diagnosis in the field, especially in resource-limited settings.
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Affiliation(s)
- Fanwen Zeng
- Guangdong Laboratory Animals Monitoring Institute and Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China; College of Animal Science of South China Agricultural University, Guangzhou, 510640, China
| | - Miaoli Wu
- Guangdong Laboratory Animals Monitoring Institute and Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China
| | - Lei Ma
- Guangdong Laboratory Animals Monitoring Institute and Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China
| | - Zongxi Han
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150026, China
| | - Yue Shi
- Beijing Senkang Biotech Development Co., Ltd., Beijing, 101400, China
| | - Yanping Zhang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150026, China
| | - Changjun Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150026, China
| | - Shouquan Zhang
- College of Animal Science of South China Agricultural University, Guangzhou, 510640, China.
| | - Feng Cong
- Guangdong Laboratory Animals Monitoring Institute and Guangdong Provincial Key Laboratory of Laboratory Animals, Guangzhou, 510633, China.
| | - Shengwang Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150026, China.
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31
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Mescolini G, Lupini C, Davidson I, Massi P, Tosi G, Catelli E. Marek's disease viruses circulating in commercial poultry in Italy in the years 2015-2018 are closely related by their meq gene phylogeny. Transbound Emerg Dis 2019; 67:98-107. [PMID: 31411371 DOI: 10.1111/tbed.13327] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/23/2019] [Accepted: 08/07/2019] [Indexed: 02/06/2023]
Abstract
Marek's disease (MD) is a lymphoproliferative disease important to the poultry industry worldwide; it is caused by Gallid alphaherpesvirus 2 (GaHV-2). The virulence of GaHV-2 isolates has shifted over the years from mild to virulent, very virulent and very virulent +. Nowadays the disease is controlled by vaccination, but field strains of increased virulence are emerging worldwide. Economic losses due to MD are mostly associated with its acute form, characterized by visceral lymphomas. The present study aimed to molecularly classify a group of 13 GaHV-2 strains detected in vaccinated Italian commercial chicken flocks during acute MD outbreaks, and to scrutinize the ability of predicting GaHV-2 virulence, according to the meq gene sequence. The full-length meq genes were amplified, and the obtained amino acid (aa) sequences were analysed, focusing mainly on the number of stretches of four proline molecules (PPPP) within the transactivation domain. Phylogenetic analysis was carried out with the Maximum Likelihood method using the obtained aa sequences, and the sequences of Italian strains detected in backyard flocks and of selected strains retrieved from GenBank. All the analysed strains showed 100% sequence identity in the meq gene, which encodes a Meq protein of 339 aa. The Meq protein includes four PPPP motifs in the transactivation domain and an interruption of a PPPP motif due to a proline-to-serine substitution at position 218. These features are typically encountered in highly virulent isolates. Phylogenetic analysis revealed that the analysed strains belonged to a cluster that includes high-virulence GaHV-2 strains detected in Italian backyard flocks and a hypervirulent Polish strain. Our results support the hypothesis that the virulence of field isolates can be suggested by meq aa sequence analysis.
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Affiliation(s)
- Giulia Mescolini
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Italy
| | - Caterina Lupini
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Italy
| | - Irit Davidson
- Division of Avian Diseases, Kimron Veterinary Institute, Bet Dagan, Israel
| | - Paola Massi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Sezione Diagnostica di Forlì, Forlì, Italy
| | - Giovanni Tosi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Sezione Diagnostica di Forlì, Forlì, Italy
| | - Elena Catelli
- Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia, Italy
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32
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Mescolini G, Lupini C, Felice V, Guerrini A, Silveira F, Cecchinato M, Catelli E. Molecular characterization of the meq gene of Marek's disease viruses detected in unvaccinated backyard chickens reveals the circulation of low- and high-virulence strains. Poult Sci 2019; 98:3130-3137. [PMID: 30850833 DOI: 10.3382/ps/pez095] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/13/2019] [Indexed: 11/20/2022] Open
Abstract
Marek's disease (MD) is an important lymphoproliferative disease of chickens, caused by Gallid alphaherpesvirus 2 (GaHV-2). Outbreaks are commonly reported in commercial flocks, but also in backyard chickens. Whereas the molecular characteristics of GaHV-2 strains from the commercial poultry sector have been reported, no recent data are available for the rural sector. To fill this gap, 19 GaHV-2 strains detected in 19 Italian backyard chicken flocks during suspected MD outbreaks were molecularly characterized through an analysis of the meq gene, the major GaHV-2 oncogene. The number of four consecutive prolines (PPPP) within the proline-rich repeats of the Meq transactivation domain, the proline content, and the presence of amino acid (aa) substitutions were determined. Phylogenetic analysis was performed using the Maximum Likelihood method. Sequence analysis revealed a heterogeneous population of GaHV-2 strains circulating in Italian backyard flocks. Seven strains, detected from birds affected by classical MD, showed a unique meq isoform of 418 aa with a very high number of PPPP motifs. Molecular and clinical features are suggestive of a low oncogenic potential of these strains. The remaining 12 strains, detected from flocks experiencing acute MD, transient paralysis, or sudden death, had shorter Meq protein isoforms (298 or 339 aa) with a lower number of PPPP motifs and point mutations interrupting PPPP. These features allow us to assert the high virulence of these strains. These findings reveal the circulation of low- and high-virulence GaHV-2 strains in the Italian rural sector.
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Affiliation(s)
- Giulia Mescolini
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano dell'Emilia (BO), Italy
| | - Caterina Lupini
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano dell'Emilia (BO), Italy
| | - Viviana Felice
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano dell'Emilia (BO), Italy
| | - Alessandro Guerrini
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano dell'Emilia (BO), Italy
| | - Flavio Silveira
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano dell'Emilia (BO), Italy
| | - Mattia Cecchinato
- Department of Animal Medicine, Production and Health, University of Padua, 35020 Legnaro (PD), Italy
| | - Elena Catelli
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Ozzano dell'Emilia (BO), Italy
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33
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Dunn JR, Black Pyrkosz A, Steep A, Cheng HH. Identification of Marek's disease virus genes associated with virulence of US strains. J Gen Virol 2019; 100:1132-1139. [PMID: 31184569 DOI: 10.1099/jgv.0.001288] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Marek's disease virus (MDV) is the most well-cited example of vaccine-driven virulence evolution. MDV induces a lymphoproliferative disease in chickens, which is currently controlled by widespread vaccination of flocks. Unfortunately, Marek's disease (MD) vaccines, while effective in preventing tumours, do not prevent viral replication and mutation, which has been hypothesized as the major driving force for increased MDV virulence of field strains during the past 40 years in US commercial flocks. To limit future virulence increases, there is interest in characterizing MDV strain genomes collected over the years and associating genetic variations with variation in virulence. In this study, we characterized 70 MDV genomes with known virulence by complete or targeted DNA sequencing, and identified genetic variants that showed association with virulence. Our results revealed a number of MDV genes as would be expected for a complex trait. In addition, phylogenetic analysis revealed a clear separation of strains that varied by virulence. Interestingly, high virulence isolates from the same farms persisted over years despite eradication attempts, which has implications on control efforts. Given the growing ability to bioengineer the MDV genome, it should be feasible to experimentally test whether these individual variants influence virulence markers alone or combinations. Once validated, these markers may provide an alternative to live bird testing for evaluating virulence of new MDV field strains.
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Affiliation(s)
- John R Dunn
- Avian Disease and Oncology Laboratory, Agricultural Research Service, United States Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI, 48823, USA
| | - Alexis Black Pyrkosz
- Avian Disease and Oncology Laboratory, Agricultural Research Service, United States Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI, 48823, USA
| | - Alec Steep
- Avian Disease and Oncology Laboratory, Agricultural Research Service, United States Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI, 48823, USA.,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
| | - Hans H Cheng
- Avian Disease and Oncology Laboratory, Agricultural Research Service, United States Department of Agriculture, 4279 E. Mount Hope Road, East Lansing, MI, 48823, USA
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Bell AS, Kennedy DA, Jones MJ, Cairns CL, Pandey U, Dunn PA, Szpara ML, Read AF. Molecular epidemiology of Marek's disease virus in central Pennsylvania, USA. Virus Evol 2019; 5:vey042. [PMID: 31024735 PMCID: PMC6478013 DOI: 10.1093/ve/vey042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The evolution of Marek’s disease virus (MDV, Gallid herpesvirus 2) has threatened the sustainability of poultry farming in the past and its continued evolution remains a concern. Genetic diversity is key to understanding evolution, yet little is known about the diversity of MDV in the poultry industry. Here, we investigate the diversity of MDV on 19 Pennsylvanian poultry farms over a 3-year period. Using eight polymorphic markers, we found that at least twelve MDV haplotypes were co-circulating within a radius of 40 km. MDV diversity showed no obvious spatial clustering nor any apparent clustering by bird line: all of the virus haplotypes identified on the commercial farms could be found within a single, commonly reared bird line. On some farms, a single virus haplotype dominated for an extended period of time, while on other farms the observed haplotypes changed over time. In some instances, multiple haplotypes were found simultaneously on a farm, and even within a single dust sample. On one farm, co-occurring haplotypes clustered into phylogenetically distinct clades, putatively assigned as high and low virulence pathotypes. Although the vast majority of our samples came from commercial poultry farms, we found the most haplotype diversity on a noncommercial backyard farm experiencing an outbreak of clinical Marek’s disease. Future work to explore the evolutionary potential of MDV might therefore direct efforts toward farms that harbor multiple virus haplotypes, including both backyard farms and farms experiencing clinical Marek’s disease.
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Affiliation(s)
- Andrew S Bell
- Department of Biology, The Pennsylvania State University, University Park, PA, USA.,Department of Entomology, The Pennsylvania State University, University Park, PA, USA.,Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
| | - David A Kennedy
- Department of Biology, The Pennsylvania State University, University Park, PA, USA.,Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
| | - Matthew J Jones
- Department of Biology, The Pennsylvania State University, University Park, PA, USA.,Department of Entomology, The Pennsylvania State University, University Park, PA, USA.,Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
| | - Christopher L Cairns
- Department of Biology, The Pennsylvania State University, University Park, PA, USA.,Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
| | - Utsav Pandey
- Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Patricia A Dunn
- Animal Diagnostic Laboratory, Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Moriah L Szpara
- Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Andrew F Read
- Department of Biology, The Pennsylvania State University, University Park, PA, USA.,Department of Entomology, The Pennsylvania State University, University Park, PA, USA.,Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA
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35
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He L, Li J, Zhang Y, Luo J, Cao Y, Xue C. Phylogenetic and molecular epidemiological studies reveal evidence of recombination among Marek's disease viruses. Virology 2018; 516:202-209. [PMID: 29407378 DOI: 10.1016/j.virol.2018.01.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 01/24/2018] [Accepted: 01/25/2018] [Indexed: 01/09/2023]
Abstract
Marek's disease has brought enormous loss in chicken production worldwide and the increasing virulence of Marek's disease virus (MDV) became a severe problem. To better understand the genetic basis underlying, a Chinese MDV strain HNGS101 isolated from immunized chickens was sequenced. Phylogenetic analysis implied that HNGS101 showed more relatedness to Eurasian strains than GaHV-2 circulating in North America. Recombination networks analysis showed the evidence of recombination among MDV strains, and several recombination events in the UL and US region were found. Further analysis indicated that the HNGS101 strain seemed to be generated by the recombination of the earliest Eurasian strains and North American strains in the US region, which may be responsible for the MD outbreaks in China. In summary, this study demonstrates recombination events among MDV strains [corrected], which may shed light on the mechanism of virulence enhancement.
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Affiliation(s)
- Liangliang He
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Jie Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China; School of Biology and Food Engineering, Changshu Institute of Technology, Changshu 215500, China
| | - Yun Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Jun Luo
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China; College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471003, China
| | - Yongchang Cao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Chunyi Xue
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
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36
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Puro KU, Bhattacharjee U, Baruah S, Sen A, Das S, Ghatak S, Doley S, Sanjukta R, Shakuntala I. Characterization of Marek's disease virus and phylogenetic analyses of meq gene from an outbreak in poultry in Meghalaya of Northeast India. Virusdisease 2018; 29:167-172. [PMID: 29911149 DOI: 10.1007/s13337-018-0448-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/26/2018] [Indexed: 11/25/2022] Open
Abstract
The aim of the present study was to characterize the virus from the lesions and histopathology of organs associated with mortality in Kuroiler (dual purpose variety of poultry developed and marketed by Keggfarms Pvt. Ltd, India) birds suspected of Marek's disease. Among 1047 birds from two farms of different location with 5.5 and 34% mortality, two types of lesion were observed in post mortem examination; tumors in vital organs-liver, spleen, kidney, lung and ovaries and generalized small nodular tumour in the abdominal cavity. Molecular characterization based on detection of ICP4 gene showed the presence of Marek's disease virus (MDV) from tissues and cell culture adapted isolates in Madin Darby Canine Kidney cell lines. Histopathological examination revealed multinucleated immature lymphoid cells infiltration in the organs. Phylogenetic analysis of the isolates based on meq gene showed the isolates belongs to cluster I genotype of MDV. This is for the first time the MDV virus is characterized from an outbreak in the poultry flock in farmer's field affecting production in Meghalaya state of North east India.
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Affiliation(s)
- Kekungu-U Puro
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Uttaran Bhattacharjee
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Samprity Baruah
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Arnab Sen
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Samir Das
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Sandeep Ghatak
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Sunil Doley
- 2Poultry Section, Livestock Production Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Rajkumari Sanjukta
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
| | - Ingudam Shakuntala
- 1Animal Health Division, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya 793103 India
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37
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Faiz NM, Cortes AL, Guy JS, Fletcher OJ, Cimino T, Gimeno IM. Evaluation of factors influencing the development of late Marek's disease virus-induced immunosuppression: virus pathotype and host sex. Avian Pathol 2017; 46:376-385. [PMID: 28151004 DOI: 10.1080/03079457.2017.1290214] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Marek's disease virus (MDV) is a herpesvirus that induces lymphoma and immunosuppression in chickens. MDV-induced immunosuppression (MDV-IS) is complex and can be divided into two phases: early-MDV-IS associated with cytolytic infection in the lymphoid organs in chickens lacking maternal antibodies against MDV (MAbs) and late-MDV-IS that appears later in the pathogenesis and occurs even in chickens bearing MAbs. We have recently developed a model to reproduce late-MDV-IS under laboratory conditions. This model evaluates late-MDV-IS indirectly by assessing the effect of MDV infection on the efficacy of infectious laryngotracheitis (ILT) vaccines against challenge with ILT virus. In the present study, we have used this model to investigate the role of two factors (MDV pathotype and host sex) on the development of late-MDV-IS. Five MDV strains representing three different pathotypes: virulent (vMDV; 617A, GA), very virulent (vvMDV; Md5), and very virulent plus (vv+MDV; 648A, 686), were evaluated. Only vv+ strains were able to induce late-MDV-IS. An immunosuppression rank (IS-rank) was established based on the ability of MDV to reduce the efficacy of chicken embryo origin vaccine (values go from 0 to 100, with 100 being the highest immunosuppressive ability). The IS-rank of the evaluated MDV strains ranged from 5.97 (GA) to 20.8 (617A) in the vMDV strains, 5.97 to 16.24 in the vvMDV strain Md5, and 39.08 to 68.2 in the vv+ strains 648A and 686. In this study both male and female chickens were equally susceptible to MDV-IS by vv+MDV 686. Our findings suggest that late-MDV-IS is a unique feature of vv+ strains.
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Affiliation(s)
- Nik M Faiz
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA.,b Department of Clinical Studies , College of Veterinary Medicine, Universiti Putra Malaysia , Selangor , Malaysia
| | - Aneg L Cortes
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
| | - James S Guy
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
| | - Oscar J Fletcher
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
| | | | - Isabel M Gimeno
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
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38
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Dunn JR, Reddy SM, Niikura M, Nair V, Fulton JE, Cheng HH. Evaluation and Identification of Marek's Disease Virus BAC Clones as Standardized Reagents for Research. Avian Dis 2017; 61:107-114. [DOI: 10.1637/0005-2086-61.1.107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- John R. Dunn
- United States Department of Agriculture, Agricultural Research Service, U.S. National Poultry Research Center, Avian Disease and Oncology Laboratory, East Lansing, MI 48823
| | - Sanjay M. Reddy
- College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX 77843
| | | | - Venugopal Nair
- Pirbright Institute, Pirbright, Surrey, GU24 0NF, United Kingdom
| | | | - Hans H. Cheng
- United States Department of Agriculture, Agricultural Research Service, U.S. National Poultry Research Center, Avian Disease and Oncology Laboratory, East Lansing, MI 48823
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39
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Machida Y, Murata S, Matsuyama-Kato A, Isezaki M, Taneno A, Sakai E, Konnai S, Ohashi K. Isolation and purification of Gallid herpesvirus 2 strains currently distributed in Japan. J Vet Med Sci 2016; 79:115-122. [PMID: 27725354 PMCID: PMC5289247 DOI: 10.1292/jvms.16-0329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Gallid herpesvirus 2 (GaHV-2) causes malignant lymphomas in chickens (Marek’s disease, MD). Although MD is controlled through vaccination
efforts, field isolates of GaHV-2 have increased in virulence worldwide and even cause MD in vaccinated chickens. GaHV-2 strains are classified into four
categories (mild, virulent, very virulent and very virulent +) based on the virulence exhibited in experimental infection in unvaccinated or MD-vaccinated
susceptible chickens. Although MD cases are sporadically reported in Japan, the recent field strains of GaHV-2 in Japan have not been characterized. During
isolation of recent field strains by using primary chicken kidney cell cultures, a method classically used for GaHV-2 isolation, vaccine strains were
simultaneously isolated. Therefore, it is necessary to separate vaccine strains to characterize the virulence and pathogenicity of the GaHV-2 strains currently
distributed in Japan. In this study, we prepared cell suspensions from the spleens of MD-symptomatic chickens, inoculated day-old-chicks and isolated GaHV-2
strains by primary chicken kidney cell cultures at 2−3 weeks post inoculation. The isolated strains were passaged several times on chicken embryo fibroblast
cells, and PCR analysis revealed that the isolated strains were not contaminated with vaccine strains. Moreover, the contaminant vaccine strains were completely
removed by the purification of plaques observed in chicken kidney cells. These procedures are necessary to isolate GaHV-2 field strains from vaccine strains in
order to carry out future studies to characterize these strains and glean insights into GaHV-2 virulence and pathogenicity.
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Affiliation(s)
- Yuka Machida
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Kita-18, Nishi-9, Kita-ku, Sapporo 060-0818, Japan
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40
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Faiz NM, Cortes AL, Guy JS, Fletcher OJ, West M, Montiel E, Gimeno IM. Early infection with Marek's disease virus can jeopardize protection conferred by laryngotracheitis vaccines: a method to study MDV-induced immunosuppression. Avian Pathol 2016; 45:606-615. [PMID: 27207594 DOI: 10.1080/03079457.2016.1191618] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Marek's disease virus (MDV) is a herpesvirus that induces lymphomas and immunosuppression in chickens. MDV-induced immunosuppression (MDV-IS) is divided into two phases: early-MDV-IS occurring mainly in chickens lacking maternal antibodies (MAb) against MDV and associated with lymphoid organ atrophy; and late-MDV-IS occurring once MDV enters latency and during tumour development. Our objectives were to document the impact of late-MDV-IS on commercial poultry (meat-type chickens bearing MAb against MDV and that were vaccinated or unvaccinated against MD) and to optimize a model to study late-MDV-IS under laboratory conditions. The impact of late-MDV-IS was evaluated by assessing the effect of early infection (day of age) with a very virulent plus MDV (vv+MDV) on the efficacy of chicken-embryo-origin (CEO) infectious laryngotracheitis (ILT) virus vaccine against ILT challenge. The CEO ILT vaccine was administered in water at 14 days of age and ILT virus (ILTV) challenge was done intratracheally at 30 days of age. Development of ILT was monitored by daily evaluation of clinical signs, development of gross and histological lesions in trachea, and quantification of ILTV transcripts in trachea. Infection with vv+MDV strain 648A resulted in total abrogation of protection conferred by the CEO vaccine against ILTV challenge even in chickens vaccinated at 1 day of age with either HVT, HVT+SB-1, or CVI988. Chickens exposed to vv+MDV prior to vaccination with CEO ILTV vaccine had similar (P < 0.05) clinical scores, gross lesions, histopathologic lesion scores, and load of ILTV transcripts in trachea after ILTV challenge, as chickens that were not vaccinated with CEO ILTV vaccine.
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Affiliation(s)
- Nik M Faiz
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA.,b Department of Clinical Studies , College of Veterinary Medicine, Universiti Putra Malaysia , Selangor , Malaysia
| | - Aneg L Cortes
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
| | - James S Guy
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
| | - Oscar J Fletcher
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
| | - Melissa West
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
| | | | - Isabel M Gimeno
- a Department of Population Health and Pathobiology , Veterinary School, North Carolina State University , Raleigh , NC , USA
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Hartawan R, Dharmayanti NLPI. The Meq Gene Molecular Profile of Marek’s Disease Virus Serotype 1 From Kampung and Arabic Chicken Farms in Sukabumi, West Java, Indonesia. HAYATI JOURNAL OF BIOSCIENCES 2016. [DOI: 10.1016/j.hjb.2016.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Positive Selection Drives Rapid Evolution of the meq Oncogene of Marek's Disease Virus. PLoS One 2016; 11:e0162180. [PMID: 27662574 PMCID: PMC5035050 DOI: 10.1371/journal.pone.0162180] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/18/2016] [Indexed: 11/30/2022] Open
Abstract
Marek’s disease (MD), caused by Marek’s disease virus (MDV), a poultry-borne alphaherpesvirus, is a devastating disease of poultry causing an estimated annual loss of one billion dollars to poultry producers, worldwide. Despite decades of control through vaccination, MDV field strains continue to emerge having increased virulence. The evolutionary mechanism driving the emergence of this continuum of strains to increased MDV virulence, however, remains largely enigmatic. Increase in MDV virulence has been associated with specific amino acid changes within the C-terminus domain of Mareks’s EcoRI-Q (meq)-encoded oncoprotein. In this study, we sought to determine whether the meq gene has evolved adaptively and whether past vaccination efforts have had any significant effect on the reduction or increase of MDV diversity over time. Our analysis suggests that meq is estimated to be evolving at a much faster rate than most dsDNA viruses, and is comparable with the evolutionary rate of RNA viruses. Interestingly, most of the polymorphisms in meq gene appear to have evolved under positive selection and the time of divergence at the meq locus coincides with the period during which the poultry industry had undergone transitions in management practices including the introduction and widespread use of live attenuated vaccines. Our study has revealed that the decades-long use of vaccines did not reduce MDV diversity, but rather had a stimulating effect on the emergence of field strains with increased genetic diversity until the early 2000s. During the years 2004–2005, there was an abrupt decline in the genetic diversity of field isolates followed by a recovery from this bottleneck in the year 2010. Collectively, these data suggest that vaccination seems to not have had any effect on MDV eradication, but rather had a stimulating effect on MDV emergence through adaptation.
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Pandey U, Bell AS, Renner DW, Kennedy DA, Shreve JT, Cairns CL, Jones MJ, Dunn PA, Read AF, Szpara ML. DNA from Dust: Comparative Genomics of Large DNA Viruses in Field Surveillance Samples. mSphere 2016; 1:e00132-16. [PMID: 27747299 PMCID: PMC5064450 DOI: 10.1128/msphere.00132-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 08/25/2016] [Indexed: 12/12/2022] Open
Abstract
The intensification of the poultry industry over the last 60 years facilitated the evolution of increased virulence and vaccine breaks in Marek's disease virus (MDV-1). Full-genome sequences are essential for understanding why and how this evolution occurred, but what is known about genome-wide variation in MDV comes from laboratory culture. To rectify this, we developed methods for obtaining high-quality genome sequences directly from field samples without the need for sequence-based enrichment strategies prior to sequencing. We applied this to the first characterization of MDV-1 genomes from the field, without prior culture. These viruses were collected from vaccinated hosts that acquired naturally circulating field strains of MDV-1, in the absence of a disease outbreak. This reflects the current issue afflicting the poultry industry, where virulent field strains continue to circulate despite vaccination and can remain undetected due to the lack of overt disease symptoms. We found that viral genomes from adjacent field sites had high levels of overall DNA identity, and despite strong evidence of purifying selection, had coding variations in proteins associated with virulence and manipulation of host immunity. Our methods empower ecological field surveillance, make it possible to determine the basis of viral virulence and vaccine breaks, and can be used to obtain full genomes from clinical samples of other large DNA viruses, known and unknown. IMPORTANCE Despite both clinical and laboratory data that show increased virulence in field isolates of MDV-1 over the last half century, we do not yet understand the genetic basis of its pathogenicity. Our knowledge of genome-wide variation between strains of this virus comes exclusively from isolates that have been cultured in the laboratory. MDV-1 isolates tend to lose virulence during repeated cycles of replication in the laboratory, raising concerns about the ability of cultured isolates to accurately reflect virus in the field. The ability to directly sequence and compare field isolates of this virus is critical to understanding the genetic basis of rising virulence in the wild. Our approaches remove the prior requirement for cell culture and allow direct measurement of viral genomic variation within and between hosts, over time, and during adaptation to changing conditions.
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Affiliation(s)
- Utsav Pandey
- Department of Biochemistry and Molecular Biology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Andrew S. Bell
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Daniel W. Renner
- Department of Biochemistry and Molecular Biology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - David A. Kennedy
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Jacob T. Shreve
- Department of Biochemistry and Molecular Biology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Chris L. Cairns
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Matthew J. Jones
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Patricia A. Dunn
- Department of Veterinary and Biomedical Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Andrew F. Read
- Center for Infectious Disease Dynamics, Departments of Biology and Entomology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Moriah L. Szpara
- Department of Biochemistry and Molecular Biology, Center for Infectious Disease Dynamics, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
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Sequence analysis of Meq oncogene among Indian isolates of Marek's disease herpesvirus. Meta Gene 2016; 9:230-6. [PMID: 27617224 PMCID: PMC5006142 DOI: 10.1016/j.mgene.2016.07.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/09/2016] [Accepted: 07/10/2016] [Indexed: 11/22/2022] Open
Abstract
Marek's disease (MD), caused by Marek's disease virus (MDV), is a highly contagious neoplastic disease of chicken that can be prevented by vaccination. However, in recent years many cases of vaccine failure have been reported worldwide as chickens develop symptoms of MD in spite of proper vaccination. Distinct polymorphism and point mutations in Meq gene of MDV have been reported to be associated with virulence and oncogenicity. The present study was carried out with the objective to isolate and characterize field isolates of MDV on the basis of Meq gene. Twenty five samples of suspected cases of MD were collected and processed for virus isolation in duck embryo fibroblast (DEF) primary culture where 28% (7 of 25) samples showed characteristic cytopathic effects of MDV in the form of plaques and syncytia. Additional evidence of presence of MDV in these samples was confirmed by PCR. To analyze diversity in all seven isolates of MDV, a polymorphism study was carried out by cloning and sequencing of full length of Meq gene (1020 bp). Sequence homology of 7 isolates with 23 reference strains showed 98.10-99.40% similarity in nucleotide and 95.90-98.50% similarity in amino acid sequences. Six isolates revealed 5 repeat sequences of 4 prolines (PPPP) whereas, one isolate revealed only 4 repeats. In phylogenetic analysis, these isolates formed a separate cluster showing close relatedness to the Chinese isolates. The study indicates a high mutation rate in field isolates of MDV that may be probable cause of vaccination failure.
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Mohamed MHA, El-Sabagh IM, Al-Habeeb MA, Al-Hammady YM. Diversity of Meq gene from clinical Marek's disease virus infection in Saudi Arabia. Vet World 2016; 9:572-8. [PMID: 27397979 PMCID: PMC4937047 DOI: 10.14202/vetworld.2016.572-578] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/22/2016] [Indexed: 11/19/2022] Open
Abstract
Aim: The aim of this study was to demonstrate the genomic features of Meq gene of Marek’s disease virus (MDV) recently circulating in Saudi Arabia (SA). Materials and Methods: Two poultry flocks suffering from mortalities and visceral tumors were presented to the Veterinary Teaching Hospital, King Faisal University, SA. Subjected to different diagnostic procedures: Case history, clinical signs, and necropsy as well as polymerase chain reaction followed by Meq gene sequence analysis. Results: Case history, clinical signs, and necropsy were suggestive of MDV infection. The Meq gene was successfully detected in liver and spleen of infected chickens. A 1062 bp band including the native Meq ORF in addition to a 939 bp of S-Meq (short isoform of Meq) were amplified from Saudi 01-13 and Saudi 02-13, respectively. The nucleotide and deduced amino acids sequences of the amplified Meq genes of both Saudi isolates showed distinct polymorphism when compared with the standard USA virulent isolates Md5 and GA. The sequence analysis of the S-Meq gene showed a 123 bp deletion representing 41 amino acids between two proline-rich areas without any frameshift. The Meq gene encoded four repeats of proline-rich repeats (PRRs sequences), whereas the S-Meq contains only two PRRs. Interestingly, the phylogenetic analysis revealed that both of SA MDV isolates are closely related to the MDV strains from Poland. Conclusion: The two MDV isolates contain several nucleotide polymorphisms resulting in distinct amino acid substitutions. It is suggested that migratory and wild birds, as well as world trading of poultry and its by-products, have a great contribution in the transmission of MDVs overseas.
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Affiliation(s)
- Mahmoud H A Mohamed
- Department of Clinical Studies, College of Veterinary Medicine, King Faisal University, Al-Hufof, 31982, Saudi Arabia; Department of Avian and Rabbit Medicine, Faculty of Veterinary Medicine, Zagazig University, 44519, Zagazig, Egypt
| | - Ibrahim M El-Sabagh
- Central Biotechnology Laboratory, College of Veterinary Medicine, King Faisal University, Al-Hufof, 31982, Saudi Arabia; Department of Virology, Faculty of Veterinary Medicine, Cairo University, 12211, Giza, Egypt
| | - Malik A Al-Habeeb
- Excutive Department of Risk Assessment, Saudi Food and Drug Authority, Saudi Arabia
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Lv H, Zhang Y, Sun G, Bao K, Gao Y, Qi X, Cui H, Wang Y, Li K, Gao L, Pan Q, Wang X, Liu C. Genetic evolution of Gallid herpesvirus 2 isolated in China. INFECTION GENETICS AND EVOLUTION 2016; 51:263-274. [PMID: 27112385 DOI: 10.1016/j.meegid.2016.04.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 01/12/2023]
Abstract
Gallid herpesvirus 2 (GaHV-2), which causes Marek's disease in chickens and has caused extensive economic losses, has recently evolved increased virulence in China. To better understand the genetic basis of the pathogenic characteristics changed and increased virulence, we sequenced the genomes of six new GaHV-2 strains (LCC, LTS, WC/1203, JL/1404, CC/1409, and HS/1412) isolated from chickens with failed immunisation as well as one previously isolated Chinese GaHV-2 strain, J-1. Based on a multiple sequence alignment, several characteristic point mutations were detected in the open reading frames of the Chinese isolates. In addition, two deletions and an insertion were identified at the unique short region and terminal repeat short region junctions in Chinese isolates, and the insertion was a characteristic of the new Chinese isolates. According to a phylogenetic analysis, the GaHV-2 genome diverged substantially over the last two decades in China. Based on the internal repeat long region, the new isolates were closely related to very virulent or very virulent plus strains. Additionally, the new Chinese isolates diverged from the previously isolated strains J-1 and 814. In conclusion, our results provide evidence that Chinese GaHV-2 strains contain characteristic sequences, especially the new isolates. The observed genetic divergence in the new Chinese GaHV-2 strains over the last two decades may be related to observed changes in pathogenic characteristics and virulence.
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Affiliation(s)
- Hongchao Lv
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Yanping Zhang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Guorong Sun
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Keyan Bao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Yulong Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Xiaole Qi
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Hongyu Cui
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Yongqiang Wang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Kai Li
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Li Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Qing Pan
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China
| | - Xiaomei Wang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
| | - Changjun Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
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Ralapanawe S, Walkden-Brown SW, Renz KG, Islam AFMF. Protection provided by Rispens CVI988 vaccine against Marek's disease virus isolates of different pathotypes and early prediction of vaccine take and MD outcome. Avian Pathol 2016; 45:26-37. [DOI: 10.1080/03079457.2015.1110850] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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48
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Ralapanawe S, Walkden-Brown SW, Islam AF, Renz KG. Effects of Rispens CVI988 vaccination followed by challenge with Marek’s disease viruses of differing virulence on the replication kinetics and shedding of the vaccine and challenge viruses. Vet Microbiol 2016; 183:21-9. [DOI: 10.1016/j.vetmic.2015.11.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 11/26/2022]
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49
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Zhang YP, Lv HC, Bao KY, Gao YL, Gao HL, le Qi X, Cui HY, Wang YQ, Li K, Gao L, Wang XM, Liu CJ. Molecular and pathogenicity characterization of Gallid herpesvirus 2 newly isolated in China from 2009 to 2013. Virus Genes 2015; 52:51-60. [PMID: 26611441 DOI: 10.1007/s11262-015-1264-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/17/2015] [Indexed: 10/22/2022]
Abstract
During the course of our continuous surveillance of Gallid herpesvirus 2 (GaHV-2), 44 isolates were obtained from GaHV-2-positive chickens of different flocks in China from 2009 to 2013. The meq gene, considered as a major GaHV-2 oncogene, was sequenced and was found to contain an open reading frame of 1020 nucleotides encoding a 339 amino acid (aa) polypeptide in all isolates. Compared with the GaHV-2 GA strain, the meq genes in 15.9 % (7/44) of the isolates analyzed in this study contained an aa substitution mutation at position 88 (A to T) of which is the first report. The main characteristics of Chinese GaHV-2 isolates meq genes included the substitutions K77E, D80Y, V115A, T139A, P176R, and P217A, and the aa substitution frequency at positions 139 and 176 showed an increase. To test the pathogenicity of the isolates, a pathogenicity study and a vaccination-challenge test were performed on three selected isolates (ZY/1203, WC/1203, and WC/1110) and reference strain GA. The results showed that the three isolates induced gross Marek's disease (MD) lesions in 95.0-100 % cases, which was a higher rate than that obtained for strain GA (82.4 %). Three isolates induced mortality in 10-21.1 % of specific-pathogen-free chickens, which was similar to results with strain GA (23.5 %). The commercially available CVI988 vaccine induced lower protective indices (PIs) against ZY/1203 (82.4) and WC/1110 (83.3) as compared to those against WC/1203 (100) and GA (100). These results showed an evolving trend in the meq genes of the isolates; three isolates exhibited higher morbidity as compared to the reference strain and the vaccine induced lower PIs against two isolates as compared to that against the reference strain.
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Affiliation(s)
- Yan-Ping Zhang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Hong-Chao Lv
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Ke-Yan Bao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Yu-Long Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Hong-Lei Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Xiao- le Qi
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Hong-Yu Cui
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Yong-Qiang Wang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Kai Li
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Li Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China
| | - Xiao-Mei Wang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China.
| | - Chang-Jun Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, 150001, People's Republic of China.
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50
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Wajid SJ, Walkden-Brown SW, Vanselow BA, Islam AFMF, Renz KG. In vivo characterisation of two Australian isolates of Marek's disease virus including pathology, viral load and neuropathotyping based on clinical signs. Aust Vet J 2015; 93:240-7. [PMID: 26113349 DOI: 10.1111/avj.12342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 12/03/2014] [Accepted: 12/16/2014] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the pathogenicity of Australian Marek's disease virus (MDV) isolate MPF23 (1985) against the reference strain MPF57 based on pathology, viral load and neuropathotyping on the basis of clinical signs. PROCEDURE Two MDV challenge isolates (MPF57 or MPF23) were administered to unvaccinated specific-pathogen free (SPF) layer chicks on day 5 after hatch at three challenge doses (500, 2000 or 8000 plaque-forming units (pfu)/chick). Mortality, body weight, immune organ weights, MDV load in peripheral blood lymphocytes (PBL) and clinical signs were measured to 56 days post challenge (dpc). RESULTS MPF23 was the more pathogenic of the two viruses, inducing higher mortality (81% vs 62%) and incidence of MD lesions (100% vs 76%). MPF23 induced earlier, more sustained and more severe neurological signs in the period 26-56 dpc. However, there were few differences during the 0-23 dpc used in the neuropathotyping classification under test. The observed pattern during this earlier period classified both viruses as neuropathotype B, consistent with a very virulent pathotype. MDV load in PBL at 7 and 44 dpc did not differ between virus isolates, but the load at 7 dpc was significantly and negatively associated with time to euthanasia or death. CONCLUSION MPF23 appears to be as, or more, virulent than the MDV strains isolated over the subsequent two decades. The neuropathotyping system developed in the USA did not clearly differentiate between the two isolates under test; however, extension of the period of assessment of clinical signs beyond 26 dpc did reveal clear differences.
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Affiliation(s)
- S J Wajid
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - S W Walkden-Brown
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - B A Vanselow
- NSW Department of Primary Industries, Beef Industry Centre, University of New England, Armidale, NSW, Australia
| | - A F M F Islam
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - K G Renz
- Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
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