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Lai DC, Nguyen DMT, Nguyen TT, Ngo TNT, Do DT. Co-circulation and genetic characteristics of porcine circoviruses in postweaning multisystemic wasting syndrome cases in commercial swine farms. Virusdisease 2023; 34:531-538. [PMID: 38046060 PMCID: PMC10686971 DOI: 10.1007/s13337-023-00849-4] [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: 09/19/2023] [Accepted: 10/25/2023] [Indexed: 12/05/2023] Open
Abstract
This study aimed to investigate the co-infection and genetic characteristics of Porcine circoviruses in PMWS-affected pigs in five commercial farrow-to-finish swine farms in Vietnam. By the end of 2022, the percentage of PMWS-affected pigs in these farms has increased significantly compared to previous years. The lymph node samples from ten PMWS typical cases were randomly collected to test for the presence of PRRSV, PCV2, PCV3 and PCV4. While PRRSV and PCV4 were not found in these cases, 10 and 3 out of 10 samples were positive for PCV2 and PCV3, respectively. Three farms in the study showed the co-infection of PCV2 and PCV3 in affected pigs. Besides, all PCV-positive samples were sequenced to evaluate genetic characterization of PCVs in PMWS-affected cases. Phylogenetic analysis showed that all PCV3 strains in the study were clustered into PCV3b genotype. 8 out of 10 PCV2 strains belonged to PCV2d genotype while the remaining two strains belonged to PCV2b genotypes. Two farms had co-circulation of PCV2b and PCV2d genotypes in two different age groups of pigs, which is reported for the first time in Vietnam. Several amino acid substitutions were identified in important antigenic regions in the capsid protein of the PCV2 field strains compared to vaccine strains. Taken together, the results showed the high co-prevalence of PCV3 and PCV2, and the wide genetic diversity of PCV2 field and vaccine strains may be the cause of the increased PMWS situation in these pig farms. Supplementary Information The online version contains supplementary material available at 10.1007/s13337-023-00849-4.
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Affiliation(s)
- Danh Cong Lai
- Faculty of Animal Science and Veterinary Medicine, Nong Lam University - HCMC (NLU), Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam
- Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, NE 68583 USA
| | - Duyen My Thi Nguyen
- Faculty of Animal Science and Veterinary Medicine, Nong Lam University - HCMC (NLU), Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam
| | - Toan Tat Nguyen
- Faculty of Animal Science and Veterinary Medicine, Nong Lam University - HCMC (NLU), Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam
| | - Tram Ngoc Thi Ngo
- Faculty of Animal Science and Veterinary Medicine, Nong Lam University - HCMC (NLU), Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam
| | - Duy Tien Do
- Faculty of Animal Science and Veterinary Medicine, Nong Lam University - HCMC (NLU), Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam
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Molecular Epidemic Characteristics and Genetic Evolution of Porcine Circovirus Type 2 (PCV2) in Swine Herds of Shanghai, China. Viruses 2022; 14:v14020289. [PMID: 35215883 PMCID: PMC8879946 DOI: 10.3390/v14020289] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/17/2022] [Accepted: 01/26/2022] [Indexed: 02/07/2023] Open
Abstract
Porcine Circovirus 2 (PCV2) is a crucial swine pathogen and considered a primary causative agent of porcine circovirus-associated diseases (PCVADs), posing a serious economic threat to the swine industry across globe. The world’s biggest agricultural conglomerates have teamed up to create giant commercial pig farms across Shanghai due to the proximity of this region to more affluent lean-pork markets. Since its discovery, PCV2 has displayed extraordinary genetic diversity, and its genome is swiftly evolving through a series of mutations and recombinations. However, limited information on epidemiology, molecular characteristics, vaccine cross-protection, and the co-infection rate of PCV2 with other lethal swine diseases can adversely impact the pig production in the region. To investigate the molecular epidemic characteristics and genetic evolution of PCV2, pigs with doubtful symptoms of PCVADs were sampled from various commercial pig farms with a history of PWMS and/or PDNS across Shanghai from 2014 to 2018. Our results revealed the coexistence of multiple PCV2 genotypes (PCV2b, PCV2e, and PCV2d) among Shanghai pig herds and dominance of PCV2d among them. We also found critical amino acid substitutions in epitope regions of important capsid proteins in PCV2 isolates involved in viral replication and host immune escape. Spotted mutations may favor the prevalence and survival of various PCV2 genotypes despite availability of commercial vaccines. This study also provides insight into the co-infection status of PCV2 with major lethal swine viral diseases such as PPV and PPRSV. Collectively, these investigations will contribute to understanding the molecular epidemiology and evolution of PCV2 across the region.
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Luo Q, Ahmed W, Dai Y, Mohsin A, Hang H, Zhuang Y, Guo M. Evaluation of a Virus-like Nanoparticle Porcine Circovirus Type-2 (PCV2) Capsid Protein Fused with the Pig Immunoglobulin Fc Fragment as a Novel Vaccine Candidate against PCV2 in Mice. Vaccines (Basel) 2021; 9:1128. [PMID: 34696236 PMCID: PMC8540293 DOI: 10.3390/vaccines9101128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 11/16/2022] Open
Abstract
Porcine circovirus Type 2 (PCV2) is a primary etiological pathogen of post-weaning multi-systemic wasting syndrome (PMWS). The capsid protein of PCV2 is the crucial immunogenic protein which can induce antibody generation and immune responses. However, there is still a lack of efficient PCV2 vaccines with high immunogenicity. In the current study, we developed a novel engineered PCV2 capsid (∆1-41aa)-pFc fusion protein (PCFP), which comprised a truncated capsid protein of PCV2 and a porcine IgG Fc fragment, fused to the capsid protein of PCV2 at the C-terminus. We found that this novel fusion protein could auto-assemble into virus-like nanoparticles with an estimated mean diameter of 22.6 nm, characterized by transmission electron microscopy. Immunization of BALB/c mice with this fusion protein significantly increased the production levels of anti-PCV2-capsid protein antibody in serum. Besides, the virus-like nanoparticles, PCFP was demonstrated to induce efficient cellular immune responses in mice, as evident by the high specific T cell reactivity to the PCFP fusion protein and the high production of the immune cytokines IFN-γ and IL-10 in an ex vivo re-stimulation system. Collectively, these findings demonstrate that the PCV2 truncated capsid subunit Fc-fusion protein can induce both cellular and humoral immune responses, and it displays great application potential.
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Affiliation(s)
| | | | | | | | | | | | - Meijin Guo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; (Q.L.); (W.A.); (Y.D.); (A.M.); (H.H.); (Y.Z.)
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Link EK, Eddicks M, Nan L, Ritzmann M, Sutter G, Fux R. Discriminating the eight genotypes of the porcine circovirus type 2 with TaqMan-based real-time PCR. Virol J 2021; 18:70. [PMID: 33827614 PMCID: PMC8028161 DOI: 10.1186/s12985-021-01541-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 03/26/2021] [Indexed: 01/09/2023] Open
Abstract
Background The porcine circovirus type 2 (PCV2) is divided into eight genotypes including the previously described genotypes PCV2a to PCV2f and the two new genotypes PCV2g and PCV2h. PCV2 genotyping has become an important task in molecular epidemiology and to advance research on the prophylaxis and pathogenesis of PCV2 associated diseases. Standard genotyping of PCV2 is based on the sequencing of the viral genome or at least of the open reading frame 2. Although, the circovirus genome is small, classical sequencing is time consuming, expensive, less sensitive and less compatible with mass testing compared with modern real-time PCR assays. Here we report about a new PCV2 genotyping method using qPCR. Methods Based on the analysis of several hundred PCV2 full genome sequences, we identified PCV2 genotype specific sequences or single-nucleotide polymorphisms. We designed six TaqMan PCR assays that are specific for single genotypes PCV2a to PCV2f and two qPCRs targeting two genotypes simultaneously (PCV2g/PCV2d and PCV2h/PCV2c). To improve specific binding of oligonucleotide primers and TaqMan probes, we used locked nucleic acid technology. We evaluated amplification efficiency, diagnostic sensitivity and tested assay specificity for the respective genotypes. Results All eight PCV2 genotype specific qPCRs demonstrated appropriate amplification efficiencies between 91 and 97%. Testing samples from an epidemiological field study demonstrated a diagnostic sensitivity of the respective genotype specific qPCR that was comparable to a highly sensitive pan-PCV2 qPCR system. Genotype specificity of most qPCRs was excellent. Limited unspecific signals were obtained when a high viral load of PCV2b was tested with qPCRs targeting PCV2d or PCV2g. The same was true for the PCV2a specific qPCR when high copy numbers of PCV2d were tested. The qPCR targeting PCV2h/PCV2c showed some minor cross-reaction with PCV2d, PCV2f and PCV2g. Conclusion Genotyping of PCV2 is important for routine diagnosis as well as for epidemiological studies. The introduced genotyping qPCR system is ideal for mass testing and should be a valuable complement to PCV2 sequencing, especially in the case of simultaneous infections with multiple PCV2 genotypes, subclinically infected animals or research studies that require large sample numbers.
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Affiliation(s)
- Ellen Kathrin Link
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Veterinärstrasse 13, 80539, Munich, Germany
| | - Matthias Eddicks
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Sonnenstrasse 16, 85764, Oberschleissheim, Germany
| | - Liangliang Nan
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Veterinärstrasse 13, 80539, Munich, Germany
| | - Mathias Ritzmann
- Clinic for Swine at the Centre for Clinical Veterinary Medicine, LMU Munich, Sonnenstrasse 16, 85764, Oberschleissheim, Germany
| | - Gerd Sutter
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Veterinärstrasse 13, 80539, Munich, Germany
| | - Robert Fux
- Division of Virology, Department of Veterinary Sciences, LMU Munich, Veterinärstrasse 13, 80539, Munich, Germany.
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5
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Zheng G, Lu Q, Wang F, Xing G, Feng H, Jin Q, Guo Z, Teng M, Hao H, Li D, Wei X, Zhang Y, Deng R, Zhang G. Phylogenetic analysis of porcine circovirus type 2 (PCV2) between 2015 and 2018 in Henan Province, China. BMC Vet Res 2020; 16:6. [PMID: 31910824 PMCID: PMC6947828 DOI: 10.1186/s12917-019-2193-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/25/2019] [Indexed: 12/16/2022] Open
Abstract
Background Porcine circovirus type 2 (PCV2) is the pathogen of porcine circovirus associated diseases (PCVAD) and one of the main pathogens in the global pig industry, which has brought huge economic losses to the pig industry. In recent years, there has been limited research on the prevalence of PCV2 in Henan Province. This study investigated the genotype and evolution of PCV2 in this area. Results We collected 117 clinical samples from different regions of Henan Province from 2015 to 2018. Here, we found that the PCV2 infection rate of PCV2 was 62.4%. Thirty-seven positive clinical samples were selected to amplify the complete genome of PCV2 and were sequenced. Based on the phylogenetic analysis of PCV2 ORF2 and complete genome, it was found that the 37 newly detected strains belonged to PCV2a (3 of 37), PCV2b (21 of 37) and PCV2d (13 of 37), indicating the predominant prevalence of PCV2b and PCV2d strains. In addition, we compared the amino acid sequences and found several amino acid mutation sites among different genotypes. Furthermore, the results of selective pressure analysis showed that there were 5 positive selection sites. Conclusions This study indicated the genetic diversity, molecular epidemiology and evolution of PCV2 genotypes in Henan Province during 2015–2018.
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Affiliation(s)
- Guanmin Zheng
- College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou, 450002, China.,Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Qingxia Lu
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Fangyu Wang
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Guangxu Xing
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Hua Feng
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Qianyue Jin
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Zhenhua Guo
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Man Teng
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Huifang Hao
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Dongliang Li
- College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou, 450002, China.,Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Xin Wei
- College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou, 450002, China.,Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Yuhang Zhang
- College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou, 450002, China.,Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Ruiguang Deng
- Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China
| | - Gaiping Zhang
- College of Animal Husbandry and Veterinary Science, Henan Agricultural University, Zhengzhou, 450002, China. .,Key Laboratory of Animal Immunology of the Ministry of Agriculture, Henan Provincial Key Laboratory of Animal Immunology, Henan Academy of Agricultural Sciences, Huayuan Road No. 116, Zhengzhou, 450002, China. .,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
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6
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Affiliation(s)
- Yashpal Singh Malik
- ICAR-Indian Veterinary Research Institute (ICAR-IVRI), Izatnagar, Uttar Pradesh India
| | - Raj Kumar Singh
- ICAR-Indian Veterinary Research Institute (ICAR-IVRI), Izatnagar, Uttar Pradesh India
| | - Mahendra Pal Yadav
- ICAR-Indian Veterinary Research Institute (ICAR-IVRI), Izatnagar, Uttar Pradesh, India, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, India
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7
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Cruz TF, Magro AJ, de Castro AMMG, Pedraza-Ordoñez FJ, Tsunemi MH, Perahia D, Araujo JP. In vitro and in silico studies reveal capsid-mutant Porcine circovirus 2b with novel cytopathogenic and structural characteristics. Virus Res 2018; 251:22-33. [PMID: 29730308 DOI: 10.1016/j.virusres.2018.04.019] [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: 01/13/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 12/20/2022]
Abstract
Porcine circovirus 2 (PCV2) is an icosahedral, non-enveloped, and single-stranded circular DNA virus that belongs to the family Circoviridae, genus Circovirus, and is responsible for a complex of different diseases defined as porcine circovirus diseases (PCVDs). These diseases - including postweaning multisystemic wasting syndrome (PMWS), enteric disease, respiratory disease, porcine dermatitis and nephropathy syndrome (PDNS), and reproductive failure - are responsible for large economic losses in the pig industry. After serial passages in swine testicle (ST) cells of a wild-type virus isolated from an animal with PMWS, we identified three PCV2b viruses with capsid protein (known as Cap protein) cumulative mutations, including two novel mutants. The mutant viruses were introduced into new ST cell cultures for reisolation and showed, in comparison to the wild-type PCV2b, remarkable viral replication efficiency (> 1011 DNA copies/ml) and cell death via necrosis, which were clearly related to the accretion of capsid protein mutations. The analysis of a Cap protein/capsid model showed that the mutated residues were located in solvent-accessible positions on the external PCV2b surface. Additionally, the mutated residues were found in linear epitopes and participated in pockets on the capsid surface, indicating that these residues could also be involved in antibody recognition. Taking into account the likely natural emergence of PCV2b variants, it is possible to consider that the results of this work increase knowledge of Circovirus biology and could help to prevent future serious cases of vaccine failure that could lead to heavy losses to the swine industry.
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Affiliation(s)
- Taís Fukuta Cruz
- Departamento de Microbiologia e Imunologia, Instituto de Biociências (IB), Universidade Estadual Paulista (Unesp), Botucatu, São Paulo, Brazil; Instituto de Biotecnologia (IBTEC), Universidade Estadual Paulista (Unesp), Botucatu, São Paulo, Brazil.
| | - Angelo José Magro
- Instituto de Biotecnologia (IBTEC), Universidade Estadual Paulista (Unesp), Botucatu, São Paulo, Brazil; Departamento de Bioprocessos e Biotecnologia, Faculdade de Ciências Agronômicas (FCA), Universidade Estadual Paulista (Unesp), Botucatu, São Paulo, Brazil.
| | - Alessandra M M G de Castro
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Universidade de São Paulo (USP), São Paulo, São Paulo, Brazil
| | | | - Miriam Harumi Tsunemi
- Departamento de Bioestatística, Instituto de Biociências (IB), Universidade Estadual Paulista (Unesp), Botucatu, São Paulo, Brazil
| | - David Perahia
- Laboratoire de Biologie et de Pharmacologie Appliquée, ENS Cachan/Université Paris-Saclay, Cachan, France.
| | - João Pessoa Araujo
- Departamento de Microbiologia e Imunologia, Instituto de Biociências (IB), Universidade Estadual Paulista (Unesp), Botucatu, São Paulo, Brazil; Instituto de Biotecnologia (IBTEC), Universidade Estadual Paulista (Unesp), Botucatu, São Paulo, Brazil.
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8
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Qu T, Li R, Yan M, Luo B, Yang T, Yu X. High prevalence of PCV2d in Hunan province, China: a retrospective analysis of samples collected from 2006 to 2016. Arch Virol 2018; 163:1897-1906. [PMID: 29602974 DOI: 10.1007/s00705-018-3823-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 03/14/2018] [Indexed: 12/21/2022]
Abstract
Porcine circovirus 2 (PCV2) has been widely prevailing in China since the first report in 2001, causing huge economic losses to the pig industry. In the present study, 674 samples were collected from 2006 to 2016 in Hunan province, and 62% were positive for PCV2. An increase was observed from 2006 to 2011 (72.1%-89.1%), and a decrease was observed from 2012 to 2016 (78.9%-36.8%). The prevalence of genotype PCV2a, PCV2b, and PCV2d was 0, 44.7% and 67%, respectively. During 2006-2007, PCV2b was the main genotype circulating in Hunan, while, in 2008, PCV2d became the predominant one. Coinfection with PCV2b and PCV2d was observed frequently, and the positive rates of coinfection ranged from 6.3% to 18.9% during 2006-2016. The complete genome was sequenced for 54 positive samples, and four were identified as PCV2b-1, 22 as PCV2b-2, four as PCV2d-1 and 24 as PCV2d-2, based on phylogenetic analysis of the complete genome and ORF2 region. Recombination analysis using the complete genome sequences of these isolates revealed a high recombination rate of 27.7% (17/54), and showed that recombination occurred mainly in the ORF1 region. This shows that the prevalence of PCV2 has clearly decreased in recent years and that PCV2d has become a predominant genotype since 2008. In addition, frequent recombination events were observed in the PCV2 isolates from Hunan, China.
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Affiliation(s)
- Tailong Qu
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Runcheng Li
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Meijun Yan
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Binyu Luo
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Taotao Yang
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Xinglong Yu
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410128, Hunan, China.
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A Novel Porcine Circovirus Distantly Related to Known Circoviruses Is Associated with Porcine Dermatitis and Nephropathy Syndrome and Reproductive Failure. J Virol 2016; 91:JVI.01879-16. [PMID: 27795441 DOI: 10.1128/jvi.01879-16] [Citation(s) in RCA: 372] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 10/20/2016] [Indexed: 01/21/2023] Open
Abstract
Porcine circovirus-associated disease (PCVAD) is clinically manifested by postweaning multisystemic wasting syndrome (PMWS), respiratory and enteric disease, reproductive failure, and porcine dermatitis and nephropathy syndrome (PDNS). Porcine circovirus 2 (PCV2) is an essential component of PCVAD, although an etiologic role in PDNS is not well established. Here, a novel circovirus, designated porcine circovirus 3 (PCV3), was identified in sows that died acutely with PDNS-like clinical signs. The capsid and replicase proteins of PCV3 are only 37% and 55% identical to PCV2 and bat circoviruses, respectively. Aborted fetuses from sows with PDNS contained high levels of PCV3 (7.57 × 107 genome copies/ml), and no other viruses were detected by PCR and metagenomic sequencing. Immunohistochemistry (IHC) analysis of sow tissue samples identified PCV3 antigen in skin, kidney, lung, and lymph node samples localized in typical PDNS lesions, including necrotizing vasculitis, glomerulonephritis, granulomatous lymphadenitis, and bronchointerstitial pneumonia. Further study of archived PDNS tissue samples that were negative for PCV2 by IHC analysis identified 45 of 48 that were PCV3 positive by quantitative PCR (qPCR), with 60% of a subset also testing positive for PCV3 by IHC analysis. Analysis by qPCR of 271 porcine respiratory disease diagnostic submission samples identified 34 PCV3-positive cases (12.5%), and enzyme-linked immunosorbent assay detection of anti-PCV3 capsid antibodies in serum samples found that 46 (55%) of 83 samples tested were positive. These results suggest that PCV3 commonly circulates within U.S. swine and may play an etiologic role in reproductive failure and PDNS. Because of the high economic impact of PCV2, this novel circovirus warrants further studies to elucidate its significance and role in PCVAD. IMPORTANCE While porcine circovirus 2 (PCV2) was first identified in sporadic cases of postweaning multisystemic wasting syndrome in Canada in the early 1990s, an epidemic of severe systemic disease due to PCV2 spread worldwide in the ensuing decade. Despite being effectively controlled by commercial vaccines, PCV2 remains one of the most economically significant viruses of swine. Here, a novel porcine circovirus (PCV3) that is distantly related to known circoviruses was identified in sows with porcine dermatitis and nephropathy syndrome (PDNS) and reproductive failure. PCV2, which has previously been associated with these clinical presentations, was not identified. High levels of PCV3 nucleic acid were observed in aborted fetuses by quantitative PCR, and PCV3 antigen was localized in histologic lesions typical of PDNS in sows by immunohistochemistry (IHC) analysis. PCV3 was also identified in archival PDNS diagnostic samples that previously tested negative for PCV2 by IHC analysis. The emergence of PCV3 warrants further investigation.
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Imai DM, Cornish J, Nordhausen R, Ellis J, MacLachlan NJ. Renal Tubular Necrosis and Interstitial Hemorrhage (“Turkey-Egg Kidney”) in a Circovirus-Infected Yorkshire Cross Pig. J Vet Diagn Invest 2016; 18:496-9. [PMID: 17037624 DOI: 10.1177/104063870601800516] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A juvenile Yorkshire cross pig with rapidly progressive acute renal failure was submitted for necropsy. There was marked edema and disseminated petechiation of both kidneys, producing the “turkey-egg” appearance that is characteristic of exotic diseases such as African and classical swine fever. Microscopic findings included renal tubular epithelial necrosis with extensive interstitial edema and hemorrhage; lymphoplasmacytic, eosinophilic, and histiocytic tubulointerstitial nephritis; and numerous botryoid intracytoplasmic inclusions within the renal tubular epithelium and interstitial macrophages. Porcine circovirus 2 (PCV2) was readily identified within these lesions by both PCV2-specific immunohistochemistical staining and electron microscopy. Tests for African and classical swine fever viruses, as well as bacterial cultures, were negative. The striking renal lesions in this pig were attributed to PCV2 infection and are distinct from those that are typical of other PCV2-associated diseases.
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Affiliation(s)
- Denise M Imai
- Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, One Garrod Drive, Davis, CA 95616, USA
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11
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Kouokam Fotso GB, Bernard C, Bigault L, de Boisséson C, Mankertz A, Jestin A, Grasland B. The expression level of gC1qR is down regulated at the early time of infection with porcine circovirus of type 2 (PCV-2) and gC1qR interacts differently with the Cap proteins of porcine circoviruses. Virus Res 2016; 220:21-32. [PMID: 27063333 DOI: 10.1016/j.virusres.2016.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 04/04/2016] [Accepted: 04/06/2016] [Indexed: 01/30/2023]
Abstract
Porcine circoviruses (PCV) are small, non-enveloped single-stranded DNA-viruses. Porcine circovirus type 2 (PCV-2) is the causal agent of post-weaning multisystemic wasting syndrome (PMWS) whereas porcine circovirus of type 1 (PCV-1) is non- pathogenic. gC1qR is a membrane-located receptor of the complement protein subunit C1q and interacts with PCV capsid proteins. The mechanisms associated with the triggering of PMWS are not well known and gC1qR may have a role in the life cycle and eventually in the pathogenicity of PCV. The objectives of this study were to determine the level of expression of gC1qR during early PCV-2 infection, to determine the region of PCV-2 capsid protein (Cap) required for the interaction with gC1qR and to evaluate the interaction of gC1qR with Cap proteins of different PCV strains. The results indicate that gC1qR transcripts are downregulated in the tonsils and the tracheo-bronchial lymph nodes of piglets infected by PCV-2 at the early time of the infection. The N-terminal amino acids (a.a. 1-59) of PCV-2b Cap, an arginine rich region, are involved in the interaction with gC1qR. Porcine gC1qR interacts with Cap proteins of two pathogenic viral strains, PCV-2a and PCV-2b, while interaction has been observed with only one Cap protein of two investigated strains of PCV-1. The amino acids 30 and 49 of PCV-1Cap, solely, were not responsible of the difference of interaction observed. We have also shown that gC1qR interacts strongly with PCV-2Caps and PCV-1 GER Cap. This result suggests that the different interaction of gC1qR with PCV Cap proteins may have an impact on the pathogenicity of the PCV.
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Affiliation(s)
- Guy Baudry Kouokam Fotso
- Anses, Laboratory of Ploufragan/Plouzané, Unit of viral genetic and biosafety, Ploufragan, France
| | - Cécilia Bernard
- Anses, Laboratory of Ploufragan/Plouzané, Unit of viral genetic and biosafety, Ploufragan, France
| | - Lionel Bigault
- Anses, Laboratory of Ploufragan/Plouzané, Unit of viral genetic and biosafety, Ploufragan, France
| | - Claire de Boisséson
- Anses, Laboratory of Ploufragan/Plouzané, Unit of viral genetic and biosafety, Ploufragan, France
| | - Annette Mankertz
- Robert Koch institute, Division of viral infection, Berlin, Germany
| | - André Jestin
- Anses, Laboratory of Ploufragan/Plouzané, Unit of viral genetic and biosafety, Ploufragan, France
| | - Béatrice Grasland
- Anses, Laboratory of Ploufragan/Plouzané, Unit of viral genetic and biosafety, Ploufragan, France.
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12
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Genetic diversity of porcine circovirus type 2 and implications for detection and control. Res Vet Sci 2015; 103:179-86. [DOI: 10.1016/j.rvsc.2015.10.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 09/26/2015] [Accepted: 10/17/2015] [Indexed: 12/26/2022]
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13
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Nainys J, Lasickiene R, Petraityte-Burneikiene R, Dabrisius J, Lelesius R, Sereika V, Zvirbliene A, Sasnauskas K, Gedvilaite A. Generation in yeast of recombinant virus-like particles of porcine circovirus type 2 capsid protein and their use for a serologic assay and development of monoclonal antibodies. BMC Biotechnol 2014; 14:100. [PMID: 25487652 PMCID: PMC4265424 DOI: 10.1186/s12896-014-0100-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/18/2014] [Indexed: 11/30/2022] Open
Abstract
Background Porcine circovirus type 2 (PCV2) is considered to be an important emerging pathogen associated with a number of different syndromes and diseases in pigs known as PCV2-associated diseases. It has been responsible for significant mortality among pigs and remains a serious economic problem to the swine industry worldwide leading to significant negative impacts on profitability of pork production. Results In this study we have demonstrated that PCV2 capsid (Cap) protein based virus-like particles (VLPs) were efficiently produced in yeast S. cerevisiae and induced production of monoclonal antibodies (MAbs) reactive with virus-infected cells. Moreover, PCV2 Cap VLPs served as a highly specific recombinant antigen for the development of an indirect IgG PCV2 Cap VLP-based ELISA for the detection of virus-specific IgG antibodies in swine sera. Four hundred-nine serum samples collected from pigs in Lithuania were tested for PCV2-specific IgG to determine the sensitivity and specificity of the newly developed ELISA in parallel using a commercial SERELISA test as a gold standard. From 409 tested serum samples, 297 samples were positive by both assays. Thirty-nine sera from 112 serum samples were determined as negative by SERELISA but were found to be positive both in the newly developed indirect IgG PCV2 Cap VLP-based ELISA and the PCR test. Conclusions We have demonstrated that S. cerevisiae expression system is an alternative to insect/baculovirus expression system for production of homogenous in size and shape PCV2 Cap protein-based VLPs similar to native virions. Yeast expression system tolerated native virus genes encoding PCV2 Cap protein variants as well as the codon-optimized gene. Moreover, yeast-derived PCV2 Cap VLPs were capable to induce the generation of PCV2-specific MAbs that did not show any cross-reactivity with PCV1-infected cells. The high sensitivity and specificity of the indirect IgG PCV2 Cap VLP-based ELISA clearly suggested that this assay is potentially useful diagnostic tool for screening PCV2–suspected samples.
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Affiliation(s)
- Juozas Nainys
- Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241, Vilnius, Lithuania.
| | - Rita Lasickiene
- Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241, Vilnius, Lithuania.
| | | | - Jonas Dabrisius
- Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241, Vilnius, Lithuania.
| | - Raimundas Lelesius
- Institute of Microbiology and Virology, Veterinary Faculty of Veterinary Academy, Lithuanian University of Health Sciences, Tilzes 18, LT-47181, Kaunas, Lithuania.
| | - Vilimas Sereika
- Institute of Microbiology and Virology, Veterinary Faculty of Veterinary Academy, Lithuanian University of Health Sciences, Tilzes 18, LT-47181, Kaunas, Lithuania.
| | - Aurelija Zvirbliene
- Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241, Vilnius, Lithuania.
| | - Kestutis Sasnauskas
- Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241, Vilnius, Lithuania.
| | - Alma Gedvilaite
- Institute of Biotechnology, Vilnius University, Graiciuno 8, LT-02241, Vilnius, Lithuania.
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14
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Current understanding of genomic DNA of porcine circovirus type 2. Virus Genes 2014; 49:1-10. [DOI: 10.1007/s11262-014-1099-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 06/20/2014] [Indexed: 01/25/2023]
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15
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Phylogenetic comparison of porcine circovirus type 2 (PCV2) and porcine reproductive respiratory syndrome virus (PRRSV) strains detected in domestic pigs until 2008 and in 2012 in Croatia. Ir Vet J 2014; 67:9. [PMID: 24839544 PMCID: PMC4024209 DOI: 10.1186/2046-0481-67-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 04/28/2014] [Indexed: 11/27/2022] Open
Abstract
Background Porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) have been present for the last 2 decades in Croatia, causing large economical losses in the pig production. The clinical features of the infections are mostly manifested by the development of respiratory problems, weight loss and poor growth performance, as well as reproductive failure in pregnant sows. Even though the infections are continuously recognized in some regions in Croatia, the heterogeneity of the detected viral strains from 2012 has not yet been investigated. The objective of this study was to compare virus strains of PCV2 and PRRSV detected until 2008 in Croatia with strains isolated in 2012 to gain a better epidemiological understanding of these two infections. Results PCV2 and PRRSV strains detected in 2012 in fattening pigs from regions where these two diseases have been previously described were compared to strains that have been detected in the same regions within the past two decades. The phylogenetic analysis revealed that the circulating PCV2 and PRRSV strains are distantly related to the previously described Croatian viral strains. However, when compared to known isolates from the GenBank a high genetic identity of PRRSV isolates with isolates from Hungary, Denmark and the Netherlands was found. Conclusion The results of this study reveal that even though PCV2 and PRRSV are constantly present in the investigated regions in Croatia, the viral strains found in 2012 genetically differ from those detected in earlier years. This indicates that new entries into the pig population appeared with regard to both infections, probably as a result of pig trade.
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16
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Huang Y, Zhang X, Du Q, Wang F, Zhao X, Zhang W, Tong D. Preclinical detection of porcine circovirus type 2 infection using an ultrasensitive nanoparticle DNA probe-based PCR assay. PLoS One 2014; 9:e97869. [PMID: 24842840 PMCID: PMC4026479 DOI: 10.1371/journal.pone.0097869] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 04/25/2014] [Indexed: 12/03/2022] Open
Abstract
Porcine circovirus type 2 (PCV2) has emerged as one of the most important pathogens affecting swine production globally. Preclinical identification of PCV2 is very important for effective prophylaxis of PCV2-associated diseases. In this study, we developed an ultrasensitive nanoparticle DNA probe-based PCR assay (UNDP-PCR) for PCV2 detection. Magnetic microparticles coated with PCV2 specific DNA probes were used to enrich PCV2 DNA from samples, then gold nanoparticles coated with PCV2 specific oligonucleotides were added to form a sandwich nucleic acid-complex. After the complex was formed, the oligonucleotides were released and characterized by PCR. This assay exhibited about 500-fold more sensitive than conventional PCR, with a detection limit of 2 copies of purified PCV2 genomic DNA and 10 viral copies of PCV2 in serum. The assay has a wide detection range for all of PCV2 genotypes with reliable reproducibility. No cross-reactivity was observed from the samples of other related viruses including porcine circovirus type 1, porcine parvovirus, porcine pseudorabies virus, porcine reproductive and respiratory syndrome virus and classical swine fever virus. The positive detection rate of PCV2 specific UNDP-PCR in 40 preclinical field samples was 27.5%, which appeared greater than that by conventional and real-time PCR and appeared application potency in evaluation of the viral loads levels of preclinical infection samples. The UNDP-PCR assay reported here can reliably rule out false negative results from antibody-based assays, provide a nucleic acid extraction free, specific, ultrasensitive, economic and rapid diagnosis method for preclinical PCV2 infection in field, which may help prevent large-scale outbreaks.
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Affiliation(s)
- Yong Huang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Xiujuan Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Qian Du
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Fengyu Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Xiaomin Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Wenlong Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P. R. China
| | - Dewen Tong
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, P. R. China
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17
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Zhai SL, Chen SN, Xu ZH, Tang MH, Wang FG, Li XJ, Sun BB, Deng SF, Hu J, Lv DH, Wen XH, Yuan J, Luo ML, Wei WK. Porcine circovirus type 2 in China: an update on and insights to its prevalence and control. Virol J 2014; 11:88. [PMID: 24885983 PMCID: PMC4031328 DOI: 10.1186/1743-422x-11-88] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 05/01/2014] [Indexed: 12/30/2022] Open
Abstract
Currently, porcine circovirus type 2 (PCV2) is considered the major pathogen of porcine circovirus associated-diseases (PCVAD) that causes large economic losses for the swine industry in the world annually, including China. Since the first report of PCV2 in 1998, it has been drawing tremendous attention for the government, farming enterprises, farmers, and veterinary practitioners. Chinese researchers have conducted a number of molecular epidemiological work on PCV2 by molecular approaches in the past several years, which has resulted in the identification of novel PCV2 genotypes and PCV2-like agents as well as the description of new prevalence patterns. Since late 2009, commercial PCV2 vaccines, including the subunit vaccines and inactivated vaccines, have already been used in Chinese swine farms. The aim of this review is to update the insights into the prevalence and control of PCV2 in China, which would contribute to understanding the epidemiology, control measures and design of novel vaccines for PCV2.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Man-Lin Luo
- College of Veterinary Medicine, South China Agricultural University, No, 483 Wushan Road, Tianhe District, Guangzhou 510642, China.
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18
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Abstract
Shandong is a porcine circovirus 2b (PCV2b) strain that was isolated and purified from tissue samples from pigs with postweaning multisystemic wasting syndrome (PMWS) in the Shandong Province of China. Here, we report the complete genome sequence of strain Shandong, which may aid in understanding the molecular characteristics of this strain.
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19
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Construction and immunogenicity of recombinant swinepox virus expressing capsid protein of PCV2. Vaccine 2012; 30:6307-13. [DOI: 10.1016/j.vaccine.2012.07.082] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 07/21/2012] [Accepted: 07/30/2012] [Indexed: 11/17/2022]
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20
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Saha D, Lefebvre DJ, Ooms K, Huang L, Delputte PL, Van Doorsselaere J, Nauwynck HJ. Single amino acid mutations in the capsid switch the neutralization phenotype of porcine circovirus 2. J Gen Virol 2012; 93:1548-1555. [DOI: 10.1099/vir.0.042085-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
Porcine circovirus 2 (PCV2) is the causative agent of porcine circovirus-associated diseases in pigs. Previously, it was demonstrated that mAbs 16G12, 38C1, 63H3 and 94H8 directed against the PCV2 capsid protein recognize PCV2 strains Stoon-1010 (PCV2a), 48285 (PCV2b), 1121 (PCV2a), 1147 (PCV2b) and II9F (PCV2b), but only neutralize Stoon-1010 and 48285. This points to the existence of two distinct PCV2 neutralization phenotypes: phenotype α (mAb recognition with neutralization; Stoon-1010 and 48285) and phenotype β (mAb recognition without neutralization; 1121, 1147 and II9F). In the present study, amino acids that are important in determining the neutralization phenotype were identified in the capsid. Mutation of T at position 190 to A in strain 48285 (phenotype α) resulted in a capsid resembling that of strain 1147 (phenotype β) and caused a loss of neutralization (switch from α to β). Mutations of P at position 151 to T and A at position 190 to T in strain II9F (phenotype β) resulted in a capsid resembling that of strain 48285 (phenotype α) and gave a gain of neutralization (switch from β to α). Mutations of T at position 131 to P and of E at position 191 to R in Stoon-1010 (phenotype α) changed the capsid into that of 1121 (phenotype β) and reduced neutralization (switch from α to β). This study demonstrated that single amino acid changes in the capsid result in a phenotypic switch from α to β or β to α.
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Affiliation(s)
- Dipongkor Saha
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | | | - Karen Ooms
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Liping Huang
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Peter L. Delputte
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Jan Van Doorsselaere
- Department of Health Care and Biotechnology, KATHO Catholic University College of South-West Flanders, Wilgenstraat 32, 8800 Roeselare, Belgium
| | - Hans J. Nauwynck
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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21
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Wieland B, Werling D, Nevel A, Rycroft A, Demmers TG, Wathes CM, Grierson S, Cook AJC, Done SH, Armstrong D, Wathes CM. Porcine circovirus type 2 infection before and during an outbreak of postweaning multisystemic wasting syndrome on a pig farm in the UK. Vet Rec 2012; 170:596. [PMID: 22645151 DOI: 10.1136/vr.100276] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The presence of porcine circovirus type 2 (PCV-2) and other pathogens before and during an outbreak of postweaning multisystemic wasting syndrome (PWMS) in pigs is evaluated in this study. At the time of the outbreak on a large commercial pig farm in the UK, serum samples and data were collected in two independent on-going research projects, one in weaned pigs and the other in sows. Serum samples of growing pigs and sows were PCV-2-antibody and PCR positive before and during the PMWS outbreak. Upon sequencing, PCV-2 isolates collected before the outbreak were identified as PCV-2a, and isolates collected during the outbreak were identified as PCV-2b, suggesting a shift of PCV-2 genotypes present on the farm. Pigs in the weaner study were from sows originating from different breeders and an association of sow origin and PCV-2 serostatus in offspring was found. Further, pigs had higher odds to be PCV-2 antigen positive if the sow was PCV-2 antibody positive around farrowing, the sow was of higher parity, and were less likely to test antigen positive if the sow was sourced from a particular breeder. The findings of this study highlight the potential role of the immune status of the sow on the occurrence of PMWS.
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Affiliation(s)
- B Wieland
- Epidemiology and Veterinary Public Health, Royal Veterinary College, London, UK.
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22
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Shen HG, Halbur PG, Opriessnig T. Prevalence and phylogenetic analysis of the current porcine circovirus 2 genotypes after implementation of widespread vaccination programmes in the USA. J Gen Virol 2012; 93:1345-1355. [DOI: 10.1099/vir.0.039552-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
To determine the prevalence of porcine circovirus 2 (PCV2) genotypes in the USA during 2010–2011, 5 years after widespread PCV2 vaccination, serum samples from clinically normal pigs that were PCV2 vaccinated (n = 1177), non-vaccinated (n = 378) or of unknown vaccination status (n = 120), and 100 lung samples from pigs diagnosed with PCV-associated disease (PCVAD) were tested. The presence of PCV2, PCV1, PCV1-2a and porcine parvovirus (PPV) DNA was determined by PCR. Determination of the PCV2 genotype was done by differential PCR and sequencing. The prevalence of PCV2a and PCV2b in serum samples was 7.7 % (129/1675) and 8.4 % (141/1675), respectively. PCV2a DNA was only detected in non-vaccinated pigs. For the 100 PCVAD pigs, the prevalence of PCV2a and PCV2b in lung tissues was 13.0 and 65.0 %, respectively. Partial PCV2 ORF2 sequences (9–563 nt) were obtained from 85 PCV2 DNA-positive samples (24 normal pigs and 61 PCVAD cases). Phylogenetic analysis revealed that 12.9 % (11/85) of the sequences belonged to the 2E clade and the PCV2a genotype and 87.1 % (74/85) belonged to the 1B clade and the PCV2b genotype. The alignment of putative PCV2 capsid amino acid sequences revealed possible recombination or mutation between PCV2a and PCV2b genotypes. Chimeric PCV1-2a was not detected in any of the samples and the prevalence rates of PCV1 and PPV were low. Our results suggest PCV2b is more prevalent than PCV2a in PCVAD cases and in vaccinated herds PCV2b circulation is common. The data generated in this study provide novel information on the distribution of PCV2 genotypes in vaccinated pig populations.
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Affiliation(s)
- Hui-Gang Shen
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Patrick G. Halbur
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Tanja Opriessnig
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
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23
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Castro AMMG, Castro FG, Budiño FEL, Baldin CM, Silva SOS, Brandão PE, Richtzenhain LJ. Detection of Genetic characterization of Porcine circovirus 2 (PCV2) in Brazilian wildlife boars. Braz J Microbiol 2012; 43:1022-5. [PMID: 24031922 PMCID: PMC3768886 DOI: 10.1590/s1517-838220120003000025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 08/24/2011] [Accepted: 06/07/2012] [Indexed: 11/25/2022] Open
Abstract
A semi-intensive wildlife boars farm presented a clinical history of high mortality in 70 – 90 days-old pigs (> 50 %). Two 90 days-old animals with weight loss and wasting were necropsied and the samples tested for PCV2 by polymerase chain reaction (PCR). The genetic material of PCV2 was sequenced and classified into the PCV2a genotype together with PCV2 sequences obtained from samples of Poland, Brazil, Slovenia and Greece wild boars.
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Affiliation(s)
- A M M G Castro
- Departamento de Medicina Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo , São Paulo, SP , Brasil
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24
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Cadar D, Cságola A, Lőrincz M, Tombácz K, Spînu M, Tuboly T. Detection of natural inter- and intra-genotype recombination events revealed by cap gene analysis and decreasing prevalence of PCV2 in wild boars. INFECTION GENETICS AND EVOLUTION 2012; 12:420-7. [DOI: 10.1016/j.meegid.2012.01.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Revised: 01/12/2012] [Accepted: 01/14/2012] [Indexed: 11/16/2022]
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25
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Porcine circovirus type 2 and its associated diseases in China. Virus Res 2012; 164:100-6. [DOI: 10.1016/j.virusres.2011.10.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/08/2011] [Accepted: 10/09/2011] [Indexed: 11/17/2022]
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26
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Krakowka S, Allan G, Ellis J, Hamberg A, Charreyre C, Kaufmann E, Brooks C, Meehan B. A nine-base nucleotide sequence in the porcine circovirus type 2 (PCV2) nucleocapsid gene determines viral replication and virulence. Virus Res 2012; 164:90-9. [DOI: 10.1016/j.virusres.2011.10.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/24/2011] [Accepted: 10/24/2011] [Indexed: 10/15/2022]
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27
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Epidemiology and transmission of porcine circovirus type 2 (PCV2). Virus Res 2012; 164:78-89. [DOI: 10.1016/j.virusres.2011.12.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 11/25/2011] [Accepted: 12/01/2011] [Indexed: 12/11/2022]
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28
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Genetic variation of porcine circovirus type 2 (PCV2) and its relevance to vaccination, pathogenesis and diagnosis. Virus Res 2012; 164:68-77. [DOI: 10.1016/j.virusres.2011.11.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 11/10/2011] [Accepted: 11/21/2011] [Indexed: 12/16/2022]
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29
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Turcitu MA, Wellenberg GJ, Barboi G, Codreanu MD, Vuta VB, Nicolae S, Barbuceanu F, Coste H, Cioranu R. Genetic diversity of porcine circovirus type 2 (PCV2) in the Romanian wild boar population. Res Vet Sci 2011; 91:e103-6. [DOI: 10.1016/j.rvsc.2011.03.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 02/23/2011] [Accepted: 03/04/2011] [Indexed: 11/30/2022]
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30
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Chae C. Porcine circovirus type 2 and its associated diseases in Korea. Virus Res 2011; 164:107-13. [PMID: 22027190 DOI: 10.1016/j.virusres.2011.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/14/2011] [Accepted: 10/15/2011] [Indexed: 10/16/2022]
Abstract
This review describes the characterization of porcine circovirus type 2 (PCV2), the field situation of porcine circovirus-associated disease (PCVAD) and the PCV2 vaccine in Korea. PCVAD has been considered the most devastating disease in Korean livestock history since its first outbreak in 1999. Postweaning multisystemic wasting syndrome (PMWS) and porcine respiratory disease complex (PRDC) are the most common clinical forms of PCVAD. Interestingly, only PCV2b strains have been isolated from pigs with PMWS since 2005, but only PCV2a strains were isolated from pigs with PMWS in 2000 to 2001. Clinically, PMWS is divided into two stages: early and late. Early PMWS primarily occurs in pigs between 4 and 8 weeks of age. This form is a typical presentation of PMWS and is characterized clinically by wasting, decreased weight gain, enlarged lymph nodes, and dyspnea. Late PMWS primarily occurs in pigs between 8 and 12 weeks of age. The main clinical manifestation is diarrhea, which is often accompanied by salmonellosis coinfection. In recent years, the PCVAD disease pattern has slightly changed. The occurrence of PMWS has decreased while PRDC cases are increasing in frequency.
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Affiliation(s)
- Chanhee Chae
- Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
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Savic B, Milicevic V, Jakic-Dimic D, Bojkovski J, Prodanovic R, Kureljusic B, Potkonjak A, Savic B. Genetic characterization and phylogenetic analysis of porcine circovirus type 2 (PCV2) in Serbia. Arch Virol 2011; 157:21-8. [DOI: 10.1007/s00705-011-1130-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Accepted: 09/18/2011] [Indexed: 12/19/2022]
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Jaganathan S, Toung OP, Yee PL, Yew TD, Yoon CP, Keong LB. Genetic characterization of porcine circovirus 2 found in Malaysia. Virol J 2011; 8:437. [PMID: 21914166 PMCID: PMC3184107 DOI: 10.1186/1743-422x-8-437] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/13/2011] [Indexed: 11/23/2022] Open
Abstract
Background Porcine circovirus type 2 is the primary etiological agent associated with a group of complex multi-factorial diseases classified as Porcine Circovirus Associated Diseases (PCVAD). Sporadic cases reported in Malaysia in 2007 caused major economic losses to the 2.2 billion Malaysian ringgit (MYR) (approximately 0.7 billion US dollar) swine industry. The objective of the present study was to determine the association between the presence of PCV2 and occurrences of PCVAD. Results This study showed that 37 out of 42 farms sampled were positive for PCV2 using PCR screening. Thirteen whole genome of PCV2 isolates from pigs with typical PCVAD symptoms were successfully sequenced. These isolates shared 98.3-99.2% similarities with sequences of isolates from the Netherlands. All thirteen isolates fell into the same clade as PCV2b isolates from other countries. Amino acid sequence analysis of the putative capsid protein (ORF2) of the PCV2 revealed that there are three clusters found in Malaysia, namely cluster 1C and 1A/1B. Of interest, three of the isolates (isolates Mal 005, Mal 006 and Mal 010) had a proline substitution for arginine or isoleucine encoded at nt. position 88-89. Eight of the isolates had mutations at the C terminus of the putative capsid protein suggestive of higher pathogenicity which may account for the high reports of PCVAD clinical symptoms in 2007. Conclusion Phylogenetic study suggests that there may be a link between movements of animals by import of breeders into the country being the route of entry of the virus. While it is not possible to eradicate the virus from commercial pigs, the swine industry in Malaysia can be safeguarded by control measures implemented throughout the country. These measures should include improved biosecurity, disease surveillance; vaccination as well as enforcement of regulations formulated to control and prevent the spread of this disease on a national scale.
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Affiliation(s)
- Seetha Jaganathan
- Department of Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
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Coreplication of the major genotype group members of porcine circovirus type 2 as a prerequisite to coevolution may explain the variable disease manifestations. J Virol 2011; 85:11111-20. [PMID: 21865380 DOI: 10.1128/jvi.05156-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A member of the family Circoviridae, porcine circovirus type 2 (PCV2), is associated with postweaning multisystemic wasting syndrome (PMWS), a recent emerging disease worldwide. PCV2 is also found in clinically asymptomatic animals. This paradoxical finding makes the syndrome etiology challenging. We developed new assays to study PCV2 with links to syndrome etiology. For analysis, we used PCV2-infected tissues from subclinically infected and diseased piglets. We compared antigen- and PCV2 DNA-derived signals for tissue localization and intensity. Oligonucleotides were designed to the signature motif of the PCV2 capsid open reading frame to discriminate experimentally between PCV2 genotype groups by PCR, in situ hybridization (ISH), and fluorescence in situ hybridization (FISH). Unexpectedly, all PCV2-infected animals carried both PCV2a and PCV2b genotype group members. Using confocal microscopy, genotype single-cell infections and cell superinfections were visible. Additionally, we discriminated replicative DNA from total PCV2 DNA isoforms with FISH. This aided in our inquiry into cellular genotype-specific replication. Importantly, single-genotype-group replication was not observed. In infected cells with replicating virus, both genotype groups were equally present. These findings suggest PCV2 genotype group members relaxed replication regulation requirements and may even point to PCV2 replication cooperativity in vivo. These observations explain the readily seen PCV2 DNA recombinations and the high overall PCV2 genome plasticity. Hence, we suggest a novel mechanism of syndrome etiology that consists of a continuously changing PCV2 genome pool in hosts and pig herds, posing a constant challenge to the individual maturing immune system.
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Shuai J, Fu L, Zhang X, Zhu B, Li X, He Y, Fang W. Functional exchangeability of the nuclear localization signal (NLS) of capsid protein between PCV1 and PCV2 in vitro: Implications for the role of NLS in viral replication. Virol J 2011; 8:341. [PMID: 21733152 PMCID: PMC3145596 DOI: 10.1186/1743-422x-8-341] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Accepted: 07/06/2011] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Porcine circovirus type 2 (PCV2) is believed to be the primary causative agent of postweaning multisystemic wasting syndrome (PMWS). It is supposed that capsid protein of PCV may contribute to replication control via interaction between Cap and Rep in the nucleoplasm. In this study, we described the construction and in vitro characterization of NLS-exchanged PCV DNA clones based on a PMWS-associated PCV2b isolate from China to determine the role of ORF2 NLS in PCV replication. RESULTS The PCV1, PCV2, PCV2-NLS1 and PCV1-NLS2 DNA clone were generated by ligating a copy of respective genome in tandem with a partial duplication. The PCV2-NLS1 and PCV1-NLS2 DNA clone contained a chimeric genome in which the ORF2 NLS was exchanged. The four DNA clones were all confirmed to be infectious in vitro when transfected into PK-15 cells, as PCV capsid protein were expressed in approximately 10-20% of the transfected cells. The in vitro growth characteristics of the DNA clones were then determined and compared. All the recovered progeny viruses gave rise to increasing infectious titers during passages and were genetically stable by genomic sequencing. The chimeric PCV1-NLS2 and PCV2-NLS1 viruses had the final titers of about 104.2 and 103.8 TCID50/ml, which were significantly lower than that of PCV1 and PCV2 (105.6 and 105.0 TCID50/ml, respectively). When the ORF2 NLS exchanged, the mutant PCV2 (PCV2-NLS1) still replicated less efficiently and showed lower infectious titer than did PCV1 mutant (PCV1-NLS2), which was consistent with the distinction between wild type PCV1 and PCV2. CONCLUSIONS Recovery of the chimeiric PCV1-NLS2 and PCV2-NLS1 progeny viruses indicate that the nuclear localization signal sequence of capsid protein are functionally exchangeable between PCV1 and PCV2 with respect to the role of nuclear importing and propagation. The findings also reveal that ORF2 NLS play an accessory role in the replication of PCV. However, we found that ORF2 NLS was not responsible for the distinction of in vitro growth characteristic between PCV1 and PCV2. Further studies are required to determine the in vivo viral replication and pathogenicity of the NLS chimeric DNA clones.
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Affiliation(s)
- Jiangbing Shuai
- Institute of Preventive Veterinary Medicine, Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Zhejiang University, Hangzhou, China
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Abstract
Porcine circovirus 2 (PCV2) is a T=1 nonenveloped icosahedral virus that has had severe impact on the swine industry. Here we report the crystal structure of an N-terminally truncated PCV2 virus-like particle at 2.3-Å resolution, and the cryo-electron microscopy (cryo-EM) image reconstruction of a full-length PCV2 virus-like particle at 9.6-Å resolution. This is the first atomic structure of a circovirus. The crystal structure revealed that the capsid protein fold is a canonical viral jelly roll. The loops connecting the strands of the jelly roll define the limited features of the surface. Sulfate ions interacting with the surface and electrostatic potential calculations strongly suggest a heparan sulfate binding site that allows PCV2 to gain entry into the cell. The crystal structure also allowed previously determined epitopes of the capsid to be visualized. The cryo-EM image reconstruction showed that the location of the N terminus, absent in the crystal structure, is inside the capsid. As the N terminus was previously shown to be antigenic, it may externalize through viral "breathing."
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Allemandou A, Grasland B, Hernandez-Nignol AC, Kéranflec'h A, Cariolet R, Jestin A. Modification of PCV-2 virulence by substitution of the genogroup motif of the capsid protein. Vet Res 2011; 42:54. [PMID: 21435235 PMCID: PMC3074528 DOI: 10.1186/1297-9716-42-54] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 03/24/2011] [Indexed: 11/24/2022] Open
Abstract
Porcine circovirus type 2 (PCV-2) is the causal agent of the post-weaning multisystemic wasting syndrome (PMWS). PCV-2 are small single-stranded circular DNA viruses clustered into two main genogroups: PCV-2a and PCV-2b. Each genogroup present a specific highly-conserved motif of six amino acids (between amino acids 86 and 91) in the PCV-2 capsid protein. The aim of this study was to verify whether the motif located in the capsid protein and specific to each PCV-2 genogroup contributes to virulence. Two parental DNA clones, PCV-2a and PCV-2b, were constructed as well as two mutants DNA clones, PCV-2a/motif 2b and PCV-2b/motif 2a by exchanging the capsid motif of each genogroup. The four DNA clones were characterized in vitro as well as in vivo. Cells transfected by the four DNA clones produced infectious viruses. In specific-pathogen-free piglets transfected by the four infectious DNA clones, PCV-2b/motif 2a virulence was not attenuated while the PCV-2a/motif 2b virulence was drastically reduced compared to their parent virulence. These results suggest that the amino acids between positions 86 and 91 of the capsid protein are determinant for the virulence of isolates. However, the environment of this motif seems also involved.
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Affiliation(s)
- Aude Allemandou
- Anses, Viral genetics and biosafety unit, 22440 Ploufragan, France.
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Cortey M, Pileri E, Sibila M, Pujols J, Balasch M, Plana J, Segalés J. Genotypic shift of porcine circovirus type 2 from PCV-2a to PCV-2b in Spain from 1985 to 2008. Vet J 2011; 187:363-8. [DOI: 10.1016/j.tvjl.2009.12.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 12/16/2009] [Accepted: 12/22/2009] [Indexed: 10/19/2022]
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Puvanendiran S, Stone S, Yu W, Johnson CR, Abrahante J, Jimenez LG, Griggs T, Haley C, Wagner B, Murtaugh MP. Absence of porcine circovirus type 1 (PCV1) and high prevalence of PCV 2 exposure and infection in swine finisher herds. Virus Res 2011; 157:92-8. [PMID: 21352865 DOI: 10.1016/j.virusres.2011.02.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 02/15/2011] [Accepted: 02/17/2011] [Indexed: 11/18/2022]
Abstract
Porcine circovirus (PCV) appeared in 1974 as an unidentified, innocuous viral inhabitant of cell cultures and pigs. Today PCV1 is a contaminant of some human vaccines, and PCV2 is a major pathogen of swine. PCV1 is reportedly ubiquitous in swine but nonpathogenic. Since the interplay of PCV1 and PCV2 in swine might explain variable disease results and shed light on the potential for human exposure, we analyzed in depth the prevalence of PCV1 and PCV2 infection and exposure in the U.S. finishing swine herd. Over 82% of sera from 185 farms were positive for PCV2 by PCR, whereas only 2.4% were positive for PCV1. More than 80% of PCV2 DNA-positive swine were also positive for anti-PCV2 antibodies. PCV1 was only rarely present. Exposure of swine, and therefore humans via pigs, to PCV1 is negligible. We conclude that PCV2 causes a persistent infection in pigs and that PCV1 is absent or rare in swine.
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Affiliation(s)
- Sumathy Puvanendiran
- Department of Veterinary & Biomedical Sciences, University of Minnesota, 1971 Commonwealth Avenue, St. Paul, MN 55108, USA
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Grau-Roma L, Fraile L, Segalés J. Recent advances in the epidemiology, diagnosis and control of diseases caused by porcine circovirus type 2. Vet J 2011; 187:23-32. [DOI: 10.1016/j.tvjl.2010.01.018] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 01/26/2010] [Accepted: 01/31/2010] [Indexed: 10/19/2022]
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40
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Abstract
AbstractPorcine circovirus type 2 (PCV2) is a small, non-enveloped, circular, single-stranded DNA virus of economic importance in the swine industry worldwide. Based on the sequence analyses of PCV2 strains, isolates can be divided into five subtypes (PCV2a–e). PCV2 is an ubiquitous virus based on serological and viremia data from countries worldwide. In addition, PCV2 DNA was discovered in archived samples prior to the first recognition of clinical disease. Recently, a worldwide shift in PCV2 subtype from PCV2a to PCV2b occurred. PCV2 DNA can be detected in fecal, nasal, oral and tonsillar swabs as well as in urine and feces from both naturally and experimentally infected pigs. PCV2 DNA can be detected early in the infectious process and persists for extended periods of time. The effectiveness of disinfectants for reducing PCV2in vitrois variable and PCV2 is very stable in the pig environment. Limited data exist on the horizontal transmission of PCV2. Direct transmission of PCV2 between experimentally or naturally infected animals and naïve animals has been documented and the incorporation of clinical or subclinically infected animals into a population represents a risk to the herd. Indirect transmission through the oral, aerosol or vaccine routes is likely a lesser risk for the transmission of PCV2 in most swine populations but may be worth evaluating in high heath herds. The objective of this review was to discuss data on the epidemiology and horizontal transmission of PCV2.
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41
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Zhang X, Ma G, Li Y, Jiang X, He J, Zhou J. Characterization of monoclonal antibody against replication-associated protein of porcine circovirus. DNA Cell Biol 2010; 28:23-9. [PMID: 19072659 DOI: 10.1089/dna.2008.0800] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The replication-associated (Rep) protein of porcine circovirus (PCV) was suggested to play an essential role in the replication and translation of viral DNA. In this study, one monoclonal antibody (mAb) specific for Rep protein of porcine circovirus type 1 (PCV1), two mAbs against Rep protein of porcine circovirus type 2 (PCV2), and five mAbs to both Rep protein of PCV1 and PCV2 were generated using, respectively, Rep protein of PCV1 and PCV2 expressed in Escherichia coli as an immunogen. Western blot analysis showed that native Rep protein of PCV2 virions appeared in two forms with different molecular weight in PCV2-infected cells. Laser confocal analyses further exhibited that Rep protein distributed mainly in the cellular nucleoplasm at the early stage of PCV2 infection, and moved to the nuclear periphery and the cytoplasm at the last stage of PCV2 infection. The results from this study confirmed that Rep protein of PCV2 distributed in both nucleus and cytoplasm, and provided an mAb tool to further analyze replications of PCV1 and PCV2 in vitro and in vivo.
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Affiliation(s)
- Xin Zhang
- Key Laboratory of Animal Epidemic Etiology & Immunological Prevention of Ministry of Agriculture, Zhejiang University, Hangzhou, PR China
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42
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Genetic diversity of porcine circovirus type 2 from pigs in Republic of Korea. Res Vet Sci 2010; 88:333-8. [DOI: 10.1016/j.rvsc.2009.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/03/2009] [Accepted: 08/07/2009] [Indexed: 11/18/2022]
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43
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Dual heterologous porcine circovirus genogroup 2a/2b infection induces severe disease in germ-free pigs. Vet Microbiol 2010; 145:209-19. [PMID: 20409649 DOI: 10.1016/j.vetmic.2010.03.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Revised: 03/23/2010] [Accepted: 03/25/2010] [Indexed: 11/21/2022]
Abstract
Our primary objectives were to determine: the relative virulence of porcine circovirus (PCV) 2a and PCV2b, if heterologous infection induces severe illness, and the relative concentration of PCV2a and PCV2b in tissues of heterologously infected pigs. In experiment 1, 18 germ-free piglets served as controls or were infected with PCV2a or PCV2b. Half were immune stimulated with keyhole limpet hemocyanin (KLH) emulsified in incomplete Freund's adjuvant (2aKLH, 2bKLH). No piglets demonstrated severe illness. Lesion severity did not differ, but PCV2 capsid staining was more intense in 2a- than 2b-infected pigs (P<.05). In experiment 2, 20 germ-free piglets were dual inoculated 7 days apart with PCV2a and PCV2b (2a2b, 2b2a), PCV2b twice (2b2b), or PCV2a (2a2a) twice. Five of 9 heterologous-infected pigs developed severe illness. All heterologously infected pigs demonstrated ascites or edema, and 8/9 developed thymic atrophy. By contrast, 1 of 5 2b2b-infected pigs developed bronchopneumonia and pleural effusion. No 2a2a-infected pig developed illness. Gross lesions were more severe in heterologously infected pigs than in 2b2b pigs (P<.05), and were more severe in 2b2b than 2a2a pigs (P<.05). PCV2 capsid staining intensity did not differ by group. In heterologously infected pigs, higher levels of PCV2 DNA reflective of the first inoculum compared to the second were found in mesenteric lymph node (P=.04), spleen (P=.004) and liver (P=.04). These results indicate that dual heterologous PCV2a/2b inoculation 7 days apart may induce severe clinical illness, but PCV2a and PCV2b when administered singularly or in combination with KLH appear to be of equivalent virulence.
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Li W, Wang X, Ma T, Feng Z, Li Y, Jiang P. Genetic analysis of porcine circovirus type 2 (PCV2) strains isolated between 2001 and 2009: genotype PCV2b predominate in postweaning multisystemic wasting syndrome occurrences in eastern China. Virus Genes 2009; 40:244-51. [DOI: 10.1007/s11262-009-0438-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Accepted: 12/17/2009] [Indexed: 11/28/2022]
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Insights into the evolutionary history of an emerging livestock pathogen: porcine circovirus 2. J Virol 2009; 83:12813-21. [PMID: 19812157 DOI: 10.1128/jvi.01719-09] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Porcine circovirus 2 (PCV2) is the primary etiological agent of postweaning multisystemic wasting syndrome (PMWS), one of the most economically important emerging swine diseases worldwide. Virulent PCV2 was first identified following nearly simultaneous outbreaks of PMWS in North America and Europe in the 1990s and has since achieved global distribution. However, the processes responsible for the emergence and spread of PCV2 remain poorly understood. Here, phylogenetic and cophylogenetic inferences were utilized to address key questions on the time scale, processes, and geographic diffusion of emerging PCV2. The results of these analyses suggest that the two genotypes of PCV2 (PCV2a and PCV2b) are likely to have emerged from a common ancestor approximately 100 years ago and have been on independent evolutionary trajectories since that time, despite cocirculating in the same host species and geographic regions. The patterns of geographic movement of PCV2 that we recovered appear to mimic those of the global pig trade and suggest that the movement of asymptomatic animals is likely to have facilitated the rapid spread of virulent PCV2 around the globe. We further estimated the rate of nucleotide substitution for PCV2 to be on the order of 1.2 x 10(-3) substitutions/site/year, the highest yet recorded for a single-stranded DNA virus. This high rate of evolution may allow PCV2 to maintain evolutionary dynamics closer to those of single-stranded RNA viruses than to those of double-stranded DNA viruses, further facilitating the rapid emergence of PCV2 worldwide.
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Bálint Á, Tenk M, Deim Z, Rasmussen T, Uttenthal Å, Cságola A, Tuboly T, Farsang A, Fossum C, Timmusk S, Berg M, Belák S. Development of Primer-Probe Energy Transfer real-time PCR for the detection and quantification of porcine circovirus type 2. Acta Vet Hung 2009; 57:441-52. [PMID: 19635716 DOI: 10.1556/avet.57.2009.3.10] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A real-time PCR assay, based on Primer-Probe Energy Transfer (PriProET), was developed to improve the detection and quantification of porcine circovirus type 2 (PVC2). PCV2 is recognised as the essential infectious agent in post-weaning multisystemic wasting syndrome (PMWS) and has been associated with other disease syndromes such as porcine dermatitis and nephropathy syndrome (PDNS) and porcine respiratory disease complex (PRDC). Since circoviruses commonly occur in the pig populations and there is a correlation between the severity of the disease and the viral load in the organs and blood, it is important not only to detect PCV2 but also to determine the quantitative aspects of viral load. The PriProET real-time PCR assay described in this study was tested on various virus strains and clinical forms of PMWS in order to investigate any correlation between the clinical signs and viral loads in different organs. The data obtained in this study correlate with those described earlier; namely, the viral load in 1 ml plasma and in 500 ng tissue DNA exceeds 10(7) copies in the case of PMWS. The results indicate that the new assay provides a specific, sensitive and robust tool for the improved detection and quantification of PCV2.
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Affiliation(s)
| | - Miklós Tenk
- 1 The National Veterinary Institute & The Swedish University of Agricultural Sciences Joint R&D Division, Departments of Virology Ulls väg 2B SE-751 89 Uppsala Sweden
| | - Zoltán Deim
- 2 Central Agricultural Office Veterinary Diagnostic Directorate Budapest Hungary
| | - Thomas Rasmussen
- 3 Technical University of Denmark National Veterinary Institute Lindholm, Kalvehave Denmark
| | - Åse Uttenthal
- 3 Technical University of Denmark National Veterinary Institute Lindholm, Kalvehave Denmark
| | - Attila Cságola
- 4 Szent István University Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science Budapest Hungary
| | - Tamás Tuboly
- 4 Szent István University Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science Budapest Hungary
| | - Attila Farsang
- 5 Institute for Veterinary Medicinal Products Department of Virology Budapest Hungary
| | - Caroline Fossum
- 6 Swedish University of Agricultural Sciences Department of Biomedical Sciences and Veterinary Public Health Uppsala Sweden
| | - Sirje Timmusk
- 6 Swedish University of Agricultural Sciences Department of Biomedical Sciences and Veterinary Public Health Uppsala Sweden
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Kim HK, Luo Y, Moon HJ, Park SJ, Keum HO, Rho S, Park BK. Phylogenetic and recombination analysis of genomic sequences of PCV2 isolated in Korea. Virus Genes 2009; 39:352-8. [DOI: 10.1007/s11262-009-0395-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 08/10/2009] [Indexed: 10/20/2022]
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Marcekova Z, Psikal I, Kosinova E, Benada O, Sebo P, Bumba L. Heterologous expression of full-length capsid protein of porcine circovirus 2 in Escherichia coli and its potential use for detection of antibodies. J Virol Methods 2009; 162:133-41. [PMID: 19664658 PMCID: PMC7119500 DOI: 10.1016/j.jviromet.2009.07.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 07/23/2009] [Accepted: 07/28/2009] [Indexed: 12/02/2022]
Abstract
A capsid protein of porcine circovirus 2 (PCV 2) serves as a diagnostic antigen for the detection of PCV 2-associated disease known as a postweaning multisystemic wasting syndrome (PMWS). In this report, a bacterial expression system was developed for the expression and purification of the full-length PCV 2 capsid (Cap) protein from a codon-optimized cap gene. Replacement of rare arginine codons located at the 5′ end of the cap reading frame with codons optimal for E. coli was found to overcome the poor expression of the viral protein in the prokaryotic system. The Cap protein was purified to greater than 95% homogeneity by using a single cation-exchange chromatography at a yield of 10 mg per litre of bacterial culture. Despite the failure of the E. coli-expressed Cap protein to self-assemble into virus-like particles (VLPs), the immunization of mice with recombinant Cap yielded antibodies with the same specificity as those raised against native PCV 2 virions. In addition, the antigenic properties of the purified Cap protein were employed in a subunit-based indirect ELISA to monitor the levels of PCV 2 specific antibodies in piglets originating from a herd which was experiencing PCV 2 infection. These results pave the way for a straightforward large-scale production of the recombinant PCV 2 capsid protein and its use as a diagnostic antigen or a PCV 2 subunit vaccine.
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Affiliation(s)
- Zuzana Marcekova
- Proteix s. r. o., Nad Safinou II/365 Vestec, 252 42 Jesenice u Prahy, Czech Republic
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Rose N, Eveno E, Grasland B, Nignol AC, Oger A, Jestin A, Madec F. Individual risk factors for Post-weaning Multisystemic Wasting Syndrome (PMWS) in pigs: A hierarchical Bayesian survival analysis. Prev Vet Med 2009; 90:168-79. [DOI: 10.1016/j.prevetmed.2009.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 04/15/2009] [Accepted: 04/21/2009] [Indexed: 11/29/2022]
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Genetic variation analysis of Chinese strains of porcine circovirus type 2. Virus Res 2009; 145:151-6. [PMID: 19540280 DOI: 10.1016/j.virusres.2009.05.015] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 05/29/2009] [Accepted: 05/29/2009] [Indexed: 11/23/2022]
Abstract
Forty Chinese PCV2 strains collected between 2004 and 2008 were sequenced and their genetic variations were analyzed together with nine previous PCV2 isolates. Phylogenetic analysis indicated that these Chinese PCV2 strains could be divided into four genotypes (PCV-2a, PCV-2b, PCV-2d and PCV-2e), and the genotype PCV-2c defined in Denmark was not found. PCV-2d and PCV-2e were two genotypes firstly determined in our study. Variation analysis of amino acids of capsid protein revealed that Chinese PCV2 strains clustered within PCV-2d had four amino acid marker positions and the isolates within PCV-2e had seven unique amino acid mutations. Our analysis also showed that PCV-2b became dominating in China in recent years. These data contribute to the understanding of PCV2 molecular epidemiology.
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