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Holling C, Grosse Beilage E, Vidondo B, Nathues C. Provision of straw by a foraging tower -effect on tail biting in weaners and fattening pigs. Porcine Health Manag 2017; 3:4. [PMID: 28405460 PMCID: PMC5382410 DOI: 10.1186/s40813-017-0052-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 01/04/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Straw is one of the most effective rooting materials to reduce tail biting in pigs. A so-called foraging-tower (FT) provides only small quantities of straw compatible with liquid manure systems. The focus of the present study was on the effect of providing straw by FT in order to prevent tail biting in tail docked pigs. Four consecutive batches of 160 pigs, randomly divided into a straw (SG) and a control group (CG) were followed up from weaning to slaughter. RESULTS Tail wounds (Score ≥ 2) were detected in 104 out of 12,032 single observations (SG n = 48; CG n = 56) in 9 pens (SG n = 4/32; CG n = 5/32) mainly focused on the fattening period of batch 2 due to a failure in the ventilation system. No significant differences concerning the distribution of Score ≥ 2 in pens of the SG and CG could be identified. Bite marks (Score 1) were documented in 395 observations at animal level (SG n = 197, CG n = 198) in all batches. In the nursery period, the air velocity significantly increased the chance that at least one pig per pen and week showed a tail lesion score ≥1 (p = 0.024). In the fattening period ammonia concentration was positively associated with tail lesions (p = 0.007). The investigation of blood samples revealed infections with Mycoplasma hyopneumoniae in all batches and a circulation of Porcine Reproductive and Respiratory Syndrome Virus (NA-vaccine strain) and Porcine Circovirus Type 2 in two batches each. The average daily straw consumption was 3.5 g/pig (standard deviation (SD) = 1.1) during the rearing period and 31.9 g/pig (SD = 7.7) during the fattening period. CONCLUSION Due to the low prevalence of tail biting in all batches the effect of the FT tower could not be evaluated conclusively. The operation of the FT with an average daily straw consumption of 3.5 g/pig (SD = 1.1) during the rearing period and 31.9 g/pig (SD = 7.7) during the fattening period did not affect the weight gain. Exploratory behaviour seems to cause bite marks (score 1), which do not necessarily result in tail biting. The main outbreak of tail biting was probably triggered by a failure of the ventilation system, which resulted in a number of climatic and air quality changes including higher ammonia concentrations and sudden temperature changes.
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Affiliation(s)
- Carolin Holling
- University of Veterinary Medicine Hannover, Field Station for Epidemiology, Büscheler Str. 9, D-49456 Bakum, Germany
| | - Elisabeth Grosse Beilage
- University of Veterinary Medicine Hannover, Field Station for Epidemiology, Büscheler Str. 9, D-49456 Bakum, Germany
| | - Beatriz Vidondo
- Veterinary Public Health Institute, Vetsuisse Faculty, Schwarzenburgstrasse 155, CH-3097 Liebefeld, BE Switzerland
| | - Christina Nathues
- Veterinary Public Health Institute, Vetsuisse Faculty, Schwarzenburgstrasse 155, CH-3097 Liebefeld, BE Switzerland
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Wang J, Wang J, Liu L, Li R, Yuan W. Rapid detection of Porcine circovirus 2 by recombinase polymerase amplification. J Vet Diagn Invest 2016; 28:574-8. [PMID: 27493138 DOI: 10.1177/1040638716654201] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Porcine circovirus-associated disease, caused primarily by Porcine circovirus 2 (PCV-2), has become endemic in many pig-producing countries and has resulted in significant economic losses to the swine industry worldwide. Tests for PCV-2 infection include PCR, nested PCR, competitive PCR, and real-time PCR (rtPCR). Recombinase polymerase amplification (RPA) has emerged as an isothermal gene amplification technology for the molecular detection of infectious disease agents. RPA is performed at a constant temperature and therefore can be carried out in a water bath. In addition, RPA is completed in ~30 min, much faster than PCR, which usually takes >60 min. We developed a RPA-based method for the detection of PCV-2. The detection limit of RPA was 10(2) copies of PCV-2 genomic DNA. RPA showed the same sensitivity as rtPCR but was 10 times more sensitive than conventional PCR. Successful amplification of PCV-2 DNA, but not other viral templates, demonstrated high specificity of the RPA assay. This method was also validated using clinical samples. The results showed that the RPA assay had a diagnostic agreement rate of 93.7% with conventional PCR and 100% with rtPCR. These findings suggest that the RPA assay is a simple, rapid, and cost-effective method for PCV-2 detection, which could be potentially applied in clinical diagnosis and field surveillance of PCV-2 infection.
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Affiliation(s)
- Jianchang Wang
- Inspection and Quarantine Technical Center of Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang, Hebei, China (Jianchang Wang, Jinfeng Wang, Liu)College of Veterinary Medicine, Agricultural University of Hebei, Baoding, Hebei, China (Li, Yuan)
| | - Jinfeng Wang
- Inspection and Quarantine Technical Center of Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang, Hebei, China (Jianchang Wang, Jinfeng Wang, Liu)College of Veterinary Medicine, Agricultural University of Hebei, Baoding, Hebei, China (Li, Yuan)
| | - Libing Liu
- Inspection and Quarantine Technical Center of Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang, Hebei, China (Jianchang Wang, Jinfeng Wang, Liu)College of Veterinary Medicine, Agricultural University of Hebei, Baoding, Hebei, China (Li, Yuan)
| | - Ruiwen Li
- Inspection and Quarantine Technical Center of Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang, Hebei, China (Jianchang Wang, Jinfeng Wang, Liu)College of Veterinary Medicine, Agricultural University of Hebei, Baoding, Hebei, China (Li, Yuan)
| | - Wanzhe Yuan
- Inspection and Quarantine Technical Center of Hebei Entry-Exit Inspection and Quarantine Bureau, Shijiazhuang, Hebei, China (Jianchang Wang, Jinfeng Wang, Liu)College of Veterinary Medicine, Agricultural University of Hebei, Baoding, Hebei, China (Li, Yuan)
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Dvorak CMT, Yang Y, Haley C, Sharma N, Murtaugh MP. National reduction in porcine circovirus type 2 prevalence following introduction of vaccination. Vet Microbiol 2016; 189:86-90. [PMID: 27259831 DOI: 10.1016/j.vetmic.2016.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/28/2016] [Accepted: 05/02/2016] [Indexed: 10/21/2022]
Abstract
Porcine circovirus type 2 (PCV2), a small, single-stranded circular DNA virus and the causative agent of porcine circovirus associated disease (PCVAD), was first observed in the mid-1990s in pigs with a post-weaning wasting disease. In 2006 the number of PCVAD cases greatly increased, marking it as an important viral pathogen for the United States (US) swine industry. PCV2 vaccines were introduced to the US in 2006 in response to widespread outbreaks of PCVAD. These vaccines were effective in preventing disease, but did not eliminate virus from the animals. In 2006, prior to vaccine use, a study of PCV2 prevalence in pig herds across the US was performed in conjunction with the US National Animal Health Monitoring System. In 2012, 6 years after widespread PCV2 vaccination, this study was repeated. Since the introduction of PCV2 vaccines in 2006, viral presence and viral loads have greatly decreased, and a genotypic shift dominated by PCV2b has occurred. Antibody levels have decreased in the pig population, but approximately 95% of sites continue to be antibody-positive. Widespread vaccination has controlled PCVAD and decreased PCV2 prevalence to the point that viremia is not detected on many sites. Thus, continued vaccination may lead to PCV2 elimination in the national herd over time.
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Affiliation(s)
- Cheryl M T Dvorak
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Ave, St. Paul, MN 55108, USA.
| | - Yan Yang
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Ave, St. Paul, MN 55108, USA.
| | - Charles Haley
- Centers for Epidemiology and Animal Health, USDA-APHIS-VS, 2150 Centre Avenue, Building B, MS 2E7 Fort Collins, CO, USA.
| | - Nikita Sharma
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Ave, St. Paul, MN 55108, USA.
| | - Michael P Murtaugh
- Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Ave, St. Paul, MN 55108, USA.
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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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He KW, Wen LB, Wang YS, Lu CP. Development of real-time PCR assay for detection of porcine circovirus-like virus P1 in domestic pigs in China. BMC Vet Res 2015; 11:240. [PMID: 26404908 PMCID: PMC4583164 DOI: 10.1186/s12917-015-0509-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 07/28/2015] [Indexed: 11/18/2022] Open
Abstract
Background The porcine circovirus-like agent P1 is a newly discovered DNA virus with a single-stranded circular genome that is highly homologous to that of porcine circovirus type 2. P1 infection can cause symptoms resembling postweaning multisystemic wasting syndrome. This study aims to develop a rapid, sensitive and specific method to detect P1. Results A pair of primers was designed and used to amplify a 119 bp DNA fragment to generate a recombinant plasmid which was served as the standard. A SYBR I qPCR protocol was established using the P1 recombinant plasmid standard and the sensitivity, specificity and stability of this method was analyzed. The results demonstrate a strong correlation with P1 recombinant plasmid titers when virus DNA copy numbers fall in between 100 ~ 109 copies/μL. This method doesn’t detect pseudo rabies, porcine parvovirus or porcine reproductive and respiratory syndrome virus; moreover it can distinguish porcine circovirus type 2 from P1 by melting temperature analysis. Coefficient of variation for each batch of reaction is less than 5 %. The serum virus titers of P1 positive in this study were measured by this protocol to be 103 to 107 copies/mL. Conclusions The established qPCR is sensitive, specific, and reliable, which could be a useful tool when applied to quantification of P1 in a variety of samples from infected pigs.
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Affiliation(s)
- Kong-wang He
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China. .,Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, National Center for Engineering Research of Veterinary Bio-products, Nanjing, 210014, China.
| | - Li-bin Wen
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, National Center for Engineering Research of Veterinary Bio-products, Nanjing, 210014, China.
| | - Yong-shan Wang
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, National Center for Engineering Research of Veterinary Bio-products, Nanjing, 210014, China.
| | - Cheng-ping Lu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.
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Zhao S, Lin H, Chen S, Yang M, Yan Q, Wen C, Hao Z, Yan Y, Sun Y, Hu J, Chen Z, Xi L. Sensitive detection of Porcine circovirus-2 by droplet digital polymerase chain reaction. J Vet Diagn Invest 2015; 27:784-8. [PMID: 26391713 DOI: 10.1177/1040638715608358] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sensitive detection of Porcine circovirus-2 (PCV-2) is very important for surveillance of postweaning multisystemic wasting syndrome. Droplet digital polymerase chain reaction (ddPCR) is novel PCR method that can achieve high precision. Our study aimed to develop a sensitive assay utilizing ddPCR to detect PCV-2. Specificity of the assay was confirmed by the failure of amplification of DNA of other relevant viruses. The detection limit for ddPCR was 25 copies/μL, a 4-fold greater sensitivity than TaqMan real-time PCR. Both methods showed a high degree of linearity (R(2) = ~1), although TaqMan real-time PCR showed less sensitivity than ddPCR for clinical detection. Our findings indicate that ddPCR might represent a promising platform for detecting PCV-2 viral loads.
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Affiliation(s)
- Shan Zhao
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Hua Lin
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Shijie Chen
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Miao Yang
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Qigui Yan
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Caifang Wen
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Zhongxiang Hao
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Yubao Yan
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Yingjie Sun
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Juan Hu
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Zhenrong Chen
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
| | - Lixin Xi
- College of Veterinary Medicine (Zhao, Q Yan, Wen, Hao, Z Chen, Xi) and Key Laboratory of Animal Disease and Human Health of Sichuan Province (Q Yan), Sichuan Agricultural University, Chengdu, ChinaSichuan Entry-Exit Inspection and Quarantine Bureau, Chengdu, China (Lin, S Chen, Yang, Y Yan, Sun, Hu)
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Kweon CH, Nguyen LTK, Yoo MS, Kang SW. Differential recognition of the ORF2 region in a complete genome sequence of porcine circovirus type 2 (PCV2) isolated from boar bone marrow in Korea. Gene 2015; 569:308-12. [DOI: 10.1016/j.gene.2015.04.055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 03/30/2015] [Accepted: 04/21/2015] [Indexed: 10/23/2022]
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Lee Y, Lin CM, Jeng CR, Chang HW, Chang CC, Pang VF. The pathogenic role of torque teno sus virus 1 and 2 and their correlations with various viral pathogens and host immunocytes in wasting pigs. Vet Microbiol 2015; 180:186-95. [PMID: 26390821 DOI: 10.1016/j.vetmic.2015.08.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 11/28/2022]
Abstract
The pathogenic role of torque teno sus virus (TTSuV) in swine is controversial among different studies. The present study intended to evaluate the potential pathogenicity of TTSuV based on its correlations with the histopathological changes, various common concurrently infected viral pathogens including porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), and porcine parvovirus (PPV), as well as changes in the distribution and population of host immunocytes such as B lymphocytes, T lymphocytes, and macrophages by using the superficial inguinal lymph nodes (siLNs) of wasting pigs. A tissue microarray consisting of 270 available siLNs collected from 262 clinically wasting and 8 healthy pigs, respectively, were used for the detection of TTSuV1, TTSuV2, PCV2, PRRSV, and PPV by either in situ hybridization (ISH) or immunohistochemical (IHC) staining, and for the detection of various subsets of immunocytes by IHC staining with monoclonal antibodies to CD3, CD79a, and lysozyme. The slides were then subject to digital scanning followed by a semi-quantitative positive pixel evaluation for further statistical analysis. Although a high prevalence of TTSuV1 and/or TTSuV2 infection was noted in both wasting and healthy pigs, the wasting pigs had a significantly higher intensity in both TTSuV1 and TTSuV2 ISH-positive signals than healthy ones did. In the wasting pigs, a significant positive correlation in the tissue viral load was noted between TTSuV1 and TTSuV2 and between TTSuV2 and PCV2, but not between TTSuV1 and PCV2. Conversely, a significant negative correlation in the tissue viral load was revealed between TTSuV2, but not TTSuV1, and PRRSV. The tissue viral load of TTSuV1 was significantly correlated with B cell hyperplasia, while the tissue viral load of TTSuV2 was significantly correlated with increased macrophage population. The ISH positivity of TTSuV2 was significantly correlated with lymphoid depletion and granulomatous inflammation, which are the characteristic histopathological findings in postweaning multisystemic wasting syndrome-affected pigs. These findings suggest that both TTSuV species may have the potential involving the development of porcine circovirus-associated lymphoid lesions via alternating the host immune system.
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Affiliation(s)
- Yao Lee
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan, ROC; Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Chun-Ming Lin
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan, ROC
| | - Chian-Ren Jeng
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan, ROC
| | - Hui-Wen Chang
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan, ROC
| | - Chih-Cheng Chang
- Department of Veterinary Medicine, National Chiayi University, Chiayi 60054, Taiwan, ROC.
| | - Victor Fei Pang
- Graduate Institute of Molecular and Comparative Pathobiology, School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan, ROC.
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Teixeira TF, Cibulski SP, dos Santos HF, Wendlant A, de Sales Lima FE, Schmidt C, Franco AC, Roehe PM. Torque teno sus virus 1 (TTSuV1) and 2 (TTSuV2) viral loads in serum of postweaning multisystemic wasting syndrome (PMWS)-affected and healthy pigs in Brazil. Res Vet Sci 2015; 101:38-41. [DOI: 10.1016/j.rvsc.2015.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/21/2015] [Accepted: 05/30/2015] [Indexed: 10/23/2022]
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Yang S, Shang Y, Wang D, Yin S, Cai J, Liu X. Diagnosis of porcine circovirus type 2 infection with a combination of immunomagnetic beads, single-domain antibody, and fluorescent quantum dot probes. Arch Virol 2015; 160:2325-34. [PMID: 26153546 DOI: 10.1007/s00705-015-2508-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 06/20/2015] [Indexed: 01/03/2023]
Abstract
The use of a specific antibody conjugated with nanobeads, forming immunomagnetic nanobeads (IMNBs), has been demonstrated to be useful for the capture and detection of viruses. In this study, IMNBs functionalized with a single-domain antibody against the capsid protein (Cap) of porcine circovirus type 2 (PCV2), hereafter denoted as psdAb, were evaluated and used to capture PCV2. Quantum dots (QDs) conjugated with psdAb were used as a fluorescence probe to visualize PCV2 captured by IMNBs. The specificity and sensitivity of this method were further evaluated using common pathogens of pig viral disease and PCV2. To assess its practicality, clinical samples were tested in this study. The results showed that 2.57 ± 0.13 mg Cap or 0.97 ± 0.064 × 10(6) copies of PCV2 particles could be captured by 1 mg of IMNBs in 30 min. This suggests that the IMNBs have the ability to efficiently capture PCV2 with good specificity, as there was no cross-reaction with other pathogens, and with strong sensitivity, with a detection limit as low as 10(3) copies/ml of PCV2 particles. Moreover, PCV2 in inguinal lymph node, lung, spleen, serum, and fecal samples was successfully detected by IMNBs. The results demonstrate that this method is promising for the rapid and effective detection of PCV2 in complex clinical samples.
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Affiliation(s)
- Shunli Yang
- State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Yanchangbu, Lanzhou, 730046, Gansu, China,
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61
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Kristensen CS, Hjulsager CK, Larsen LE. A two-year follow-up study of the PCV2 status of a Danish pig herd that was initially assumed to be PCV2-free. Porcine Health Manag 2015; 1:5. [PMID: 28405414 PMCID: PMC5375122 DOI: 10.1186/2055-5660-1-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/24/2014] [Indexed: 11/10/2022] Open
Abstract
Background A longitudinal study was carried out to investigate whether a herd that had previously tested negative for porcine circovirus type 2 (PCV2) by polymerase chain reaction (PCR) was free of PCV2 or whether the negative profiles indicate that the level of PCV2 varies over time. Results In eight Danish herds that had initially tested negative for PCV2 by quantitative polymerase chain reaction (PCR), additional sampling was performed. Only one of the herds was still PCV2-negative in the additional sampling and was included in the study. The herd was a finishing herd, subclinically infected with PCV2, but vaccinated against PCV2 to improve performance. The herd was monitored by taking blood samples every seventh week over a period of two years and was not found to be continuously negative for PCV2 by PCR. The first time PCV2 was detected by PCR, in May 2010, PCV2 vaccination had been withdrawn from the herd, and at the same time the herd was infected with porcine reproductive and respiratory syndrome virus (PRRS). The PCV2-negative status, measured by PCR, was obtained in the first sampling after the PCV2 vaccination had been reintroduced. When PCV2 vaccination was withdrawn again in September 2011, the herd tested positive for PCV2 by PCR, and this time it continued to be PCV2-positive, even though PCV2 vaccination had been reintroduced. Conclusion A Danish finishing herd that appeared to be PCV2-free from the start of a period of two years was not free of PCV2 during the entire period.
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Affiliation(s)
- Charlotte S Kristensen
- Danish Agriculture and Food Council, Pig Research Centre, Vinkelvej 11, DK-8620 Kjellerup, Denmark
| | - Charlotte K Hjulsager
- National Veterinary Institute, Technical University of Denmark, National Veterinary Institute, Frederiksberg C, Denmark
| | - Lars E Larsen
- National Veterinary Institute, Technical University of Denmark, National Veterinary Institute, Frederiksberg C, Denmark
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Monger VR, Loeffen WLA, Kus K, Stegeman JA, Dukpa K, Szymanek K, Podgórska K. Genetic Characterization of Porcine Circovirus Type 2 (PCV2) in Pigs of Bhutan. Transbound Emerg Dis 2015; 64:442-448. [PMID: 26032877 DOI: 10.1111/tbed.12383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Indexed: 12/26/2022]
Abstract
Porcine circovirus (PCV) is a small non-enveloped virus with a single-stranded circular DNA with two antigenically and genetically different species, PCV1 and PCV2. Among these two, PCV2 is responsible for multifactorial disease syndromes, the most important disease known as PCV2-systemic disease (PCV2-SD), previously known as post-weaning multisystemic wasting syndrome (PMWS). The epidemiological situation is dynamically changing and new strains including recombinant PCV2 have emerged in Asia. In Bhutan, pigs are important livestock and play a very important role in providing meat and income for rural farmers. Although high rate of pigs seropositive against PCV2 was described in Bhutan, there was no virological evidence for PCV2 infections. This study was conducted to confirm the presence of PCV2 through detection of PCV2 DNA and molecular characterization of PCV2 strains in tissue and blood samples collected from Bhutanese pigs. Porcine circovirus type 2 genome was detected in 16 of 34 tissue samples pigs from the government farm. In 9 pigs, very high level of viral replication indicated that PCV2-SD was detected. Phylogenetic analysis performed with a set of GenBank sequences revealed that the Bhutanese PCV2 strains belonged to the PCV2b genotype and grouped with cluster 1C.
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Affiliation(s)
- V R Monger
- Department of Virology, Central Veterinary Institute of Wageningen UR, Lelystad, The Netherlands.,Department of Livestock, National Centre for Animal Health, Ministry of Agriculture and Forests, Thimphu, Bhutan
| | - W L A Loeffen
- Department of Virology, Central Veterinary Institute of Wageningen UR, Lelystad, The Netherlands
| | - K Kus
- Department of Swine Diseases, National Veterinary Research Institute, Pulawy, Poland
| | - J A Stegeman
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - K Dukpa
- Department of Livestock, National Centre for Animal Health, Ministry of Agriculture and Forests, Thimphu, Bhutan
| | - K Szymanek
- Department of Swine Diseases, National Veterinary Research Institute, Pulawy, Poland
| | - K Podgórska
- Department of Swine Diseases, National Veterinary Research Institute, Pulawy, Poland
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Patterson R, Nevel A, Diaz AV, Martineau HM, Demmers T, Browne C, Mavrommatis B, Werling D. Exposure to environmental stressors result in increased viral load and further reduction of production parameters in pigs experimentally infected with PCV2b. Vet Microbiol 2015; 177:261-9. [PMID: 25866129 PMCID: PMC4441105 DOI: 10.1016/j.vetmic.2015.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Revised: 03/06/2015] [Accepted: 03/12/2015] [Indexed: 11/30/2022]
Abstract
Environmental stress increases viral load of PCV2b in serum and tissue. Environmental stress exacerbates PCV2b induced weight loss. Environmental stress and PCV2b reduce ADG and impact negatively on FCR.
Porcine circovirus type 2 (PCV2) has been identified as the essential, but not sole, underlying infectious component for PCV-associated diseases (PCVAD). Several co-factors have been suggested to convert an infection with PCV2 into the clinical signs of PCVAD, including co-infection with a secondary pathogen and the genetic background of the pig. In the present study, we investigated the role of environmental stressors in the form of changes in environmental temperature and increased stocking-density on viral load in serum and tissue, average daily weight gain (ADG) and food conversion rate (FCR) of pigs experimentally infected with a defined PCV2b strain over an eight week period. These stressors were identified recently as risk factors leading to the occurrence of severe PCVAD on a farm level. In the current study, PCV2-free pigs were housed in separate, environmentally controlled rooms, and the experiment was performed in a 2 × 2 factorial design. In general, PCV2b infection reduced ADG and increased FCR, and these were further impacted on by the environmental stressors. Furthermore, all stressors led to an increased viral load in serum and tissue as assessed by qPCR, although levels did not reach statistical significance. Our data suggest that there is no need for an additional pathogen to develop PCVAD in conventional status pigs, and growth retardation and clinical signs can be induced in PCV2 infected pigs that are exposed to environmental stressors alone.
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Affiliation(s)
- Robert Patterson
- Royal Veterinary College, Department of Pathology and Pathogen Biology, Hawkshead Lane, AL9 7TA, UK
| | - Amanda Nevel
- Royal Veterinary College, Department of Pathology and Pathogen Biology, Hawkshead Lane, AL9 7TA, UK
| | - Adriana V Diaz
- Royal Veterinary College, Department of Pathology and Pathogen Biology, Hawkshead Lane, AL9 7TA, UK
| | - Henny M Martineau
- Royal Veterinary College, Department of Pathology and Pathogen Biology, Hawkshead Lane, AL9 7TA, UK
| | - Theo Demmers
- Royal Veterinary College, Department of Clinical Sciences, Hawkshead Lane, AL9 7TA, UK
| | - Christopher Browne
- Royal Veterinary College, Department of Pathology and Pathogen Biology, Hawkshead Lane, AL9 7TA, UK
| | - Bettina Mavrommatis
- Royal Veterinary College, Department of Pathology and Pathogen Biology, Hawkshead Lane, AL9 7TA, UK
| | - Dirk Werling
- Royal Veterinary College, Department of Pathology and Pathogen Biology, Hawkshead Lane, AL9 7TA, UK.
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64
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Savard C, Provost C, Alvarez F, Pinilla V, Music N, Jacques M, Gagnon CA, Chorfi Y. Effect of deoxynivalenol (DON) mycotoxin on in vivo and in vitro porcine circovirus type 2 infections. Vet Microbiol 2015; 176:257-67. [PMID: 25717015 DOI: 10.1016/j.vetmic.2015.02.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 12/22/2014] [Accepted: 02/03/2015] [Indexed: 12/30/2022]
Abstract
Deoxynivalenol (DON) is a mycotoxin produced by Fusarium spp and is a common contaminant of grains in North America. Among farm animals, swine are the most susceptible to DON because it markedly reduces feed intake and decreases weight gain. Porcine circovirus type 2 (PCV2) is the main causative agent of several syndromes in weaning piglets collectively known as porcine circovirus-associated disease (PCVAD). The objectives of this study were to investigate the impact of DON on PCV2 replication in NPTr permissive cell line, and to determine eventual potentiating effects of DON on PCV2 infection in pigs. Noninfected and infected cells with PCV2 were treated with increasing concentrations of DON (0, 70, 140, 280, 560, 1200 ng/mL) and cell survival and virus titer were evaluated 72 h postinfection. Thirty commercial piglets were randomly divided into 3 experimental groups of 10 animals based on DON content of served diets (0, 2.5 and 3.5 mg/kg DON). All groups were further divided into subgroups of 6 pigs and were inoculated with PCV2b virus. The remaining pigs (control) were sham-inoculated with PBS. In vitro results showed that low concentrations of DON could potentially increase PCV2 replication depending on virus genotype. In vivo results showed that even though viremia and lung viral load tend to be higher in animal ingesting DON contaminated diet at 2.5 mg/kg, DON had no significant effect on clinical manifestation of PCVAD in PCV2b infected animals. DON has neither in vitro nor in vivo clear potentiating effects in the development of porcine circovirus infection despite slight increases in viral replication.
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Affiliation(s)
- Christian Savard
- Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Centre de recherche en infectiologie porcine et avicole (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - Chantale Provost
- Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Centre de recherche en infectiologie porcine et avicole (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - Fernando Alvarez
- Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Centre de recherche en infectiologie porcine et avicole (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - Vicente Pinilla
- Département de Biomédecine vétérinaire, Saint-Hyacinthe, QC, Canada
| | - Nedzad Music
- Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Centre de recherche en infectiologie porcine et avicole (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - Mario Jacques
- Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Centre de recherche en infectiologie porcine et avicole (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - Carl A Gagnon
- Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Centre de recherche en infectiologie porcine et avicole (CRIPA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada
| | - Younes Chorfi
- Département de Biomédecine vétérinaire, Saint-Hyacinthe, QC, Canada.
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65
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Gleeson BL, Collins AM. Under what conditions is it possible to produce pigs without using antimicrobials? ANIMAL PRODUCTION SCIENCE 2015. [DOI: 10.1071/an15271] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Antimicrobials are commonly used in pig production to control bacterial infections. However, there is increasing pressure from supermarkets and consumers and other sectors to reduce or eliminate the use of antimicrobials in animal agriculture. Banning the use of antimicrobials in some countries has led to increased disease and welfare problems, so it is important to know under what conditions pigs can be produced without the use of antimicrobials. In this review, practices that can prevent disease, and therefore reduce the need for antimicrobials were researched from published experimental challenge trials, field studies and risk factor analyses. Disease prevention practices were examined from pathogen survival and transmission studies, vaccine and disinfectant efficacy studies and nutrition trials. From these studies we collated the important practices that manage or prevent disease and improve pig health. We also reviewed new diagnostic assays and technologies to better monitor the pig and its environment at the herd level. Many of the conditions necessary to produce pigs without antimicrobials have been known and understood for a long time. The application of high standards of biosecurity and hygiene is crucial for creating the conditions for reduction of antimicrobial use. Factors important in preventing disease include eradication or elimination of pathogens, minimising mixing of pigs, cleaning and disinfection of pens and sheds, ventilation to improve air quality, reducing stocking density and eliminating potential vectors of disease. Improving the health of pigs also relies on vaccination and improved consistency of nutrition. The development of diagnostic technologies that correlate with disease and production will enable the detection of potential disease problems at the individual or herd level before disease outbreaks occur and before antimicrobials are needed. The development of vaccination technologies for prevention of disease and diagnostic technologies that can be used on-farm to predict disease outbreaks are integral to safely moving towards antimicrobial-free pork. Pig production without the use of antimicrobials is not simply a matter of substituting conventional antimicrobials with alternative antimicrobial substances and expecting the same result. Any move to antimicrobial-free production requires an acknowledgement that pig production costs may increase and that many pig production practices must change. Such changes must also ensure that animal welfare and food safety and quality standards are maintained or improved, and that reliable markets for the product are found. This paper does not seek to argue the science or opinion of reasons behind the desire to reduce antimicrobial use in animal agriculture, but rather discuss the circumstances under which reduction or elimination of antimicrobial use in pig production is possible.
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66
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Wu H, Rao P, Jiang Y, Opriessnig T, Yang Z. A sensitive multiplex real-time PCR panel for rapid diagnosis of viruses associated with porcine respiratory and reproductive disorders. Mol Cell Probes 2014; 28:264-70. [DOI: 10.1016/j.mcp.2014.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/19/2014] [Accepted: 07/11/2014] [Indexed: 10/25/2022]
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67
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Beak and feather disease virus: correlation between viral load and clinical signs in wild Cape parrots (Poicepahlus robustus) in South Africa. Arch Virol 2014; 160:339-44. [PMID: 25193072 DOI: 10.1007/s00705-014-2225-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/30/2014] [Indexed: 10/24/2022]
Abstract
Psittacine beak and feather disease (PBFD), the most prevalent viral disease affecting psittacines, is caused by beak and feather disease virus (BFDV). This study assessed viral load using qPCR in a wild Cape parrot population affected by PBFD and compared it to overall physical condition based on clinical signs attributable to PBFD. A significant inverse correlation between viral load and overall physical condition was found, which confirmed that clinical signs may confidently be used to diagnose the relative severity of BFDV infections in wild populations. This is the first assessment of BFDV viral load in a wild psittacine population.
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68
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Impact of porcine circovirus type 2 (PCV2) vaccination on boar semen quality and quantity using two different vaccines. Theriogenology 2014; 82:574-9. [DOI: 10.1016/j.theriogenology.2014.05.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 05/15/2014] [Accepted: 05/17/2014] [Indexed: 01/02/2023]
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69
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Halami MY, Freick M, Shehata AA, Müller H, Vahlenkamp TW. Susceptibility of calves to porcine circovirus-2 (PCV2). Vet Microbiol 2014; 173:125-31. [PMID: 25085519 DOI: 10.1016/j.vetmic.2014.06.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 06/25/2014] [Indexed: 02/04/2023]
Abstract
Circoviruses are known to infect pigs and birds and cause severe diseases with various clinical signs. Porcine circovirus-2 (PCV2), associated with severe economic losses, was detected in rodents, mosquitoes, cattle, and in calves affected with bovine neonatal pancytopenia (BNP). However, molecular and serological investigations on circovirus infections in cattle revealed inconsistent results. The aim of the study was to investigate the susceptibility and immune response of calves to experimental PCV2 inoculation. Animals were either intravenously inoculated with tissue-culture grown PCV2, with bone marrow from PCV2 positive and negative calves or immunized with a commercial inactivated PCV2 vaccine. The results showed that the animals inoculated with tissue-culture grown PCV2 and with PCV2 positive bone marrow displayed clinical signs including lymph node swelling, reddening of oral and ocular mucosa, and diarrhoea 7-18 days post inoculation (p.i.). PCV2-specific antibodies were detected in the tissue-culture grown PCV2-infected animals and in the PCV2-immunized animals from day 11 and 7 p.i. onwards, respectively, but were absent in both bone marrow inoculated groups. PCV2 was detected by real-time quantitative PCR only in blood samples of the tissue-culture grown PCV2-infected animals and in various tissues (e.g. spleen, lymph nodes, thymus), with high copy numbers in blood between day 4 (5.16log10 genomic copy number/ml) and 46 (5.33log10 genomic copy number/ml) p.i. In conclusion, the seroconversion and the detection of PCV2 in lymphoid tissues for more than five weeks p.i. revealed that host susceptibility of PCV2 is not solely restricted to pigs.
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Affiliation(s)
- Mohammad Y Halami
- Institute of Virology, Center for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 29, 04103 Leipzig, Germany.
| | - Markus Freick
- Tierarztpraxis Zettlitz, Straße der Jugend 68, 09306 Zettlitz OT Methau, Germany
| | - Awad A Shehata
- Institute of Virology, Center for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 29, 04103 Leipzig, Germany
| | - Hermann Müller
- Institute of Virology, Center for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 29, 04103 Leipzig, Germany
| | - Thomas W Vahlenkamp
- Institute of Virology, Center for Infectious Diseases, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 29, 04103 Leipzig, Germany
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70
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Identification of recently described porcine parvoviruses in archived North American samples from 1996 and association with porcine circovirus associated disease. Vet Microbiol 2014; 173:9-16. [PMID: 25081955 DOI: 10.1016/j.vetmic.2014.06.024] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/18/2014] [Accepted: 06/25/2014] [Indexed: 12/25/2022]
Abstract
The association of porcine circovirus (PCV) type 2 and porcine parvovirus (PPV) type 1 as a cause of porcine circovirus associated disease (PCVAD) is well established. The objective of this study was to investigate the prevalence rates of classical PPV1 and recently recognized PPV2-5 in serum and lung samples from pigs and farms with known PCV2 status. A total of 586 serum samples and 164 lung homogenates collected from 1996 to 2013 in the USA and Canada were utilized. All samples were tested for PPV1-5 and PCV2. PCV2 was detected in 27.7% (162/586) and PPV in 48.8% (286/586) of the serum samples, whereas 78.7% (129/164) of the lung tissues were positive for PCV2 and 56.7% (93/164) were positive for PPV. Overall, PPV2 had the highest prevalence rates in sera (35.2%) and tissues (42.7%). Concurrent infection of PCV2 and PPV occurred in 14.3% (84/586) of the serum samples and in 49.4% (81/164) of the tissue samples. Moreover, the prevalence of PPV1 or PPV2 DNA was significantly higher in tissues containing high amounts of PCV2 DNA compared to non-PCVAD cases. The frequency of concurrent PPV/PCV2 infection was higher for PCVAD herds compared to negative or subclinically infected herds. PPV2, PPV3 and PPV4 were all identified in samples collected in 1998 and PPV5 was first identified in 2006. The obtained findings indicate that similar to PCV2, PPVs are widespread in North American pigs. Nevertheless, diagnostic investigations into PCVAD cases should give more consideration to the role of PPV1 and PPV2 as contributing cofactors.
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71
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Chang CY, Deng MC, Wang FI, Tsai HJ, Yang CH, Chang C, Huang YL. The application of a duplex reverse transcription real-time PCR for the surveillance of porcine reproductive and respiratory syndrome virus and porcine circovirus type 2. J Virol Methods 2014; 201:13-9. [PMID: 24560782 DOI: 10.1016/j.jviromet.2014.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 12/16/2013] [Accepted: 01/24/2014] [Indexed: 10/25/2022]
Abstract
The porcine respiratory disease complex (PRDC) is the most common disease in commercial pork production worldwide. Porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV), the most important agents of PRDC, usually co-infect in the same pigs. In order to survey the prevalence of PCV2 and PRRSV in pigs of various ages, a duplex reverse transcription real-time PCR (DRT-rPCR) was developed and applied in the present study. The DRT-rPCR did not cross-react with 10 swine viruses other than PCV2 and PRRSV, with detection limits of 1 TCID50/ml for PCV2 and 6.3 TCID50/ml for PRRSV. Surveillance using DRT-rPCR together with serology revealed that in the five farms studied, pigs were most susceptible to PRRSV at 6-14 weeks of age, whereas susceptibility to PCV2 varied by the management system but was mostly at 10-14 weeks of age. Cross analysis of viral loads versus antibody titers revealed that PCV2 load was affected negatively by anti-PCV2 ORF2 antibody, which constituted the most important non-infectious factor affecting the development of PMWS. These results indicated that DRT-rPCR was developed and applied successfully to the surveillance of PCV2 and PRRSV in the field.
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Affiliation(s)
- Chia-Yi Chang
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan
| | - Ming-Chung Deng
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan
| | - Fun-In Wang
- School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617 Taiwan
| | - Hsiang-Jung Tsai
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan; School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617 Taiwan
| | - Chia-Huei Yang
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan
| | - Chieh Chang
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan
| | - Yu-Liang Huang
- Animal Health Research Institute, Council of Agriculture, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan.
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72
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Seo HW, Han K, Park C, Chae C. Clinical, virological, immunological and pathological evaluation of four porcine circovirus type 2 vaccines. Vet J 2014; 200:65-70. [PMID: 24618398 DOI: 10.1016/j.tvjl.2014.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 01/29/2014] [Accepted: 02/07/2014] [Indexed: 10/25/2022]
Abstract
The objective of this study was to rigorously compare the efficacy of four porcine circovirus type 2 (PCV2) vaccines of varying antigen type and dose under experimental conditions based on well-defined clinical (average daily weight gain [ADWG]), virological (evidence of viraemia), immunological (presence of PCV2-specific neutralising antibodies [NA], interferon-γ-secreting cells [IFN-γ-SCs], and CD3(+) and CD4(+) T cell subsets), and pathological (lymphoid lesion and PCV2 antigen score) criteria. A total of 60, 3-week old piglets were assigned to six groups of 10/group and were vaccinated either with 1/4 commercially available one-dose vaccines or were not vaccinated. At 7 weeks of age, vaccinated and control animals were inoculated intranasally with 2 mL of PCV2b. All pigs were euthanased and subjected to post-mortem examination at 25 weeks of age. From 9 to 16 weeks of age, the ADWG of vaccinated animals was significantly higher than that of non-vaccinates. Significant (P<0.05) differences were observed between vaccinated and positive control groups in the quantity of log-transformed PCV2b DNA in the blood and nasal swabs, log-transformed NA titres, and PCV2-specific IFN-γ-SCs at 0, 7, 14, 21, and 42 days post challenge (dpc). The proportion of CD4(+) cells at 7 and 14 dpc was also significantly different between vaccinated and control pigs (P<0.05). The histopathological lesions and PCV2-antigen scores in the lymph nodes were significantly lower (P<0.05) in vaccinated animals. All four vaccines were found to be highly efficacious in controlling experimental PCV2 challenge based on this range of criteria.
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Affiliation(s)
- Hwi Won Seo
- Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Kiwon Han
- Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Changhoon Park
- Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Chanhee Chae
- Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
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73
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Fossum C, Hjertner B, Lövgren T, Fuxler L, Charerntantanakul W, Wallgren P. PCV2 on the spot-A new method for the detection of single porcine circovirus type 2 secreting cells. J Virol Methods 2013; 196:185-92. [PMID: 24269204 DOI: 10.1016/j.jviromet.2013.10.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 10/26/2013] [Accepted: 10/30/2013] [Indexed: 10/26/2022]
Abstract
A porcine circovirus type 2 SPOT (PCV2-SPOT) assay was established to enumerate virus-secreting lymphocytes obtained from naturally infected pigs. The assay is based on the same principle as general ELISPOT assays but instead of detecting cytokine or immunoglobulin secretion, PCV2 particles are immobilized and detected as filter spots. The method was used to evaluate the influence of various cell activators on the PCV2 secretion in vitro and was also applied to study the PCV2 secretion by lymphocytes obtained from pigs in healthy herds and in a herd afflicted by postweaning multisystemic wasting disease (PMWS). Peripheral blood mononuclear cells (PBMCs) obtained from a pig with severe PMWS produced PCV2-SPOTs spontaneously whereas PBMCs obtained from pigs infected subclinically only generated PCV2-SPOTs upon in vitro stimulation. The PCV2 secretion potential was related to the PCV2 DNA content in the PBMCs as determined by two PCV2 real-time PCR assays, developed to differentiate between Swedish PCV2 genogroups 1 (PCV2a) and 3 (PCV2b). Besides the current application these qPCRs could simplify future epidemiological studies and allow genogroup detection/quantitation in dual infection experiments and similar studies. The developed PCV2-SPOT assay offers a semi-quantitative approach to evaluate the potential of PCV2-infected porcine cells to release PCV2 viral particles as well as a system to evaluate the ability of different cell types or compounds to affect PCV2 replication and secretion.
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Affiliation(s)
- Caroline Fossum
- Section of Immunology, Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 588, BMC, SE-751 23 Uppsala, Sweden.
| | - Bernt Hjertner
- Section of Immunology, Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 588, BMC, SE-751 23 Uppsala, Sweden
| | - Tanja Lövgren
- Section of Immunology, Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 588, BMC, SE-751 23 Uppsala, Sweden
| | - Lisbeth Fuxler
- Section of Immunology, Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 588, BMC, SE-751 23 Uppsala, Sweden
| | - Wasin Charerntantanakul
- Section of Immunology, Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, P.O. Box 588, BMC, SE-751 23 Uppsala, Sweden; Research Laboratory for Immunity Enhancement in Humans and Domestic Animals, Maejo University, Chiang Mai 50290, Thailand
| | - Per Wallgren
- National Veterinary Institute, SVA, SE-751 89 Uppsala, Sweden
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74
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Lin CN, Lin WH, Hung LN, Wang SY, Chiou MT. Comparison of viremia of type II porcine reproductive and respiratory syndrome virus in naturally infected pigs by zip nucleic acid probe-based real-time PCR. BMC Vet Res 2013; 9:181. [PMID: 24028493 PMCID: PMC3847877 DOI: 10.1186/1746-6148-9-181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 09/10/2013] [Indexed: 01/11/2023] Open
Abstract
Background Porcine reproductive and respiratory syndrome virus (PRRSV) is a RNA virus with high genetic variation. This virus causes significant economic losses in most pig-producing countries. The clinical presentation of PRRSV ranges from asymptomatic to devastating. In this study, we developed a sensitive and specific zip nucleic acid probe-based real-time PCR assay to evaluate the viremia of natural PRRSV-infected pigs in Taiwan. Serum samples were collected from 577 pigs aged 5–12 weeks. These include 444 clinically healthy pigs and 133 symptomatic pigs were confirmed to have porcine respiratory disease complex (PRDC). Results Viremia was quantified in 79 of the 444 (17.8%) clinically healthy pigs and in 112 of the 133 (84.2%) PRDC cases. Viremias were significantly more common in pigs with PRDC compared with the clinically healthy pigs (P <0.0001). These results suggest that a high viral load is a major feature of PRRSV-affected pigs. Conclusions ZNA probe-based real-time PCR can be a useful tool to diagnose symptomatic and asymptomatic PRRSV-infected pigs. The presence of this marker in a sample of animals with high PRRSV loads (>104.2 PRRSV genomes/μl of serum) seems to indicate that it correlates with the presence of PRDC in pigs.
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Affiliation(s)
- Chao-Nan Lin
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan, Republic of China.
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75
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Vero cells expressing porcine circovirus type 2-capsid protein and their diagnostic application. J Virol Methods 2013; 194:26-32. [PMID: 23954842 DOI: 10.1016/j.jviromet.2013.07.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 07/11/2013] [Accepted: 07/18/2013] [Indexed: 11/21/2022]
Abstract
Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS) in swine. Although the incidences of PCV2-related diseases are ubiquitous throughout the world, the serological tools are rather limited, mainly because the virus does not induce any cytopathic effects in cells. The purpose of this study was to develop a rapid, sensitive and easy quantitative immunofluorescence assay (QIFA) using the recombinant PCV2 nucleocapsid protein (NCP) for the detection of PCV2-specific antibodies in pig sera. The recombinant PCV2 NCP was expressed in Vero cells by a lentivirus system. The performance of QIFA using these Vero cells as a diagnostic antigen was compared with currently available C-ELISA and I-ELISA; the relative sensitivity turned out to range from 92.5% up to 99.3%. The relative specificity was 93.3% when compared to C-ELISA as the gold standard. The serological experiment also indicated the inverse relationship between QIFA and the viral load in serum, semen, feces samples from 7 PCV2-positive boars. In addition, the PCV2 sequence detected from bone marrow cells shows 99% of sequence identity with PCV2 genome, confirming the infectivity of PCV2.
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Deng Z, Yuan A, Luo W, Wang N, Gong Q, Yu X, Xue L. Transmission of porcine circovirus type 2b (PCV2b) in Kunming mice. Acta Vet Hung 2013; 61:234-43. [PMID: 23661391 DOI: 10.1556/avet.2013.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To investigate porcine circovirus type 2b (PCV2b) transmission by contact and vertical infection in Kunming mice (an outbred mouse stock deriving from Swiss albino mice with a high ratio of gene heterozygosis), four mice in cage 6 were inoculated with PCV2b and 25 mice without any treatment were placed into cages 1 to 5 (five mice in each cage). Seven days after being infected, the PCV2-binoculated mice were co-mingled with non-inoculated mice from cages 1 to 5 successively at 7, 14, 21, 28 and 35 days post infection (dpi), respectively, for 3 days. In addition, eleven pregnant mice were injected with PCV2b. Samples were collected from non-inoculated mice and three newborn mice from each litter for PCV2b detection by polymerase chain reaction (PCR) and immunohistochemistry (IHC). The PCR results showed that PCV2b transmission rate among mice in cages 1, 2, 3, 4 and 5 was 0/5, 2/5, 5/5, 5/5 and 1/5, respectively. PCV2b antigen signals generally appeared in most organs of the non-inoculated mice in which viruses were detected by PCR. PCV2b DNA was also detected in newborn mice of PCV2b-infected litters, and viral antigen signals were observed in their organs as well. PCV2b was transmitted in Kunming mice by contact, and it also caused vertical infection through the placenta.
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Affiliation(s)
- Zhi Deng
- 1 Hunan Agricultural University College of Veterinary Medicine Changsha, Hunan 410128 China
| | - An Yuan
- 1 Hunan Agricultural University College of Veterinary Medicine Changsha, Hunan 410128 China
| | - Wei Luo
- 1 Hunan Agricultural University College of Veterinary Medicine Changsha, Hunan 410128 China
| | - Nai Wang
- 1 Hunan Agricultural University College of Veterinary Medicine Changsha, Hunan 410128 China
| | - Qian Gong
- 1 Hunan Agricultural University College of Veterinary Medicine Changsha, Hunan 410128 China
| | - Xing Yu
- 1 Hunan Agricultural University College of Veterinary Medicine Changsha, Hunan 410128 China
| | - Li Xue
- 1 Hunan Agricultural University College of Veterinary Medicine Changsha, Hunan 410128 China
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77
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Lin CM, Jeng CR, Liu JP, Lin EC, Chang CC, Huang YL, Tsai YC, Chia MY, Wan CH, Pang VF. Immune gene expression profiles in swine inguinal lymph nodes with different viral loads of porcine circovirus type 2. Vet Microbiol 2013; 162:519-529. [DOI: 10.1016/j.vetmic.2012.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 11/04/2012] [Accepted: 11/07/2012] [Indexed: 01/19/2023]
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78
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Single-tube multiplexed molecular detection of endemic porcine viruses in combination with background screening for transboundary diseases. J Clin Microbiol 2013; 51:938-44. [PMID: 23303496 DOI: 10.1128/jcm.02947-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Detection of several pathogens with multiplexed real-time quantitative PCR (qPCR) assays in a one-step setup allows the simultaneous detection of two endemic porcine and four different selected transboundary viruses. Reverse transcription (RT)-qPCR systems for the detection of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2), two of the most economically important pathogens of swine worldwide, were combined with a screening system for diseases notifiable to the World Organization of Animal Health, namely, classical and African swine fever, foot-and-mouth disease, and Aujeszky's disease. Background screening was implemented using the identical fluorophore for all four different RT-qPCR assays. The novel multiplex RT-qPCR system was validated with a large panel of different body fluids and tissues from pigs and other animal species. Both reference samples and clinical specimens were used for a complete evaluation. It could be demonstrated that a highly sensitive and specific parallel detection of the different viruses was possible. The assays for the notifiable diseases were even not affected by the simultaneous amplification of very high loads of PRRSV- and PCV2-specific sequences. The novel broad-spectrum multiplex assay allows in a unique form the routine investigation for endemic porcine pathogens with exclusion diagnostics of the most important transboundary diseases in samples from pigs with unspecific clinical signs, such as fever or hemorrhages. The new system could significantly improve early detection of the most important notifiable diseases of swine and could lead to a new approach in syndromic surveillance.
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79
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Heißenberger B, Weissenbacher-Lang C, Hennig-Pauka I, Ritzmann M, Ladinig A. Efficacy of vaccination of 3-week-old piglets with Circovac® against porcine circovirus diseases (PCVD). ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.trivac.2013.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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80
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Chae C. Commercial porcine circovirus type 2 vaccines: Efficacy and clinical application. Vet J 2012; 194:151-7. [DOI: 10.1016/j.tvjl.2012.06.031] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 06/22/2012] [Accepted: 06/24/2012] [Indexed: 11/24/2022]
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81
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Vervoort MTW, Vonk JA, Mooijman PJW, Van den Elsen SJJ, Van Megen HHB, Veenhuizen P, Landeweert R, Bakker J, Mulder C, Helder J. SSU ribosomal DNA-based monitoring of nematode assemblages reveals distinct seasonal fluctuations within evolutionary heterogeneous feeding guilds. PLoS One 2012; 7:e47555. [PMID: 23112818 PMCID: PMC3480422 DOI: 10.1371/journal.pone.0047555] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 09/18/2012] [Indexed: 11/19/2022] Open
Abstract
Soils are among the most complex, diverse and competitive habitats on Earth and soil biota are responsible for ecosystem services such as nutrient cycling, carbon sequestration and remediation of freshwater. The extreme biodiversity prohibits the making of a full inventory of soil life. Hence, an appropriate indicator group should be selected to determine the biological condition of soil systems. Due to their ubiquity and the diverse responses to abiotic and biotic changes, nematodes are suitable indicators for environmental monitoring. However, the time-consuming microscopic analysis of nematode communities has limited the scale at which this indicator group is used. In an attempt to circumvent this problem, a quantitative PCR-based tool for the detection of a consistent part of the soil nematofauna was developed based on a phylum-wide molecular framework consisting of 2,400 full-length SSU rDNA sequences. Taxon-specific primers were designed and tested for specificity. Furthermore, relationships were determined between the quantitative PCR output and numbers of target nematodes. As a first field test for this DNA sequence signature-based approach, seasonal fluctuations of nematode assemblages under open canopy (one field) and closed canopy (one forest) were monitored. Fifteen taxa from four feeding guilds (covering ∼ 65% of the free-living nematode biodiversity at higher taxonomical level) were detected at two trophic levels. These four feeding guilds are composed of taxa that developed independently by parallel evolution and we detected ecologically interpretable patterns for free-living nematodes belonging to the lower trophic level of soil food webs. Our results show temporal fluctuations, which can be even opposite within taxa belonging to the same guild. This research on nematode assemblages revealed ecological information about the soil food web that had been partly overlooked.
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Affiliation(s)
- Mariëtte T. W. Vervoort
- Laboratory of Nematology, Department of Plant Sciences, Wageningen University (WUR), Wageningen, The Netherlands
| | - J. Arie Vonk
- Laboratory for Ecological Risk Assessment, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Paul J. W. Mooijman
- Laboratory of Nematology, Department of Plant Sciences, Wageningen University (WUR), Wageningen, The Netherlands
| | - Sven J. J. Van den Elsen
- Laboratory of Nematology, Department of Plant Sciences, Wageningen University (WUR), Wageningen, The Netherlands
| | - Hanny H. B. Van Megen
- Laboratory of Nematology, Department of Plant Sciences, Wageningen University (WUR), Wageningen, The Netherlands
| | - Peter Veenhuizen
- Laboratory for Soil and Crop Research (BLGG AgroXpertus), Wageningen, The Netherlands
| | - Renske Landeweert
- Laboratory for Soil and Crop Research (BLGG AgroXpertus), Wageningen, The Netherlands
| | - Jaap Bakker
- Laboratory of Nematology, Department of Plant Sciences, Wageningen University (WUR), Wageningen, The Netherlands
| | - Christian Mulder
- Laboratory for Ecological Risk Assessment, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - Johannes Helder
- Laboratory of Nematology, Department of Plant Sciences, Wageningen University (WUR), Wageningen, The Netherlands
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82
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Pontes NE, Barbosa CN, Jesus ALS, Silva JG, Freitas AC. Development and evaluation of single-tube nested PCR (STNPCR) for the detection of porcine circovirus type 2 (PCV2). Transbound Emerg Dis 2012; 61:233-8. [PMID: 23078249 DOI: 10.1111/tbed.12022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Indexed: 11/29/2022]
Abstract
Porcine circovirus 2 (PCV2) is a common virus in pig population and is associated with the postweaning multisystemic wasting disease (PMWS). In this study, it was developed and evaluated the single-tube nested PCR (STNPCR) method for the detection of PCV2 DNA. PCV2 reference controls and swine tissue samples were used, and primers were selected for targeting specific regions of the viral genome. In comparison of the methods, STNPCR was 10 times more sensitive than conventional PCR and showed the same sensitivity to nested PCR (NPCR), but with reduction in the risk of cross-contamination. In clinical application, 55 tissue samples were analysed by conventional PCR and resulted in 67% (37/55) of positive reactions, while the NPCR and STNPCR were able to identify the presence of viral DNA in 100% (55/55) of the samples. The high sensitivity combined with the elimination of cross-contamination makes the STNPCR method suitable for the epidemiological studies of PCV2 and can aid in the diagnosis of PMWS.
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Affiliation(s)
- N E Pontes
- Laboratory of Molecular Studies and Experimental Therapy, Department of Genetics, Center for Biological Sciences, Federal University of Pernambuco, Pernambuco, Brazil
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83
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Opriessnig T, Langohr I. Current State of Knowledge on Porcine Circovirus Type 2-Associated Lesions. Vet Pathol 2012; 50:23-38. [DOI: 10.1177/0300985812450726] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Porcine circovirus type 2 (PCV2), a small single-stranded DNA virus, was initially discovered in 1998 and is highly prevalent in the domestic pig population. Disease manifestations associated with PCV2 include postweaning multisystemic wasting disease (PMWS), enteric disease, respiratory disease, porcine dermatitis and nephropathy syndrome (PDNS), and reproductive failure. Although these clinical manifestations involve different organ systems, there is considerable overlap in clinical expression of disease and presence of lesions between pigs and within herds. It is now widely accepted that PCV2 can be further subdivided into different types, of which PCV2a and PCV2b are present worldwide and of greatest importance. This review will focus on PCV2-associated lesions in different organ systems.
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Affiliation(s)
- T. Opriessnig
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - I. Langohr
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, Michigan
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84
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Dezen D, Rijsewijk FAM, Teixeira TF, Holz CL, Varela AP, Cibulski SP, Gregianini TS, Batista HBCR, Franco AC, Roehe PM. Comparative evaluation of a competitive polymerase chain reaction (PCR) and a SYBR Green-based real-time PCR to quantify Porcine circovirus-2 DNA in swine tissue samples. J Vet Diagn Invest 2012; 23:1160-7. [PMID: 22362797 DOI: 10.1177/1040638711425582] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Porcine circovirus-2 (PCV-2) is considered the major etiological agent of post-weaning multisystemic wasting syndrome (PMWS) in pigs. The clinical manifestations of the disease are correlated with moderate to high amounts of PCV-2 DNA in biological samples of affected pigs. A threshold of 10(7) DNA copies/ml is suggested as the trigger factor for symptoms. A comparative study was conducted to determine which quantitative method would be more suitable to estimate the PCV-2 DNA load. Two polymerase chain reaction (PCR) assays were developed: a competitive PCR (cPCR) and a SYBR Green-based real-time PCR. The assays were compared for their capacity to detect PCV-2 in DNA samples extracted from liver, lung, spleen, mesenteric lymph nodes, and kidney of PMWS-affected (n = 23) or non-PMWS-affected pigs (n = 9). Both assays could successfully quantify PCV-2 DNA in all tissue samples and were able to detect significant differences between the numbers of PCV-2 DNA copies found in tissues of PMWS-affected and non-PMWS-affected pigs (≥ 10(2.5)). The highest mean viral loads were detected by the SYBR Green real-time PCR, up to 10(7.0 ± 1.5) copies/100 ng of total DNA sample, while the cPCR detected up to 10(4.8 ± 1.5). A mean difference of 10(1.8) was found between the amounts of PCV-2 DNA detected, using the SYBR Green real-time PCR and the cPCR, suggesting that the viral load threshold for PMWS should be determined for each particular assay.
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Affiliation(s)
- Diogenes Dezen
- Laboratório de Virologia, FEPAGRO Saúde Animal, Instituto de Pesquisas Veterinárias Desidério Finamor, Eldorado do Sul, Rio Grande do Sul, Brazil.
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85
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Faccini S, Nigrelli AD, Franzini G, Rosignoli C, Barbieri I, Alborali GL, Boniotti MB. Effects of DNA extraction method on Porcine circovirus-2 real-time polymerase chain reaction quantification in swine lymph node samples. J Vet Diagn Invest 2012; 23:1189-96. [PMID: 22362800 DOI: 10.1177/1040638711425571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Quantitative real-time polymerase chain reaction (PCR) has become an important tool for Porcine circovirus-2 (PCV-2) research and diagnosis. However, significant differences in detection limit and quantification data, among laboratories and quantitative real-time PCR methods, have been demonstrated. New efforts are required for providing more accurate and comparable results. The current study is an evaluation of the effects of DNA extraction procedures on PCV-2 quantification in lymph node samples. Differences, greater than 1 log(10) copies/g, were shown among PCV-2 loads detected after different extraction procedures. The work highlighted the critical role of the DNA extraction method in PCV-2 quantification by quantitative real-time PCR. This important aspect should be evaluated when comparing data from different laboratories or different studies. The PCV-2 quantification data should not be considered comparable before demonstrating the equivalence of the DNA extraction methods performed.
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Affiliation(s)
- Silvia Faccini
- IZSLER Diagnostic Section of Mantova, Circovallazione Sud 21/a, 46100 Mantova, Italy.
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86
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Segalés J. Porcine circovirus type 2 (PCV2) infections: Clinical signs, pathology and laboratory diagnosis. Virus Res 2012; 164:10-9. [DOI: 10.1016/j.virusres.2011.10.007] [Citation(s) in RCA: 384] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 10/10/2011] [Accepted: 10/11/2011] [Indexed: 12/18/2022]
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87
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Kumar D, Beach NM, Meng XJ, Hegde NR. Use of PCR-based assays for the detection of the adventitious agent porcine circovirus type 1 (PCV1) in vaccines, and for confirming the identity of cell substrates and viruses used in vaccine production. J Virol Methods 2011; 179:201-11. [PMID: 22079617 DOI: 10.1016/j.jviromet.2011.10.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 10/18/2011] [Accepted: 10/27/2011] [Indexed: 11/25/2022]
Abstract
Safety and quality are important issues for vaccines. Whereas reversion to virulence poses a safety risk with live attenuated vaccines, the potential for the presence of adventitious agents is also an issue of vaccine quality. The recent detection or porcine circovirus type 1 (PCV1) in human vaccines has further highlighted the importance of quality control in vaccine production. The purpose of this study was to use a novel conventional PCR to detect PCV1, and subsequently screen materials used in the manufacture of vaccines at Bharat Biotech International Limited, India. The genome or gene fragments of PCV1 were not detected in any of the vaccines and materials tested, including the live attenuated rotavirus vaccine candidate ROTAVAC(®). Further, the identity of the cells and the viruses used as starting materials in the manufacture of these vaccines was confirmed by species-specific PCR or virus-specific RT-PCR, and no cross-contamination was detected in any case. The methods can be applied for regular in-house quality control screening of raw materials and seeds/banks, as well as formulated vaccines.
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Affiliation(s)
- Deepak Kumar
- Ella Foundation, Genome Valley, Turkapally, Shameerpet Mandal, Hyderabad 500078, India
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88
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Sinha A, Shen H, Schalk S, Beach N, Huang Y, Meng X, Halbur P, Opriessnig T. Porcine reproductive and respiratory syndrome virus (PRRSV) influences infection dynamics of porcine circovirus type 2 (PCV2) subtypes PCV2a and PCV2b by prolonging PCV2 viremia and shedding. Vet Microbiol 2011; 152:235-46. [DOI: 10.1016/j.vetmic.2011.05.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 03/19/2011] [Accepted: 05/04/2011] [Indexed: 01/08/2023]
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89
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Watanabe TTN, Zlotowski P, Oliveira LGSD, Rolim VM, Gomes MJP, Snel G, Driemeier D. Rectal stenosis in pigs associated with Salmonella Typhimurium and porcine circovirus type 2 (PCV2) infection. PESQUISA VETERINÁRIA BRASILEIRA 2011. [DOI: 10.1590/s0100-736x2011000600009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rectal stricture is an acquired annular fibrous constriction of the rectum that results from a variety of chronic necrotizing enteric diseases. In pigs, it is in most cases a sequel of Salmonella infection. Porcine circovirus type 2 (PCV2) is a known pathogen causing immunosuppression in pigs worldwide. PCV2 infected pigs may be predisposed to salmonellosis. In this report, rectal stenosis was observed in 160 pigs from a herd that experienced an outbreak of enteric salmonellosis over a 4-month period. Distension of the abdominal wall and diarrhea were the main clinical signs observed. Five animals were analyzed showing annular cicatrization of the rectal wall 5.0-7.0 cm anterior to the anorectal junction and Salmonella-positive immunostaining in the large intestine. Salmonella Typhimurium was isolated from fragments of the large intestine. Porcine circovirus type 2 antigen was observed in the mesenteric lymph-node in 4 pigs and in the large intestine in 3 pigs.
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90
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Gauger PC, Lager KM, Vincent AL, Opriessnig T, Kehrli ME, Cheung AK. Postweaning multisystemic wasting syndrome produced in gnotobiotic pigs following exposure to various amounts of porcine circovirus type 2a or type 2b. Vet Microbiol 2011; 153:229-39. [PMID: 21684696 DOI: 10.1016/j.vetmic.2011.05.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 05/19/2011] [Accepted: 05/23/2011] [Indexed: 11/25/2022]
Abstract
In late 2005, a postweaning, high mortality syndrome spread rapidly through finishing barns in swine dense areas of the United States. Diagnostic investigations consistently detected porcine circovirus type 2 (PCV2) from diseased tissues. Subsequent genetic analysis revealed that the infectious agent was a PCV2 type termed "PCV2b". Prior to late 2004, only the PCV2a type, but not PCV2b, had been reported in North America. In this communication, we produce severe postweaning multisystemic wasting syndrome (PMWS) in gnotobiotic pigs using infectious PCV2a and PCV2b generated from DNA clones constructed from field isolates identified in the 2005 outbreak. Clinical signs exhibited by diseased pigs included anorexia, dyspnea and listlessness. Mortality was typically observed within 12h of onset of dyspnea. The most striking microscopic lesions in affected animals were severe hepatic necrosis and depletion of germinal centers in lymph nodes with associated abundant PCV2 viral antigen. Clinical signs and lesions observed in these studies were comparable to those reported in experiments with gnotobiotic pigs inoculated with a PCV2a isolate while concurrently receiving immune-stimulation or co-infection with porcine parvovirus or torque teno virus. The animals in these studies were confirmed to be free of detectable porcine parvovirus, porcine reproductive and respiratory syndrome virus, bovine viral diarrhea virus, swine hepatitis E virus, and aerobic and anaerobic bacteria. Seven out of 24 PCV2 inoculated pigs had a detectable congenital torque teno virus infection with no correlation to clinical disease. Thus, in these studies, both PCV2a and PCV2b isolates were singularly capable of inducing high mortality in the absence of any detectable infectious co-factor.
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Affiliation(s)
- P C Gauger
- Virus and Prion Diseases of Livestock Research Unit, National Animal Disease Center, USDA, Agricultural Research Service, Ames, IA 50010, USA
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91
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McClenahan SD, Krause PR, Uhlenhaut C. Molecular and infectivity studies of porcine circovirus in vaccines. Vaccine 2011; 29:4745-53. [PMID: 21569811 DOI: 10.1016/j.vaccine.2011.04.087] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 04/09/2011] [Accepted: 04/22/2011] [Indexed: 11/19/2022]
Abstract
This report describes FDA's laboratory response to the 2010 reports that porcine circovirus type 1 (PCV-1) DNA was present in U.S.-licensed rotavirus vaccines and in cells used to produce inactivated poliovirus vaccines. In the present study, Rotarix® (GlaxoSmithKline, Rixenxart, Belgium) was found to contain full-length PCV-1 genomes that are particle-associated, and cell culture assays in swine testis (ST) and PCV-free porcine kidney (PK-15) cells confirmed that PCV-1 sequences in this vaccine represent infectious virus. RotaTeq® (Merck and Co., West Point, PA, USA) contained small PCV-1 and PCV-2 genome fragments, but did not contain detectable larger portions of (or full-length) PCV genomes, and cell culture assays did not amplify PCV from this vaccine. Inactivated poliovirus vaccine bulks (GlaxoSmithKline) were also negative for the presence of PCV by cell culture infectivity assay. In these vaccines, molecular characterization of PCV nucleic acids was useful for predicting the results of cell culture assays.
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Affiliation(s)
- Shasta D McClenahan
- Office of Vaccines Research and Review, Center for Biologics Evaluation and Research, FDA/CBER, Bethesda, MD 20892-4555, United States
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92
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Zhao K, Shi W, Han F, Xu Y, Zhu L, Zou Y, Wu X, Zhu H, Tan F, Tao S, Tang X. Specific, simple and rapid detection of porcine circovirus type 2 using the loop-mediated isothermal amplification method. Virol J 2011; 8:126. [PMID: 21414233 PMCID: PMC3315793 DOI: 10.1186/1743-422x-8-126] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 03/18/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS), and porcine dermatitis and nephropathy syndrome (PDNS). It has caused heavy losses in global agriculture in recent decades. Rapid detection of PCV2 is very important for the effective prophylaxis and treatment of PMWS. RESULTS A loop-mediated isothermal amplification (LAMP) assay was used to detect PCV2 in this study. Three pairs of primers were specially designed for recognizing eight distinct sequences of the ORF2 gene. This gene lies in the PCV2 virus genome sequence, and encodes the Rep protein that is involved in virus replication. Time and temperature conditions for amplification of PCV2 genes were optimized to be 55 min at 59°C. The analysis of clinical samples indicated that the LAMP method was highly sensitive. The detection limit for PCV2 by the LAMP assay was 10 copies, whereas the limit by conventional PCR was 1000 copies. The assay did not cross-react with PCV1, porcine reproductive and respiratory syndrome virus, porcine epidemic diarrhea virus, transmissible gastroenteritis of pigs virus or rotavirus. When 110 samples were tested using the established LAMP system, 95 were detected as positive. CONCLUSION The newly developed LAMP detection method for PCV2 was more specific, sensitive, rapid and simple than before. It complements and extends previous methods for PCV2 detection and provides an alternative approach for detection of PCV2.
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Affiliation(s)
- Kai Zhao
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Road, Shanghai, 201106, People's Republic of China
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93
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Cortey M, Napp S, Alba A, Pileri E, Grau-Roma L, Sibila M, Segalés J. Theoretical and Experimental Approaches to Estimate the Usefulness of Pooled Serum Samples for the Diagnosis of Postweaning Multisystemic Wasting Syndrome. J Vet Diagn Invest 2011; 23:233-40. [DOI: 10.1177/104063871102300206] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Classical postweaning multisystemic wasting syndrome (PMWS) diagnosis is based on postmortem findings (histopathology plus viral detection in lymphoid tissues). Because one of the major differences between PMWS-affected and nonaffected pigs is Porcine circovirus-2 (PCV-2) load in serum and tissues, real-time quantitative polymerase chain reaction (qPCR) has been suggested as a potential diagnostic technique for the disease. The objective of the present study was to assess the applicability of qPCR to quantify PCV-2 loads in pooled serum samples as an easy-to-use PMWS diagnostic tool at the herd level. The experimental design included two simulation studies with several serum pool sizes from pigs already screened for PMWS (by histopathology and detection of PCV-2 by qPCR). Several qPCR thresholds were defined and validated with experimental pools created in the laboratory. Quantitative PCR on pooled serum samples did not result in a sufficiently reliable alternate method to the classical PMWS diagnosis method based on individual clinical, histopathological, and PCV-2 detection criteria. However, serum pools seemed to be an alternative at a low economic cost for the quantification of PCV-2 loads in suspicious herds. A targeted (including only clinically diseased animals) sampling approach did not give better estimates compared with a random sampling approach.
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Affiliation(s)
- Martí Cortey
- Centre de Recerca en Sanitat Animal (CReSA), UABIRTA Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
| | - Sebastian Napp
- Centre de Recerca en Sanitat Animal (CReSA), UABIRTA Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
| | - Anna Alba
- Centre de Recerca en Sanitat Animal (CReSA), UABIRTA Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
| | - Emanuela Pileri
- Centre de Recerca en Sanitat Animal (CReSA), UABIRTA Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
| | - Llorenç Grau-Roma
- Centre de Recerca en Sanitat Animal (CReSA), UABIRTA Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
| | - Marina Sibila
- Centre de Recerca en Sanitat Animal (CReSA), UABIRTA Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
| | - Joaquim Segalés
- Centre de Recerca en Sanitat Animal (CReSA), UABIRTA Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
- the Departament de Sanitat Animal, Facultat de Veterinària Universitat Autònoma de Barcelona, Campus Bellaterra, Barcelona, Spain
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94
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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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95
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Thanakiatkrai P, Welch L. Using the Taguchi method for rapid quantitative PCR optimization with SYBR Green I. Int J Legal Med 2011; 126:161-5. [PMID: 21336638 DOI: 10.1007/s00414-011-0558-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 02/04/2011] [Indexed: 01/20/2023]
Abstract
Here, we applied the Taguchi method, an engineering optimization process, to successfully determine the optimal conditions for three SYBR Green I-based quantitative PCR assays. This method balanced the effects of all factors and their associated levels by using an orthogonal array rather than a factorial array. Instead of running 27 experiments with the conventional factorial method, the Taguchi method achieved the same optimal conditions using only nine experiments, saving valuable resources.
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96
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Shen HG, Schalk S, Halbur PG, Campbell JM, Russell LE, Opriessnig T. Commercially produced spray-dried porcine plasma contains increased concentrations of porcine circovirus type 2 DNA but does not transmit porcine circovirus type 2 when fed to naive pigs. J Anim Sci 2011; 89:1930-8. [PMID: 21278103 DOI: 10.2527/jas.2010-3502] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The porcine circovirus type 2 (PCV2) antibody and DNA status of porcine plasma products collected during the commercial spray-drying process were evaluated. Samples evaluated included 52 pooled liquid plasma (fresh) samples collected at 14 regional abattoirs before transport to 1 of 2 spray-drying facilities, 32 pooled liquid plasma (concentrated) samples collected after arrival at the spray-drying facilities at different stages before the spray-drying process, and 32 samples in powdered form (spray-dried) collected after spray drying. All 116 samples were positive for PCV2 antibody, with PCV2 ELISA sample-to-positive ratios ranging from 9.2 to 13.6 on a DM basis. Porcine circovirus type 2 DNA (4.5 to 7.9 log(10) PCV2 copies/mL, DM basis) was present in 82.7% (43/52) of the fresh plasma samples, 71.9% (23/32) of the concentrated plasma samples and 78.1% (25/32) of the spray-dried plasma samples, with a greater prevalence of PCV2b than PCV2a. To determine the infectivity of PCV2 DNA-positive commercial spray-dried plasma, nine 10-wk-old 68-kg PCV2-naïve pigs were randomly assigned to 1 of 3 treatment groups and rooms: 1) a negative control (no plasma in the feed, not inoculated with PCV2); 2) a positive control (no plasma in the feed, inoculated with PCV2); and 3) plasma-fed pigs (4% porcine plasma in the feed for 42 d, not inoculated with PCV2). All positive control pigs became viremic by 7 d postinoculation and seroconverted by 42 d postinoculation, whereas pigs in the negative control group and in the spray-dried plasma group were PCV2 PCR negative and did not seroconvert to PCV2 for the duration of the study. The results indicate that PCV2 DNA and antibodies are commonly found in commercial spray-dried plasma. However, no evidence of infectivity of the PCV2 DNA was found in naïve pigs when commercial spray-dried plasma was included in the diet under the conditions of this study.
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Affiliation(s)
- H G Shen
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, 50011, USA
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97
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Cheung AK, Greenlee JJ. Identification of an amino acid domain encoded by the capsid gene of porcine circovirus type 2 that modulates intracellular viral protein distribution during replication. Virus Res 2011; 155:358-62. [DOI: 10.1016/j.virusres.2010.09.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 09/21/2010] [Accepted: 09/30/2010] [Indexed: 11/26/2022]
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98
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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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99
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Zhao K, Han F, Zou Y, Zhu L, Li C, Xu Y, Zhang C, Tan F, Wang J, Tao S, He X, Zhou Z, Tang X. Rapid detection of porcine circovirus type 2 using a TaqMan-based real-time PCR. Virol J 2010; 7:374. [PMID: 21192832 PMCID: PMC3023794 DOI: 10.1186/1743-422x-7-374] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 12/31/2010] [Indexed: 11/16/2022] Open
Abstract
Porcine circovirus type 2 (PCV2) and the associated disease postweaning multisystemic wasting syndrome (PMWS) have caused heavy losses in global agriculture in recent decades. Rapid detection of PCV2 is very important for the effective prophylaxis and treatment of PMWS. To establish a sensitive, specific assay for the detection and quantitation of PCV2, we designed and synthesized specific primers and a probe in the open reading frame 2. The assay had a wide dynamic range with excellent linearity and reliable reproducibility, and detected between 102 and 1010 copies of the genomic DNA per reaction. The coefficient of variation for Ct values varied from 0.59% to 1.05% in the same assay and from 1.9% to 4.2% in 10 different assays. The assay did not cross-react with porcine circovirus type 1, porcine reproductive and respiratory, porcine epidemic diarrhea, transmissible gastroenteritis of pigs and rotavirus. The limits of detection and quantitation were 10 and 100 copies, respectively. Using the established real-time PCR system, 39 of the 40 samples we tested were detected as positive.
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Affiliation(s)
- Kai Zhao
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, 2901 Beidi Road, Shanghai 201106, People's Republic of China
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100
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Becskei Z, Aleksić-Kovačević S, Rusvai M, Balka G, Jakab C, Petrović T, Knežević M. Distribution of porcine circovirus 2 cap antigen in the lymphoid tissue of pigs affected by postweaning multisystemic wasting syndrome. Acta Vet Hung 2010; 58:483-98. [PMID: 21087918 DOI: 10.1556/avet.58.2010.4.9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The lymphatic organs of 50 pigs from a total of eight farms located at different sites in the epizootiological region of North Bačka County were studied to obtain data on the prevalence of circoviral infections in Serbia. All of the pigs examined had clinical signs suggestive of postweaning multisystemic wasting syndrome (PMWS). All pigs underwent necropsy and tissue samples were taken for histopathological, immunohistochemical (IHC) and PCR analysis. The presence of porcine circovirus 2 (PCV2) was established by PCR analysis in the organs of the pigs tested. The most frequent histopathological lesions of lymphoid tissue linked with the presence of positive immunostaining for PCV2 Cap antigen confirmed the existence of PMWS in all farms tested in North Bačka County. Using PCR, histopathological and IHC techniques, the presence of PMWS was proved in the Republic of Serbia. During necropsy, generalised enlargement of the lymph nodes was evident. The most common histopathological finding was lymphocyte depletion in the follicular and perifollicular areas of lymph nodes. Infiltration by macrophages was also recorded. By IHC analysis, the cytoplasm of macrophages was shown to contain a large amount of the ORF2-coded Cap antigen of PCV2. Lymphocyte depletion and large numbers of macrophages were recorded in the tonsils, spleen, intestinal lymphatic tissue, Peyer's patches and ileocaecal valve. The presence of typical granulomatous lesions with multinuclear giant cells (MGCs) was also recorded in the lymphatic tissue. Cap antigen was shown to be present in macrophages and less often in lymphocytes.
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Affiliation(s)
- Zsolt Becskei
- 1 Veterinary Specialised Institute ‘Subotica’ Segedinski put 88 24000 Subotica Serbia
| | - Sanja Aleksić-Kovačević
- 2 Belgrade University Department of Pathology, Faculty of Veterinary Medicine Belgrade Serbia
| | - Miklós Rusvai
- 3 Szent István University Department of Pathology and Forensic Veterinary Medicine, Faculty of Veterinary Science István u. 2 H-1078 Budapest Hungary
| | - Gyula Balka
- 3 Szent István University Department of Pathology and Forensic Veterinary Medicine, Faculty of Veterinary Science István u. 2 H-1078 Budapest Hungary
| | - Csaba Jakab
- 3 Szent István University Department of Pathology and Forensic Veterinary Medicine, Faculty of Veterinary Science István u. 2 H-1078 Budapest Hungary
| | - Tamaš Petrović
- 4 Scientific Veterinary Institute ‘Novi Sad’ Novi Sad Serbia
| | - Milijana Knežević
- 2 Belgrade University Department of Pathology, Faculty of Veterinary Medicine Belgrade Serbia
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