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Cuevas-Romero S, Hernández-Baumgarten E, Kennedy S, Hernández-Jáuregui P, Berg M, Moreno-López J. Long-term RNA persistence of porcine rubulavirus (PorPV-LPMV) after an outbreak of a natural infection: the detection of viral mRNA in sentinel pigs suggests viral transmission. Virus Res 2014; 188:155-61. [PMID: 24768705 DOI: 10.1016/j.virusres.2014.04.012] [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: 12/17/2013] [Revised: 04/14/2014] [Accepted: 04/15/2014] [Indexed: 11/30/2022]
Abstract
The persistence of porcine rubulavirus (PorPV-LPMV) in five pigs that had survived an outbreak of a natural infection was determined. After the resolution of the outbreak, each animal was housed in an isolation pen together with one sentinel pig. Approximately every 2 months thereafter one group of animals was euthanized and tissue samples taken for virological and serological analysis. Infectious virus was not isolated from any samples; antibodies to PorPV-LPMV were detected in convalescent pigs by virus neutralisation test and blocking ELISA but not in sentinel pigs. PorPV-LPMV mRNA of the nucleoprotein (NP) and phosphoprotein (P) genes was detected by a nested polymerase chain reaction (nPCR) in samples of trigeminal and optic nerves, cervical spinal cord, tonsils, salivary gland, lung and pancreas from convalescent pigs. mRNA was also detected in the midbrain, corpus callosum, or olfactory bulb in four out of five pigs by nRT-PCR, this result was confirmed by the sequencing of a 260bp PCR product of P gene region. The highest average viral copies/μg of total RNA occurred in the olfactory bulb and pancreas tissues of convalescent pigs and midbrain, tonsil and pancreas of sentinel pigs housed with the convalescent pigs. Satellitosis and gliosis of the midbrain, olfactory bulb, corpus callosum, medulla oblongata or choroid plexus were microscopically observed in four convalescent pigs. The control pig remained negative in all tests. The results indicate that PorPV-LPMV mRNA persists and induces a durable humoral immune response in pigs that have recovered from a natural infection. After a possible reactivation of the virus, it was transmitted to sentinel pigs in contact with the convalescent pigs.
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Affiliation(s)
- S Cuevas-Romero
- Division of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden; Centro Nacional de Investigación Disciplinaria en Microbiología Animal, INIFAP, Mexico DF, Mexico.
| | - E Hernández-Baumgarten
- Facultad de Estudios Superiores Cuautitlán (FES-C), Universidad Nacional Autónoma de México (UNAM), Mexico
| | - S Kennedy
- Veterinary Sciences Division, Agri-Food and Biosciences Institute, Stoney Road, Stormont, Belfast, Northern Ireland, United Kingdom
| | | | - M Berg
- Division of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - J Moreno-López
- Division of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
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102
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Validation of a real time PCR for classical Swine Fever diagnosis. Vet Med Int 2014; 2014:171235. [PMID: 24818039 PMCID: PMC4000670 DOI: 10.1155/2014/171235] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 03/23/2014] [Indexed: 11/17/2022] Open
Abstract
The viral disease classical swine fever (CSF), caused by a Pestivirus, is one of the major causes of economic losses for pig farming. The aim of this work was to validate a RT-qPCR using Taqman for detection of CSF in swine tissues. The parameters for the validation followed the specifications of the Manual of Diagnostic Tests and Vaccines for Terrestrial Animals of the World Organization for Animal Health (OIE) and the guide ABNT NBR ISO/IEC 17025:2005. The analysis of the 5'NTR region of CSF virus was performed in 145 samples from 29 infected pigs and in 240 samples from 80 pigs originated in the Brazilian CSF-free zone. The tissues tested were spleen, kidney, blood, tonsils, and lymph nodes. Sequencing of the positive samples for 5'NTR region was performed to evaluate the specificity of the RT-qPCR. Tests performed for the RT-qPCR validation demonstrated that the PCR assay was efficient in detecting RNA from CSF virus in all materials from different tissues of infected animals. Furthermore, RNA from CSF virus was not detected in samples of swine originated from the Brazilian CSF-free zone. Hence, it is concluded that RT-qPCR can be used as a complementary diagnostic for CSF.
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103
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Kim YK, Lim SI, Cho YY, Song JY, Kim J, An DJ. The CSFV DNAChip: a novel diagnostic assay for classical swine fever virus. J Virol Methods 2014; 204:44-8. [PMID: 24698761 DOI: 10.1016/j.jviromet.2014.03.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 02/25/2014] [Accepted: 03/21/2014] [Indexed: 10/25/2022]
Abstract
A novel assay, the CSFV DNAChip, was developed to clearly and rapidly discriminate three genotypes of classical swine fever virus (CSFV). Total RNA was extracted from clinical samples and then subjected to a one-step reverse-transcription polymerase chain reaction (RT-PCR) using Cy3-labeled primers from the 5' non-coding region (NCR) of CSFV. Amplicons were hybridized to the CSFV DNAChip and fluorescence scanning was performed for detection of CSFV. A cut-off fluorescence intensity value of 5000 was determined by two-graph receiver operating curve (TG-ROC) analysis. The limit of detection values for the developed DNA chip assay were 0.313ng/μL for amplicon concentration and 1TCID50/100μL for virus titer. Using the developed DNA chip, 157 field samples (91 CSFV-positive and 66 CSFV-negative) were investigated. The genotypes determined by the CSFV DNAChip agreed completely with those determined by nucleotide sequence analysis of the viral genome. The developed CSFV DNAChip will be helpful in implementing a CSFV eradication strategy, as it provides a rapid and accurate diagnostic assay that can discriminate easily among CSFV genotypes.
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Affiliation(s)
- Yong Kwan Kim
- Viral Disease Division, Animal and Plant Quarantine Agency, Anyang, Gyeonggi-do, 430-757, Republic of Korea
| | - Seong-In Lim
- Viral Disease Division, Animal and Plant Quarantine Agency, Anyang, Gyeonggi-do, 430-757, Republic of Korea
| | - Yoon-Young Cho
- Viral Disease Division, Animal and Plant Quarantine Agency, Anyang, Gyeonggi-do, 430-757, Republic of Korea
| | - Jae-Young Song
- Viral Disease Division, Animal and Plant Quarantine Agency, Anyang, Gyeonggi-do, 430-757, Republic of Korea
| | - JoonBae Kim
- Median Diagnostics Inc, Chuncheon, Gangwon-do, 200-883, Republic of Korea
| | - Dong-Jun An
- Viral Disease Division, Animal and Plant Quarantine Agency, Anyang, Gyeonggi-do, 430-757, Republic of Korea.
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104
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Fischer M, Freuling CM, Müller T, Wegelt A, Kooi EA, Rasmussen TB, Voller K, Marston DA, Fooks AR, Beer M, Hoffmann B. Molecular double-check strategy for the identification and characterization of European Lyssaviruses. J Virol Methods 2014; 203:23-32. [PMID: 24681051 DOI: 10.1016/j.jviromet.2014.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 03/14/2014] [Accepted: 03/18/2014] [Indexed: 10/25/2022]
Abstract
The "gold standard" for post-mortem rabies diagnosis is the direct fluorescent antibody test (FAT). However, in the case of ante-mortem non-neural sample material or decomposed tissues, the FAT reaches its limit, and the use of molecular techniques can be advantageous. In this study, we developed and validated a reverse transcription PCR cascade protocol feasible for the classification of samples, even those for which there is no epidemiological background knowledge. This study emphasises on the most relevant European lyssaviruses. In a first step, two independent N- and L-gene based pan-lyssavirus intercalating dye assays are performed in a double-check application to increase the method's diagnostic safety. For the second step, characterization of the lyssavirus positive samples via two independent multiplex PCR-systems was performed. Both assays were probe-based, species-specific multiplex PCR-systems for Rabies virus, European bat lyssavirus type 1 and 2 as well as Bokeloh bat lyssavirus. All assays were validated successfully with a comprehensive panel of lyssavirus positive samples, as well as negative material from various host species. This double-check strategy allows for both safe and sensitive screening, detection and characterization of all lyssavirus species of humans and animals, as well as the rapid identification of currently unknown lyssaviruses in bats in Europe.
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Affiliation(s)
- Melina Fischer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
| | - Conrad M Freuling
- Institute of Molecular Biology, Friedrich-Loeffler-Institut, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
| | - Thomas Müller
- Institute of Molecular Biology, Friedrich-Loeffler-Institut, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
| | - Anne Wegelt
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
| | - Engbert A Kooi
- Central Veterinary Institute of Wageningen UR, Houtribweg 39, NL-8221 RA Lelystad, The Netherlands
| | - Thomas B Rasmussen
- DTU National Veterinary Institute, Technical University of Denmark, Lindholm, DK-4771 Kalvehave, Denmark
| | - Katja Voller
- Animal Health & Veterinary Laboratories Agency (AHVLA, Weybridge), New Haw, Addlestone, Surrey KT15 3NB, United Kingdom
| | - Denise A Marston
- Animal Health & Veterinary Laboratories Agency (AHVLA, Weybridge), New Haw, Addlestone, Surrey KT15 3NB, United Kingdom
| | - Anthony R Fooks
- Animal Health & Veterinary Laboratories Agency (AHVLA, Weybridge), New Haw, Addlestone, Surrey KT15 3NB, United Kingdom; Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, Merseyside L69 7BE, United Kingdom
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
| | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, D-17493 Greifswald-Insel Riems, Germany.
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105
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Novel rope-based sampling of classical swine fever shedding in a group of wild boar showing low contagiosity upon experimental infection with a classical swine fever field strain of genotype 2.3. Vet Microbiol 2014; 170:425-9. [PMID: 24698133 DOI: 10.1016/j.vetmic.2014.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/21/2014] [Accepted: 03/03/2014] [Indexed: 11/23/2022]
Abstract
Several classical swine fever (CSF) epidemics in wild boar and domestic pigs in Europe during the last decades have been caused by CSF virus (CSFV) strains of genotype 2.3. This genotype is known to be virulent leading to high morbidity and mortality. We experimentally infected two eight months old wild boar with 10(5,5) TCID50 of CSFV genotype 2.3 and kept the animals together with five noninoculated wild boar of the same age. Our original purpose was to evaluate a non-invasive sampling method based on saliva collection using "rope-in-a-bait" sampling baits. While expecting high morbidity, high level of virus shedding and some mortality, we actually observed a subclinical course of infection with an unexpected low contagiosity. The two inoculated animals infected only three contact animals while two contact animals remained uninfected. These findings substantially add to our epidemiological understanding of CSFV circulation in wild boar populations. CSFV infected animals older than six months and in good condition may not shed sufficient virus to transmit infection to all seronegative in-contact animals. The contagiosity in relation to the animal's age is discussed. This supports the hypothesis of silent perpetuation of CSFV in wild boar populations for several months if the wild boar density is sufficiently high. The feasibility of the "rope-in-a-bait" sampling method could be proven during the short viraemic phase of infected animals during the second week of infection.
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106
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Blome S, Gabriel C, Schmeiser S, Meyer D, Meindl-Böhmer A, Koenen F, Beer M. Efficacy of marker vaccine candidate CP7_E2alf against challenge with classical swine fever virus isolates of different genotypes. Vet Microbiol 2013; 169:8-17. [PMID: 24411658 DOI: 10.1016/j.vetmic.2013.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 11/30/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
Abstract
Classical swine fever (CSF) is among the most important viral disease of domestic and feral pigs and has a serious impact on animal health and pig industry. In most countries with industrialized pig production, prophylactic vaccination against CSF is banned, and all efforts are directed towards eradication of the disease, e.g. by culling of infected herds and animal movement restrictions. Nevertheless, emergency vaccination remains an option to minimize the socio-economic impact of outbreaks. For this application, potent vaccines are needed that allow differentiation of infected from vaccinated animals. Among the promising candidates for next generation marker vaccines is the chimeric pestivirus CP7_E2alf. Efficacy studies are usually carried out using highly virulent CSFV strains of genotype 1 that do not mirror the current field situation where strains of genotype 2 predominate. To prove that CP7_E2alf also protects against these strains, efficacy was assessed after single oral vaccination of wild boar and single intramuscular vaccination of domestic pigs using challenge models with recent CSFV strains and the highly virulent strain "Koslov" (genotype 1.1). It could be demonstrated that CP7_E2alf pilot vaccine batches for intramuscular and oral use were able to protect pigs from challenge infection with a highly virulent CSFV. Moreover, solid protection was also achieved in case of challenge infection with recent field strains of genotypes 2.1 and 2.3. Thus, broad applicability under field conditions can be assumed.
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Affiliation(s)
- Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald - Insel Riems, Germany.
| | - Claudia Gabriel
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald - Insel Riems, Germany
| | - Stefanie Schmeiser
- European Union Reference Laboratory for CSF, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany
| | - Denise Meyer
- European Union Reference Laboratory for CSF, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany
| | - Alexandra Meindl-Böhmer
- European Union Reference Laboratory for CSF, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Buenteweg 17, 30559 Hannover, Germany
| | - Frank Koenen
- CODA-CERVA, Groeselenberg 99, 1180 Ukkel, Belgium
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald - Insel Riems, Germany
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107
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Bone mesenchymal stem cells contributed to the neointimal formation after arterial injury. PLoS One 2013; 8:e82743. [PMID: 24349351 PMCID: PMC3857273 DOI: 10.1371/journal.pone.0082743] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/28/2013] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVES Recent findings suggest that in response to repair-to-injury bone marrow mesenchymal stem cells (BMSCs) participate in the process of angiogenesis. It is unclear what role BMSCs play in the structure of the vessel wall. In present study, we aimed to determine whether BMSCs had the capacity of endothelial cells (ECs). METHODS BMSCs were separated and cultured. FACS and RT-PCR analysis confirmed the gene expression phenotype. The capacity of migration and adhesion and the ultrastructure of BMSCs were examined. The effect of BMSCs transplantation on the vascular repair was investigated in a murine carotid artery-injured model. RESULTS BMSCs could express some markers and form the tube-like structure. The migration and adhesion capacity of BMSCs increased significantly after stimulated. In addition, BMSCs had the intact cell junction. In vivo the local transfer of BMSCs differentiated into neo-endothelial cells in the injury model for carotid artery and contributed to the vascular remodeling. CONCLUSION These results showed that BMSCs could contribute to neointimal formation for vascular lesion and might be associated with the differentiation into ECs, which indicated the important therapeutic implications for vascular diseases.
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108
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Chowdry VK, Luo Y, Widén F, Qiu HJ, Shan H, Belák S, Liu L. Development of a loop-mediated isothermal amplification assay combined with a lateral flow dipstick for rapid and simple detection of classical swine fever virus in the field. J Virol Methods 2013; 197:14-8. [PMID: 24300833 DOI: 10.1016/j.jviromet.2013.11.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/20/2013] [Accepted: 11/22/2013] [Indexed: 11/30/2022]
Abstract
Classical swine fever (CSF) is a highly contagious viral disease and may cause heavy economic loss to farmers. The rapid, simple and accurate diagnosis of the disease at the frontline, for example on the farms of concern is crucial for disease control. This study describes the development and evaluation of a new loop-mediated isothermal amplification (LAMP) assay coupled with lateral flow dipstick (LFD) for the detection of classical swine fever virus (CSFV). This RT-LAMP-LFD assay combines the efficient one-step isothermal amplification of CSF viral RNA and the simplicity of the LFD to read the results within two to five minutes. Seven genotypes (1.1, 1.2, 1.3, 2.1, 2.2, 2.3 and 3.1), but not genotype 3.4, were successfully detected by the RT-LAMP-LFD assay, indicating that the method has a broad range of detection and can be applied in different geographical areas where CSFV strains belonging to these genotypes are present. The performance of this RT-LAMP-LFD assay was similar to that of the real-time RT-PCR. The analytical sensitivity was about 100copies per reaction when testing two genotypes (1.1 and 2.3). No cross-reactivity to non-CSFV pestiviruses was observed. This RT-LAMP-LFD assay can be a useful novel tool for the rapid, simple and economic diagnosis of classical swine fever in the field.
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Affiliation(s)
- Vinay Kumar Chowdry
- Department of Virology, Immunobiology and Parasitology, National Veterinary Institute, Uppsala, Sweden
| | - Yuzi Luo
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Frederik Widén
- Department of Virology, Immunobiology and Parasitology, National Veterinary Institute, Uppsala, Sweden
| | - Hua-Ji Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Hu Shan
- Key Laboratory of Preventive Veterinary Medicine of Shandong Province, Qingdao Agricultural University, Qingdao, China
| | - Sándor Belák
- Department of Virology, Immunobiology and Parasitology, National Veterinary Institute, Uppsala, Sweden
| | - Lihong Liu
- Department of Virology, Immunobiology and Parasitology, National Veterinary Institute, Uppsala, Sweden.
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109
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Safdar M, Abasıyanık M. Development of fast multiplex real-time PCR assays based on EvaGreen fluorescence dye for identification of beef and soybean origins in processed sausages. Food Res Int 2013. [DOI: 10.1016/j.foodres.2013.09.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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110
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Fischer M, Schirrmeier H, Wernike K, Wegelt A, Beer M, Hoffmann B. Development of a pan-Simbu real-time reverse transcriptase PCR for the detection of Simbu serogroup viruses and comparison with SBV diagnostic PCR systems. Virol J 2013; 10:327. [PMID: 24188175 PMCID: PMC4228258 DOI: 10.1186/1743-422x-10-327] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 10/29/2013] [Indexed: 01/03/2023] Open
Abstract
Background Schmallenberg virus (SBV), a novel orthobunyavirus of the Simbu serogroup, was first identified in October 2011 in dairy cattle in Germany, where it caused fever, diarrhea and a drop in milk yield. Since then, SBV additionally has been detected in adult sheep and goats. Although symptoms of acute infection were not observed, infection during a vulnerable phase of pregnancy caused congenital malformations and stillbirths. In view of the current situation and the possible emergence of further Simbu serogroup members, a pan-Simbu real-time reverse transcriptase (RT) PCR system for the reliable detection of Simbu serogroup viruses should be developed. Methods In this study a pan-Simbu real-time RT-PCR system was established and compared to several SBV real-time RT-PCR assays. All PCR-systems were tested using a panel of different Simbu serogroup viruses as well as several field samples from diseased cattle, sheep and goats originating from all over Germany. Several pan-Simbu real-time RT-PCR products were sequenced via Sanger sequencing. Furthermore, in silico analyses were performed to investigate suitability for the detection of further orthobunyaviruses. Results All tested members of the Simbu serogroup (n = 14) as well as most of the field samples were successfully detected by the pan-Simbu real-time RT-PCR system. The comparison of this intercalating dye assay with different TaqMan probe-based assays developed for SBV diagnostics confirmed the functionality of the pan-Simbu assay for screening purposes. However, the SBV-TaqMan-assay SBV-S3 delivered the highest analytical sensitivity of less than ten copies per reaction for duplex systems including an internal control. In addition, for confirmation of SBV-genome detection the highly specific SBV-M1 assay was established. Conclusion The pan-Simbu real-time RT-PCR system was able to detect all tested members of the Simbu serogroup, most of the SBV field samples as well as three tested Bunyamwera serogroup viruses with a suitable sensitivity. According to in silico analyses, this system seems to be able to detect a broad orthobunyavirus spectrum. As an additional feature of the pan-Simbu real-time RT-PCR system, subsequent species classification via sequencing is feasible. Regarding SBV diagnostics, the performance of the S-segment targeting SBV-S3 assay was superior with respect to the analytical sensitivity.
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Affiliation(s)
| | | | | | | | | | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, D-17493, Greifswald-Insel Riems, Germany.
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111
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Wernike K, Beer M, Hoffmann B. Rapid detection of foot-and-mouth disease virus, influenza A virus and classical swine fever virus by high-speed real-time RT-PCR. J Virol Methods 2013; 193:50-4. [DOI: 10.1016/j.jviromet.2013.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 05/07/2013] [Accepted: 05/13/2013] [Indexed: 01/24/2023]
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112
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Simultaneous Identification of Pork and Poultry Origins in Pet Foods by a Quick Multiplex Real-Time PCR Assay Using EvaGreen Florescence Dye. Appl Biochem Biotechnol 2013; 171:1855-64. [DOI: 10.1007/s12010-013-0485-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 08/26/2013] [Indexed: 11/26/2022]
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113
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Assessment of the phenotype and functionality of porcine CD8 T cell responses following vaccination with live attenuated classical swine fever virus (CSFV) and virulent CSFV challenge. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 20:1604-16. [PMID: 23966552 DOI: 10.1128/cvi.00415-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vaccination with live attenuated classical swine fever virus (CSFV) induces solid protection after only 5 days, which has been associated with virus-specific T cell gamma interferon (IFN-γ) responses. In this study, we employed flow cytometry to characterize T cell responses following vaccination and subsequent challenge infections with virulent CSFV. The CD3(+) CD4(-) CD8(hi) T cell population was the first and major source of CSFV-specific IFN-γ. A proportion of these cells showed evidence for cytotoxicity, as evidenced by CD107a mobilization, and coexpressed tumor necrosis factor alpha (TNF-α). To assess the durability and recall of these responses, a second experiment was conducted where vaccinated animals were challenged with virulent CSFV after 5 days and again after a further 28 days. While virus-specific CD4 T cell (CD3(+) CD4(+) CD8α(+)) responses were detected, the dominant response was again from the CD8 T cell population, with the highest numbers of these cells being detected 14 and 7 days after the primary and secondary challenges, respectively. These CD8 T cells were further characterized as CD44(hi) CD62L(-) and expressed variable levels of CD25 and CD27, indicative of a mixed effector and effector memory phenotype. The majority of virus-specific IFN-γ(+) CD8 T cells isolated at the peaks of the response after each challenge displayed CD107a on their surface, and subpopulations that coexpressed TNF-α and interleukin 2 (IL-2) were identified. While it is hoped that these data will aid the rational design and/or evaluation of next-generation marker CSFV vaccines, the novel flow cytometric panels developed should also be of value in the study of porcine T cell responses to other pathogens/vaccines.
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114
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Development and validation of a multiplex, real-time RT PCR assay for the simultaneous detection of classical and African swine fever viruses. PLoS One 2013; 8:e71019. [PMID: 23923045 PMCID: PMC3724773 DOI: 10.1371/journal.pone.0071019] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 06/28/2013] [Indexed: 11/19/2022] Open
Abstract
A single-step, multiplex, real-time polymerase chain reaction (RT-PCR) was developed for the simultaneous and differential laboratory diagnosis of Classical swine fever virus (CSFV) and African swine fever virus (ASFV) alongside an exogenous internal control RNA (IC-RNA). Combining a single extraction methodology and primer and probe sets for detection of the three target nucleic acids CSFV, ASFV and IC-RNA, had no effect on the analytical sensitivity of the assay and the new triplex RT-PCR was comparable to standard PCR techniques for CSFV and ASFV diagnosis. After optimisation the assay had a detection limit of 5 CSFV genome copies and 22 ASFV genome copies. Analytical specificity of the triplex assay was validated using a panel of viruses representing 9 of the 11 CSFV subgenotypes, at least 8 of the 22 ASFV genotypes as well as non-CSFV pestiviruses. Positive and negative clinical samples from animals infected experimentally, due to field exposure or collected from the UK which is free from both swine diseases, were used to evaluate the diagnostic sensitivity and specificity for detection of both viruses. The diagnostic sensitivity was 100% for both viruses whilst diagnostic specificity estimates were 100% for CSFV detection and 97.3% for ASFV detection. The inclusion of a heterologous internal control allowed identification of false negative results, which occurred at a higher level than expected. The triplex assay described here offers a valuable new tool for the differential detection of the causative viruses of two clinically indistinguishable porcine diseases, whose geographical occurrence is increasingly overlapping.
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115
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Python S, Gerber M, Suter R, Ruggli N, Summerfield A. Efficient sensing of infected cells in absence of virus particles by plasmacytoid dendritic cells is blocked by the viral ribonuclease E(rns.). PLoS Pathog 2013; 9:e1003412. [PMID: 23785283 PMCID: PMC3681750 DOI: 10.1371/journal.ppat.1003412] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 04/25/2013] [Indexed: 02/07/2023] Open
Abstract
Plasmacytoid dendritic cells (pDC) have been shown to efficiently sense HCV- or HIV-infected cells, using a virion-free pathway. Here, we demonstrate for classical swine fever virus, a member of the Flaviviridae, that this process is much more efficient in terms of interferon-alpha induction when compared to direct stimulation by virus particles. By employment of virus replicon particles or infectious RNA which can replicate but not form de novo virions, we exclude a transfer of virus from the donor cell to the pDC. pDC activation by infected cells was mediated by a contact-dependent RNA transfer to pDC, which was sensitive to a TLR7 inhibitor. This was inhibited by drugs affecting the cytoskeleton and membrane cholesterol. We further demonstrate that a unique viral protein with ribonuclease activity, the viral Erns protein of pestiviruses, efficiently prevented this process. This required intact ribonuclease function in intracellular compartments. We propose that this pathway of activation could be of particular importance for viruses which tend to be mostly cell-associated, cause persistent infection, and are non-cytopathogenic. Plasmacytoid dendritic cells (pDC) represent the most potent producers of interferon type I and are therefore of major importance in antiviral defences. A TLR7-dependent induction of interferon-α in pDC by infected cells in the absence of virions has been demonstrated for hepatitis C virus. Here, we show that this pathway is also very efficient for classical swine fever virus, a pestivirus that is also a member of the Flaviviridae. Our data indicate a transfer of RNA from the donor cell to pDC in a cell-contact-dependent manner requiring intact lipid rafts and cytoskeleton of the donor cell. Importantly, we demonstrate that the enigmatic viral Erns protein unique to pestiviruses efficiently prevents this pathway of pDC activation. This novel function of Erns is dependent on its RNase activity within intracellular compartments. The present study underlines the importance of pDC activation by infected cells and identifies a novel pathway of virus escaping the interferon system. Considering that Erns is required for pestiviruses to establish persistent infection of foetuses after transplacental virus transmission resulting in the development of immunotolerant animals, this report also points on a possible role of pDC in preventing immunotolerance after viral infection of foetuses.
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Affiliation(s)
- Sylvie Python
- Institute of Virology and Immunology, Mittelhäusern, Switzerland
| | - Markus Gerber
- Institute of Virology and Immunology, Mittelhäusern, Switzerland
| | - Rolf Suter
- Institute of Virology and Immunology, Mittelhäusern, Switzerland
| | - Nicolas Ruggli
- Institute of Virology and Immunology, Mittelhäusern, Switzerland
- * E-mail: (NR); (AS)
| | - Artur Summerfield
- Institute of Virology and Immunology, Mittelhäusern, Switzerland
- * E-mail: (NR); (AS)
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116
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Li Z, Qi X, Zhou M, Bao C, Hu J, Wu B, Wang S, Tan Z, Fu J, Shan J, Zhu Y, Tang F. A two-tube multiplex real-time RT-PCR assay for the detection of four hemorrhagic fever viruses: severe fever with thrombocytopenia syndrome virus, Hantaan virus, Seoul virus, and dengue virus. Arch Virol 2013; 158:1857-63. [DOI: 10.1007/s00705-013-1677-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 02/13/2013] [Indexed: 11/29/2022]
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117
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Rivera-Benitez JF, García-Contreras ADC, Reyes-Leyva J, Hernández J, Sánchez-Betancourt JI, Ramírez-Mendoza H. Efficacy of quantitative RT-PCR for detection of the nucleoprotein gene from different porcine rubulavirus strains. Arch Virol 2013; 158:1849-56. [PMID: 23525730 DOI: 10.1007/s00705-013-1672-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 02/09/2013] [Indexed: 10/27/2022]
Abstract
Blue-eye disease is an emergent viral swine infection caused by porcine rubulavirus (PoRV). We have developed a qRT-PCR method to detect and quantify expression of the nucleoprotein gene for different PoRV strains. The limit of detection for this assay was 10(2) copies of synthetic RNA. Viral RNA from PoRV was detectable at a TCID50 of 0.01. Significant differences were observed between viral RNA quantification and virus titration results for nine PoRV strains. For nasal and oral swab samples that were collected from experimentally infected pigs, the qRT-PCR assay was more sensitive (87.1-83.9 %) for the detection of positive samples than methods involving isolation of virus. The implementation of highly sensitive assays that yield results quickly will be of great assistance in the eradication of PoRV from Mexico. We also believe that the newly developed qRT-PCR assay will help reduce the spread of this viral infection to other countries.
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Affiliation(s)
- José Francisco Rivera-Benitez
- Facultad de Medicina Veterinaria y Zootecnia, Departamento de Microbiología e Inmunología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
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118
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Qiu Y, Wang Z, Liu Y, Qi N, Miao M, Si J, Xiang X, Cai D, Hu Y, Zhou X. Membrane association of Wuhan nodavirus protein A is required for its ability to accumulate genomic RNA1 template. Virology 2013; 439:140-51. [PMID: 23490047 DOI: 10.1016/j.virol.2013.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/16/2013] [Accepted: 02/13/2013] [Indexed: 01/13/2023]
Abstract
One common feature of positive-strand RNA viruses is the association of viral RNA and viral RNA replicase proteins with specific intracellular membranes to form RNA replication complexes. Wuhan nodavirus (WhNV) encodes protein A, which is the sole viral RNA replicase. Here, we showed that WhNV protein A closely associates with mitochondrial outer membranes and colocalizes with viral RNA replication sites. We further identified the transmembrane domains (N-terminal aa 33-64 and aa 212-254) of protein A for membrane association and mitochondrial localization. Moreover, we found that protein A accumulates genomic RNA by stabilizing the RNA. And our further investigation revealed that the ability of WhNV protein A to associate with membranes is closely linked with its ability for membrane recruitment and stabilization of viral genomic RNA templates. This study represents an advance toward understanding the mechanism of the RNA replication of WhNV and probably other nodaviruses.
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Affiliation(s)
- Yang Qiu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan, Hubei 430072, China
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119
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Töpfer A, Höper D, Blome S, Beer M, Beerenwinkel N, Ruggli N, Leifer I. Sequencing approach to analyze the role of quasispecies for classical swine fever. Virology 2013; 438:14-9. [PMID: 23415390 DOI: 10.1016/j.virol.2012.11.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
Abstract
Classical swine fever virus (CSFV) is a positive-sense RNA virus with a high degree of genetic variability among isolates. High diversity is also found in virulence, with strains covering the complete spectrum from avirulent to highly virulent. The underlying genetic determinants are far from being understood. Since RNA polymerases of RNA viruses lack any proof-reading activity, different genome variations called haplotypes, occur during replication. A set of haplotypes is referred to as a viral quasispecies. Genetic variability can be a fitness advantage through facilitating of a more effective escape from the host immune response. In order to investigate the correlation of quasispecies composition and virulence in vivo, we analyzed next-generation sequencing data of CSFV isolates of varying virulence. Viral samples from pigs infected with the highly virulent isolates "Koslov" and "Brescia" showed higher quasispecies diversity and more nucleotide variability, compared to samples of pigs infected with low and moderately virulent isolates.
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Affiliation(s)
- Armin Töpfer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland.
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120
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Milicevic V, Dietze K, Plavsic B, Tikvicki M, Pinto J, Depner K. Oral vaccination of backyard pigs against classical swine fever. Vet Microbiol 2012; 163:167-71. [PMID: 23287388 DOI: 10.1016/j.vetmic.2012.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 11/27/2012] [Accepted: 12/06/2012] [Indexed: 12/15/2022]
Abstract
Vaccination represents a key pillar of most classical swine fever (CSF) control programmes. In backyard production systems the systematic implementation of parenteral vaccination proves to be difficult and alternative delivery mechanisms might be needed. In this study the use of oral vaccination against CSF in backyard pigs was tested under field conditions. The main objective was to assess uptake efficacy and immune response after oral vaccination of backyard pigs with bait vaccine currently used in the European Union for CSF control in wild boar (RIEMSER(®) Schweinepestoralvakzine). In total 85 backyard pigs belonging to 16 holdings were vaccinated orally by distributing four baits per pig, given on two consecutive days. The baits were distributed on pen floors. 73% of the pigs older than 12 weeks (n=41) had protective antibody titres 28 days after oral vaccination. The seroconversion rate in young piglets (n=44, younger than 12 weeks) was 64%. Based on the results obtained we concluded that in an endemic situation where usual control measures (stamping out, zoning with restrictive measures, parenteral vaccination, etc.) may prove to be insufficient, a systematic vaccination based on the use of oral vaccine can be an appropriate tool for an improved CSF control in backyard production systems.
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Affiliation(s)
- Vesna Milicevic
- Institute of Veterinary Medicine of Serbia, Vojvode Totze 14, 1000 Belgrade, Serbia
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121
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Transient elimination of circulating bovine viral diarrhoea virus by colostral antibodies in persistently infected calves: a pitfall for BVDV-eradication programs? Vet Microbiol 2012; 161:13-9. [DOI: 10.1016/j.vetmic.2012.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 06/20/2012] [Accepted: 07/02/2012] [Indexed: 11/18/2022]
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122
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Tarradas J, Monsó M, Fraile L, de la Torre BG, Muñoz M, Rosell R, Riquelme C, Pérez LJ, Nofrarías M, Domingo M, Sobrino F, Andreu D, Ganges L. A T-cell epitope on NS3 non-structural protein enhances the B and T cell responses elicited by dendrimeric constructions against CSFV in domestic pigs. Vet Immunol Immunopathol 2012; 150:36-46. [PMID: 22959286 DOI: 10.1016/j.vetimm.2012.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 08/05/2012] [Accepted: 08/08/2012] [Indexed: 12/15/2022]
Abstract
It has been recently reported by our group that dendrimeric constructs combining B- and T-cell epitopes from classical swine fever virus (CSFV) provided partial protection against experimental infection. This research evaluated four newly designed constructions while taking into account our previous work, including the direct implication that a T-cell epitope from the NS3 protein contributes to the generation of the immune response against CSFV. To this end, the dendrimeric constructions, including either this NS3 T-cell epitope alone or two different B-cell epitopes without this T-cell epitope, were used to immunise pigs. Thus, construct 1, containing the NS3 T-cell epitope and four copies of a previously described B-cell epitope, significantly reduced the clinical scores and RNA viral loads after challenge relative to the control group. In three out of six animals in this group, vaccination achieved partial protection and was associated with IFN-gamma producing-cells and neutralising antibodies. In contrast, the pigs immunised with construct 2, again with four copies of the B epitope of construct 1 but lacking the T-cell motif, developed more severe clinical signs. Finally, the additional constructs 3 and 4 included four copies of a B epitope that was different from the epitope used in constructs 1 and 2 with or without the abovementioned NS3 T-cell epitope, respectively. Pigs immunised with these latter constructs developed low levels of peptide-specific antibodies that correlated with equally low levels of cellular responses, an absence of neutralising antibodies and a lack of protection. Even so, the clinical scores in the first week after the challenge were less severe for animals vaccinated with construct 3 than for those given construct 4. Our results confirm the relevant role of the B-cell epitope in residues 694-712 of the glycoprotein E2 (which is used in both constructs 1 and 2) for protection against CSFV, as well as the appropriateness of the newly used NS3 peptide as a specific T-cell epitope in domestic pigs.
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Affiliation(s)
- Joan Tarradas
- Centre de Recerca en Sanitat Animal (CReSA), IRTA-UAB, Campus de la UAB, 08193 Bellaterra, Barcelona, Spain
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123
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Schrader C, Schielke A, Ellerbroek L, Johne R. PCR inhibitors - occurrence, properties and removal. J Appl Microbiol 2012; 113:1014-26. [PMID: 22747964 DOI: 10.1111/j.1365-2672.2012.05384.x] [Citation(s) in RCA: 1091] [Impact Index Per Article: 90.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 06/14/2012] [Accepted: 06/27/2012] [Indexed: 12/21/2022]
Abstract
The polymerase chain reaction (PCR) is increasingly used as the standard method for detection and characterization of microorganisms and genetic markers in a variety of sample types. However, the method is prone to inhibiting substances, which may be present in the analysed sample and which may affect the sensitivity of the assay or even lead to false-negative results. The PCR inhibitors represent a diverse group of substances with different properties and mechanisms of action. Some of them are predominantly found in specific types of samples thus necessitating matrix-specific protocols for preparation of nucleic acids before PCR. A variety of protocols have been developed to remove the PCR inhibitors. This review focuses on the general properties of PCR inhibitors and their occurrence in specific matrices. Strategies for their removal from the sample and for quality control by assessing their influence on the individual PCR test are presented and discussed.
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Affiliation(s)
- C Schrader
- Food Hygiene and Safety Concepts, Federal Institute for Risk Assessment, Berlin, Germany
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124
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Wernike K, Hoffmann B, Dauber M, Lange E, Schirrmeier H, Beer M. Detection and typing of highly pathogenic porcine reproductive and respiratory syndrome virus by multiplex real-time rt-PCR. PLoS One 2012; 7:e38251. [PMID: 22768042 PMCID: PMC3387184 DOI: 10.1371/journal.pone.0038251] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 05/04/2012] [Indexed: 11/24/2022] Open
Abstract
Porcine reproductive and respiratory syndrome (PRRS) causes economic losses in the pig industry worldwide, and PRRS viruses (PRRSV) are classified into the two distinct genotypes “North American (NA, type 2)” and “European (EU, type 1)”. In 2006, a highly pathogenic NA strain of PRRSV (HP-PRRSV), characterized by high fever as well as high morbidity and mortality, emerged in swine farms in China. Therefore, a real-time reverse transcription polymerase chain reaction (RT-qPCR) assay specific for HP-PRRSV was developed and combined with type 1- and type 2-specific RT-qPCR systems. Furthermore, an internal control, based on a heterologous RNA, was successfully introduced. This final multiplex PRRSV RT-qPCR, detecting and typing PRRSV, had an analytical sensitivity of less than 200 copies per µl for the type 1-assay and 20 copies per µl for the type 2- and HP assays and a high diagnostic sensitivity. A panel of reference strains and field isolates was reliably detected and samples from an animal trial with a Chinese HP-PRRS strain were used for test validation. The new multiplex PRRSV RT-qPCR system allows for the first time the highly sensitive detection and rapid differentiation of PRRSV of both genotypes as well as the direct detection of HP-PRRSV.
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Affiliation(s)
- Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Malte Dauber
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Elke Lange
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Horst Schirrmeier
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
- * E-mail:
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125
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Postel A, Schmeiser S, Bernau J, Meindl-Boehmer A, Pridotkas G, Dirbakova Z, Mojzis M, Becher P. Improved strategy for phylogenetic analysis of classical swine fever virus based on full-length E2 encoding sequences. Vet Res 2012; 43:50. [PMID: 22676246 PMCID: PMC3403906 DOI: 10.1186/1297-9716-43-50] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/07/2012] [Indexed: 01/21/2023] Open
Abstract
Molecular epidemiology has proven to be an essential tool in the control of classical swine fever (CSF) and its use has significantly increased during the past two decades. Phylogenetic analysis is a prerequisite for virus tracing and thus allows implementing more effective control measures. So far, fragments of the 5´NTR (150 nucleotides, nt) and the E2 gene (190 nt) have frequently been used for phylogenetic analyses. The short sequence lengths represent a limiting factor for differentiation of closely related isolates and also for confidence levels of proposed CSFV groups and subgroups. In this study, we used a set of 33 CSFV isolates in order to determine the nucleotide sequences of a 3508-3510 nt region within the 5´ terminal third of the viral genome. Including 22 additional sequences from GenBank database different regions of the genome, comprising the formerly used short 5´NTR and E2 fragments as well as the genomic regions encoding the individual viral proteins Npro, C, Erns, E1, and E2, were compared with respect to variability and suitability for phylogenetic analysis. Full-length E2 encoding sequences (1119 nt) proved to be most suitable for reliable and statistically significant phylogeny and analyses revealed results as good as obtained with the much longer entire 5´NTR-E2 sequences. This strategy is therefore recommended by the EU and OIE Reference Laboratory for CSF as it provides a solid and improved basis for CSFV molecular epidemiology. Finally, the power of this method is illustrated by the phylogenetic analysis of closely related CSFV isolates from a recent outbreak in Lithuania.
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Affiliation(s)
- Alexander Postel
- EU and OIE Reference Laboratory for Classical Swine Fever, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine, Hannover, Germany.
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126
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Selection of classical swine fever virus with enhanced pathogenicity reveals synergistic virulence determinants in E2 and NS4B. J Virol 2012; 86:8602-13. [PMID: 22674973 DOI: 10.1128/jvi.00551-12] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), a highly contagious disease of pigs. There are numerous CSFV strains that differ in virulence, resulting in clinical disease with different degrees of severity. Low-virulent and moderately virulent isolates cause a mild and often chronic disease, while highly virulent isolates cause an acute and mostly lethal hemorrhagic fever. The live attenuated vaccine strain GPE(-) was produced by multiple passages of the virulent ALD strain in cells of swine, bovine, and guinea pig origin. With the aim of identifying the determinants responsible for the attenuation, the GPE(-) vaccine virus was readapted to pigs by serial passages of infected tonsil homogenates until prolonged viremia and typical signs of CSF were observed. The GPE(-)/P-11 virus isolated from the tonsils after the 11th passage in vivo had acquired 3 amino acid substitutions in E2 (T830A) and NS4B (V2475A and A2563V) compared with the virus before passages. Experimental infection of pigs with the mutants reconstructed by reverse genetics confirmed that these amino acid substitutions were responsible for the acquisition of pathogenicity. Studies in vitro indicated that the substitution in E2 influenced virus spreading and that the changes in NS4B enhanced the viral RNA replication. In conclusion, the present study identified residues in E2 and NS4B of CSFV that can act synergistically to influence virus replication efficiency in vitro and pathogenicity in pigs.
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127
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Leifer I, Blome S, Blohm U, König P, Küster H, Lange B, Beer M. Characterization of C-strain "Riems" TAV-epitope escape variants obtained through selective antibody pressure in cell culture. Vet Res 2012; 43:33. [PMID: 22515281 PMCID: PMC3463427 DOI: 10.1186/1297-9716-43-33] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 02/23/2012] [Indexed: 02/02/2023] Open
Abstract
Classical swine fever virus (CSFV) C-strain “Riems” escape variants generated under selective antibody pressure with monoclonal antibodies and a peptide-specific antiserum in cell culture were investigated. Candidates with up to three amino acid exchanges in the immunodominant and highly conserved linear TAV-epitope of the E2-glycoprotein, and additional mutations in the envelope proteins ERNS and E1, were characterized both in vitro and in vivo. It was further demonstrated, that intramuscular immunization of weaner pigs with variants selected after a series of passages elicited full protection against lethal CSFV challenge infection. These novel CSFV C-strain variants with exchanges in the TAV-epitope present potential marker vaccine candidates. The DIVA (differentiating infected from vaccinated animals) principle was tested for those variants using commercially available E2 antibody detection ELISA. Moreover, direct virus differentiation is possible using a real-time RT-PCR system specific for the new C-strain virus escape variants or using differential immunofluorescence staining.
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Affiliation(s)
- Immanuel Leifer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
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128
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Gabriel C, Blome S, Urniza A, Juanola S, Koenen F, Beer M. Towards licensing of CP7_E2alf as marker vaccine against classical swine fever-Duration of immunity. Vaccine 2012; 30:2928-36. [PMID: 22406108 DOI: 10.1016/j.vaccine.2012.02.065] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/19/2012] [Accepted: 02/25/2012] [Indexed: 11/24/2022]
Abstract
Classical swine fever (CSF) marker vaccine candidate CP7_E2alf was tested in a "duration of immunity" trial according to the World Organisation for Animal Heath (OIE) guidelines. To this means, 15 weaner pigs were either orally or intramuscularly vaccinated with a single dose of CP7_E2alf vaccine produced under Good Laboratory Practice (GLP) conditions. Ten additional pigs were included as controls. Six months later, all animals were oronasally challenged with highly virulent CSF virus (CSFV) strain "Koslov". Upon vaccination, all but one orally and all intramuscularly vaccinated pigs developed rising and later on stable CSFV glycoprotein E2-specific antibodies. In contrast, no CSFV E(rns)-specific "marker" antibodies were detectable prior to challenge infection. None of the co-housed control animals seroconverted. Upon challenge infection, all seropositive animals were protected from lethal challenge, whereas all control animals and the non-responder developed severe signs of CSF. One control animal recovered, the others had to be euthanised due to animal welfare reasons between days 4 and 7 post challenge infection. All protected animals showed quickly rising neutralizing antibodies reaching high titres by the end of the trial. At the end of the trial, the marker ELISA was positive for most challenged animals that survived the CSFV infection (27 out of 30). Using reverse transcription polymerase chain reaction, low level genome detection was seen in all vaccinated animals between days 4 and 10 post challenge infection, but no virus could be isolated from any samples of these animals. The OIE guidelines require seroconversion in at least 8 out of 10 vaccinated animals. This requirement was fulfilled. Moreover, only control animals should die. With this requirement, only the intramuscular vaccination fully complied as one orally vaccinated pig did not respond. Concluding, CP7_E2alf induced stable antibodies that led to protection from lethal challenge with highly virulent CSFV strain "Koslov" six months after vaccination, with the exception of one non-responder after oral vaccination.
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Affiliation(s)
- Claudia Gabriel
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
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129
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Blome S, Aebischer A, Lange E, Hofmann M, Leifer I, Loeffen W, Koenen F, Beer M. Comparative evaluation of live marker vaccine candidates "CP7_E2alf" and "flc11" along with C-strain "Riems" after oral vaccination. Vet Microbiol 2012; 158:42-59. [PMID: 22397931 DOI: 10.1016/j.vetmic.2012.02.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 02/04/2012] [Accepted: 02/09/2012] [Indexed: 10/28/2022]
Abstract
Due to the tremendous socio-economic impact of classical swine fever (CSF) outbreaks, emergency vaccination scenarios are continuously under discussion. Unfortunately, all currently available vaccines show restrictions either in terms of marker capacities or immunogenicity. Recent research efforts were therefore directed at the design of new modified live marker vaccines. Among the most promising candidates the chimeric pestiviruses "CP7_E2alf" and "flc11" were identified. Within an international research project, these candidates were comparatively tested in challenge experiments after a single oral vaccination. Challenge infection was carried out with highly virulent CSF virus strain "Koslov", 14 or 21 days post vaccination (dpv), respectively. Safety, efficacy, and marker potential were addressed. All assessments were done in comparison with the conventional "gold standard" C-strain "Riems" vaccine. In addition to the challenge trials, multiple vaccinations with both candidates were performed to further assess their marker vaccine potential. All vaccines were safe and yielded full protection upon challenge 21 days post vaccination. Neither serological nor virological investigations showed major differences among the three vaccines. Whereas CP7_E2alf also provided clinical protection upon challenge at 14 days post vaccination, only 50% of animals vaccinated with flc11, and 83% vaccinated with C-strain "Riems" survived challenge at this time point. No marked differences were seen in protected animals. Despite the fact that all multiple-vaccinated animals stayed sero-negative in the accompanying marker test, the discriminatory assay remains a weak point due to delayed or inexistent detection of some of the vaccinated and subsequently infected animals. Nevertheless, the potential as live marker vaccines could be confirmed for both vaccine candidates. Future efforts will therefore be directed at the licensing of "Cp7_E2alf" as the first live marker vaccine for CSF.
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Affiliation(s)
- Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Suedufer 10, 17493 Greifswald - Insel Riems, Germany
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130
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Şakalar E, Abasıyanık MF. The devolopment of duplex real-time PCR based on SYBR Green florescence for rapid ıdentification of ruminant and poultry origins in foodstuff. Food Chem 2012. [DOI: 10.1016/j.foodchem.2011.07.130] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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131
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Hoffmann B, Blome S, Bonilauri P, Fernández-Piñero J, Greiser-Wilke I, Haegeman A, Isaksson M, Koenen F, LeBlanc N, Leifer I, Le Potier MF, Loeffen W, Rasmussen TB, Stadejek T, Ståhl K, Tignon M, Uttenthal Å, van der Poel W, Beer M. Classical swine fever virus detection. J Vet Diagn Invest 2011; 23:999-1004. [DOI: 10.1177/1040638711416849] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The current study reports on a real-time reverse transcription polymerase chain reaction (real-time RT-PCR) ring trial for the detection of Classical swine fever virus (CSFV) genomic RNA undertaken by 10 European laboratories. All laboratories were asked to use their routine in-house real-time RT-PCR protocols and a standardized protocol commonly used by the Friedrich-Loeffler-Institute (FLI) on a panel of well-characterized samples. In general, all participants produced results within the acceptable range. The FLI assay, several in-house assays, and the commercial kits had high analytical sensitivity and specificity values. Nevertheless, some in-house systems had unspecific reactions or suboptimal sensitivity with only a single CSFV genotype. Follow-up actions involved either improvement of suboptimal assays or replacement of specific laboratory assays with the FLI protocol, with or without modifications. In conclusion, the ring trial showed reliability of classical swine fever diagnosis on an international level and helped to optimize CSFV-specific RT-PCR diagnostics.
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Affiliation(s)
- Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Paolo Bonilauri
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Jovita Fernández-Piñero
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Irene Greiser-Wilke
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Andy Haegeman
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Mats Isaksson
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Frank Koenen
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Neil LeBlanc
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Immanuel Leifer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Marie-Frederique Le Potier
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Willie Loeffen
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Thomas Bruun Rasmussen
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Tomasz Stadejek
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Karl Ståhl
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Marylène Tignon
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Åse Uttenthal
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Wim van der Poel
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Riems Island, Germany (Hoffmann, Blome, Beer)
- Diagnostic Section of Reggio Emilia, Lombardy and Emilia Romagna Experimental Zootechnic Institute, Reggio Emilia, Italy (Bonilauri)
- Animal Health Research Center, Madrid, Spain (Fernández-Piñero)
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine, Hannover, Germany (Greiser-Wilke)
- Veterinary and Agrochemical Research Center, Ukkel, Belgium (Haegeman, Koenen, Tignon)
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Schröer D, Veits J, Keil G, Römer-Oberdörfer A, Weber S, Mettenleiter TC. Efficacy of Newcastle disease virus recombinant expressing avian influenza virus H6 hemagglutinin against Newcastle disease and low pathogenic avian influenza in chickens and turkeys. Avian Dis 2011; 55:201-11. [PMID: 21793434 DOI: 10.1637/9539-092710-reg.1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A recombinant Newcastle disease virus (NDV) expressing H6 hemagglutinin (HA) of a low pathogenic avian influenza virus (LPAIV) was generated by reverse genetics (NDVH6). The H6 open reading frame was inserted as an additional transcription unit between the fusion and hemagglutinin-neuraminidase (HN) gene of lentogenic NDV clone 30. Expression of the foreign gene was demonstrated by northern blot, western blot, and indirect immunofluorescence analyses. The protective efficacy against Newcastle disease and avian influenza of subtype H6 was evaluated in 3-wk-old chickens and turkeys. A single vaccination protected specific-pathogen-free (SPF) chickens against a subsequent lethal NDV infection and prevented shedding of AIV after homologous H6 LPAIV infection. Furthermore, vaccinated and AIV-infected animals could be differentiated by detection of AIV nucleoprotein-specific antibodies. Three-week-old commercial turkeys, exhibiting NDV-specific maternal antibodies, were partially protected against a lethal NDV challenge infection. The mortality rate of NDVH6-immunized turkeys was reduced to 40% compared to 90% in unvaccinated birds. After H6 LPAIV infection, shedding in NDVH6-immunized turkeys was only marginally reduced compared to NDV-immunized control birds. We previously described HA-expressing NDV recombinants as potent bivalent vaccines against Newcastle disease and highly pathogenic avian influenza of subtype H5 or H7. The results presented here are in contrast to the high protective efficacy in SPF chickens, as a single vaccination with NDVH6 was insufficient in turkeys in the presence of maternal antibodies against NDV. Therefore, the vector virus has to be improved to overcome these limitations.
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Affiliation(s)
- Diana Schröer
- Institute of Molecular Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, D-17493 Greifswald-Insel Riems, Germany
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133
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Immunomodulatory effect of swine CCL20 chemokine in DNA vaccination against CSFV. Vet Immunol Immunopathol 2011; 142:243-51. [DOI: 10.1016/j.vetimm.2011.05.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 04/15/2011] [Accepted: 05/17/2011] [Indexed: 11/22/2022]
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134
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Development and validation of a novel SYBR Green real-time RT-PCR assay for the detection of classical swine fever virus evaluated on different real-time PCR platforms. J Virol Methods 2011; 174:53-9. [DOI: 10.1016/j.jviromet.2011.03.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Revised: 03/16/2011] [Accepted: 03/23/2011] [Indexed: 11/19/2022]
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135
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Partial protection against classical swine fever virus elicited by dendrimeric vaccine-candidate peptides in domestic pigs. Vaccine 2011; 29:4422-9. [DOI: 10.1016/j.vaccine.2011.03.095] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 03/24/2011] [Accepted: 03/28/2011] [Indexed: 11/23/2022]
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136
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Blome S, Gabriel C, Staubach C, Leifer I, Strebelow G, Beer M. Genetic differentiation of infected from vaccinated animals after implementation of an emergency vaccination strategy against classical swine fever in wild boar. Vet Microbiol 2011; 153:373-6. [PMID: 21684092 DOI: 10.1016/j.vetmic.2011.05.039] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/20/2011] [Accepted: 05/23/2011] [Indexed: 11/30/2022]
Abstract
Oral emergency vaccination against classical swine fever is a powerful tool to control disease outbreaks among European wild boar and thus to safeguard domestic pigs in affected regions. In the past, when virus detection was mainly done using virus isolation in cell culture or antigen enzyme-linked immunosorbent assays, modified live vaccine strains like C-strain "Riems", were barely detectable after oral vaccination campaigns. Nowadays, the use of highly sensitive molecular techniques has given rise to an increase in vaccine virus detections. This was also the case during the 2009 outbreak among German wild boar and the subsequent vaccination campaigns. To guarantee a rapid differentiation of truly infected from C-strain vaccinated animals, a combination of differentiating multiplex rRT-PCR assays with partial sequencing was implemented. Here, we report on the rational and use of this approach and the lessons learned during execution. It was shown that positive results in the recently developed vaccine strain (genotype) specific rRT-PCR assay can be taken as almost evidentiary whereas negative results should be confirmed by partial sequencing. Thus, combination of multiplex rRT-PCR assays as a first line differentiation with partial sequencing can be recommended for a genetic DIVA strategy in areas with oral vaccination against classical swine fever in wild boars.
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Affiliation(s)
- Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, Südufer 10, 17493 Greifswald - Insel Riems, Germany.
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137
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Liu J, Fan XZ, Wang Q, Xu L, Zhao QZ, Huang W, Zhou YC, Tang B, Chen L, Zou XQ, Sha S, Zhu YY. Dynamic distribution and tissue tropism of classical swine fever virus in experimentally infected pigs. Virol J 2011; 8:201. [PMID: 21535885 PMCID: PMC3107811 DOI: 10.1186/1743-422x-8-201] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 05/02/2011] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Classical swine fever (CSF), caused by the Classical swine fever virus (CSFV), is an Office International des Epizooties (OIE) notifiable disease. However, we are far from fully understand the distribution, tissue tropism, pathogenesis, replication and excretion of CSFV in pigs. In this report, we investigated the dynamic distribution and tissue tropism of the virus in internal organs of the experimentally infected pigs using real-time RT-PCR and immunohistochemistry (IHC). RESULTS A relative quantification real-time PCR was established and used to detect the virus load in internal organs of the experimentally infected pigs. The study revealed that the virus was detected in all 21 of the internal organs and blood collected from pigs at day 1 to day 8 post infections, and had an increasing virus load from day 1 to day 8 post infections. However, there was irregular distribution virus load in most internal organs over the first 2 days post infection. Blood, lymphoid tissue, pancreas and ileum usually contain the highest viral loads, while heart, duodenum and brain show relatively low viral loads. CONCLUSIONS All the data suggest that CSFV had an increasing virus load from day 1 to day 8 post infections in experimentally infected pigs detected by real-time RT-PCR, which was in consistent with the result of the IHC staining. The data also show that CSFV was likely to reproduce in blood, lymphoid tissue, pancreas and the ileum, while unlikely to replicate in the heart, duodenum and brain. The results provide a foundation for further clarification of the pathogenic mechanism of CSFV in internal organs, and indicate that blood, lymphoid tissue, pancreas and ileum may be preferred sites of acute infection.
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Affiliation(s)
- Jun Liu
- China Institute of Veterinary Drug Control, National Classical Swine Fever Reference Laboratory, Beijing 100081, China
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138
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Thulke HH, Eisinger D, Beer M. The role of movement restrictions and pre-emptive destruction in the emergency control strategy against CSF outbreaks in domestic pigs. Prev Vet Med 2011; 99:28-37. [PMID: 21300412 DOI: 10.1016/j.prevetmed.2011.01.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Classical swine fever (CSF) outbreaks in domestic pig herds lead to the implementation of standard control measures according to legislative regulations. Ideal outbreak control entails the swift and efficient culling of all pigs on premises detected positive for CSF virus. Often all pig holdings around the detected cases are pre-emptively destroyed to exclude transmission into the neighbourhood. In addition to these measures, zones are defined in which surveillance and protection measures are intensified to prevent further distant disease spread. In particular, all movements are prohibited within standstill areas. Standstill also excludes the transport of fattened pigs to slaughter. Historical outbreaks provide evidence of the success of this control strategy. However, the extent to which the individual strategy elements contribute to this success is unknown. Therefore, we applied a spatially and temporally explicit epidemic model to the problem. Its rule-based formulation is tailored to a one-by-one model implementation of existing control concepts. Using a comparative model analysis the individual contributions of single measures to overall control success were revealed. From the results of the model we concluded that movement restrictions had the dominant impact on strategy performance suggesting a reversal of the current conceptual thinking. Additional measures such as pre-emptive culling only became relevant under imperfect compliance with movement restrictions. The importance of movement restrictions for the overall control success illustrates the need for explicit consideration of this measure when contingency strategies are being amended (e.g. emergency vaccination) and associated risks assessed.
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Affiliation(s)
- Hans-Hermann Thulke
- UFZ, Helmholtz Centre for Environmental Research - UFZ, Department of Ecological Modelling, Permoserstr. 15, 04318 Leipzig, Germany.
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139
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Wernike K, Hoffmann B, Kalthoff D, König P, Beer M. Development and validation of a triplex real-time PCR assay for the rapid detection and differentiation of wild-type and glycoprotein E-deleted vaccine strains of Bovine herpesvirus type 1. J Virol Methods 2011; 174:77-84. [PMID: 21458493 DOI: 10.1016/j.jviromet.2011.03.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/22/2011] [Accepted: 03/24/2011] [Indexed: 12/22/2022]
Abstract
Two important components of control programs for Bovine herpesvirus type 1 (BoHV-1), a major pathogen of cattle, are the detection of outbreaks and vaccination with glycoprotein E (gE)-deleted marker vaccines. In addition to serology, rapid and accurate investigation of BoHV-1 and genetic differentiation of vaccine and wild-type strains are also important methods. Therefore, a triplex quantitative real-time polymerase chain reaction (qPCR) for testing BoHV-1 was developed. Apart from a BoHV-1 specific glycoprotein D (gD) assay, a gE-specific system for differentiation between wild-type BoHV-1 and gE-deleted vaccine strains was established. Finally, an internal control, based on the beta-actin gene was introduced successfully completing the multiplex system. The triplex BoHV-1-qPCR has an analytical sensitivity of less than 10 genome copies per reaction, and the diagnostic sensitivity was equal to or even greater than that of the 'gold standard' method of virus isolation in cell culture. A series of reference strains, including gE-deleted BoHV-1 and field isolates were detected reliably. For validation of the specificity of the test, nasal swabs, semen and different organ material from cattle, negative for BoHV-1, and genetically related herpesvirus strains were examined. The new multiplex BoHV-1-specific qPCR system allows highly sensitive and rapid genetic detection and differentiation of BoHV-1 and will be a valuable method for the control of BoHV-1 infection.
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Affiliation(s)
- Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
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140
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Penrith ML, Vosloo W, Mather C. Classical swine fever (hog cholera): review of aspects relevant to control. Transbound Emerg Dis 2011; 58:187-96. [PMID: 21303492 DOI: 10.1111/j.1865-1682.2011.01205.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Classical swine fever (CSF) has the ability to spread over large distances when human intervention such as illegal swill feeding facilitates its movement. This was apparent during 2005 when CSF appeared in South Africa (SA) after an absence of 87 years. In this review, various newly published developments in terms of the diagnosis of the disease and vaccination are described and applied to situations similar to SA. The role of wildlife such as feral pigs and European wild boar in the dissemination and maintenance of CSF virus are discussed, and the dearth of knowledge on the potential of other wild pig species prevalent on southern Africa noted. The modes of spread and control measures to prevent introduction as well as during outbreaks are discussed.
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Affiliation(s)
- M-L Penrith
- TAD Scientific C.C., Menlo Park, South Africa.
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141
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Leifer I, Blome S, Beer M, Hoffmann B. Development of a highly sensitive real-time RT-PCR protocol for the detection of Classical swine fever virus independent of the 5' untranslated region. J Virol Methods 2010; 171:314-7. [PMID: 21111760 DOI: 10.1016/j.jviromet.2010.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 11/15/2010] [Accepted: 11/18/2010] [Indexed: 11/30/2022]
Abstract
Classical swine fever (CSF) is one of the most severe diseases of pigs, and can cause immense economic losses. Real-time reverse transcription polymerase chain reaction (rRT-PCR) can be used as a sensitive and specific method for detection of Classical swine fever virus (CSFV). Different published protocols are used routinely for CSFV diagnosis. However, almost all these systems use the highly conserved 5' untranslated region (5'UTR) of the CSFV genome as template. For a reliable diagnosis in outbreaks, a confirmatory assay that amplifies a different genome region is advisable. In this study a new CSFV specific rRT-PCR system using the NS5A region as template is described. The assay is multiplexed with a β-actin detection system that is used as an internal control in a single tube assay. The system was validated using recent European CSFV field isolates, dilution series of an in vitro transcribed RNA standard, and a panel of RNAs representing all available Pestivirus species and genotypes. It was shown that the new assay allows reliable detection of CSFV genomes independent of the 5'UTR region. It presents a very useful diagnostic tool, also allowing a 'double check' approach to rule out 5'UTR amplicon contaminations.
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Affiliation(s)
- Immanuel Leifer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
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142
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Li M, Yu J, Li Y, Li D, Yan D, Ruan Q. CXCR4+ progenitors derived from bone mesenchymal stem cells differentiate into endothelial cells capable of vascular repair after arterial injury. Cell Reprogram 2010; 12:405-15. [PMID: 20698779 DOI: 10.1089/cell.2009.0088] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent findings indicate that bone marrow mesenchymal stem cells (BMSCs) participate in the process of neovascularization in response to repair to injury and are involved in postinfarction myocardial repair. It is unclear what special characteristics the vascular progenitors of bone marrow origin has. CXCR4(+) stem/progenitor cells mobilized to the infarct area and improved the myocardial repair. In present study, we aimed to determine whether CXCR4(+)BMSCs contribute to the angiogenic capacity in vitro and in vivo. CXCR4(+)BMSCs were separated by using paramagnetic microbeads and cultured. RT-PCR and FACS analysis confirmed the gene expression phenotype. The uptake of acetylated low density lipoprotein (acLDL) and the tube formation evaluated the function of CXCR4(+)BMSCs. The effect of CXCR4(+)BMSCs transplantation on neovascularization was investigated in a murine model hindlimb ischemia. After induced by VEGF, CXCR4(+)BMSCs expressed the endothelial cells (ECs) phenotype. The expression of EC markers, PECAM-1, and von Willebrand factor (vWF) increased significantly at both the mRNA and protein levels. In addition, CXCR4(+)BMSCs enhanced the uptakes of Dil-acLDL and form capillary-like tubes in vitro. In vivo the local transfer of CXCR4(+)BMSCs increased neovascularization in ischemic hindlimb. These results demonstrate that CXCR4(+)BMSCs differentiate into ECs and contribute to neovascularization in the vascular lesion,, which indicate the important therapeutic implications for cardiovascular diseases and a new cell source for cell-based vascular engineering and repair in the future.
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Affiliation(s)
- Mincai Li
- Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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143
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Kang X, Li Y, Liu H, Lin F, Cai X, Sun T, Chang G, Zhu Q, Yang Y. A duplex real-time reverse transcriptase polymerase chain reaction assay for detecting western equine and eastern equine encephalitis viruses. Virol J 2010; 7:284. [PMID: 20977706 PMCID: PMC2974676 DOI: 10.1186/1743-422x-7-284] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 10/26/2010] [Indexed: 11/10/2022] Open
Abstract
In order to establish an accurate, ready-to-use assay for simultaneous detection of Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus (WEEV), we developed one duplex TaqMan real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay, which can be used in human and vector surveillance. First, we selected the primers and FAM-labeled TaqMan-probe specific for WEEV from the consensus sequence of NSP3 and the primers and HEX-labeled TaqMan-probe specific for EEEV from the consensus sequence of E3, respectively. Then we constructed and optimized the duplex real-time RT-PCR assay by adjusting the concentrations of primers and probes. Using a series of dilutions of transcripts containing target genes as template, we showed that the sensitivity of the assay reached 1 copy/reaction for EEEV and WEEV, and the performance was linear within the range of at least 106 transcript copies. Moreover, we evaluated the specificity of the duplex system using other encephalitis virus RNA as template, and found no cross-reactivity. Compared with virus isolation, the gold standard, the duplex real time RT-PCR assay we developed was 10-fold more sensitive for both WEEV and EEEV detection.
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Affiliation(s)
- Xiaoping Kang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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144
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Podgórska K, Stadejek T. Optimisation of reverse transcription can improve the sensitivity of RT-PCR for detection of classical swine fever virus. Acta Vet Hung 2010; 58:257-64. [PMID: 20460224 DOI: 10.1556/avet.58.2010.2.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Classical swine fever is a highly contagious, notifiable disease of pigs and wild boars listed by the World Organisation for Animal Health (OIE). Therefore, methods employed in the diagnosis of CSF should be fast, sensitive and specific. The aim of this study was optimisation of the reverse transcription reaction to increase the sensitivity of real-time RT-PCR for the detection of classical swine fever virus, the aetiological agent of the disease. The efficiency of reverse transcription reaction was compared including a range of reverse transcriptases, thermal conditions and priming methods based on results obtained in the following realtime PCR. Depending on catalysis and the priming method used in the study a significant diversity of results was observed. The best efficacy of reverse transcription was obtained using SuperScript II reverse transcriptase and priming with random nonamers and reverse, gene-specific primer. This combination improved the sensitivity of RT-PCR nearly 1000 times as compared to the method with AMV reverse transcriptase coupled with random hexamers. In summary, this study has demonstrated that the optimisation of reverse transcription can contribute to a higher sensitivity of RT-PCR diagnostic methods.
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Affiliation(s)
- Katarzyna Podgórska
- 1 National Veterinary Research Institute Swine Diseases Department Al. Partyzantów 57 24-100 Puławy Poland
| | - Tomasz Stadejek
- 1 National Veterinary Research Institute Swine Diseases Department Al. Partyzantów 57 24-100 Puławy Poland
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145
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Zhang XJ, Xia H, Everett H, Sosan O, Crooke H, Belák S, Widén F, Qiu HJ, Liu L. Evaluation of a primer-probe energy transfer real-time PCR assay for detection of classical swine fever virus. J Virol Methods 2010; 168:259-61. [PMID: 20471428 DOI: 10.1016/j.jviromet.2010.05.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 04/28/2010] [Accepted: 05/05/2010] [Indexed: 11/15/2022]
Abstract
This study describes evaluation of a real-time PCR assay based on primer-probe energy transfer (PriProET) technology for detection of classical swine fever virus (CSFV). The PriProET technology allows melting curve analysis following PCR amplification and thus provides a higher specificity. The assay was compared with a TaqMan assay by testing a total of 203 samples including 175 clinical specimens and 28 batches of Hog Cholera Lapinized Virus (HCLV) vaccine. The two assays gave the same results for 184 (91%) samples. Compared with the TaqMan assay, 19 additional samples were found to be positive for CSFV using the PriProET assay. In an RNA mixture of both wild type CSFV and C-strain vaccine, the melting curves displayed only one curve: either a wild type-like or a vaccine-like depending on the dominating RNA. The PriProET assay can be a routine molecular tool or a confirmative tool for diagnosis of classical swine fever (CSF), especially in the case of samples that yield an inconclusive result by the TaqMan assay.
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Affiliation(s)
- Xing-Juan Zhang
- Division of Swine Infectious Diseases, National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 150001 Harbin, China
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146
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Reimann I, Depner K, Utke K, Leifer I, Lange E, Beer M. Characterization of a new chimeric marker vaccine candidate with a mutated antigenic E2-epitope. Vet Microbiol 2010; 142:45-50. [DOI: 10.1016/j.vetmic.2009.09.042] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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147
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Tignon M, Kulcsár G, Haegeman A, Barna T, Fábián K, Lévai R, Van der Stede Y, Farsang A, Vrancken R, Belák K, Koenen F. Classical swine fever: Comparison of oronasal immunisation with CP7E2alf marker and C-strain vaccines in domestic pigs. Vet Microbiol 2010; 142:59-68. [DOI: 10.1016/j.vetmic.2009.09.044] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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148
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Kaden V, Lange E, Küster H, Müller T, Lange B. An update on safety studies on the attenuated "RIEMSER Schweinepestoralvakzine" for vaccination of wild boar against classical swine fever. Vet Microbiol 2009; 143:133-8. [PMID: 20022716 DOI: 10.1016/j.vetmic.2009.11.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 10/15/2009] [Accepted: 11/16/2009] [Indexed: 10/20/2022]
Abstract
The RIEMSER Schweinepestoralvakzine is an attenuated vaccine for oral vaccination of wild boar against classical swine fever (CSF). The safety of this licensed bait vaccine which is based on the CSF virus (CSFV) strain "C" was investigated in eight animal species, e.g. weaner pigs (n=111), wild boar (n=11), ruminants (cattle, goats and sheep, n=11), foxes (n=5), rabbits (n=12), and mice (n=10). Animals were vaccinated either with a single vaccine dose containing at least 10(4.5) TCID(50), or with overdoses, i.e. the 10-fold dose, or they were subjected to repeated application schemes. During the entire observation period none of the animals which were given the vaccine virus showed clinical signs, with the exception of rabbits. These reacted to the vaccination with fever. Orally vaccinated pigs did not transmit vaccine virus to susceptible contact animals (sentinels). In none of the species examined neither vaccine virus nor viral RNA could be detected in blood after vaccination. In one wild boar viral RNA could be established in the tonsil 21 days post-vaccination (dpv); all other organ samples tested virologically negative. Up to 77.5% of the pigs and wild boar developed virus neutralising antibodies (VNA) already 14 dpv. The mean VNA titres observed in the vaccination groups seemed to depend rather on individual factors than on the administered virus dose (virus titre per dose) or the vaccination scheme. These results are comparable with findings obtained during oral vaccination campaigns in wild boar and after parenteral vaccination with this C-strain virus. From the results presented here it can be concluded that RIEMSER Schweinepestoralvakzine is safe for target and non-target species.
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Affiliation(s)
- Volker Kaden
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Infectology, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
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149
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Modified live marker vaccine candidate CP7_E2alf provides early onset of protection against lethal challenge infection with classical swine fever virus after both intramuscular and oral immunization. Vaccine 2009; 27:6522-9. [DOI: 10.1016/j.vaccine.2009.08.057] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 08/17/2009] [Accepted: 08/17/2009] [Indexed: 11/23/2022]
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150
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LeBlanc N, Leijon M, Jobs M, Blomberg J, Belák S. A novel combination of TaqMan RT-PCR and a suspension microarray assay for the detection and species identification of pestiviruses. Vet Microbiol 2009; 142:81-6. [PMID: 19854591 DOI: 10.1016/j.vetmic.2009.09.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The genus pestivirus contains four recognized species: classical swine fever virus, border disease virus, bovine viral diarrhoea virus types 1 and 2. All are economically important and globally distributed but classical swine fever is the most serious, concerning losses and control measures. It affects both domestic pigs and wild boars. Outbreaks of this disease in domestic pigs call for the most serious measures of disease control, including a stamping out policy in Europe. Since all the members of the pestivirus genus can infect swine, differential diagnosis using traditional methods poses some problems. Antibody tests may lack specificity due to cross-reactions, antigen capture ELISAs may have low sensitivity, and virus isolation may take several days or even longer time to complete. PCR-based tests overcome these problems for the most part, but in general lack the multiplexing capability to detect and differentiate all the pestiviruses simultaneously. The assay platform described here addresses all of these issues by combining the advantages of real-time PCR with the multiplexing capability of microarray technology. The platform includes a TaqMan real-time PCR designed for the universal detection of pestiviruses and a microarray assay that can use the amplicons produced in the real-time PCR to identify the specific pestivirus.
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Affiliation(s)
- Neil LeBlanc
- Joint R&D Division, Department of Virology, Immunobiology and Parasitology, National Veterinary Institute (SVA) and Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences (SLU), SE-751 89 Uppsala, Sweden.
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