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Jelsma T, Wijnker JJ, van der Poel WHM, Wisselink HJ. Intestinal Viral Loads and Inactivation Kinetics of Livestock Viruses Relevant for Natural Casing Production: a Systematic Review and Meta-Analysis. Pathogens 2021; 10:pathogens10020173. [PMID: 33557372 PMCID: PMC7915499 DOI: 10.3390/pathogens10020173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/15/2021] [Accepted: 01/29/2021] [Indexed: 01/26/2023] Open
Abstract
Animal intestines are the source of edible sausage casings, which are traded worldwide and may come from areas where notifiable infectious animal diseases are prevalent. To estimate the risks of virus contamination, knowledge about the quantity of virus and decimal reduction values of the standard preservation method by salting is of great importance. A literature search, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, was performed in search engine CAB Abstracts to determine the viral load of 14 relevant animal viruses in natural casings or intestines. Only a very limited number of scientific publications per virus were found and viral loads in the intestines varied from high for ASFV (five publications), BVDV (3), CSFV (6), PPRV (3), RPV (2) and TGEV (3) to moderate for PEDV (2) and SVDV (3), low for HEV (2) and FMDV (5), very low for VESV (1) and negative for PrV (2) and VSV (1). PRRSV was found in intestines, however, viral titers were not published. Three viruses (BVDV, CSFV and PPRV) with high viral loads were selected to search for their inactivation kinetics. For casings, no inactivation data were found, however, thermal inactivation data of these viruses were available, but differed in quantity, quality and matrices. In conclusion, important data gaps still exist when it comes to the quantitative inactivation of viruses in sausage casings or livestock intestines.
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Affiliation(s)
- Tinka Jelsma
- Department of Virology, Wageningen Bioveterinary Research (WBVR) Part of Wageningen University & Research (WUR), P.O. Box 65, 8200 AB Lelystad, The Netherlands;
- Correspondence:
| | - Joris J. Wijnker
- Department of Population Health Sciences, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80178, 3508 TD Utrecht, The Netherlands;
| | - Wim H. M. van der Poel
- Department of Virology, Wageningen Bioveterinary Research (WBVR) Part of Wageningen University & Research (WUR), P.O. Box 65, 8200 AB Lelystad, The Netherlands;
| | - Henk J. Wisselink
- Department of Infection Biology, Wageningen Bioveterinary Research (WBVR) Part of Wageningen University & Research (WUR), P.O. Box 65, 8200 AB Lelystad, The Netherlands;
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Wang L, Madera R, Li Y, McVey DS, Drolet BS, Shi J. Recent Advances in the Diagnosis of Classical Swine Fever and Future Perspectives. Pathogens 2020; 9:pathogens9080658. [PMID: 32824178 PMCID: PMC7460108 DOI: 10.3390/pathogens9080658] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 11/16/2022] Open
Abstract
Classical swine fever (CSF) is a highly contagious viral disease of pigs, including wild boar. It is regarded as one of the major problems in the pig industry as it is still endemic in many regions of the world and has the potential to cause devastating epidemics, particularly in countries free of the disease. Rapid and reliable diagnosis is of utmost importance in the control of CSF. Since clinical presentations of CSF are highly variable and may be confused with other viral diseases in pigs, laboratory diagnosis is indispensable for an unambiguous diagnosis. On an international level, well-established diagnostic tests of CSF such as virus isolation, fluorescent antibody test (FAT), antigen capture antibody enzyme-linked immunosorbent assay (ELISA), reverse-transcription polymerase chain reaction (RT-PCR), virus neutralization test (VNT), and antibody ELISA have been described in detail in the OIE Terrestrial Manual. However, improved CSF diagnostic methods or alternatives based on modern technologies have been developed in recent years. This review thus presents recent advances in the diagnosis of CSF and future perspectives.
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Affiliation(s)
- Lihua Wang
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
- Correspondence: (L.W.); (J.S.); Tel.: +1-785-532-4397 (L.W.); +1-785-532-4506 (J.S.)
| | - Rachel Madera
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
| | - Yuzhen Li
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
| | - David Scott McVey
- United States Department of Agriculture, Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Manhattan, KS 66502, USA; (D.S.M.); (B.S.D.)
| | - Barbara S. Drolet
- United States Department of Agriculture, Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Manhattan, KS 66502, USA; (D.S.M.); (B.S.D.)
| | - Jishu Shi
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (R.M.); (Y.L.)
- Correspondence: (L.W.); (J.S.); Tel.: +1-785-532-4397 (L.W.); +1-785-532-4506 (J.S.)
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3
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Jelsma T, Wijnker JJ, Smid B, Verheij E, van der Poel WH, Wisselink HJ. Salt inactivation of classical swine fever virus and African swine fever virus in porcine intestines confirms the existing in vitro casings model. Vet Microbiol 2019; 238:108424. [DOI: 10.1016/j.vetmic.2019.108424] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/20/2019] [Accepted: 09/20/2019] [Indexed: 11/25/2022]
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4
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Development of a triplex TaqMan real-time RT-PCR assay for differential detection of wild-type and HCLV vaccine strains of classical swine fever virus and bovine viral diarrhea virus 1. Res Vet Sci 2012; 92:512-8. [DOI: 10.1016/j.rvsc.2011.03.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/25/2011] [Accepted: 03/30/2011] [Indexed: 11/30/2022]
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5
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Animal health safety of fresh meat derived from pigs vaccinated against Classic Swine Fever. EFSA J 2009. [DOI: 10.2903/j.efsa.2009.933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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6
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7
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Chen HT, Zhang J, Ma LN, Ma YP, Ding YZ, Liu XT, Chen L, Ma LQ, Zhang YG, Liu YS. Rapid pre-clinical detection of classical swine fever by reverse transcription loop-mediated isothermal amplification. Mol Cell Probes 2008; 23:71-4. [PMID: 19103283 PMCID: PMC7126361 DOI: 10.1016/j.mcp.2008.12.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 11/22/2008] [Accepted: 12/05/2008] [Indexed: 12/04/2022]
Abstract
The usefulness of reverse transcription loop-mediated isothermal amplification (RT-LAMP) for rapid pre-clinical detection of classical swine fever virus (CSFV) infection was evaluated. The RT-LAMP reaction could be finished in 60 min under isothermal condition at 65 °C by employing a set of four primers targeting the 5′ untranslated region of CSFV. The RT-LAMP assay of CSFV showed higher sensitivities than that of RT-PCR, with a detection limit of 5 copies per reaction. No cross-reactivity was observed from the samples of other related viruses including porcine circovirus type 2, porcine parvovirus, porcine pseudorabies virus, Japanese encephalitis virus, and porcine reproductive and respiratory syndrome virus. The detection rates of CSFV RT-LAMP, RT-PCR and virus isolation for samples including blood, tonsil, nasal and rectal swabs from uninoculated pigs without any clear clinical symptom were 89%, 78% and 71%, respectively. Furthermore, all of the assays showed higher sensitivity for blood and tonsil swabs samples than nasal and rectal swabs. These results indicate that the CSFV RT-LAMP assay is a valuable tool for its rapid, cost-effective detection and has potential usefulness for rapid pre-clinical detection and surveillance of classical swine fever in developing countries.
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Affiliation(s)
- Hao-tai Chen
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
| | - Jie Zhang
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
| | - Li-na Ma
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
| | - Yan-ping Ma
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
| | - Yao-zhong Ding
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
| | - Xiang-tao Liu
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
| | - Lei Chen
- China Institute of Veterinary Drug Control, Beijing 100081, China
| | - Li-qing Ma
- Qinghai Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining 810003, China
| | - Yong-guang Zhang
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
| | - Yong-sheng Liu
- Key Laboratory of Animal Virology of Ministry of Agriculture, Key Laboratory of Veterinary Public Health of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 1 Xujiaping Road, Chengguan District, Lanzhou, Gansu Province 730046, China
- Corresponding author. Tel.: +86 931 8342166; fax: +86 931 8340977.
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8
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Development and evaluation of a rapid immunomagnetic bead assay for the detection of classical swine fever virus antigen. Trop Anim Health Prod 2008; 41:913-20. [DOI: 10.1007/s11250-008-9279-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 05/06/2007] [Indexed: 11/25/2022]
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9
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Khounsy S, Gleeson LJ, Van Aken D, Westbury HA, Blacksell SD. Diagnosis of classical swine fever virus in a limited resource setting: the influence of pig breed on methodology and sample selection. Trop Anim Health Prod 2007; 39:21-5. [PMID: 17941484 DOI: 10.1007/s11250-006-4442-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S Khounsy
- Department of Livestock and Fisheries, Ministry of Agriculture and Forestry, Vientiane, Lao People's Democratic Republic
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10
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Li Y, Zhao JJ, Li N, Shi Z, Cheng D, Zhu QH, Tu C, Tong GZ, Qiu HJ. A multiplex nested RT-PCR for the detection and differentiation of wild-type viruses from C-strain vaccine of classical swine fever virus. J Virol Methods 2007; 143:16-22. [PMID: 17346808 DOI: 10.1016/j.jviromet.2007.01.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 01/29/2007] [Accepted: 01/31/2007] [Indexed: 10/23/2022]
Abstract
A multiplex nested RT-PCR (RT-nPCR) was developed for the detection and differentiation of classical swine fever virus (CSFV). A fragment of 447 or 343 bp was amplified from the genomic RNA of C-strain or virulent Shimen strain, respectively, and two fragments of 447 and 343 bp were simultaneously amplified from the mixed samples of C-strain and Shimen. When detecting several wild-type isolates representative of different subgroups (1.1, 2.1, 2.2, and 2.3) circulating in Mainland China and samples from pigs experimentally infected with Shimen strain, the RT-nPCR resulted in an amplification pattern similar to Shimen. No amplification was achieved for uninfected cells, or cells infected with bovine viral diarrhea virus (BVDV), and other viruses of porcine origin. The RT-nPCR was able to detect as little as 0.04 pg of CSFV RNA. The restrictive fragment length polymorphism (RFLP) demonstrated unique patterns of wild-type viruses and C-strain. Among the 133 field samples, 42 were tested to contain wild-type viruses and 18 showing presence of C-strain. The RT-nPCR can be used to detect and differentiate pigs infected with wild-type CSFV from those vaccinated with C-strain vaccine, thus minimizing the risk of culling vaccinates during outbreaks.
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Affiliation(s)
- Yan Li
- Division of Swine Infectious Diseases, National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Harbin 150001, Heilongjiang, China
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11
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Zhao JJ, Cheng D, Li N, Sun Y, Shi Z, Zhu QH, Tu C, Tong GZ, Qiu HJ. Evaluation of a multiplex real-time RT-PCR for quantitative and differential detection of wild-type viruses and C-strain vaccine of Classical swine fever virus. Vet Microbiol 2007; 126:1-10. [PMID: 17658704 DOI: 10.1016/j.vetmic.2007.04.046] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Revised: 04/18/2007] [Accepted: 04/25/2007] [Indexed: 11/23/2022]
Abstract
Classical swine fever virus (CSFV) is the causative agent of classical swine fever (CSF), one of OIE listed diseases. Most of the currently available detection methods do not allow discrimination between wild-type CSF viruses and the vaccine strains. This study was designed to develop a multiplex real-time RT-PCR for the quantitative and differential detection of wild-type viruses and C-strain vaccine widely used in China. CSFV specific primers and two differently labeled TaqMan probes for the differentiation of wild-type viruses from C-strain vaccine were designed in the 5'-untranslated region of the viral genome of CSFV. The two TaqMan probes specifically hybridize wild-type viruses of different subgroups and C-strain vaccine, respectively, in the multiplex real-time RT-PCR, with no cross-reaction to a number of non-CSFV porcine viruses. The sensitivity of the assay for detecting wild-type and C-strain-type vaccine viruses was determined to be 41.8 and 81.5copies/microL viral RNA, respectively. Completely correct differentiation of wild-type viruses from C-strain vaccine was achieved when testing reference strains and characterized field isolates of CSFV in China. The multiplex real-time RT-PCR was able to detect the viral RNA in the whole blood samples of experimentally infected pigs as early as 2 days post-infection, 3 to 4 days prior to the onset of clinical signs in co-housed pigs. The agreements between the multiplex real-time RT-PCR and a multiplex RT-nested PCR for detection of wild-type and C-strain-type viruses were 96.9% and 100%, respectively, when detecting 106 different field samples. There is a positive correlation between the titers of C-strain vaccines titrated in rabbits and RNA copies quantitated by the multiplex real-time RT-PCR. The novel assay described here is rapid and sensitive, and is useful for differentiating field strains and C-strain of CSFV in China.
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Affiliation(s)
- Jian-Jun Zhao
- Division of Swine Infectious Diseases, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, 427 Maduan Street, Harbin 150001, Heilongjiang, China
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12
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Blacksell SD, Khounsy S, Van Aken D, Gleeson LJ, Westbury HA. Comparative susceptibility of indigenous and improved pig breeds to Classical swine fever virus infection: practical and epidemiological implications in a subsistence-based, developing country setting. Trop Anim Health Prod 2007; 38:467-74. [PMID: 17243474 DOI: 10.1007/s11250-006-4434-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study investigated the comparative susceptibility of indigenous Moo Laat and improved Large White/Landrace pig breeds to infection with classical swine fever virus (CSFV) under controlled conditions in the Lao People's Democratic Republic (Lao PDR). The Moo Laat (ML) and Large White/Landrace cross-breed (LWC) pigs were inoculated with a standard challenge strain designated Lao/Kham225 (infectivity titre of 10(2.75) TCID50/ml). The results demonstrated that both the native breed and an improved pig breed are fully susceptible to CSFV infection and the mortality rate is high. LWC pigs demonstrated lower (or shorter) survival times (50% survival time: 11 days), earlier and higher pyrexia and earlier onset of viraemia compared to ML pigs (50% survival time: 18 days). In the context of village-based pig production, the longer time from infection to death in native ML pigs means that incubating or early sick pigs are likely to be sold once an outbreak of CSF is recognized in a village. This increased longevity probably contributes to the maintenance and spread of disease in a population where generally the contact rate is low.
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Affiliation(s)
- S D Blacksell
- CSIRO Australian Animal Health Laboratory, Geelong, Victoria, Australia.
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13
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Ophuis RJAO, Morrissy CJ, Boyle DB. Detection and quantitative pathogenesis study of classical swine fever virus using a real time RT-PCR assay. J Virol Methods 2005; 131:78-85. [PMID: 16139899 DOI: 10.1016/j.jviromet.2005.07.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 07/05/2005] [Accepted: 07/06/2005] [Indexed: 10/25/2022]
Abstract
A real time reverse transcription (RT) TaqMan PCR assay for the detection of classical swine fever virus (CSFV) previously described for use on a SmartCycler was validated on the Applied Biosystems AB 7700 Sequence Detection System using the Roche MagNA pure instrument for nucleic acid extraction and reaction set up. The primers and probe were specific for the CSFV strains (NSW, Baker and Weybridge) and did not react with other pestiviruses (BDV Tobias, BDV #327, BVDV non-CPE and BVDV C24V). Analysis of blood samples collected from pigs 1-6 and 8 days post-oronasal infection showed that over >10(6) range there was a linear relationship between log10TCID50ml-1 blood and the log10 normalised genetic load measured by quantitative TaqMan assay. The assay was used to assess CSFV shedding from infected pigs by quantitative TaqMan assay of virus genetic loads in tonsil, nasal and rectal swabs. Infection of tonsils was detected as early as 1 day post-inoculation. Shedding of virus detected by nasal and rectal swabs commenced on the third day post-inoculation. Quantitative TaqMan was used to analyse virus genetic load in tissues collected from pigs killed on days 1-3, 5 and 8 post-infection. Virus infection appeared first in tonsil (day 1), then submandibular lymph node, spleen, ileum and mesenteric lymph node (by day 3). Thereafter, virus spread to the visceral organs and finally to the pancreas and brain. Tonsil, nasal and rectal swabs as well as whole blood were found to be suitable samples for the rapid detection of CSFV using the TaqMan assay and automated nucleic acid extraction and reaction set up.
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Affiliation(s)
- Ralph J A Oude Ophuis
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Private Bag 24, Geelong, Vic. 3220, Australia
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14
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Risatti G, Holinka L, Lu Z, Kutish G, Callahan JD, Nelson WM, Brea Tió E, Borca MV. Diagnostic evaluation of a real-time reverse transcriptase PCR assay for detection of classical swine fever virus. J Clin Microbiol 2005; 43:468-71. [PMID: 15635018 PMCID: PMC540099 DOI: 10.1128/jcm.43.1.468-471.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A fluorogenic-probe hydrolysis (TaqMan)-reverse transcriptase (RT) PCR for classical swine fever virus (CSFV) was evaluated for diagnostic sensitivity and specificity by using clinical samples obtained from the Dominican Republic, where the disease is enzootic. The sensitivity of this test, using nasal swab samples taken from both symptomatic and asymptomatic animals, exceeded the diagnostic sensitivity of virus isolation (100% versus 72.4%, respectively) with little loss of specificity (98.9% versus 100%, respectively). At the herd level, three of four infected farms were identified by virus isolation, while the CSFV real-time RT-PCR assay identified all four infected premises. This simple and accurate test permits rapid detection of CSFV in affected herds.
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Affiliation(s)
- G Risatti
- Plum Island Animal Disease Center, Agricultual Research Service, United States Department of Agriculture, P.O. Box 848, Greenport, NY 11944-0848, USA
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15
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Blacksell SD, Khounsy S, Boyle DB, Greiser-Wilke I, Gleeson LJ, Westbury HA, Mackenzie JS. Phylogenetic analysis of the E2 gene of classical swine fever viruses from Lao PDR. Virus Res 2004; 104:87-92. [PMID: 15177896 DOI: 10.1016/j.virusres.2004.02.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2003] [Revised: 02/27/2004] [Accepted: 02/27/2004] [Indexed: 11/26/2022]
Abstract
The E2 genes of 21 classical swine fever viruses (CSFV) were genetically characterized and compared with reference CSF viruses. The viruses originated from CSF outbreaks that occurred in the Lao People's Democratic Republic (Lao PDR) during 1997 though to 1999. All viruses characterized belonged to genogroup 2 and were members of subgroups 2.1 and 2.2. Results demonstrated a geographic delineation between subgroups 2.1 that was only found in the North-Central region, and subgroup 2.2 that was mostly found in the South-Central regions of Lao PDR. Although it was not possible to determine the origin of these viruses, it is probable that they may have been introduced to Lao PDR following cross-border trade. Alternatively, they have evolved independently of other viruses in the region.
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Affiliation(s)
- Stuart D Blacksell
- Australian Animal Health Laboratory, CSIRO Livestock Industries, Geelong, Victoria, Australia.
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16
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Blacksell SD, Khounsy S, Westbury HA. The effect of sample degradation and RNA stabilization on classical swine fever virus RT-PCR and ELISA methods. J Virol Methods 2004; 118:33-7. [PMID: 15158066 DOI: 10.1016/j.jviromet.2004.01.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Revised: 01/06/2004] [Accepted: 01/07/2004] [Indexed: 11/26/2022]
Abstract
Classical swine fever (CSF), also known as hog cholera, is a highly contagious viral infection of swine caused by a member of the genus pestivirus of the family, Flaviviridae. The need for accurate laboratory diagnosis of CSF is particularly important as it is more reliable than clinical diagnosis. CSF is endemic in many tropical countries where the climate is characterized by high ambient temperature and humidity. This study details the effect of sample quality on CSF antigen-capture ELISA (AC-ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR) methods. RT-PCR assessment of AC-ELISA-positive spleen samples stored in a conventional glycerol/saline buffer demonstrated that the RT-PCR was detrimentally affected by poor sample quality. To provide a more accurate representation of this effect, a 14 days study was performed to determine the effect of tropical ambient conditions on CSF virus-positive spleen samples stored in two transport media; glycerol/saline and a proprietary RNA preservation solution (RNAlater). A protective effect was demonstrated in both assays with RNAlater as samples were positive in both assays until day 14 post-exposure. Samples stored in glycerol/saline were negative at RT-PCR at day 3 post-exposure although AC-ELISA was still positive at day 14 post-exposure.
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Affiliation(s)
- Stuart D Blacksell
- CSIRO Australian Animal Health Laboratory, P.O. Bag 24, Geelong, Victoria 3200, Australia.
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17
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Hammond JM, Jansen ES, Morrissy CJ, Hodgson ALM, Johnson MA. Protection of pigs against ‘in contact’ challenge with classical swine fever following oral or subcutaneous vaccination with a recombinant porcine adenovirus. Virus Res 2003; 97:151-7. [PMID: 14602208 DOI: 10.1016/j.virusres.2003.08.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A recombinant porcine adenovirus expressing the classical swine fever virus (CSFV) gp55 gene (rPAdV-gp55) was administered to commercially available outbred pigs via the subcutaneous or oral route and their susceptibility to 'in contact' challenge with classical swine fever determined. Animals vaccinated subcutaneously with a single dose of recombinant vaccine and challenged by 'in contact' exposure were protected from disease, whereas pigs given an equivalent single oral dose did not survive challenge. However, pigs given two oral doses of rPAdV-gp55, 22 days apart, were completely protected from disease. In addition, two doses of rPAdV-gp55 given subcutaneously was shown to boost CSFV neutralising antibody compared with a single dose, but neither a single dose nor two doses given orally induced detectable neutralising antibody responses.
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Affiliation(s)
- Jef M Hammond
- Australian Animal Health Laboratory, CSIRO Livestock Industries, Private Mail Bag 24, Geelong, Vic. 3220, Australia
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18
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Risatti GR, Callahan JD, Nelson WM, Borca MV. Rapid detection of classical swine fever virus by a portable real-time reverse transcriptase PCR assay. J Clin Microbiol 2003; 41:500-5. [PMID: 12517907 PMCID: PMC149591 DOI: 10.1128/jcm.41.1.500-505.2003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A fluorogenic-probe hydrolysis (TaqMan)-reverse transcriptase PCR assay for classical swine fever virus (CSFV) was developed and evaluated in experimentally infected swine. The assay detected CSFV, representing different phylogenetic groupings, but did not amplify viral RNA from related pestiviruses. The assay met or exceeded the sensitivity (1 to 100 50% tissue culture infective doses per ml) of viral cultures of samples from experimentally infected animals. Viral RNA was detected in nasal and tonsil scraping samples 2 to 4 days prior to the onset of clinical disease. The assay can be performed in 2 h or less, thus providing a rapid method for the diagnosis of classical swine fever.
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Affiliation(s)
- G R Risatti
- Plum Island Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Greenport, New York 11944, USA
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19
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Detection of the classical swine fever virus antigen following experimental infection. ACTA VET-BEOGRAD 2002. [DOI: 10.2298/avb0203117m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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20
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Gómez-Villamandos JC, Ruiz-Villamor E, Bautista MJ, Sánchez CP, Sánchez-Cordón PJ, Salguero FJ, Jover A. Morphological and immunohistochemical changes in splenic macrophages of pigs infected with classical swine fever. J Comp Pathol 2001; 125:98-109. [PMID: 11578124 DOI: 10.1053/jcpa.2001.0487] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Classical swine fever (CSF) was induced in 20 pigs by inoculation with a virulent strain of CSF virus to determine sequential changes (2, 4, 7, 10 and 14 days post-inoculation) in the number and morphology of splenic macrophages (red pulp and lymphoid marginal zone) and thus to assess the role of these cells in the pathogenesis of the disease. The first splenic cells to be infected with CSF virus were macrophages in the marginal zone followed by other macrophage populations. The initial phase of CSF was associated with an increase in splenic macrophage numbers in the marginal zone and a decrease in the red pulp. Subsequently, the numbers in the red pulp increased. The study suggested that infection, mobilization and apoptosis of splenic macrophages play an important role in the spread of CSF virus in vivo. Moreover, the secretory changes that occurred in macrophages in the initial phase of the infection suggested that macrophages release chemical mediators capable of modulating pathogenesis.
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Affiliation(s)
- J C Gómez-Villamandos
- Departamento Anatomía Patológica, Facultad de Veterinaria, Campus Universitario de Rabaneles, 14014 Córdoba, Spain
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21
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Hammond JM, Jansen ES, Morrissy CJ, Goff WV, Meehan GC, Williamson MM, Lenghaus C, Sproat KW, Andrew ME, Coupar BE, Johnson MA. A prime-boost vaccination strategy using naked DNA followed by recombinant porcine adenovirus protects pigs from classical swine fever. Vet Microbiol 2001; 80:101-19. [PMID: 11295331 DOI: 10.1016/s0378-1135(00)00388-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Weaned pigs (6-week-old) and 7-day-old pre-weaned piglets were vaccinated with naked plasmid DNA expressing the gp55/E2 gene from classical swine fever virus (CSFV). Both groups of pigs were then given a booster dose of recombinant porcine adenovirus expressing the gp55 gene (rPAV-gp55). Following challenge with CSFV, 100% of weaned pigs and 75% pre-weaned piglets were protected from disease. Weaned pigs given a single dose of rPAV-gp55 were also protected, but showed a slight increase in temperature immediately post-challenge. However, weaned animals given a DNA prime before rPAV-gp55 showed no fluctuation in body temperature following challenge and no pathology in spleen or lymph nodes upon post-mortem. In addition, no CSFV could be re-isolated from the rPAV vaccinated group and from only one pig in the prime-boost group following challenge, suggesting that both vaccination regimes have the potential to reduce or prevent virus shedding following experimental challenge.
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Affiliation(s)
- J M Hammond
- CSIRO, Australian Animal Health Laboratory, Geelong, 3220 Vic., Australia
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22
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Liu JJ, Wong ML, Chen PF, Chang TJ. Cloning, expression and sequence analysis of the classical swine fever virus nucleocapsid protein. Virus Genes 1998; 16:225-34. [PMID: 9608668 DOI: 10.1023/a:1007976208935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The DNA complementary to the 5'-terminal 1929 nucleotides of classical swine fever virus (CSFV; alias hog cholera virus, HCV) LPC vaccine strain RNA was cloned and sequenced. The sequence encompasses a 5'-noncoding region (NCR) of 264 nucleotides and an open reading frame (ORF) of 1665 nucleotides. The cloned sequence contains genes of four viral proteins, P23, nucleocapsid (core) protein, E0 and part of E1 proteins. Alignment of the 5'-terminal 1929 nucleotides of LPC strain with other strains of CSFV showed well conservation and a homology as high as 84-95% was found between these strains. The cDNA of CSFV-LPC core was cloned into an expression vector, and a fusion protein of 38.5 kDa was obtained which reacted strongly to CSFV antiserum. Purification of the core fusion protein was achieved by a single-step affinity chromatography and the purified product could be recognized by the sera of CSFV-infected swine in ELISA assay. Phylogenetic analysis of the 5'-terminal 1929 nucleotides between pestiviruses revealed that the 5'-end region seems to be suitable for differentiation of different strains of CSFV.
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Affiliation(s)
- J J Liu
- Department of Veterinary Medicine, National Chung-Hsing University, Taichung, Taiwan
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23
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McGoldrick A, Lowings JP, Ibata G, Sands JJ, Belak S, Paton DJ. A novel approach to the detection of classical swine fever virus by RT-PCR with a fluorogenic probe (TaqMan). J Virol Methods 1998; 72:125-35. [PMID: 9694320 DOI: 10.1016/s0166-0934(97)00208-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Detection of classical swine fever virus (CSFV) and its discrimination from other pestiviruses can be achieved by virus isolation (VI) in cell cultures, antigen detection, or molecular analysis. To simplify the latter, a 5'-nuclease assay (TaqMan) was developed for the rapid and specific detection of CSFV with the minimum of downstream PCR processing. A pair of 5'-non-coding region, panpestivirus-specific PCR primers were assessed in a one-step reverse transcription-PCR with each of 36 diverse pestiviruses. The PCR products were subsequently reamplified, in conjunction with a CSFV-specific fluorogenic probe, in a nested-PCR with a second set of panpestivirus PCR primers. During nested PCR, when the target of interest was present, the CSFV probe annealed to the amplicon between the forward and reverse primers and was subsequently cleaved via the 5'-3' nucleolytic activity of the DNA polymerase resulting in the release of the fluorescent reporter dye. Each PCR tube was then placed directly into a luminescence spectrometer to monitor for any increase in fluorescence due to cleavage of the probe. This assay detected representatives of all genetic sub-groups of CSFV, but gave negative results for other pestiviruses. A preliminary assessment showed that the method could be used to detect CSFV RNA extracted from infected pig blood with a sensitivity greater than that of VI.
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Affiliation(s)
- A McGoldrick
- Central Veterinary Laboratory, Veterinary Laboratories Agency, Addlestone, Surrey, UK
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24
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Wong ML, Liu JJ, Chang Y, Chang TJ. Expression of the glycoprotein E2 of the classical swine fever virus in Escherichia coli. J Vet Med Sci 1998; 60:541-4. [PMID: 9592734 DOI: 10.1292/jvms.60.541] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The glycoprotein E2 sequences of classical swine fever virus (strain p97) were cloned, sequenced and expressed in E. coli. Result from SDS-polyacrylamide gel electrophoresis analysis of expressed proteins revealed the presence of a prominently stained band corresponding to a molecular mass of 61 kDa, which is in agreement with the predicted size from the DNA sequence. The recombinant E2 protein contained an aminoterminal tag of six histidines that could be used for purification by the nickel chelate affinity chromatography. The elution fractions of the expressed protein also contain additional bands of 40 and 35 kDa proteins, indicating proteolytic cleavages might occur. Our Western blotting result also supported that the expression of the recombinant E2 protein of the classical swine fever virus were accomplished.
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Affiliation(s)
- M L Wong
- Department of Veterinary Medicine, National Chung-Hsing University, Taichung, Taiwan
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25
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Blacksell SD, Cameron AR, Chamnanpood C, Chamnanpood P, Tatong D, Monpolsiri M, Westbury HA. Implementation of internal laboratory quality control procedures for the monitoring of ELISA performance at a regional veterinary laboratory. Vet Microbiol 1996; 51:1-9. [PMID: 8828117 DOI: 10.1016/0378-1135(95)00204-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Quality control (QC) procedures for antigen detection enzyme-linked immunosorbent assays (ELISAs) for hog cholera (HC) virus, foot and mouth disease (FMD) virus, and an antibody detection ELISA for FMD virus were established at a regional veterinary laboratory in northern Thailand. A recently developed computer software package, QCEL, was used to facilitate management and analysis of QC data. The program was used to assess test performance by producing Shewhart-CUSUM control charts which monitored control data for unacceptable fluctuations or trends. QCEL-generated control charts and analyses are presented and discussed. The use of a simple integrated computerised system for storage and analysis of QC control data provided the laboratory with the opportunity to achieve increased confidence in the results of tests performed.
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Affiliation(s)
- S D Blacksell
- CSIRO Australian Animal Health Laboratory, Geelong, Victoria, Australia.
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26
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Abstract
Monoclonal antibody typing of pestiviruses, supplemented with genetic sequence comparisons, has shown that at least four antigenic clusters can be identified within the genus. One cluster represents "classic" bovine viral diarrhea strains, which also have been isolated occasionally from sheep and pigs, whereas a second group corresponds to classic swine fever (hog cholera) strains. A distinct group of "true" border disease isolates is found in sheep and has been isolated occasionally from swine. The fourth group is antigenically quite distinct form the others and has been isolated from sheep, pigs, and cattle. It includes recent American isolates from cases of acute severe hemorrhagic disease. The implications of these findings for diagnosis and control are discussed.
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Affiliation(s)
- S Edwards
- Virology Department, Ministry of Agriculture, Fisheries, and Food, Central Veterinary Laboratory, Weybridge, United Kingdom
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