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Staebler S, Buergi E, Litzenberger B, McCullough K, McNair I, McNeilly F, Pospischil A, Sydler T. Porcine circovirus as a possible cause of postweaning wasting in pigs in Switzerland. SCHWEIZ ARCH TIERH 2012; 146:461-8; discussion 469. [PMID: 15526602 DOI: 10.1024/0036-7281.146.10.461] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Postweaning wasting is a major worldwide problem in pig production, particularly with respect to the disease termed postweaning multisystemic wasting syndrome (PMWS). In addition to wasting, PMWS symptoms include respiratory distress, diarrhoea, pallor and occasional cases of jaundice. The causative agent is porcine circovirus type 2 (PCV-2). The objective of the present study was to determine the significance of PMWS and similar conditions in Switzerland. A total of 72 weaned piglets from 26 farms showing wasting were examined for the presence of PCV-2 by immunohistochemical and histological analysis and 57 piglets from 21 farms were examined serologically. Possible causes for wasting other than PCV-2 were investigated by macroscopic, histological and bacteriological methods. PCV-2 antigen was identified immunohistochemically in the lymphatic organs in 11 of these 72 piglets. However, only 4 animals showed histological changes typical of PMWS. PCV-2 antibodies were found in 70% of the piglets. Piglets with wasting syndrome not associated with PCV-2 infection suffered from conditions including porcine proliferative enteropathy, gastric ulcers, polyserositis and polyarthritis. The most frequent condition was chronic enteritis not associated to circovirus infection. The results from the serological analyses indicate a wide distribution of PCV-2 in the Swiss pig population. However, confirmed cases of PMWS were rare in the investigated piglets.
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Affiliation(s)
- S Staebler
- Institute of Veterinary Pathology, University of Zurich, Switzerland
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2
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Rodriguez-Cariño C, Duffy C, Sánchez-Chardi A, McNeilly F, Allan G, Segalés J. Porcine Circovirus Type 2 (PCV-2) Morphogenesis in a Clone Derived from the L35 Lymphoblastoid Cell Line. J Comp Pathol 2010. [DOI: 10.1016/j.jcpa.2010.09.074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Todd D, Trudgett J, McNeilly F, McBride N, Donnelly B, Smyth VJ, Jewhurst HL, Adair BM. Development and application of an RT-PCR test for detecting avian nephritis virus. Avian Pathol 2010; 39:207-13. [PMID: 20544427 DOI: 10.1080/03079451003767253] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The development of a reverse transcriptase-polymerase chain reaction (RT-PCR) test for detecting avian nephritis virus (ANV) is described. Primers, which amplified a fragment of 182 base pairs (bp), were located in the conserved 3' untranslated region (UTR) of the genome. The limit of detection of the test was estimated to be approximately 18 viral copies using a 10-fold dilution series of in vitro transcribed RNA. Positive signals were produced with representative ANV samples, some of which were not detected by previously described RT-PCR tests for detecting ANV, but other avian astroviruses including chicken astrovirus isolates and duck hepatitis virus types 2 and 3 tested negative. When applied to gut content samples from UK, German and US broiler flocks with enteritis/growth problems, ANVs were detected by RT-PCR in 82/82 (100%) samples. ANVs were also detected in 80/96 (83%) pooled gut content samples from longitudinal surveys of four broiler flocks displaying below-average performance. Whereas all samples collected on day 0 from the surveys were negative for ANV, all samples collected at days 4/5, 7, 10, 14, 21 and 28 tested positive. Sequence determinations performed with amplicons produced with 14 field samples confirmed the ANV specificity of the test, while comparative and phylogenetic analyses based on 109-nucleotide 3'-UTR sequences demonstrated that the majority of ANVs investigated were more closely related to the serotype 2 ANV (accession number AB 046864) than to the serotype 1 ANV (accession number NC 003790).
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Affiliation(s)
- D Todd
- Agri-Food & Biosciences Institute, Stoney Road, Stormont, Belfast, UK.
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4
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Rodríguez-Cariño C, Duffy C, Sánchez-Chardi A, McNeilly F, Allan GM, Segalés J. Porcine circovirus type 2 morphogenesis in a clone derived from the l35 lymphoblastoid cell line. J Comp Pathol 2010; 144:91-102. [PMID: 20800239 DOI: 10.1016/j.jcpa.2010.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 04/29/2010] [Accepted: 07/03/2010] [Indexed: 11/28/2022]
Abstract
Porcine circovirus type 2 (PCV2) is the essential infectious agent of post-weaning multisystemic wasting syndrome (PMWS), one of the most important diseases of swine. Although several studies have described different biological properties of the virus, some aspects of its replication cycle, including ultrastructural alterations, remain unknown. The aim of the present study was to describe for the first time a complete morphogenesis study of PCV2 in a clone of the lymphoblastoid L35 cell line at the ultrastructural level using electron microscopy techniques. Cells were infected with PCV2 at a multiplicity of infection of 10 and examined at 0, 6, 12, 24, 48, 60 and 72h post-infection. PCV2 was internalized by endocytosis, after which the virus aggregated in intracytoplasmic inclusion bodies (ICIs). Subsequently, PCV2 was closely associated with mitochondria, completing a first cytoplasmic phase. The virus entered the nucleus for replication and virus assembly and encapsidation occurred with the participation of the nuclear membrane. Immature virions left the nucleus and formed ICIs in a second cytoplasmic phase. The results suggest that at the end of the replication cycle (between 24 and 48h), PCV2 was released either by budding of mature virion clusters or by lysis of apoptotic or dead cells. In conclusion, the L35-derived clone represents a suitable in-vitro model for PCV2 morphogenesis studies and characterization of the PCV2 replication cycle.
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Affiliation(s)
- C Rodríguez-Cariño
- Centre de Recerca en Sanitat Animal, Departament de Sanitat i Anatomia Animals, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
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McNeilly F, Walker I, Allan GM, Adair BM. Bursal lymphocyte proliferation in the presence of phorbol myristate acetate: Effect of IBDV strains on the proliferation response. Avian Pathol 2010; 28:301-3. [DOI: 10.1080/03079459994795] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Welsh MD, Baird PM, Guelbenzu-Gonzalo MP, Hanna A, Reid SM, Essen S, Russell C, Thomas S, Barrass L, McNeilly F, McKillen J, Todd D, Harkin V, McDowell S, Choudhury B, Irvine RM, Borobia J, Grant J, Brown IH. Initial incursion of pandemic (H1N1) 2009 influenza A virus into European pigs. Vet Rec 2010; 166:642-5. [PMID: 20495164 DOI: 10.1136/vr.4851] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The initial incursion of pandemic (H1N1) 2009 influenza A virus (pH1N1) into a European pig population is reported. Diagnosis of swine influenza caused by pandemic virus was made during September 2009 following routine submission of samples for differential diagnosis of causative agents of respiratory disease, including influenza A virus. All four pigs (aged six weeks) submitted for investigation from a pig herd of approximately 5000 animals in Northern Ireland, experiencing acute-onset respiratory signs in finishing and growing pigs, were positive by immunofluorescence for influenza A. Follow-up analysis of lung tissue homogenates by real-time RT-PCR confirmed the presence of pH1N1. The virus was subsequently detected on two other premises in Northern Ireland; on one premises, detection followed the pre-export health certification testing of samples from pigs presumed to be subclinically infected as no clinical signs were apparent. None of the premises was linked to another epidemiologically. Sequencing of the haemagglutinin and neuraminidase genes revealed high nucleotide identity (>99.4 per cent) with other pH1N1s isolated from human beings. Genotypic analyses revealed all gene segments to be most closely related to those of contemporary pH1N1 viruses in human beings. It is concluded that all three outbreaks occurred independently, potentially as a result of transmission of the virus from human beings to pigs.
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Affiliation(s)
- M D Welsh
- Agri-Food and Biosciences Institute, Veterinary Sciences Division, Stoney Road, Omagh, 43 Beltany Road, Omagh BT78 5NF, UK.
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Margolis IJ, McNeilly F, Maguire C, Howie R, DeRuyte D. Picis: a New Fish in the Electronic Charting Sea. Paediatr Child Health 2009. [DOI: 10.1093/pch/14.suppl_a.33ab] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
Sera from chickens, turkeys and ducks were examined for antibody to avian nephritis virus, by indirect immunofluorescence. Antibody was found to be widespread in commercial fowls and turkeys and was also detected in sera from specific pathogen-free chickens. No antibody was detected in a limited number of duck sera tested. The possibility of contamination of avian vaccines with avian nephritis virus is discussed.
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Affiliation(s)
- T J Connor
- Veterinary Research Laboratories, Stormont, Belfast, Northern Ireland
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Abstract
The antigenic relationships and in vitro growth properties of 10 avian enteroviruses and enterovirus-like viruses were investigated. By cross-indirect immunofluorescence tests, six serogroups were identified. The lack of an antigenic relationship between viruses selected from three of these serogroups was confirmed by cross-neutralisation tests. Most of the viruses grew poorly or not at all in a range of primary avian cell cultures, but the majority grew following inoculation of chick embryos via the yolk sac. The ability of these viruses to produce growth retardation in commercial broiler chickens was variable. Following oral inoculation of 1-day-old chicks, most had little or no effect. The most severe growth retardation was observed with avian encephalomyelitis virus and an enterovirus-like virus isolated from broilers in Northern Ireland which subsequently developed the runting-stunting syndrome. The latter produced 28 to 37% growth retardation in a 14-day period.
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Affiliation(s)
- M S McNulty
- Veterinary Research Laboratories, Belfast, Northern Ireland
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10
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Abstract
FP3 and 612 viruses are enterovirus-like viruses. Antibody to these viruses is widespread in chicken flocks, but nothing is known about their pathogenicity. Seven experiments were carried out to investigate the tissue tropism and associated pathology of these novel fowl enterovirus-like viruses and to compare these with the effects of the previously studied enterovirus-like viruses, ELV-1 and avian nephritis (ANV). ANV is now classified as an astrovirus. Preliminary experiments were carried out with FP3 virus, 612 virus and ELV-1 to determine the distribution of viral antigen. Each preliminary experiment was followed by a larger experiment that included more birds and in which a greater range of tissues was studied. It was shown that all four viruses studied replicated in the intestine and had differing abilities to spread to other tissues. Histological changes were present in most antigen-positive tissues but they were usually relatively mild. ELV-1 was associated with the most severe intestinal lesions, followed by FP3 virus. FP3 virus produced lesions in the kidney that were marginally more severe than those caused by the G-4260 strain of ANV. FP3 virus also caused pancreatic lesions. The 612 virus was found to be only mildly pathogenic in specific pathogen free chickens.
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Affiliation(s)
- J A Smyth
- Veterinary Sciences Division, Belfast, BT4 3SD, UK.
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Allan GM, Caprioli A, McNair I, Lagan-Tregaskis P, Ellis J, Krakowka S, McKillen J, Ostanello F, McNeilly F. Porcine Circovirus 2 Replication in Colostrum-deprived Piglets Following Experimental Infection and Immune Stimulation Using A Modified Live Vaccine against Porcine Respiratory and Reproductive Syndrome Virus. Zoonoses Public Health 2007; 54:214-22. [PMID: 17542965 DOI: 10.1111/j.1863-2378.2007.01041.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Porcine circovirus type 2 (PCV2) infection is now recognized as the major factor in the development of post-weaning multisystemic wasting syndrome (PMWS). Although Koch's postulates have been fulfilled for PCV2 and PMWS, the severe clinical expression of the disease observed in field cases has been difficult to reproduce experimentally. Some studies have demonstrated that immune stimulation associated with the use of some commercially available swine vaccines may trigger progression of PCV2 infection to disease and lesions characteristic of PMWS. Here we describe the effects on PCV2 infection in an experimental model following the use of a commercially available modified live vaccine to porcine respiratory and reproductive syndrome virus (PRRSV). Although none of the piglets infected with PCV2 developed clinical PMWS, the severity of microscopical lesions and the PCV2 antigen load associated with these lesions were higher in the PRRSV-vaccinated piglets compared with those detected in the PCV2 only infected animals.
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Affiliation(s)
- G M Allan
- Veterinary Sciences Division, Virology Section, Department of Agriculture and Rural Development for Northern Ireland, Stormont, Belfast BT4 3SD, UK
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Caprioli A, McNeilly F, McNair I, Lagan-Tregaskis P, Ellis J, Krakowka S, McKillen J, Ostanello F, Allan G. PCR detection of porcine circovirus type 2 (PCV2) DNA in blood, tonsillar and faecal swabs from experimentally infected pigs. Res Vet Sci 2006; 81:287-92. [PMID: 16481016 DOI: 10.1016/j.rvsc.2006.01.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Revised: 12/17/2005] [Accepted: 01/06/2006] [Indexed: 11/16/2022]
Abstract
PCV2 infection is now recognized as the major factor in the development of post-weaning multisystemic wasting syndrome (PMWS). In this study we evaluated the use of PCR to detect the presence of PCV2 DNA in blood, faecal and tonsillar swabs collected from 12 pigs experimentally infected with PCV2 and sampled at selected time points post-infection. The PCR results were evaluated together with the presence of PMWS typical histopathological lesions and the presence of PCV2 antigen. PCV2 DNA was present in the blood of all 12 infected pigs at the end of the experiment and faecal and tonsillar swabs of 11 of the 12 pigs. The rate of PCR-positive serum and plasma samples was significantly higher in four pigs that showed virological and pathological evidence of PMWS, than in infected pigs without evidence of disease. In conclusion this study confirms that PCR cannot substitute for the traditional methods used for diagnosis of PMWS, however, PCR amplification of PCV2 DNA from serum or plasma could be a useful tool to support an early diagnosis of PMWS in live animals.
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Affiliation(s)
- A Caprioli
- Department of Veterinary Public Health and Animal Pathology, Faculty of Veterinary Medicine, Bologna University, Via Tolara di Sopra 50, 40064 Ozzano dell'Emilia, BO, Italy.
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13
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Ostanello F, Caprioli A, Di Francesco A, Battilani M, Sala G, Sarli G, Mandrioli L, McNeilly F, Allan GM, Prosperi S. Experimental infection of 3-week-old conventional colostrum-fed pigs with porcine circovirus type 2 and porcine parvovirus. Vet Microbiol 2005; 108:179-86. [PMID: 15916871 DOI: 10.1016/j.vetmic.2005.04.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Revised: 03/07/2005] [Accepted: 04/07/2005] [Indexed: 11/17/2022]
Abstract
This report describes an experimental infection with porcine circovirus type 2 (PCV2) in combination with porcine parvovirus (PPV) in 3-week-old conventional colostrum-fed pigs with maternal antibodies to both viruses. Two groups of four pigs each were inoculated with PCV2 and PPV. One of the groups received also a commercial inactivated vaccine against porcine pleuropneumonia to evaluate possible effects of the stimulation of the immune system of pigs on the infection. Another group of four pigs was kept as uninfected control. Clinical signs, rectal temperatures and body weights were recorded. Serum antibody titers to PCV2 and PPV were determined at weekly intervals. Pigs were killed 42 days after inoculation and tissue samples were examined for the presence of gross and microscopic lesions. Tissues were also analyzed for the presence of PCV2 and PPV DNA by PCR, and for the presence of PCV2 antigen by immunohistochemistry (IHC). All the pigs had serum antibodies to PCV2 and PPV at the beginning of the trial. None of them developed clinical symptoms or pathological lesions typical of post-weaning multisystemic wasting syndrome (PMWS), a disease associated to PCV2 infection. However, IHC and/or PCR analyses showed that clinically silent PCV2 infection developed in five of the eight inoculated pigs, regardless of the administration of the vaccine. In particular, PCV2 DNA and/or antigen were detected in most of the tissues examined in the two pigs with the lowest titer of maternal PCV2 antibodies at the beginning of the trial. PPV DNA was not detected in any of the samples examined. The five pigs with PCR and/or IHC evidence of PCV2 infection had a mean weight gain during the experiment lower than that of the inoculated PCR-negative pigs considered together and that of the control pigs. In conclusion, it would appear that passive immunity against PCV2 can play a role in preventing the development of PMWS, but is not able to prevent the establishing of clinically silent PCV2 infections. The dissemination and persistence of the virus in the tissues may depend on the level of PCV2 antibodies at the time of inoculation.
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Affiliation(s)
- F Ostanello
- Department of Veterinary Public Health and Animal Pathology, Faculty of Veterinary Medicine, Bologna University, Via Tolara di Sopra 50, 40064 Ozzano Emilia (BO), Italy.
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Staebler S, Sydler T, Buergi E, McCullough K, McNeilly F, Allan G, Pospischil A. PMWS: an emerging disease identified in archived porcine tissues. Vet J 2005; 170:132-4. [PMID: 15993797 DOI: 10.1016/j.tvjl.2004.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2004] [Indexed: 11/26/2022]
Abstract
Postweaning multisystemic wasting syndrome (PMWS) is a disease caused by porcine circovirus type 2 (PCV-2). The disease was present as early as 1986 in Spain, 1989 in Japan and 1993 in Thailand. In view of this, we considered it possible that the disease may also have been present in Switzerland prior to its first description in 2001. A retrospective investigation was performed on paraffin-embedded lymphoid organs and ileum from 496 pigs aged 5-13 weeks collected between 1976 and mid-2001. The sections were investigated immunohistochemically using a monoclonal antibody specific for PCV-2 capsid antigen encoded by ORF2. Virus antigen was detected in tissue samples of 39 pigs from 28 farms. The earliest positive sample originated from 1986. After 1989, positive pigs were found almost every year among the 20-40 cases investigated annually. These results indicate that PCV-2 has been present in Switzerland for some time, and at least since 1986.
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Affiliation(s)
- S Staebler
- Institute of Veterinary Pathology, University of Zurich, Winterthurerstrasse 268, CH-8057 Zurich, Switzerland.
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Hasslung F, Wallgren P, Ladekjaer-Hansen AS, Bøtner A, Nielsen J, Wattrang E, Allan GM, McNeilly F, Ellis J, Timmusk S, Belák K, Segall T, Melin L, Berg M, Fossum C. Experimental reproduction of postweaning multisystemic wasting syndrome (PMWS) in pigs in Sweden and Denmark with a Swedish isolate of porcine circovirus type 2. Vet Microbiol 2005; 106:49-60. [PMID: 15737473 PMCID: PMC7117216 DOI: 10.1016/j.vetmic.2004.12.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 11/19/2004] [Accepted: 12/01/2004] [Indexed: 10/27/2022]
Abstract
An experimental model using 3-day-old snatch-farrowed colostrum-deprived piglets co-infected with porcine circovirus type 2 (PCV2) and porcine parvovirus (PPV) is at present one of the best methods to study factors affecting development of postweaning multisystemic wasting syndrome (PMWS). A Swedish isolate of PCV2 (S-PCV2) retrieved in 1993 from a healthy pig has been used in this model to reproduce PMWS in pigs from Northern Ireland. This virus has been present in the Swedish pig population for at least a decade without causing any known PMWS disease problems, despite its potential pathogenicity. The reasons for this are unknown, but could be related to genetics, absence of triggers for PCV2 upregulation (infectious agent and/or management forms) within Swedish pig husbandry. In order to confirm the pathogenicity of S-PCV2, Swedish and Danish pigs were experimentally infected with this isolate according to the established model. Swedish pigs were also infected with a reference isolate of PCV2 (PCV2-1010) to compare the severity of disease caused by the two isolates in Swedish pigs. Both Danish and Swedish pigs developed PMWS after the experimental infection with S-PCV2. Antibodies to PCV2 developed later and reached lower levels in serum from pigs infected with S-PCV2 than in pigs inoculated with PCV2-1010. In general, pigs infected with S-PCV2 showed more severe clinical signs of disease than pigs infected with PCV2-1010, but pigs from all PCV2-inoculated groups displayed gross and histological lesions consistent with PMWS. All pigs inoculated with PPV, alone or in combination with PCV2, displayed interleukin-10 responses in serum while only pigs infected with PPV in combination with PCV2 showed interferon-alpha in serum on repeated occasions. Thus, the pathogenicity of S-PCV2 was confirmed and a role for cytokines in the etiology of PMWS was indicated.
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Affiliation(s)
- F Hasslung
- Department of Molecular Biosciences, Section of Veterinary Immunology and Virology, Swedish University of Agricultural Sciences, Biomedical Centre, PO Box 588, SE-751 23 Uppsala, Sweden.
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Krakowka S, Ellis J, McNeilly F, Meehan B, Oglesbee M, Alldinger S, Allan G. Features of cell degeneration and death in hepatic failure and systemic lymphoid depletion characteristic of porcine circovirus-2-associated postweaning multisystemic wasting disease. Vet Pathol 2004; 41:471-81. [PMID: 15347819 DOI: 10.1354/vp.41-5-471] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Tissue section replicates from lymphoid tissues and livers of gnotobiotic swine were examined by immunohistochemistry for the colocalization of porcine circovirus-2 (PCV-2) nucleocapsid and terminal deoxynucleotidyl transferase (TdT)-mediated incorporation of biotinylated nucleotides (UTP) onto the 3'-exposed hydroxyl groups (nick end labeling) nuclear deoxyribonucleic acid (TUNEL), a marker for apoptosis. Single- and dually stained replicates from uninfected controls, subclinically affected PCV-2-infected gnotobiotic pigs, PCV-2-infected piglets immunosuppressed with cyclosporine (Cys), and PCV-2-infected piglets with post-weaning multisystemic wasting syndrome (PMWS) were evaluated. Thymuses were used as positive controls for apoptosis absent PCV-2, tissue sections from dogs given hyperthermic stress were examined as positive controls for induced TUNEL. Tissues from heat-stressed dogs contained TUNEL-positive cell nuclei in both lymphoid tissues and liver, TUNEL was greatest shortly after the delivery of the hyperthermic insult. In uninfected control and subclinically affected PCV-2-infected gnotobiotic pigs, rare hepatocytes and lymphoid cells were TUNEL positive, the frequency of these was similar to that seen in uninfected controls. In PMWS-affected and Cys-treated PCV-2 piglets, the only consistent strongly positive TUNEL signal was contained within the cytoplasm of virus-positive phagocytic mononuclear cells. In phagocytes, some PCV-2 inclusions were TUNEL positive. Collectively, these data indicate that apoptosis is not the primary mechanism of lymphoid depletion and hepatocyte loss in PMWS. Apoptosis associated with systemic viral diseases may be attributable to pyrexia rather than direct or indirect effects of viruses on target cells.
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Affiliation(s)
- S Krakowka
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210, USA.
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Meerts P, Misinzo G, McNeilly F, Nauwynck HJ. Replication kinetics of different porcine circovirus 2 strains in PK-15 cells, fetal cardiomyocytes and macrophages. Arch Virol 2004; 150:427-41. [PMID: 15578238 PMCID: PMC7086899 DOI: 10.1007/s00705-004-0444-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Accepted: 10/11/2004] [Indexed: 11/26/2022]
Abstract
In this in vitro study, the replication kinetics of porcine circovirus type 2 (PCV2) in porcine alveolar macrophages (PAM) and fetal cardiomyocytes (FCM), two target cells in vivo, was compared with that in PK-15 cells. Cultures were inoculated with either the postweaning multisystemic wasting syndrome (PMWS)-associated strain Stoon-1010 or the abortion-associated strain 1121. Viral proteins were visualized and virus production was determined. In PK-15 cells, the capsid protein was expressed between 6 and 12 hours post inoculation (hpi), it relocated to the nucleus between 12 and 24 hpi. At that time, Rep protein was also detected in the nucleus. This sequence of events also occurred in FCM and PAM but nuclear localized antigens appeared later (48 hpi) and in a lower percentage of cells. In PAM, clear differences in susceptibility were seen between pigs. In PAM from two out of five tested pigs, nuclear localized antigens were not detected, whereas in PAM from three other pigs they were seen in up to 20% of the antigen-positive cells. Virus production was observed in PK-15 but not in PAM or FCM cultures. In a second study, the replication kinetics of seven different PCV2 strains were compared in PK-15 cells. It was shown that the two abortion-associated strains had a different replication kinetics in comparison with PMWS or porcine dermatitis and nephropathy syndrome associated strains. With the abortion-associated strains, a higher number of infected cells was observed at 24 hpi and the percentage of infected cells with nuclear localised antigens was lower compared to that of other strains.
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Affiliation(s)
- P Meerts
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
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Carrasco CP, Rigden RC, Vincent IE, Balmelli C, Ceppi M, Bauhofer O, Tâche V, Hjertner B, McNeilly F, van Gennip HG, McCullough KC, Summerfield A. Interaction of classical swine fever virus with dendritic cells. J Gen Virol 2004; 85:1633-1641. [PMID: 15166448 DOI: 10.1099/vir.0.19716-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Functional disruption of dendritic cells (DCs) is an important strategy for viral pathogens to evade host defences. Monocytotropic viruses such as classical swine fever virus (CSFV) could employ such a mechanism, since the virus can suppress immune responses and induce apoptosis without infecting lymphocytes. Here, CSFV was shown to infect and efficiently replicate in monocyte- and in bone marrow-derived DCs. Interestingly, the infected DCs displayed neither modulated MHC nor CD80/86 expression. Stimulation of DCs with IFN-α/TNF-α or polyinosinic–polycytidylic acid (pIC) induced phenotypic maturation with increased MHC and CD80/86 expression, both with mock-treated and infected DCs. In addition, the T cell stimulatory capacity of CSFV-infected DCs was maintained both in a polyclonal T cell stimulation and in specific antigen-presentation assays, requiring antigen uptake and processing. Interestingly, similar to macrophages, CSFV did not induce IFN-α responses in these DCs and even suppressed pIC-induced IFN-α induction. Other cytokines including interleukin (IL)-6, IL-10, IL-12 and TNF-α were not modulated. Taken together, these results demonstrated that CSFV can replicate in DCs and control IFN type I responses, without interfering with the immune reactivity. These results are interesting considering that DC infection with RNA viruses usually results in DC activation.
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Affiliation(s)
- C P Carrasco
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - R C Rigden
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - I E Vincent
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - C Balmelli
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - M Ceppi
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - O Bauhofer
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - V Tâche
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - B Hjertner
- Department of Agriculture for Northern Ireland, Veterinary Sciences Division, Belfast, UK
| | - F McNeilly
- Department of Agriculture for Northern Ireland, Veterinary Sciences Division, Belfast, UK
| | - H G van Gennip
- Animal Sciences Group, 8200 AB Lelystad, The Netherlands
| | - K C McCullough
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
| | - A Summerfield
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland
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19
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Allan GM, McNeilly F, Ellis J, Krakowka S, Botner A, McCullough K, Nauwynck H, Kennedy S, Meehan B, Charreyre C. PMWS: experimental model and co-infections. Vet Microbiol 2004; 98:165-8. [PMID: 14741129 DOI: 10.1016/j.vetmic.2003.10.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Porcine circovirus type 2 (PCV2) is now recognised as the causal agent of porcine multisystemic wasting syndrome (PMWS), an economically important wasting disease of young pigs [J. Vet. Diagn. Invest. 12 (2000) 3]. Gross lesions of PMWS include generalised lymphadenopathy, hepatitis, nephritis and pneumonia and typical histological lesions include lymphocytic depletion and multinucleated giant cell formation in lymph nodes, degeneration and necrosis of hepatocytes, and multifocal lymphohistocytic interstitial pneumonia. This communication will review the results of experimental infections of gnotobiotic (GN), colostrum-deprived (CD) and colostrum-fed (CF) pigs within our group, and elsewhere, with PCV2 and the conclusions that can be drawn from this work.
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Affiliation(s)
- G M Allan
- Virology Department, Veterinary Research Laboratory, Veterinary Sciences Division, Stoney Road Stormont, DARDNI, Stormont, BT4 SD Belfast, Northern Ireland, UK.
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20
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Gilpin DF, McCullough K, Meehan BM, McNeilly F, McNair I, Stevenson LS, Foster JC, Ellis JA, Krakowka S, Adair BM, Allan GM. In vitro studies on the infection and replication of porcine circovirus type 2 in cells of the porcine immune system. Vet Immunol Immunopathol 2003; 94:149-61. [PMID: 12909411 DOI: 10.1016/s0165-2427(03)00087-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Porcine circovirus type 2 (PCV2) nucleic acid and/or antigens are consistently observed in cells of monocytic morphology in lesions of pigs affected by post-weaning multisystemic wasting syndrome (PMWS). In this study, PCV2 antigen was detected in the cytoplasm of monocytes, pulmonary macrophages (PMs) and monocyte-derived macrophages exposed to the virus in vitro, by immunofluorescence analysis (IFA) and the phenotype of these cells confirmed by detection of monocytic cell surface markers using flow cytometry. Viral antigen was not observed in lymphocytic cells. Replication of the virus in PMs was investigated further by comparison to that observed in the continuous pig kidney cell line (PK15A) using quantitative virus titration, quantitative PCR and by the detection of double stranded DNA intermediates of viral replication by Southern blotting analyses. Although increases in viral DNA and levels of infectious virus progeny and the presence of replicative intermediates, indicative of viral replication, were observed in PK15A cells, no such changes were observed in PMs in spite of the fact that infectious virus, viral antigen and viral DNA persisted in the cells for at least the duration of the experiment. These results suggest that in vivo, monocytic cells may not represent the primary target for PCV2 replication.
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MESH Headings
- Animals
- Antigens, Viral/immunology
- Blotting, Southern/veterinary
- Cell Division/immunology
- Circoviridae Infections/immunology
- Circoviridae Infections/veterinary
- Circoviridae Infections/virology
- Circovirus/genetics
- Circovirus/immunology
- Circovirus/physiology
- DNA, Viral/chemistry
- DNA, Viral/genetics
- Flow Cytometry/veterinary
- Fluorescent Antibody Technique, Direct/veterinary
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/virology
- Macrophages, Alveolar/cytology
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/virology
- Polymerase Chain Reaction
- Swine
- Swine Diseases/immunology
- Swine Diseases/virology
- Virus Replication
- Wasting Syndrome/immunology
- Wasting Syndrome/veterinary
- Wasting Syndrome/virology
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Affiliation(s)
- D F Gilpin
- Department of Veterinary Science, Queens University Belfast, Stoney Road, Stormont, Belfast, BT4 3SD, UK
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21
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Tucker AW, McNeilly F, Meehan B, Galbraith D, McArdle PD, Allan G, Patience C. Methods for the exclusion of circoviruses and gammaherpesviruses from pigs. Xenotransplantation 2003; 10:343-8. [PMID: 12795683 DOI: 10.1034/j.1399-3089.2003.02048.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The use of porcine tissues is being developed as a means to alleviate the shortage of allogeneic tissues and organs available for transplantation. To reduce the possibility of a microorganism of pigs being inadvertently transferred to the recipient of the xenograft, recommendations have been published on the microbiological specifications for organ source pigs. The porcine circoviruses (PCV1 and PCV2) and porcine lymphotropic herpesviruses (PLHV1 and PLHV2) are two infectious agents of pigs which are considered to be of significance for the microbiological safety of xenotransplantation. To ensure the exclusion of these microorganisms from animals destined for use under clinical conditions, reliable breeding methodologies are required. We investigated the efficiency of established derivation procedures for the removal of PCV and PLHV. In comparison with conventionally reared pigs, caesarian and barrier derived animals showed a markedly reduced prevalence of PCVs and PLHVs. Our results indicate that the derivation of animals free of both of these microorganisms is achievable and will enhance the microbiological safety of xenotransplantation.
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Affiliation(s)
- A W Tucker
- Imutran Ltd. (A Novartis Pharma AG Co.), Cambridge, UK
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22
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Núñez A, McNeilly F, Perea A, Sánchez-Cordón PJ, Huerta B, Allan G, Carrasco L. Coinfection by Cryptosporidium parvum and porcine circovirus type 2 in weaned pigs. J Vet Med B Infect Dis Vet Public Health 2003; 50:255-8. [PMID: 12864903 DOI: 10.1046/j.1439-0450.2003.00664.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Routine histopathological diagnosis of one representative 3-month-old pig from a group suffering from diarrhoea revealed a massive degree of parasitation by Cryptosporidium parvum, with a concomitant infection by porcine circovirus type 2 (PCV2), that was confirmed by immunohistochemical procedures. The areas of intestine where parasites were more numerous presented abundant PCV2 infected cells in mucosa and submucosa. The concurrence of C. parvum, a rare primary intestinal pathogen in post-weaning and growing pigs, and PCV2 infections suggest an increased susceptibility as a result of an immunosuppression state.
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Affiliation(s)
- A Núñez
- Departamento de Anatomía y Anatomía Patológica Comparadas, Edificio de Sanidad Animal, Facultad de Veterinaria, Universidad de Córdoba, Campus Universitario de Rabanales, 14014 Córdoba, Spain.
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23
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Stevenson L, Gilpin D, Douglas A, Adair B, McNeilly F, McNair I, Allan G. 116. An in vitro study of the immune response to PCV2 infection in pigs. Res Vet Sci 2003. [DOI: 10.1016/s0034-5288(03)90115-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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24
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Ladekjaer-Mikkelsen AS, Nielsen J, Stadejek T, Storgaard T, Krakowka S, Ellis J, McNeilly F, Allan G, Bøtner A. Reproduction of postweaning multisystemic wasting syndrome (PMWS) in immunostimulated and non-immunostimulated 3-week-old piglets experimentally infected with porcine circovirus type 2 (PCV2). Vet Microbiol 2002; 89:97-114. [PMID: 12243888 PMCID: PMC7117141 DOI: 10.1016/s0378-1135(02)00174-8] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Postweaning multisystemic wasting syndrome (PMWS) in swine is causally associated with the newly recognised pathogen, porcine circovirus type 2 (PCV2). In this study, 3-week-old SPF PCV2-seronegative piglets were inoculated intranasally with PCV2. The effect of immunostimulation on the induction of PMWS was investigated by immunisation with keyhole limpet hemocyanin (KLH) emulsified in incomplete Freunds adjuvant. The study was terminated 5 weeks after inoculation. While disease was not observed in the age-matched controls, two out of five non-immunised PCV2-infected piglets died on postinoculation day (PID) 21, and one was euthanized on PID 25 in moribund condition. These animals had appeared lethargic with persistent fever from PID 12 onwards. The euthanized pig appeared smaller than littermates and suffered from jaundice. At postmortem examination, gastric ulceration, icterus, and liver and thymus atrophy were observed. Furthermore, histological lesions of degenerating hepatocytes and hepatitis in combination with lymphoid depletion and syncytial cells in lymph nodes were consistent with the diagnosis of PMWS. One out of five immunostimulated PCV2-infected piglets was euthanized on PID 22 with convulsions after a period with wasting. This pig was lethargic from PID 14 onwards with persistent fever from PID 8 and transient dyspnoea. No differences in clinical signs, gross pathologic or histological findings were observed for the remaining non-immunostimulated and immunostimulated PCV2-infected piglets. All 10 PCV2-inoculated piglets seroconverted to PCV2 within 14 days after inoculation. By virus isolation, quantitative polymerase chain reaction (Q-PCR), and immunostaining of cryostat sections, it was demonstrated that lymphoid tissue contained abundant PCV2 antigen. Viral DNA load in serum samples was assessed by Q-PCR. All four PMWS-affected piglets had high levels of PCV2 DNA in serum, suggesting that there was a correlation between high levels of viral DNA in serum and the development of PMWS. In conclusion, infection with PCV2 caused PMWS in SPF piglets, however, the immunostimulation did not seem to play a critical role.
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25
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McNeilly F, McNair I, O'Connor M, Brockbank S, Gilpin D, Lasagna C, Boriosi G, Meehan B, Ellis J, Krakowka S, Allan GM. Evaluation of a porcine circovirus type 2-specific antigen-capture enzyme-linked immunosorbent assay for the diagnosis of postweaning multisystemic wasting syndrome in pigs: comparison with virus isolation, immunohistochemistry, and the polymerase chain reaction. J Vet Diagn Invest 2002; 14:106-12. [PMID: 11939330 DOI: 10.1177/104063870201400203] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Quantitative virus isolation, immunohistochemistry, polymerase chain reaction (PCR) assay, and a porcine circovirus 2 (PCV2)-specific antigen-capture enzyme-linked immunosorbent assay (ELISA) were used for differentiation between clinical and subclinical PCV2 infections of swine. Tissue samples from pigs experimentally infected with PCV2 and field cases of postweaning multisystemic wasting syndrome and PCV2-associated reproductive disorders were used in this evaluation. In initial studies on 6 PCV2 pools using 3 previously published PCR protocols for PCV2 detection, quantitative virus isolation, and antigen-capture ELISA, substantial differences in sensitivity were identified among these procedures. Examination of tissue samples from diseased and clinically normal pigs indicated that immunohistochemistry, quantitative virus isolation, and antigen-capture ELISA could be used to differentiate between clinical and subclinical PCV2 infections, but the PCR assay could not. Because subclinical infections of pigs with PCV2 are common, the use of nonquantitative PCR as a diagnostic tool for PCV2-related diseases should be discouraged and the PCV2-specific antigen-capture ELISA evaluated further.
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Affiliation(s)
- F McNeilly
- Department of Agriculture and Rural Development for Northern Ireland, Veterinary Sciences Division, Stormont, Belfast
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26
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Allan GM, McNeilly F, Meehan B, Kennedy S, Johnston D, Ellis J, Krakowka S, Fossum C, Wattrang E, Wallgren P. Reproduction of PMWS with a 1993 Swedish isolate of PCV-2. Vet Rec 2002; 150:255-6. [PMID: 11916032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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27
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Sanchez RE, Nauwynck HJ, McNeilly F, Allan GM, Pensaert MB. Porcine circovirus 2 infection in swine foetuses inoculated at different stages of gestation. Vet Microbiol 2001; 83:169-76. [PMID: 11557157 DOI: 10.1016/s0378-1135(01)00425-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The ability of porcine circovirus 2 (PCV2) to replicate and cause pathologic abnormalities in foetuses at selected time points of gestation was examined in this study. Two foetuses were inoculated in utero in each of two sows at 57, 75 and 92 days of gestation, respectively, with PCV2 (1121). The remaining foetuses were left uninoculated to assess whether intra-uterine spread occurred. Twenty-one days after inoculation, the foetuses were collected and examined for gross lesions and for virus and infected cells in different organs. Serum samples from all foetuses were tested for PCV2 antibodies. Virus replication was detected in all inoculated foetuses. Spread to non-inoculated foetuses did not occur. Virus replication was significantly higher in foetuses inoculated at 57 days compared to that inoculated at 75 and 92 days. The heart contained the highest virus titre and highest number of viral antigen positive cells. Gross lesions were observed only in foetuses inoculated at 57 days of age. PCV2 antibodies were detected only in foetuses inoculated at 75 and 92 days. This study shows the ability of PCV2 to replicate in foetuses at different stages of gestation and to cause pathologic abnormalities in foetuses inoculated at 57 gestational days.
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Affiliation(s)
- R E Sanchez
- Laboratory of Virology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820, Merelbeke, Belgium
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28
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McNeilly F, McNair I, Mackie DP, Meehan BM, Kennedy S, Moffett D, Ellis J, Krakowka S, Allan GM. Production, characterisation and applications of monoclonal antibodies to porcine circovirus 2. Arch Virol 2001; 146:909-22. [PMID: 11448029 DOI: 10.1007/s007050170124] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The production, preliminary characterisation and applications of monoclonal antibodies (mabs) against six porcine circovirus 2 isolates are described. A total of 14 stable hybridomas were produced, of which 7 were characterised. All of the mabs characterised were of IgG isotype. All the mabs tested reacted by IIF with acetone-fixed cell cultures infected with PCV2 isolates from Canada, France, Spain, Denmark, USA and UK. No cross-reactivity with a porcine circovirus 1 field isolate was demonstrated using the panel of mabs tested. In addition, one of the seven mabs tested demonstrated neutralising activity against PCV2 isolates from Canada and France. The use of selected PCV2-specific mabs for the development of virus detection methodologies is described.
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Affiliation(s)
- F McNeilly
- Virology Department, Department of Agriculture and Rural Development for N. Ireland, Belfast, UK
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29
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Meehan BM, McNeilly F, McNair I, Walker I, Ellis JA, Krakowka S, Allan GM. Isolation and characterization of porcine circovirus 2 from cases of sow abortion and porcine dermatitis and nephropathy syndrome. Arch Virol 2001; 146:835-42. [PMID: 11402869 DOI: 10.1007/s007050170152] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report the isolation and characterisation of porcine circovirus 2 (PCV2) from cases of sow abortion and porcine dermatitis and nephropathy syndrome. The results suggest that the clinical scope of PCV2 infections requires continuous re-evaluation.
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Affiliation(s)
- B M Meehan
- Department of Veterinary Science, Queen's University of Belfast, Belfast, U.K.
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30
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Bogdan J, West K, Clark E, Konoby C, Haines D, Allan G, McNeilly F, Meehan B, Krakowka S, Ellis JA. Association of porcine circovirus 2 with reproductive failure in pigs: a retrospective study, 1995-1998. Can Vet J 2001; 42:548-50. [PMID: 11467183 PMCID: PMC1476628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
In order to determine if vertically transmitted porcine circovirus (PCV) has played a role in reproductive failure in pigs in areas of endemic infection, archival fixed tissues were examined by polymerase chain reaction (PCR) and immunohistochemistry. Tissues tested were from routine cases of abortion or reproductive failure submitted between 1995 and 1998 to the diagnostic laboratory at the Western College of Veterinary Medicine, Saskatoon. They originated from 29 high-health herds in the provinces of Alberta and Saskatchewan and comprised a total of 36 individual submissions. Porcine circovirus type 1 (PCV1) was not detected by PCR in any submitted tissues. Porcine circovirus type 2 (PCV2) was not detected by PCR or immunohistochemistry in any of the submitted tissue. The effect of extended formalin fixation on the detection of PCV2 by PCR was assessed and fixation for up to one week had no gross effect on sensitivity of detection using this PCR technique. Failure to detect porcine circoviruses in cases of reproductive failure prior to 1999 in areas of endemic infections, suggests that reproductive disease may be a new clinical manifestation of PCV2 infection, and that vertical transmission may not have been the primary mechanism of initial dissemination of the virus in the pig population.
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Affiliation(s)
- J Bogdan
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4
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31
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Ladekjaer-Mikkelsen AS, Nielsen J, Storgaard T, Bøtner A, Allan G, McNeilly F. Transplacental infection with PCV-2 associated with reproductive failure in a gilt. Vet Rec 2001; 148:759-60. [PMID: 11442241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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32
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Ellis JA, Konoby C, West KH, Allan GM, Krakowka S, McNeilly F, Meehan B, Walker I. Lack of antibodies to porcine circovirus type 2 virus in beef and dairy cattle and horses in western Canada. Can Vet J 2001; 42:461-4. [PMID: 11424578 PMCID: PMC1476552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Porcine circovirus type 2 (PCV2) is a recently recognized agent that is consistently associated with postweaning multisystemic wasting disease in swine. There are conflicting data concerning the ability of this virus to infect and cause disease in other species. To determine if normal cattle, cattle affected with various illnesses, and normal horses in endemic areas of PCV2 infection in swine have had PCV2 infections, 100 randomly selected bovine sera, 100 equine sera, and 100 colostrum samples from clinically normal dairy cattle were examined for the presence of antibodies to porcine circoviruses by using ELISAs. All samples tested were negative for antibodies to porcine circoviruses. As well, a seronegative neonatal Holstein calf and 6 seronegative, 6-month-old beef calves that were experimentally infected with PCV2 failed to develop antibodies to the virus. These results suggest that natural infection of cattle and horses with PCV2 does not occur, or is a rare event, in western Canada.
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Affiliation(s)
- J A Ellis
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4
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33
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Allan GM, McNeilly F, Ellis J, Krakowka S, Meehan B, McNair I, Walker I, Kennedy S. Experimental infection of colostrum deprived piglets with porcine circovirus 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) potentiates PCV2 replication. Arch Virol 2001; 145:2421-9. [PMID: 11205128 DOI: 10.1007/s007050070031] [Citation(s) in RCA: 189] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Experimental infection of colostrum-deprived (CD) pigs with a combined inoculum of porcine circovirus 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) potentiated the replication and distribution of PCV2 virus, when compared with pigs inoculated with PCV2 alone. The replication and distribution of PRRSV in dually infected pigs was not enhanced, when compared to pigs inoculated with PRRSV alone. The mechanisms involved in the potentiation of PCV2 replication in PCV2/PRRSV and PCV2/porcine parvovirus (PPV) dually infected pigs may relate to the fact that monocyte/macrophage cell types are common targets of these 3 viruses.
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Affiliation(s)
- G M Allan
- Virology Department, Department of Agriculture and Rural Development for N. Ireland, Belfast
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34
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Summerfield A, McNeilly F, Walker I, Allan G, Knoetig SM, McCullough KC. Depletion of CD4(+) and CD8(high+) T-cells before the onset of viraemia during classical swine fever. Vet Immunol Immunopathol 2001; 78:3-19. [PMID: 11182144 DOI: 10.1016/s0165-2427(00)00248-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Leukopenia, in particular lymphopenia, is a characteristic early event during classical swine fever (CSF). This was the case in both highly virulent (CSF virus (CSFV) strain Brescia) and moderately virulent (CSFV Uelzen) infections. The leukopenia involved leukocyte sub-populations in a disparate manner, with B-lymphocytes, helper T-cells and cytotoxic T-cells being the most affected. Depletion of lymphocyte sub-populations occurred 1-4 days before virus could be detected by RT-PCR in the serum. With the virulent Brescia virus, depletion was evident by 2 days post-infection (p.i.) but not until 3 days p.i. with an equivalent dose of the low virulent Uelzen strain. A lower (1000-fold) dose of the latter virus delayed these kinetics. gammadelta-TCR(+) T-cells were also reduced, but more so with the virulent Brescia infection. The final level of B-and alphabeta-T-cell lymphopenia was similar for all animals, including those infected with the lower virus dose. AnnexinV staining revealed that cell viability was clearly diminished, particularly interesting, considering the clinical differences between infections by Brescia and Uelzen viruses. It was the time p.i. and rate of appearance of dying cells which was more rapid in the virulent Brescia infections. Interestingly, the repeated blood sampling resulted in depletion of some leukocyte populations also in non-infected control animals. Particularly neutrophils and NK cells, and to a lower extent CD4(+), CD8(+) T-lymphocytes and B-lymphocytes were affected. Taken together, the data show that the alphabeta-T-lymphocyte subsets are particularly susceptible to modulation during the acute phase of CSF, being detectable before the onset of viraemia. The pathogenic mechanism therein would involve indirect virus-host interactions, probably originating from the site of primary infection, rather than a direct effect of the virus or viral protein. Furthermore, these characteristics offer an explanation for the retardation of the cellular and humoral immune response observed during classical swine fever.
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MESH Headings
- Animals
- Antibodies, Monoclonal
- Antigens, Viral/blood
- Apoptosis
- B-Lymphocytes/cytology
- B-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/virology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/virology
- Classical Swine Fever/blood
- Classical Swine Fever/immunology
- Classical Swine Fever/virology
- Classical Swine Fever Virus/genetics
- Classical Swine Fever Virus/pathogenicity
- DNA, Viral/chemistry
- Flow Cytometry/veterinary
- Leukocyte Count
- Lymphocyte Subsets/immunology
- RNA, Viral/chemistry
- RNA, Viral/isolation & purification
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, gamma-delta/immunology
- Reverse Transcriptase Polymerase Chain Reaction/veterinary
- Specific Pathogen-Free Organisms
- Swine
- Viremia/immunology
- Viremia/veterinary
- Viremia/virology
- Virulence
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Affiliation(s)
- A Summerfield
- Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, 3147, Mittelhäusern, Switzerland.
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35
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Krakowka S, Ellis JA, McNeilly F, Ringler S, Rings DM, Allan G. Activation of the immune system is the pivotal event in the production of wasting disease in pigs infected with porcine circovirus-2 (PCV-2). Vet Pathol 2001; 38:31-42. [PMID: 11199162 DOI: 10.1354/vp.38-1-31] [Citation(s) in RCA: 214] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Porcine circovirus (PCV)-2, a newly described single-stranded circular DNA virus pathogen of swine is the cause of postweaning multisystemic wasting syndrome (PMWS). In gnotobiotic piglets, PCV-2 infection alone produces asymptomatic infection without evidence of overt PMWS. Gnotobiotic piglets infected with PCV-2 were injected with keyhole limpet hemocyanin in incomplete Freund's adjuvant (KLH/ICFA), and the effects on virus production and development of PMWS were determined. In the first experiment, piglets were injected subcutaneously on the left hip and shoulder, and viral burden was assessed in regional lymph nodes draining the injection sites and in contralateral lymph nodes 13-14 days after infection. Immune activation increased the number of virus antigen-positive cells in draining lymph nodes and increased the amount of infectious virus recovered by 1-4 log10. In a second experiment, the effects of injections of KLH/ICFA with or without concurrent stimulation of peritoneal macrophages by intraperitoneal injections of thioglycollate broth on induction of PMWS was assessed. All immunized piglets developed moderate to severe PMWS, whereas none of the piglets infected with PCV-2 alone developed PMWS. In PMWS-affected piglets, extensive replication of PCV-2 was documented by both immunocytochemistry and quantitative viral titrations. Thus, immune activation is a key component of the pathogenesis of PCV-2-associated PMWS in swine.
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Affiliation(s)
- S Krakowka
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, USA.
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36
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Ellis JA, Wiseman BM, Allan G, Konoby C, Krakowka S, Meehan BM, McNeilly F. Analysis of seroconversion to porcine circovirus 2 among veterinarians from the United States and Canada. J Am Vet Med Assoc 2000; 217:1645-6. [PMID: 11110452 DOI: 10.2460/javma.2000.217.1645] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- J A Ellis
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
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37
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Spagnuolo-Weaver M, Walker IW, Campbell ST, McNeilly F, Adair BM, Allan GM. Rapid detection of porcine reproductive and respiratory syndrome viral nucleic acid in blood using a fluorimeter based PCR method. Vet Microbiol 2000; 76:15-23. [PMID: 10925037 DOI: 10.1016/s0378-1135(00)00222-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is an Arterivirus recognised world wide as an important cause of reproductive failure and pneumonia in pigs. American and European strains of PRRSV, differentiated antigenically and genomically, have been reported. PRRSV infections are currently diagnosed using serology, virus isolation and/or immunocytochemistry. In order to overcome various drawbacks associated with these techniques, conventional, block-based RT-PCR methods for the detection of PRRSV nucleic acid in clinical samples have been described. These methods require gel electrophoresis for analysis of PCR products and present high risk of DNA carry-over contamination between the samples tested. We describe the detection of PRRSV RNA in serum samples and in blood impregnated filter disks (FDs), obtained from experimentally inoculated pigs, using a closed-tube, fluorimeter-based PCR assay. The assay eliminates the use of gel electrophoresis, and is as sensitive and specific as the conventional block-based PCR assay, detecting positive samples as early as 1 day post-inoculation. We also report a rapid fluorimeter based PCR method for differentiating American and European strains of PRRSV.
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Affiliation(s)
- M Spagnuolo-Weaver
- Department of Veterinary Sciences, The Queen's University of Belfast, BT 4 3SD, Northern Ireland, UK
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38
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Walker IW, Konoby CA, Jewhurst VA, McNair I, McNeilly F, Meehan BM, Cottrell TS, Ellis JA, Allan GM. Development and application of a competitive enzyme-linked immunosorbent assay for the detection of serum antibodies to porcine circovirus type 2. J Vet Diagn Invest 2000; 12:400-5. [PMID: 11021425 DOI: 10.1177/104063870001200502] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We report the development of a competitive enzyme-linked immunosorbent assay (c-ELISA) for the detection of antibodies to porcine circovirus type 2 (PCV2), the agent associated with the recently described postweaning multisystemic wasting syndrome in pigs. At present, no method has been published describing a c-ELISA for the detection of antibodies to PCV2, and currently employed tests are impractical for use in some laboratories. The assay described here uses a cell culture isolate of porcine circovirus type 2 as antigen and a PCV2-specific monoclonal antibody as the competing reagent. Evaluation of the ELISA was performed by comparison with results obtained using an indirect immunofluorescent test on 484 sera from pig herds in the United Kingdom, Canada, France, and the USA and serial bleeds from pigs experimentally infected with porcine circoviruses. The sensitivity and specificity of the ELISA were determined as 99.58% and 97.14%, respectively, at 2 standard deviations (SD) from the mean or 95.81% and 100% at 3 SD from the mean. Using this ELISA, a serologic survey of 461 sera collected from commercial pig herds in Northern Ireland between 1973 and 1999 was undertaken. Analysis of the results of this survey demonstrated that the number of ELISA-positive sera detected in an individual year during this period ranged from 55% to 100%. This c-ELISA has applications for large-scale rapid diagnosis of PCV2 infection in pig populations worldwide and for immunoscreening of sera from other species for antibodies to PCV2.
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Affiliation(s)
- I W Walker
- Department of Agriculture for Northern Ireland, Belfast, UK
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39
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Allan GM, McNeilly F, Kennedy S, Meehan B, Ellis J, Krakowka S. Immunostimulation, PCV-2 and PMWS. Vet Rec 2000; 147:170-1. [PMID: 10975340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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40
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Allan GM, McNeilly F, McNair I, Curran MD, Walker I, Ellis J, Konoby C, Kennedy S, Meehan B. Absence of evidence for porcine circovirus type 2 in cattle and humans, and lack of seroconversion or lesions in experimentally infected sheep. Arch Virol 2000; 145:853-7. [PMID: 10893163 DOI: 10.1007/s007050050678] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
No antibodies to porcine circovirus type 2 were detected in sera from cattle, sheep and humans. Experimental infection of lambs with this virus failed to produce lesions or seroconversion.
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Affiliation(s)
- G M Allan
- Veterinary Sciences Division, Belfast, Northern Ireland
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41
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Thomson J, Smith B, Allan G, McNeilly F, McVicar C. PDNS, PMWS and porcine circovirus type 2 in Scotland. Porcine dermatitis and nephropathy syndrome. Post-weaning multisystemic wasting syndrome. Vet Rec 2000; 146:651-2. [PMID: 10872790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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42
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Krakowka S, Ellis JA, Meehan B, Kennedy S, McNeilly F, Allan G. Viral wasting syndrome of swine: experimental reproduction of postweaning multisystemic wasting syndrome in gnotobiotic swine by coinfection with porcine circovirus 2 and porcine parvovirus. Vet Pathol 2000; 37:254-63. [PMID: 10810990 DOI: 10.1354/vp.37-3-254] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
One-day-old gnotobiotic piglets were inoculated intranasally with in vitro passaged porcine circovirus 1 (PCV-1), PCV-2, and porcine parvovirus (PPV) alone or in combination (PCV-1/PCV-2, PCV-1/PPV, and PCV-2/PPV). Piglets were evaluated for 1) the development of porcine postweaning multisystemic wasting syndrome (PMWS), 2) distribution of viral antigens by immunochemistry, and 3) viremia and the presence of viral DNA in nasal and ocular secretions and feces. All single agent-infected piglets and piglets infected with PCV-1/PCV-2 or PCV-1/PPV were clinically asymptomatic. They were transiently viremic and seroconverted to homologous virus(es). At termination of the study on postinfection day (PID) 35, microscopic lesions were restricted to focal inflammatory cell infiltrates in livers and myocardia. One piglet given PCV-1/PPV was PPV viremic for 2 weeks after infection and had lymphangiectasia of the spiral and descending colon associated with granulomatous inflammation. All four PCV-2/PPV-inoculated piglets developed PMWS, characterized by sudden onset of depression and anorexia, icterus, and submucosal edema. One piglet became moribund on PID 27, and the remaining three piglets were euthanatized between PID 27 and PID 30 because of severe disease. Lymph nodes were small and the livers were mottled. Disseminated angiocentric granulomatous inflammation was present in all tissues examined except the brain. Multiple lightly basophilic intracytoplasmic inclusion bodies were identified in macrophages and histiocytes. PCV-2 antigen was widely distributed within macrophages; PPV antigen was sparse. Hepatocellular necrosis and bile retention were prominent. PCV-2 DNA was identified in ocular, fecal, and nasal secretions. Terminal sera contained antibodies to PPV (4/4) and PCV-2 (3/ 4). Production of PMWS in gnotobiotic swine appears to require PCV-2 and additional infectious agents such as PPV for full disease expression in gnotobiotic piglets.
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Affiliation(s)
- S Krakowka
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, USA.
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43
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Allan GM, McNeilly F, Meehan BM, Ellis JA, Connor TJ, McNair I, Krakowka S, Kennedy S. A sequential study of experimental infection of pigs with porcine circovirus and porcine parvovirus: immunostaining of cryostat sections and virus isolation. J Vet Med B Infect Dis Vet Public Health 2000; 47:81-94. [PMID: 10763376 DOI: 10.1046/j.1439-0450.2000.00364.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The sequential tissue distribution of virus was investigated using virus isolation and immunofluorescence tests in 1-day-old piglets inoculated with porcine circovirus 2 (PCV2) and/or porcine parvovirus (PPV). Enlarged mesenteric lymph nodes were seen in the pig inoculated with PCV2 alone and killed at 26 days post-inoculation (PI). One of the pigs inoculated with PCV2 and PPV and killed at 21 days PI had an enlarged liver. The pig killed at 26 days PI in this group had enlarged liver, kidneys and heart. Histopathological changes were seen in lymphoid tissues of the pigs inoculated with PCV2 alone and killed at 14 and 26 days PI. Similar, but more severe, lesions were observed in the pigs infected with PCV2 and PPV and killed from 10 days PI onwards. Histological lesions of nephritis, pneumonia and hepatitis were also apparent in these animals. Mild nephritis was also seen in the pigs infected with PPV alone and killed at 14 and 26 days PI. Moderate amounts of PPV antigen were detected in tissues from the pigs inoculated with PPV alone and killed at 14 days PI. Low levels of PCV antigen were detected, mainly in lymphoid tissues, in the pigs inoculated with PCV alone and killed at 14 days PI. Low to moderate amounts of PCV antigen were detected in a wider range of tissues in the pig in this group killed at 26 days PI. In the pigs inoculated with both viruses, PPV antigen was detected in tissues of pigs killed from 3 to 26 days PI with maximal amounts detected between 6 and 14 days PI. PCV2 antigen was detected in low to moderate amounts in the tissues of pigs killed at 14 days PI. Large amounts of PCV2 antigen were detected in most of the tissues from pigs in this group killed between 17 and 26 days PI. Virus isolation results for PCV2 generally correlated well with the results for immunofluorescent staining. PPV was isolated from almost all tissues from pigs inoculated with PCV2 and PPV, a much higher incidence of positive tissues than observed for immunofluorescent staining.
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Affiliation(s)
- G M Allan
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
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44
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Gresham A, Jackson G, Giles N, Allan G, McNeilly F, Kennedy S. PMWS and porcine dermatitis nephropathy syndrome in Great Britain. Vet Rec 2000; 146:143. [PMID: 10706335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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45
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Ellis JA, Bratanich A, Clark EG, Allan G, Meehan B, Haines DM, Harding J, West KH, Krakowka S, Konoby C, Hassard L, Martin K, McNeilly F. Coinfection by porcine circoviruses and porcine parvovirus in pigs with naturally acquired postweaning multisystemic wasting syndrome. J Vet Diagn Invest 2000; 12:21-7. [PMID: 10690771 DOI: 10.1177/104063870001200104] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Postweaning multisystemic wasting syndrome (PMWS) is an emerging disease in swine. Recently, the disease has been reproduced with inocula containing a newly described porcine circovirus (PCV), designated PCV 2, and porcine parvovirus (PPV). In order to determine if these viruses interact in naturally acquired PMWS, affected tissues from field cases were examined by immunohistochemistry (IHC) and polymerase chain reaction (PCR) for PCV 2 and PPV, as well as by PCR for the other recognized porcine circovirus, PCV 1. Porcine circovirus 2 was detected by PCR or IHC in affected fixed or frozen tissues from 69 of 69 cases of PMWS collected over 3 years from 25 farms. Porcine parvovirus was detected in 12 of the same cases, and PCV 1 was detected in 9 of 69; however, an apparent decrease was found in the sensitivity of the PCRs used to detect the latter 2 viruses when fixed tissue from the same cases were compared with the use of frozen tissues. Porcine circovirus 2 was not detected by PCR in affected tissues from 16 age-matched pigs that had Streptococcus suis-associated disease. Electron microscopic examination of plasma pooled from 15 pigs with PMWS revealed the presence of PCV and PPV, whereas these viruses were not observed in pooled plasma from 5 age-matched clinically normal pigs. These results confirm and extend previous findings documenting a consistent association of PCV 2 with PMWS. As well, infection by PPV or PCV 1 or both may be an important cofactor in the pathogenesis of some, but apparently not all, cases of PMWS.
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Affiliation(s)
- J A Ellis
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon Canada
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46
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Kennedy S, Moffett D, McNeilly F, Meehan B, Ellis J, Krakowka S, Allan GM. Reproduction of lesions of postweaning multisystemic wasting syndrome by infection of conventional pigs with porcine circovirus type 2 alone or in combination with porcine parvovirus. J Comp Pathol 2000; 122:9-24. [PMID: 10627387 DOI: 10.1053/jcpa.1999.0337] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Post-weaning multisystemic wasting syndrome (PMWS) has recently emerged as an important disease of pigs in North America, Europe and Asia. Porcine circovirus type 2 (PCV2) and porcine parvovirus (PPV) have been isolated from affected pigs. To investigate the pathogenicity of these isolates, groups of colostrum-deprived conventional pigs were inoculated with PCV2 alone (n=4), PPV alone (n=3) or dually with PCV2 and PPV (n=7) and examined post mortem between 21 and 26 days post-infection (dpi). Two control pigs were inoculated with an uninfected cell culture lysate. All pigs that received both viruses became dull at approximately 10-12 dpi and six of these animals subsequently developed jaundice. Hepatomegaly and enlarged kidneys were prominent post-mortem findings in these animals. Histopathological examination revealed severe macrophage infiltration, syncytia formation and numerous cytoplasmic and nuclear amphophilic inclusion bodies in lymphoid tissues. Granulomatous lesions were apparent in liver, lung, kidney, pancreas, myocardium, intestines, testis, brain and salivary, thyroid and adrenal glands. Abundant PCV2 antigen was detected in affected tissues. Only one of the four pigs inoculated with PCV2 alone developed clinical signs, but they all had histopathological lesions which, although less severe, were similar to those in the dually infected animals. The control pigs and those infected with PPV alone remained clinically normal and did not have gross lesions. The only histopathological lesion seen in these animals was mild interstitial nephritis in the pigs infected with PPV alone. These results indicate that lesions of PMWS can be induced by inoculating pigs with PCV2 alone, thereby fulfilling Koch's postulates. Concurrent infection with PPV increased the severity of the lesions, suggesting that co-factors are important in the pathogenesis of PMWS.
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Affiliation(s)
- S Kennedy
- Veterinary Sciences Division, Department of Agriculture for Northern Ireland, Department of Veterinary Science, Stoney Road, Belfast, Stormont, BT4 3SD, UK
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47
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Spagnuolo-Weaver M, Fuerst R, Campbell ST, Meehan BM, McNeilly F, Adair B, Allan G. A fluorimeter-based RT-PCR method for the detection and quantitation of porcine cytokines. J Immunol Methods 1999; 230:19-27. [PMID: 10594350 DOI: 10.1016/s0022-1759(99)00114-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In this paper, we describe a fluorimeter-based, closed-tube, polymerase chain reaction (PCR) assay for the detection and quantification of the mRNA of porcine interleukin 1alpha (IL1alpha) and interleukin 2 (IL2) cytokines in peripheral blood leukocytes (PBLs) using melting curve analysis and compare it to a standard PCR performed in a block-based thermocycler.
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Affiliation(s)
- M Spagnuolo-Weaver
- Department of Virology, Veterinary Sciences Division, Stormont, Belfast, UK.
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48
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West KH, Bystrom JM, Wojnarowicz C, Shantz N, Jacobson M, Allan GM, Haines DM, Clark EG, Krakowka S, McNeilly F, Konoby C, Martin K, Ellis JA. Myocarditis and abortion associated with intrauterine infection of sows with porcine circovirus 2. J Vet Diagn Invest 1999; 11:530-2. [PMID: 12968736 DOI: 10.1177/104063879901100608] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Porcine circovirus 2 (PCV2) is a recently identified agent that has been associated with postweaning multisystemic wasting syndrome (PMWS) in swine populations. In this report, the potential spectrum of disease associated with PCV2 is expanded by evidence of vertical transmission and associated reproductive failure. PCV2 was isolated from a litter of aborted piglets from a farm experiencing late-term abortions and stillbirths. Severe, diffuse myocarditis was present in 1 piglet associated with extensive immunohistochemical staining for PCV2 antigen. Variable amounts of PCV2 antigen were also present in liver, lung, and kidney of multiple fetuses. The presence of other agents that have been associated with fetal lesions and abortion in swine, including porcine parvovirus, porcine reproductive respiratory syndrome virus, encephalomyocarditis virus, and enterovirus, could not be established.
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Affiliation(s)
- K H West
- Prairie Diagnostic Service, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada
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49
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Nordengrahn A, Svenda M, Moreno-Lopez J, Bergvall A, Hernandez P, McNeilly F, Allan G, Merza M. Development of a blocking ELISA for screening antibodies to porcine rubulavirus, La Piedad Michoacan Virus. J Vet Diagn Invest 1999; 11:319-23. [PMID: 10424646 DOI: 10.1177/104063879901100404] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A blocking enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies to porcine rubulavirus (La Piedad Michoacan Virus [LPMV]) in serum samples from pigs. The test, based on a monoclonal antibody against the LPMV hemagglutinin-neuraminidase glycoprotein, had a sensitivity of 99% and a specificity of 97%. The results of this test were in agreement with those obtained by an indirect ELISA and hemagglutination inhibition, indirect immunofluorescence, and virus neutralization tests. The blocking ELISA is considered the most suitable test for routine screening for antibodies against LPMV.
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Affiliation(s)
- A Nordengrahn
- SVANOVA Biotech, National Veterinary Institute, Uppsala Science Park, Glunten, Sweden
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50
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McNeilly F, Kennedy S, Moffett D, Meehan BM, Foster JC, Clarke EG, Ellis JA, Haines DM, Adair BM, Allan GM. A comparison of in situ hybridization and immunohistochemistry for the detection of a new porcine circovirus in formalin-fixed tissues from pigs with post-weaning multisystemic wasting syndrome (PMWS). J Virol Methods 1999; 80:123-8. [PMID: 10471021 DOI: 10.1016/s0166-0934(99)00043-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Post-weaning multisystemic wasting syndrome (PMWS) is a recently identified condition affecting pigs in North America and Europe. Porcine circovirus antigen and nucleic acid have been demonstrated associated with lesions, and a new porcine circovirus designated PCV2 has been recovered from tissues of these animals. In this study, in situ hybridisation and immunohistochemical protocols were developed, optimized and compared for their relative sensitivity in detecting PCV2 antigens and nucleic acid in tissues from cases of PMWS that had been fixed for up to 6 months in formalin. For both immunohistochemistry and in situ hybridization, an increase in specific signal was observed following increased exposure to both protease XIV and proteinase K. Maximum signal and minimal loss of tissue morphology was seen after 40 min treatment with protease XIV (0.5 mg/ml). After optimisation, a comparison of these techniques on sequential sections demonstrated that both techniques successfully detected antigen or nucleic acid in all of the tissues examined. More positive cells, with increased signal intensity, were detected following immunohistochemistry.
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Affiliation(s)
- F McNeilly
- Veterinary Sciences Division, Department of Agriculture for Northern Ireland, Stormont, Belfast, UK
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