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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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Blunt R, McOrist S, McKillen J, McNair I, Jiang T, Mellits K. House fly vector for porcine circovirus 2b on commercial pig farms. Vet Microbiol 2010; 149:452-5. [PMID: 21145672 DOI: 10.1016/j.vetmic.2010.11.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 11/08/2010] [Accepted: 11/12/2010] [Indexed: 10/18/2022]
Abstract
We investigated the on-farm potential of common farm invertebrates to transmit porcine circovirus genotype 2 (PCV2) and other non-enveloped viruses. In 2007 (pre-PCV2 vaccination) and 2008 (post-PCV2 vaccination), invertebrate communities were trap-collected (8 trap-dates per year), counted and sorted into genus and species groups on 5 farm study sites within England. Total DNA was extracted from feces of representational cross-sections of pigs on each farm in each year and also from intact samples of Diptera flies (ca. 20 flies per trap) and dissected viscera of any cockroaches (ca. 5 per trap). Each DNA sample was tested for the presence of PCV2 DNA by separate PCRs for ORF1 and ORF2. Positive samples were sub-typed via DNA sequencing of PCR products. The pig-associated Diptera fly community was dominated by Musca domestica (house fly) in both years on all 5 farms; numerous Blatta orientalis cockroaches were only noted on 1 farm throughout. Specific PCV2b DNA elements were routinely detected (25-60% of samples) in weaner/nursery pig feces in 2007, but not in other age groups. Musca collected on 4 of the 5 farms in 2007 was also positive for PCV2b DNA elements. Comparison of ORF2 sequences indicated that ORF2 sequences indicating PCV2b genotype were identical in pigs and flies. Minor changes were noted in ORF1 sequences from different samples. Flies collected in the weaner/nursery area were most likely to be positive (22-50% of fly-trap samples). DNA extracted from all cockroaches (2007 and 2008) and all flies and pig feces in 2008 were also negative throughout. We suggest that Musca flies have the most likely on-farm potential to carry and transmit PCV2b due to their life cycle incorporating stages in close association with pigs and their habitat. Vaccination appeared to reduce environmental load of PCV2b.
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Affiliation(s)
- R Blunt
- University of Nottingham, School of Veterinary Medicine and Science, Sutton Bonington LE12 5RD, United Kingdom
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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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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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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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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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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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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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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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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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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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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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