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Song H, Gao X, Li J, Dong X, Fu Y, Shao L, Zhang J, Qiu HJ, Luo Y. Development and application of an indirect ELISA for detection of antibodies against emerging atypical porcine pestivirus. Virol J 2024; 21:53. [PMID: 38438894 PMCID: PMC10910838 DOI: 10.1186/s12985-024-02330-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 02/27/2024] [Indexed: 03/06/2024] Open
Abstract
BACKGROUND Atypical porcine pestivirus (APPV) is a newly discovered swine pestivirus, which can cause congenital tremor and high mortality in newborn piglets and subclinical infection in adult pigs, leading to significant impacts on the pig industry. Currently, there is no approved serological method to assess APPV infection status in pig farms. METHODS In this study, the envelope glycoprotein E2 of APPV was highly expressed in suspension HEK293 cells, and further an indirect enzyme-linked immunosorbent assay based on the recombinant E2 protein (E2-iELISA) was developed and evaluated. RESULTS The reaction parameters of the E2-iELISA were optimized, and the cutoff value was determined to be 0.2 by analyzing S/P values of 165 negative sera against APPV that were confirmed by virus neutralization test (VNT). Specificity test showed that the method had no cross-reaction with other common swine viruses. The E2-iELISA was evaluated using a panel of swine sera, and showed high sensitivity (113/120, 94.2%) and specificity (65/70, 92.9%), and the agreement rate with VNT was 93.7% (178/190). Subsequently, the E2-iELISA was utilized to investigate the seroprevalence of APPV in pig herds of China. When detecting 1368 pig serum samples collected from nine provinces in China, the overall seroprevalence of APPV was 73.9% (1011/1368). CONCLUSION Our findings suggest that the E2-iELISA is specific and sensitive, and could be a valuable tool for serological surveillance of APPV infection in pigs.
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Affiliation(s)
- Hao Song
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China
| | - Xiaowei Gao
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China
| | - Jing Li
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China
| | - Xinying Dong
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China
| | - Yanhui Fu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China
| | - Lina Shao
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China
| | - Jiaoer Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China
| | - Hua-Ji Qiu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China.
| | - Yuzi Luo
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin, 150069, China.
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Song H, Gao X, Fu Y, Li J, Fan G, Shao L, Zhang J, Qiu HJ, Luo Y. Isolation and Molecular Characterization of Atypical Porcine Pestivirus Emerging in China. Viruses 2023; 15:2149. [PMID: 38005827 PMCID: PMC10675531 DOI: 10.3390/v15112149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Atypical porcine pestivirus (APPV) is a recently discovered and very divergent species of the genus Pestivirus within the family Flaviviridae, which causes congenital tremor (CT) in newborn piglets. In this study, an APPV epidemiological investigation was conducted by studying 975 swine samples (562 tissue and 413 serum samples) collected from different parts of China from 2017 to 2021. The results revealed that the overall positive rate of the APPV genome was 7.08% (69/975), among which 50.7% (35/69) of the samples tested positive for one or more other common swine viruses, especially porcine circovirus type 2 (PCV2) with a coinfection rate of 36.2% (25/69). Subsequently, a novel APPV strain, named China/HLJ491/2017, was isolated in porcine kidney (PK)-15 cells for the first time from a weaned piglet that was infected with both APPV and PCV2. The new APPV isolate was confirmed by RT-PCR, sequencing, immunofluorescence assay, and transmission electron microscopy. After clearing PCV2, a pure APPV strain was obtained and further stably propagated in PK-15 cells for more than 30 passages. Full genome sequencing and phylogenetic analysis showed that the China/HLJ491/2017 strain was classified as genotype 2, sharing 80.8 to 97.6% of its nucleotide identity with previously published APPV strains. In conclusion, this study enhanced our knowledge of this new pestivirus and the successful isolation of the APPV strain provides critical material for the investigation of the biological and pathogenic properties of this emerging virus, as well as the development of vaccines and diagnostic reagents.
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Affiliation(s)
| | | | | | | | | | | | | | - Hua-Ji Qiu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, China; (H.S.); (X.G.); (Y.F.); (J.L.); (G.F.); (L.S.); (J.Z.)
| | - Yuzi Luo
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Road, Harbin 150069, China; (H.S.); (X.G.); (Y.F.); (J.L.); (G.F.); (L.S.); (J.Z.)
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Stenberg H, Malmberg M, Hayer J. Screening for atypical porcine pestivirus in Swedish boar semen used for artificial insemination and a characterisation of the seminal RNA microbiome including the virome. BMC Vet Res 2023; 19:219. [PMID: 37864222 PMCID: PMC10588136 DOI: 10.1186/s12917-023-03762-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 09/30/2023] [Indexed: 10/22/2023] Open
Abstract
BACKGROUND This study aimed to characterise the RNA microbiome, including the virome of extended semen from Swedish breeding boars, with particular focus on Atypical porcine pestivirus (APPV). This neurotropic virus, associated with congenital tremor type A-II in piglets, was recently demonstrated to induce the disease through insemination with semen from infected boars. RESULTS From 124 Artificial Insemination (AI) doses from Swedish breeding boars, APPV was detected in one dose in addition to a sparse seminal RNA virome, characterised by retroviruses, phages, and some fecal-associated contaminants. The detected seminal microbiome was large and characterized by Gram-negative bacteria from the phylum Proteobacteria, mainly consisting of apathogenic or opportunistic bacteria. The proportion of bacteria with a pathogenic potential was low, and no antimicrobial resistance genes (ARGs) were detected in the datasets. CONCLUSION Overall, the results indicate a good health status among Swedish breeding boars. The detection of APPV in semen raises the question of whether routine screening for APPV in breeding boars should be instigated.
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Affiliation(s)
- Hedvig Stenberg
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SLU, P.O. Box 7028, 750 07, Uppsala, Sweden.
| | - Maja Malmberg
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SLU, P.O. Box 7028, 750 07, Uppsala, Sweden
| | - Juliette Hayer
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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Buckley AC, Mora-Díaz JC, Magtoto RL, Hulzen AV, Ferreyra FM, Falkenberg SM, Giménez-Lirola LG, Arruda BL. Dynamics of Infection of Atypical Porcine Pestivirus in Commercial Pigs from Birth to Market: A Longitudinal Study. Viruses 2023; 15:1767. [PMID: 37632109 PMCID: PMC10458225 DOI: 10.3390/v15081767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Atypical porcine pestivirus (APPV) was found to be associated with pigs demonstrating congenital tremors (CT), and clinical signs in pigs have been reproduced after experimental challenge. Subsequently, APPV has been identified in both symptomatic and asymptomatic swine of all ages globally. The objective of this research was to perform a longitudinal study following two cohorts of pigs, those born in litters with pigs exhibiting CT and those born in litters without CT, to analyze the virus and antibody dynamics of APPV infection in serum from birth to market. There was a wide range in the percentage of affected pigs (8-75%) within CT-positive litters. After co-mingling with CT-positive litters at weaning, pigs from CT-negative litters developed viremia that was cleared after approximately 2 months, with the majority seroconverting by the end of the study. In contrast, a greater percentage of pigs exhibiting CT remained PCR positive throughout the growing phase, with less than one-third of these animals seroconverting. APPV RNA was present in multiple tissues from pigs in both groups at the time of marketing. This study improved our understanding of the infection dynamics of APPV in swine and the impact that the immune status and timing of infection have on the persistence of APPV in serum and tissues.
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Affiliation(s)
- Alexandra C. Buckley
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
| | - Juan-Carlos Mora-Díaz
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011, USA; (J.-C.M.-D.); (R.L.M.); (A.V.H.); (F.M.F.); (L.G.G.-L.)
| | - Ronaldo L. Magtoto
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011, USA; (J.-C.M.-D.); (R.L.M.); (A.V.H.); (F.M.F.); (L.G.G.-L.)
| | - Amberly Van Hulzen
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011, USA; (J.-C.M.-D.); (R.L.M.); (A.V.H.); (F.M.F.); (L.G.G.-L.)
| | - Franco Matias Ferreyra
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011, USA; (J.-C.M.-D.); (R.L.M.); (A.V.H.); (F.M.F.); (L.G.G.-L.)
- Kansas State Veterinary Diagnostic Laboratory, Kansas State University, Manhattan, KS 66506, USA
| | - Shollie M. Falkenberg
- Ruminant Disease and Immunology Research Unit, National Animal Disease Center, U.S. Department of Agriculture, Agricultural Research Service, Ames, IA 50010, USA;
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
| | - Luis G. Giménez-Lirola
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA 50011, USA; (J.-C.M.-D.); (R.L.M.); (A.V.H.); (F.M.F.); (L.G.G.-L.)
| | - Bailey L. Arruda
- Virus and Prion Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, IA 50010, USA
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Development and Evaluation of Antigen-Specific Dual Matrix Pestivirus K ELISAs Using Longitudinal Known Infectious Status Samples. J Clin Microbiol 2022; 60:e0069722. [PMID: 36222547 PMCID: PMC9667771 DOI: 10.1128/jcm.00697-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pestivirus K, commonly known as atypical porcine pestivirus (APPV), is the most common cause of congenital tremor (CT) in pigs. Currently, there is limited information on the infection dynamics of and immune response against APPV and no robust serologic assay to assess the effectiveness of preventative measures. To that end, known infection status samples were generated using experimental inoculation of cesarean-derived, colostrum-deprived pigs. Pigs (2 per pen) were inoculated with minimum essential medium (n = 6; negative control) or APPV (n = 16). Serum, pen-based oral fluid samples, and nasal swabs were collected through 70 days postinoculation (dpi). The immune response to recombinant APPV Erns, E2, or NS3 antigens was evaluated using both serum and oral fluids via indirect enzyme-linked immunosorbent assays (ELISAs). APPV was detected by real-time reverse transcription-PCR (RT-qPCR) in all oral fluid and serum samples from APPV-inoculated animals by 24 and 35 dpi, respectively. All samples remained genome positive until 70 dpi. Detection of nasal shedding was less consistent, with APPV being detected by RT-qPCR in all inoculated animals at 42, 49, and 56 dpi. Antibodies were first detected in oral fluids at 14 dpi, 10 days before serum detection, and concurrently with the first oral fluids RT-qPCR detection. Across sample types and time points, the Erns ELISA outperformed the other targets. In conclusion, both oral fluid and serum APPV Erns ELISAs can be used to economically evaluate the individual and herd status prior to and following intervention strategies.
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Stenberg H, Hellman S, Lindström L, Jacobson M, Fossum C, Hayer J, Malmberg M. Congenital tremor and splay leg in piglets – insights into the virome, local cytokine response, and histology. BMC Vet Res 2022; 18:348. [PMID: 36109741 PMCID: PMC9479355 DOI: 10.1186/s12917-022-03443-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 09/05/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Atypical porcine pestivirus (APPV) is a neurotropic virus associated with congenital tremor type A-II. A few experimental studies also indicate an association between APPV and splay leg. The overarching aim of the present study was to provide insights into the virome, local cytokine response, and histology of the CNS in piglets with signs of congenital tremor or splay leg.
Results
Characterization of the cytokine profile and virome of the brain in piglets with signs of congenital tremor revealed an APPV-associated upregulation of Stimulator of interferon genes (STING). The upregulation of STING was associated with an increased expression of the gene encoding IFN-α but no differential expression was recorded for the genes encoding CXCL8, IFN-β, IFN-γ, IL-1β, IL-6, or IL-10. No viral agents or cytokine upregulation could be detected in the spinal cord of piglets with signs of splay leg or in the brain of piglets without an APPV-infection. The histopathological examination showed no lesions in the CNS that could be attributed to the APPV-infection, as no difference between sick and healthy piglets could be seen.
Conclusion
The results from this study provide evidence of an APPV-induced antiviral cytokine response but found no lesions related to the infection nor any support for a common causative agent.
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DNAJC14-Independent Replication of the Atypical Porcine Pestivirus. J Virol 2022; 96:e0198021. [PMID: 35852352 PMCID: PMC9364808 DOI: 10.1128/jvi.01980-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atypical porcine pestiviruses (APPV; Pestivirus K) are a recently discovered, very divergent species of the genus Pestivirus within the family Flaviviridae. The presence of APPV in piglet-producing farms is associated with the occurrence of so-called “shaking piglets,” suffering from mild to severe congenital tremor type A-II. Previous studies showed that the cellular protein DNAJC14 is an essential cofactor of the NS2 autoprotease of all classical pestiviruses. Consequently, genetically engineered DNAJC14 knockout cell lines were resistant to all tested noncytopathogenic (non-cp) pestiviruses. Surprisingly, we found that the non-cp APPV can replicate in these cells in the absence of DNAJC14, suggesting a divergent mechanism of polyprotein processing. A complete laboratory system for the study of APPV was established to learn more about the replication of this unusual virus. The inactivation of the APPV NS2 autoprotease using reverse genetics resulted in nonreplicative genomes. To further investigate whether a regulation of the NS2-3 cleavage is also existing in APPV, we constructed synthetic viral genomes with deletions and duplications leading to the NS2 independent release of mature NS3. As observed with other pestiviruses, the increase of mature NS3 resulted in elevated viral RNA replication levels and increased protein expression. Our data suggest that APPV exhibit a divergent mechanism for the regulation of the NS2 autoprotease activity most likely utilizing a different cellular protein for the adjustment of replication levels. IMPORTANCE DNAJC14 is an essential cofactor of the pestiviral NS2 autoprotease, limiting replication to tolerable levels as a prerequisite for the noncytopathogenic biotype of pestiviruses. Surprisingly, we found that the atypical porcine pestivirus (APPV) is able to replicate in the absence of DNAJC14. We further investigated the NS2-3 processing of APPV using a molecular clone, monoclonal antibodies, and DNAJC14 knockout cells. We identified two potential active site residues of the NS2 autoprotease and could demonstrate that the release of NS3 by the NS2 autoprotease is essential for APPV replication. Defective interfering genomes and viral genomes with duplicated NS3 sequences that produce mature NS3 independent of the NS2 autoprotease activity showed increased replication and antigen expression. It seems likely that an alternative cellular cofactor controls NS2-3 cleavage and thus replication of APPV. The replication-optimized synthetic APPV genomes might be suitable live vaccine candidates, whose establishment and testing warrant further research.
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Ren X, Qian P, Liu S, Chen H, Li X. Fc-Mediated E2-Dimer Subunit Vaccines of Atypical Porcine Pestivirus Induce Efficient Humoral and Cellular Immune Responses in Piglets. Viruses 2021; 13:v13122443. [PMID: 34960713 PMCID: PMC8703287 DOI: 10.3390/v13122443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/27/2021] [Accepted: 12/02/2021] [Indexed: 01/05/2023] Open
Abstract
Congenital tremor (CT) type A-II in piglets is caused by an emerging atypical porcine pestivirus (APPV), which is prevalent in swine herds and a serious threat to the pig production industry. This study aimed to construct APPV E2 subunit vaccines fused with Fc fragments and evaluate their immunogenicity in piglets. Here, APPV E2Fc and E2ΔFc fusion proteins expressed in Drosophila Schneider 2 (S2) cells were demonstrated to form stable dimers in SDS-PAGE and western blotting assays. Functional analysis revealed that aE2Fc and aE2ΔFc fusion proteins could bind to FcγRI on antigen-presenting cells (APCs), with the affinity of aE2Fc to FcγRI being higher than that of aE2ΔFc. Moreover, subunit vaccines based on aE2, aE2Fc, and aE2ΔFc fusion proteins were prepared, and their immunogenicity was evaluated in piglets. The results showed that the Fc fusion proteins emulsified with the ISA 201VG adjuvant elicited stronger humoral and cellular immune responses than the IMS 1313VG adjuvant. These findings suggest that APPV E2 subunit vaccines fused with Fc fragments may be a promising vaccine candidate against APPV.
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Affiliation(s)
- Xujiao Ren
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; (X.R.); (P.Q.); (S.L.); (H.C.)
- Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Ping Qian
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; (X.R.); (P.Q.); (S.L.); (H.C.)
- Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Shudan Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; (X.R.); (P.Q.); (S.L.); (H.C.)
- Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; (X.R.); (P.Q.); (S.L.); (H.C.)
- Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Xiangmin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; (X.R.); (P.Q.); (S.L.); (H.C.)
- Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
- Correspondence: ; Tel.: +86-27-87282608
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Postel A, Smith DB, Becher P. Proposed Update to the Taxonomy of Pestiviruses: Eight Additional Species within the Genus Pestivirus, Family Flaviviridae. Viruses 2021; 13:v13081542. [PMID: 34452407 PMCID: PMC8402895 DOI: 10.3390/v13081542] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/29/2021] [Accepted: 08/02/2021] [Indexed: 12/29/2022] Open
Abstract
Pestiviruses are plus-stranded RNA viruses belonging to the family Flaviviridae. They comprise several important pathogens like classical swine fever virus and bovine viral diarrhea virus that induce economically important animal diseases. In 2017, the last update of pestivirus taxonomy resulted in demarcation of 11 species designated Pestivirus A through Pestivirus K. Since then, multiple new pestiviruses have been reported including pathogens associated with disease in pigs or small ruminants. In addition, pestivirus sequences have been found during metagenomics analysis of different non-ungulate hosts (bats, rodents, whale, and pangolin), but the consequences of this pestivirus diversity for animal health still need to be established. To provide a systematic classification of the newly discovered viruses, we analyzed the genetic relationship based on complete coding sequences (cds) and deduced polyprotein sequences and calculated pairwise distances that allow species demarcation. In addition, phylogenetic analysis was performed based on a highly conserved region within the non-structural protein NS5B. Taking into account the genetic relationships observed together with available information about antigenic properties, host origin, and characteristics of disease, we propose to expand the number of pestivirus species to 19 by adding eight additional species designated Pestivirus L through Pestivirus S.
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Affiliation(s)
- Alexander Postel
- Institute of Virology, University of Veterinary Medicine, 30559 Hannover, Germany;
| | - Donald B. Smith
- Nuffield Department of Experimental Medicine, University of Oxford, Peter Medawar Building, South Parks Road, Oxford OX1 3SY, UK;
| | - Paul Becher
- Institute of Virology, University of Veterinary Medicine, 30559 Hannover, Germany;
- Correspondence: ; Tel.: +49-511-953-8840
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Stenberg H, Leveringhaus E, Malmsten A, Dalin AM, Postel A, Malmberg M. Atypical porcine pestivirus-A widespread virus in the Swedish wild boar population. Transbound Emerg Dis 2021; 69:2349-2360. [PMID: 34331830 DOI: 10.1111/tbed.14251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/08/2021] [Accepted: 07/20/2021] [Indexed: 01/23/2023]
Abstract
The recently identified causative agent of congenital tremor in domestic piglets, atypical porcine pestivirus (APPV), was detected in serum from Swedish wild boar. A previous study from Sweden described APPV in domestic piglets suffering from congenital tremor, but the APPV situation in the wild boar population was unknown. In this study, 595 serum samples from wild boar originating from 13 counties in the south and central parts of Sweden, collected between 2000 and 2018, were analysed for the presence of the APPV-genome and for antibodies against the APPV-glycoprotein Erns . The results revealed that APPV is highly abundant in the Swedish wild boar population; 12% (73/595) were APPV-genome positive in serum and 72% (433/595) of the tested wild boars displayed APPV-specific antibodies. The present study also shows that APPV has been present in the Swedish wild boar population since at least the year 2000. The viral sequences obtained from the wild boars were highly similar to those obtained from Swedish domestic pigs positive for APPV and suffering from congenital tremor, suggesting a viral exchange between wild boars and domestic pigs. The high proportion of viraemic and seropositive wild boar is indicative of wild boar being an important reservoir for APPV.
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Affiliation(s)
- Hedvig Stenberg
- Section of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Elena Leveringhaus
- Institute for Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Anne-Marie Dalin
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Alexander Postel
- Institute for Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Maja Malmberg
- Section of Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.,SLU Global Bioinformatics Centre, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Liu J, Zhang P, Chen Y, Zhong W, Li B, Pi M, Ning Z. Vaccination with virus-like particles of atypical porcine pestivirus inhibits virus replication in tissues of BALB/c mice. Arch Virol 2021; 166:2733-2741. [PMID: 34322722 PMCID: PMC8317679 DOI: 10.1007/s00705-021-05185-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/05/2021] [Indexed: 11/24/2022]
Abstract
Congenital tremor (CT) type A-II in piglets is a worldwide disease caused by an emerging atypical porcine pestivirus (APPV). Preparation and evaluation of vaccines in laboratory animals is an important preliminary step toward prevention and control of the disease. Here, virus-like particles (VLPs) of APPV were prepared and VLPs vaccine was evaluated in BALB/c mice. Purified Erns and E2 proteins expressed in E. coli were allowed to self-assemble into VLPs, which had the appearance of hollow spherical particles with a diameter of about 100 nm by transmission electron microscopy (TEM). The VLPs induced strong antibody responses and reduced the viral load in tissues of BALB/c mice. The data from animal challenge experiments, RT-PCR, and immunohistochemical analysis demonstrated that BALB/c mice are an appropriate laboratory model for APPV. These results suggest the feasibility of using VLPs as a vaccine for the prevention and control of APPV and provide useful information for further study of APPV in laboratory animals.
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Affiliation(s)
- Jianxin Liu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Pengtao Zhang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Yongjie Chen
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Wenxia Zhong
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Baojian Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Molin Pi
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China
| | - Zhangyong Ning
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. .,Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Maoming, 525000, China.
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Prevalence of Linda Virus Neutralizing Antibodies in the Austrian Pig Population. Viruses 2021; 13:v13061001. [PMID: 34071946 PMCID: PMC8229103 DOI: 10.3390/v13061001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 12/12/2022] Open
Abstract
A novel pestivirus species, termed Lateral-shaking Inducing Neuro-Degenerative Agent virus (LindaV), was discovered in a piglet-producing farm in Austria in 2015 related to severe congenital tremor cases. Since the initial outbreak LindaV has not been found anywhere else. In this study, we determined the seroprevalence of LindaV infections in the domestic pig population of Austria. A fluorophore labeled infectious cDNA clone of LindaV (mCherry-LindaV) was generated and used in serum virus neutralization (SVN) assays for the detection of LindaV specific neutralizing antibodies in porcine serum samples. In total, 637 sera from sows and gilts from five federal states of Austria, collected between the years 2015 and 2020, were analyzed. We identified a single serum showing a high neutralizing antibody titer, that originated from a farm (Farm S2) in the proximity of the initially affected farm. The analysis of 57 additional sera from Farm S2 revealed a wider spread of LindaV in this pig herd. Furthermore, a second LindaV strain originating from this farm could be isolated in cell culture and was further characterized at the genetic level. Possible transmission routes and virus reservoir hosts of this emerging porcine virus need to be addressed in future studies.
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Riedel C, Aitkenhead H, El Omari K, Rümenapf T. Atypical Porcine Pestiviruses: Relationships and Conserved Structural Features. Viruses 2021; 13:v13050760. [PMID: 33926056 PMCID: PMC8146772 DOI: 10.3390/v13050760] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/23/2021] [Accepted: 04/23/2021] [Indexed: 01/22/2023] Open
Abstract
For two decades, the genus pestivirus has been expanding and the host range now extends to rodents, bats and marine mammals. In this review, we focus on one of the most diverse pestiviruses, atypical porcine pestivirus or pestivirus K, comparing its special traits to what is already known at the structural and functional level from other pestiviruses.
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Affiliation(s)
- Christiane Riedel
- Institute of Virology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria;
- Correspondence:
| | - Hazel Aitkenhead
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (H.A.); (K.E.O.)
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0FA, UK
| | - Kamel El Omari
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK; (H.A.); (K.E.O.)
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot OX11 0FA, UK
| | - Till Rümenapf
- Institute of Virology, Department of Pathobiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria;
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14
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Detection of Atypical Porcine Pestivirus in Piglets from Danish Sow Herds. Viruses 2021; 13:v13050717. [PMID: 33919031 PMCID: PMC8142981 DOI: 10.3390/v13050717] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 01/22/2023] Open
Abstract
Atypical porcine pestivirus (APPV) was first discovered in North America in 2015 and was later shown to be associated with congenital tremor (CT) in piglets. CT is an occasional challenge in some Danish sow herds. Therefore, we initiated an observational case control study to clarify a possible relationship between CT and APPV in Danish pig production. Blood samples were collected from piglets affected by CT (n = 55) in ten different sow herds and from healthy piglets in five sow herds without a history of CT piglets (n = 25), as well as one sow herd with a sporadic occurrence of CT (n = 5). APPV was detected by RT-qPCR in all samples from piglets affected by CT and in three out of five samples from piglets in the herd with a sporadic occurrence of CT. In the herds without a history of CT, only one out of 25 piglets were positive for APPV. In addition, farmers or veterinarians in CT-affected herds were asked about their experience of the issue. CT is most often seen in gilt litters, and a substantial increase in pre-weaning mortality is only observed in severe cases. According to our investigations, APPV is a common finding in piglets suffering from CT in Denmark.
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15
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Porcine Complement Regulatory Protein CD46 Is a Major Receptor for Atypical Porcine Pestivirus but Not for Classical Swine Fever Virus. J Virol 2021; 95:JVI.02186-20. [PMID: 33568504 PMCID: PMC8104093 DOI: 10.1128/jvi.02186-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/28/2021] [Indexed: 01/02/2023] Open
Abstract
Pestiviruses comprise animal pathogens such as classical swine fever virus (CSFV) and bovine viral diarrhea virus (BVDV) that cause notifiable diseases with great economic impact. Several additional pestivirus species affecting animal health were recently identified, including atypical porcine pestivirus (APPV). Pestiviruses such as bovine viral diarrhea virus (BVDV) and classical swine fever virus (CSFV) belong to the family Flaviviridae and represent pathogens of outstanding veterinary relevance. Pestiviruses enter cells via receptor-mediated endocytosis. For entry in bovine cells, complement regulatory protein CD46bov serves as a cellular receptor for BVDV. In this study, the role of porcine CD46pig in cellular entry was investigated for the recently discovered atypical porcine pestivirus (APPV), CSFV, and Bungowannah virus (BuPV) in order to elucidate the observed differences in host cell tropism. A cell culture-adapted APPV variant, which shows enhanced viral replication in vitro, was generated and demonstrated a strict tropism of APPV for porcine cells. One of the porcine cell lines displayed areas of CD46pig-expressing cells and areas of nonexpressing cells, and one single cell line revealed not to express any CD46pig. The CD46pig-deficient porcine lymphoma cell line, known to facilitate CSFV replication, was the only porcine cell line nonpermissive to APPV, indicating a significant difference in the entry mechanism of APPV and CSFV. Infection experiments with a set of genetically engineered CD46pig knockout cells confirmed that CD46pig is a major receptor of APPV as CD46bov is for BVDV. In contrast, it is apparently not an essential determinant in host cell entry of other porcine pestiviruses such as CSFV and BuPV. Existence of a CD46pig-independent entry mechanism illustrates that the pestiviral entry process is more diverse than previously recognized. IMPORTANCE Pestiviruses comprise animal pathogens such as classical swine fever virus (CSFV) and bovine viral diarrhea virus (BVDV) that cause notifiable diseases with great economic impact. Several additional pestivirus species affecting animal health were recently identified, including atypical porcine pestivirus (APPV). APPV is associated with health problems in piglets and is highly abundant in pig populations worldwide. Complement control protein CD46 serves as a receptor for diverse bacterial and viral pathogens, including particular adenoviruses, herpesviruses, measles virus (MeV), and BVDV. Porcine CD46 (CD46pig) was suggested to be a major receptor for CSFV. Here, we identified remarkable differences in relevance of CD46pig during entry of porcine pestiviruses. Resembling BVDV, efficient APPV infection in cell culture depends on CD46pig, while other porcine pestiviruses can efficiently enter and infect cells in the absence of CD46pig. Thus, the study provides insights into the entry process of these pathogens and may help to understand differences in their biology.
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16
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Yu X, Liu J, Li H, Liu B, Zhao B, Ning Z. Comprehensive Analysis of Synonymous Codon Usage Bias for Complete Genomes and E2 Gene of Atypical Porcine Pestivirus. Biochem Genet 2021; 59:799-812. [PMID: 33538926 PMCID: PMC7860996 DOI: 10.1007/s10528-021-10037-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/19/2021] [Indexed: 11/29/2022]
Abstract
Atypical porcine pestivirus (APPV) is an emerging novel pestivirus causing the congenital tremor (CT) in piglets. The worldwide distribution characteristic of APPV make it a threat to global swine health. E2 is the major envelope glycoprotein of APPV and the crucial target for vaccine development. Considering the genetic variability of APPV complete genomes and its E2 gene as well as gaps for codon analysis, a comprehensive analysis of codon usage patterns was performed. Relative synonymous codon usage (RSCU) and effective number of codon (ENC) analyses showed that a relatively instable change existed and a slight low codon usage bias (CUB) were displayed in APPV genomes. ENC-plot analysis and correlation analyses of nucleotide compositions and ENC showed that mutation pressure and natural selection both affected the codon usage bias of the APPV and natural selection had a more obvious influence for E2 gene compared with complete genomes. Principal component analysis (PCA) and correlation analyses confirmed the above results. Correlation analyses between Gravy and Aromaticity values and the codon bias showed that natural selection played an important role in shaping the synonymous codon bias. Furthermore, neutrality plot analysis showed that natural selection was the main force while mutation pressure was a minor force influencing the codon usage pattern of the APPV E2 gene and complete genomes. The results could illustrate the codon usage patterns of APPV genomes and provided valuable basic data for further fundamental research of evolution of APPV.
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Affiliation(s)
- Xianglong Yu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Jianxin Liu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Huizi Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Boyang Liu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Bingqian Zhao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, People's Republic of China
| | - Zhangyong Ning
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, People's Republic of China.
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Mou C, Pan S, Wu H, Chen Z. Disruption of interferon-β production by the N pro of atypical porcine pestivirus. Virulence 2021; 12:654-665. [PMID: 33538238 PMCID: PMC7872032 DOI: 10.1080/21505594.2021.1880773] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Atypical porcine pestivirus (APPV) is an emerging porcine virus that threatens global swine production. Pestiviruses can prevent interferon (IFN) production to avoid the host innate immune response, and the Npro viral protein can play a critical role. Knowledge of the host immune response to APPV infection is limited. Here, we showed that the IFN-β production was suppressed by APPV-Npro and the IFN regulatory factor 3 (IRF3) promoter activity stimulated by adaptor molecules of the IFN-β signaling pathway was also inhibited in the APPV-Npro-expressed cells. The APPV-Npro was able to interact with IRF3 and interfere the phosphorylation of IRF3, indicated that the IFN-β antagonism of APPV-Npro mainly depended on blocking IRF3 activity. To identify the functional region of APPV-Npro, a panel of truncated APPV-Npro was constructed, and its influence on the IRF3 activation was investigated. The results showed that the N-terminal 31–51 amino acids of APPV-Npro were mainly associated with inhibition of the IFN-β response. Taken together, this is the first study focusing on elucidating the function of APPV protein by revealing a novel mechanism of Npro in disruption of host IFN-β production, which will enlighten future study in addressing APPV pathogenesis and immune evasion.
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Affiliation(s)
- Chunxiao Mou
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
| | - Shuonan Pan
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
| | - Huiguang Wu
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
| | - Zhenhai Chen
- College of Veterinary Medicine, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, Jiangsu Province, People's Republic of China
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18
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Atypical Porcine Pestivirus Circulation and Molecular Evolution within an Affected Swine Herd. Viruses 2020; 12:v12101080. [PMID: 32992946 PMCID: PMC7599615 DOI: 10.3390/v12101080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/17/2020] [Accepted: 09/23/2020] [Indexed: 01/27/2023] Open
Abstract
Atypical porcine pestivirus (APPV) is a single-stranded RNA virus from the family Flaviviridae, which is linked to congenital tremor (CT) type A-II in newborn piglets. Here, we retrospectively investigated the molecular evolution of APPV on an affected herd between 2013 and 2019. Monitoring was done at regular intervals, and the same genotype of APPV was found during the entire study period, suggesting no introductions from outside the farm. The nucleotide substitutions over time did not show substantial amino acid variation in the structural glycoproteins. Furthermore, the evolution of the virus showed mainly purifying selection, and no positive selection. The limited pressure on the virus to change at immune-dominant regions suggested that the immune pressure at the farm might be low. In conclusion, farms can have circulation of APPV for years, and massive testing and removal of infected animals are not sufficient to clear the virus from affected farms.
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19
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Dall Agnol AM, Alfieri AF, Alfieri AA. Pestivirus K (Atypical Porcine Pestivirus): Update on the Virus, Viral Infection, and the Association with Congenital Tremor in Newborn Piglets. Viruses 2020; 12:v12080903. [PMID: 32824845 PMCID: PMC7472392 DOI: 10.3390/v12080903] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/16/2022] Open
Abstract
The atypical porcine pestivirus (APPV) belongs to the species Pestivirus K of the genus Pestivirus and the family Flaviviridae, and it has been associated with congenital tremor (CT) type A-II in newborn piglets. Although APPV was discovered in 2015, evidence shows that APPV has circulated in pig herds for many years, at least since 1986. Due to the frequently reported outbreaks of CT on different continents, the importance of this virus for global pig production is notable. Since 2015, several studies have been conducted to clarify the association between APPV and CT. However, some findings regarding APPV infection and the measures taken to control and prevent the spread of this virus need to be contextualized to understand the infection better. This review attempts to highlight advances in the understanding of APPV associated with type A-II CT, such as etiology, epidemiology, diagnosis, and control and prevention measures, and also describes the pathophysiology of the infection and its consequences for pig production. Further research still needs to be conducted to elucidate the host's immune response to APPV infection, the control and prevention of this infection, and the possible development of vaccines.
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Affiliation(s)
- Alais M. Dall Agnol
- Laboratory of Animal Virology, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina, Londrina, CEP 86057-970 Paraná, Brazil; (A.M.D.A.); (A.F.A.)
- Multi-User Animal Health Laboratory, Molecular Biology Unit, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina, CEP 86057-970 Paraná, Brazil
- Rodovia Celso Garcia Cid Road-Campus Universitário, Londrina, PO Box 10011, CEP 86057-970 Paraná, Brazil
| | - Alice F. Alfieri
- Laboratory of Animal Virology, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina, Londrina, CEP 86057-970 Paraná, Brazil; (A.M.D.A.); (A.F.A.)
- Multi-User Animal Health Laboratory, Molecular Biology Unit, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina, CEP 86057-970 Paraná, Brazil
- Rodovia Celso Garcia Cid Road-Campus Universitário, Londrina, PO Box 10011, CEP 86057-970 Paraná, Brazil
| | - Amauri A. Alfieri
- Laboratory of Animal Virology, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina, Londrina, CEP 86057-970 Paraná, Brazil; (A.M.D.A.); (A.F.A.)
- Multi-User Animal Health Laboratory, Molecular Biology Unit, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina, CEP 86057-970 Paraná, Brazil
- Rodovia Celso Garcia Cid Road-Campus Universitário, Londrina, PO Box 10011, CEP 86057-970 Paraná, Brazil
- Correspondence: ; Tel.: +55-43-3371-5876; Fax: +55-43-3371-4485
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20
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Grahofer A, Zeeh F, Nathues H. Seroprevalence of atypical porcine pestivirus in a closed pig herd with subclinical infection. Transbound Emerg Dis 2020; 67:2770-2774. [PMID: 32441848 DOI: 10.1111/tbed.13636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/13/2020] [Accepted: 05/15/2020] [Indexed: 01/02/2023]
Abstract
Atypical porcine pestivirus (APPV) has recently been reported to be associated with congenital tremor in newborn piglets. Only limited information is available about the prevalence at herd level in endemically infected herds. Therefore, the aim of this study was to determine the within-herd prevalence of APPV in a sub-clinically infected sow herd in Switzerland and to analyse associations between the serological status as well as the age and sex of the pigs, litter number and days after the last insemination. In a census sampling, blood was collected from 125 sows, aged 180 days or older, and six boars. Sera were examined applying an indirect APPV-specific ELISA to individual sera and an APPV RT-PCR targeting the NS3 encoding regions of APPV to pools of five. The APPV antibody status was classified into low (S/P value ≤ 0.5), intermediate (S/P value = 0.5-1) and high reactivity (S/P value > 1.0). None of the pooled serum samples was positive for specific genome fragments of APPV. Of the 131 samples, 53.4% were highly reactive, 39.7% showed an intermediate reactivity, and 6.9% showed a low reactivity in the indirect ELISA, that is, were serologically negative. Significant associations between the S/P values and the age of the pigs (p < .001), the litter number (p < .001) and the numbers of days after the last insemination (p = .0188) were observed. The results indicate that this sow herd was previously infected with APPV, while viremia was not detected in any of the adult pigs. This might explain the absence of clinical signs in the suckling pigs. Potential reinfection and circulation of APPV in this sow herd might be due to semen from commercial boar studs or APPV-positive animals in the absence of specific clinical signs.
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Affiliation(s)
- Alexander Grahofer
- Clinic for Swine, Department for Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Friederike Zeeh
- Clinic for Swine, Department for Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland.,Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, HongKong, China
| | - Heiko Nathues
- Clinic for Swine, Department for Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Michelitsch A, Dalmann A, Wernike K, Reimann I, Beer M. Seroprevalences of Newly Discovered Porcine Pestiviruses in German Pig Farms. Vet Sci 2019; 6:E86. [PMID: 31717716 PMCID: PMC6958323 DOI: 10.3390/vetsci6040086] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/11/2019] [Accepted: 10/23/2019] [Indexed: 02/02/2023] Open
Abstract
Several novel porcine pestiviruses that are linked to disease outbreaks in commercial pig farms were discovered during recent years. Bungowannah pestivirus (BuPV; new species Pestivirus F) causes sudden death in young pigs, but has only ever been isolated in the Australian region Bungowannah. Atypical porcine pestivirus (APPV; new species Pestivirus K) on the other hand has been found in multiple countries worldwide and is potentially linked to congenital tremor, a disease that causes considerable production problems in pig farms. To assess the seroprevalences of both viruses in German commercial farms during the years 2009/10 and 2018, two approaches were selected. Antibodies against Pestivirus F were detected by a traditional in-house indirect immunofluorescence test against the culture-grown virus isolate, while for the detection of Pestivirus K-specific antibodies, a newly developed test system utilizing a chimeric construct of bovine viral diarrhea virus 1 (BVDV-1; species Pestivirus A) containing the E1 and E2 encoding sequences of APPV was established. A total of 1115 samples originating from 122 farms located in seven German federal states were investigated. Antibodies against Bungowannah virus could not be detected, confirming the absence of this virus in other regions than the initially affected Australian pig farm complex. In contrast, antibodies against APPV were highly prevalent throughout Germany at both investigated time points. The seroprevalence at the state level fluctuated to some degree, but the overall percentage remained stable, as is to be expected for an endemic pestivirus lacking any form of control measures.
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Affiliation(s)
| | | | - Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, 17493 Greifswald—Insel Riems, Germany; (A.M.); (A.D.); (I.R.); (M.B.)
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