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Villalba R, Tena-Tomás C, Ruano MJ, Valero-Lorenzo M, López-Herranz A, Cano-Gómez C, Agüero M. Development and Validation of Three Triplex Real-Time RT-PCR Assays for Typing African Horse Sickness Virus: Utility for Disease Control and Other Laboratory Applications. Viruses 2024; 16:470. [PMID: 38543834 PMCID: PMC10974454 DOI: 10.3390/v16030470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/08/2024] [Accepted: 03/14/2024] [Indexed: 05/23/2024] Open
Abstract
The African horse sickness virus (AHSV) belongs to the Genus Orbivirus, family Sedoreoviridae, and nine serotypes of the virus have been described to date. The AHSV genome is composed of ten linear segments of double-stranded (ds) RNA, numbered in decreasing size order (Seg-1 to Seg-10). Genome segment 2 (Seg-2) encodes outer-capsid protein VP2, the most variable AHSV protein and the primary target for neutralizing antibodies. Consequently, Seg-2 determines the identity of the virus serotype. An African horse sickness (AHS) outbreak in an AHS-free status country requires identifying the serotype as soon as possible to implement a serotype-specific vaccination program. Considering that nowadays 'polyvalent live attenuated' is the only commercially available vaccination strategy to control the disease, field and vaccine strains of different serotypes could co-circulate. Additionally, in AHS-endemic countries, more than one serotype is often circulating at the same time. Therefore, a strategy to rapidly determine the virus serotype in an AHS-positive sample is strongly recommended in both epidemiological situations. The main objective of this study is to describe the development and validation of three triplex real-time RT-PCR (rRT-PCR) methods for rapid AHSV serotype detection. Samples from recent AHS outbreaks in Kenia (2015-2017), Thailand (2020), and Nigeria (2023), and from the AHS outbreak in Spain (1987-1990), were included in the study for the validation of these methods.
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Affiliation(s)
- Rubén Villalba
- Laboratorio Central de Veterinaria, Ministry of Agriculture, Fisheries and Food, 28110 Algete, Spain; (R.V.); (M.J.R.); (M.V.-L.); (A.L.-H.); (C.C.-G.)
| | | | - María José Ruano
- Laboratorio Central de Veterinaria, Ministry of Agriculture, Fisheries and Food, 28110 Algete, Spain; (R.V.); (M.J.R.); (M.V.-L.); (A.L.-H.); (C.C.-G.)
| | - Marta Valero-Lorenzo
- Laboratorio Central de Veterinaria, Ministry of Agriculture, Fisheries and Food, 28110 Algete, Spain; (R.V.); (M.J.R.); (M.V.-L.); (A.L.-H.); (C.C.-G.)
| | - Ana López-Herranz
- Laboratorio Central de Veterinaria, Ministry of Agriculture, Fisheries and Food, 28110 Algete, Spain; (R.V.); (M.J.R.); (M.V.-L.); (A.L.-H.); (C.C.-G.)
| | - Cristina Cano-Gómez
- Laboratorio Central de Veterinaria, Ministry of Agriculture, Fisheries and Food, 28110 Algete, Spain; (R.V.); (M.J.R.); (M.V.-L.); (A.L.-H.); (C.C.-G.)
| | - Montserrat Agüero
- Laboratorio Central de Veterinaria, Ministry of Agriculture, Fisheries and Food, 28110 Algete, Spain; (R.V.); (M.J.R.); (M.V.-L.); (A.L.-H.); (C.C.-G.)
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Wall GV, Wright IM, Barnardo C, Erasmus BJ, van Staden V, Potgieter AC. African horse sickness virus NS4 protein is an important virulence factor and interferes with JAK-STAT signaling during viral infection. Virus Res 2021; 298:198407. [PMID: 33812899 DOI: 10.1016/j.virusres.2021.198407] [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: 01/16/2021] [Revised: 03/25/2021] [Accepted: 03/29/2021] [Indexed: 12/24/2022]
Abstract
African horse sickness virus (AHSV) non-structural protein NS4 is a nucleocytoplasmic protein that is expressed in the heart, lung, and spleen of infected horses, binds dsDNA, and colocalizes with promyelocytic leukemia nuclear bodies (PML-NBs). The aim of this study was to investigate the role of AHSV NS4 in viral replication, virulence and the host immune response. Using a reverse genetics-derived virulent strain of AHSV-5 and NS4 deletion mutants, we showed that knockdown of NS4 expression has no impact in cell culture, but results in virus attenuation in infected horses. RNA sequencing (RNA-seq) was used to investigate the transcriptional response in these horses, to see how the lack of NS4 mediates the transition of the virus from virulent to attenuated. The presence of NS4 was shown to result in a 24 hour (h) delay in the transcriptional activation of several immune system processes compared to when the protein was absent. Included in these processes were the RIG-I-like, Toll-like receptor, and JAK-STAT signaling pathways, which are key pathways involved in innate immunity and the antiviral response. Thus, it was shown that AHSV NS4 suppresses the host innate immune transcriptional response in the early stages of the infection cycle. We investigated whether AHSV NS4 affects the innate immune response by impacting the JAK-STAT signaling pathway specifically. Using confocal laser scanning microscopy (CLSM) we showed that AHSV NS4 disrupts JAK-STAT signaling by interfering with the phosphorylation and/or translocation of STAT1 and pSTAT1 into the nucleus. Overall, these results showed that AHSV NS4 is a key virulence factor in horses and allows AHSV to overcome host antiviral responses in order to promote viral replication and spread.
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Affiliation(s)
- Gayle V Wall
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
| | - Isabella M Wright
- Deltamune (Pty) Ltd, Moraine House - The Braes, 193 Bryanston Drive, Bryanston, Gauteng, 2191, South Africa
| | - Carin Barnardo
- Deltamune (Pty) Ltd, Moraine House - The Braes, 193 Bryanston Drive, Bryanston, Gauteng, 2191, South Africa
| | - Baltus J Erasmus
- Deltamune (Pty) Ltd, Moraine House - The Braes, 193 Bryanston Drive, Bryanston, Gauteng, 2191, South Africa
| | - Vida van Staden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
| | - A Christiaan Potgieter
- Deltamune (Pty) Ltd, Moraine House - The Braes, 193 Bryanston Drive, Bryanston, Gauteng, 2191, South Africa; Department of Biochemistry, Focus Area for Human Metabolomics, North-West University, Potchefstroom, South Africa.
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van Schalkwyk A, Ferreira ML, Romito M. Using a new serotype-specific Polymerase Chain Reaction (PCR) and sequencing to differentiate between field and vaccine-derived African Horse Sickness viruses submitted in 2016/2017. J Virol Methods 2019; 266:89-94. [PMID: 30721715 DOI: 10.1016/j.jviromet.2019.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/28/2019] [Accepted: 01/28/2019] [Indexed: 10/27/2022]
Abstract
The outer capsid viral protein 2 (VP2) of African horse sickness virus, encoded by the most variable genome segment 2 (Seg-2), is the primary target for AHSV-specific neutralising antibodies and thus determines the virus serotype. Full length segment 2 sequences from more than 100 AHSVs isolated over the last 80 years were compared and single nucleotide polymorphisms (SNPs) identified between the reference strains and recent field viruses. Regions unique to each individual serotype were identified and primers designed to differentially amplify each of the nine serotypes. The sequences of resulting amplicons contained a significant amount of SNPs to discriminate between field viruses and reference strains or live attenuated viruses. The new serotype specific RT-PCR were subsequently used to determine the prevalence of different AHSV serotypes associated with samples submitted to the Agricultural Research Council - Onderstepoort Veterinary Research Institute during the 2016 / 2017 season. Subsequent sequencing of the PCR products were used to determine if the infections were caused by field or vaccine-derived strains. The serotypes of 70 AHSV positive diagnostic samples submitted to the ARC-OVR were determined. Serotypes 2 and 6 were the most prevalent, while Serotype 1 was the only serotype where sequences identical to the ALV or reference strains were detected in field samples. Based on this study, the incidence of vaccine-derived AHS infections submitted from southern Africa were low. This serotype-specific RT-PCR and sequencing assay could assist with the surveillance and control of equines movement nationally and internationally. It could also provide valuable scientific guidance on the policies and guidelines regulating vaccination and trade of equines in South Africa.
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Affiliation(s)
- Antoinette van Schalkwyk
- Agricultural Research Council - Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort 0110, South Africa.
| | - Maryke Louise Ferreira
- Agricultural Research Council - Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort 0110, South Africa
| | - Marco Romito
- Agricultural Research Council - Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort 0110, South Africa.
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4
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Structural Protein VP2 of African Horse Sickness Virus Is Not Essential for Virus Replication In Vitro. J Virol 2017; 91:JVI.01328-16. [PMID: 27903804 DOI: 10.1128/jvi.01328-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 11/23/2016] [Indexed: 12/25/2022] Open
Abstract
The Reoviridae family consists of nonenveloped multilayered viruses with a double-stranded RNA genome consisting of 9 to 12 genome segments. The Orbivirus genus of the Reoviridae family contains African horse sickness virus (AHSV), bluetongue virus, and epizootic hemorrhagic disease virus, which cause notifiable diseases and are spread by biting Culicoides species. Here, we used reverse genetics for AHSV to study the role of outer capsid protein VP2, encoded by genome segment 2 (Seg-2). Expansion of a previously found deletion in Seg-2 indicates that structural protein VP2 of AHSV is not essential for virus replication in vitro In addition, in-frame replacement of RNA sequences in Seg-2 by that of green fluorescence protein (GFP) resulted in AHSV expressing GFP, which further confirmed that VP2 is not essential for virus replication. In contrast to virus replication without VP2 expression in mammalian cells, virus replication in insect cells was strongly reduced, and virus release from insect cells was completely abolished. Further, the other outer capsid protein, VP5, was not copurified with virions for virus mutants without VP2 expression. AHSV without VP5 expression, however, could not be recovered, indicating that outer capsid protein VP5 is essential for virus replication in vitro Our results demonstrate for the first time that a structural viral protein is not essential for orbivirus replication in vitro, which opens new possibilities for research on other members of the Reoviridae family. IMPORTANCE Members of the Reoviridae family cause major health problems worldwide, ranging from lethal diarrhea caused by rotavirus in humans to economic losses in livestock production caused by different orbiviruses. The Orbivirus genus contains many virus species, of which bluetongue virus, epizootic hemorrhagic disease virus, and African horse sickness virus (AHSV) cause notifiable diseases according to the World Organization of Animal Health. Recently, it has been shown that nonstructural proteins NS3/NS3a and NS4 are not essential for virus replication in vitro, whereas it is generally assumed that structural proteins VP1 to -7 of these nonenveloped, architecturally complex virus particles are essential. Here we demonstrate for the first time that structural protein VP2 of AHSV is not essential for virus replication in vitro Our findings are very important for virologists working in the field of nonenveloped viruses, in particular reoviruses.
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de la Poza F, Marín-López A, Castillo-Olivares J, Calvo-Pinilla E, Ortego J. Identification of CD8 T cell epitopes in VP2 and NS1 proteins of African horse sickness virus in IFNAR(-/-) mice. Virus Res 2015; 210:149-53. [PMID: 26272673 DOI: 10.1016/j.virusres.2015.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 12/17/2022]
Abstract
African horse sickness virus (AHSV) is an Orbivirus of the family Reoviridae that causes severe pathology in equids. Previous work in our laboratory showed the presence of AHSV-specific CD8(+) T cells in mice immunized with recombinant Modified Vaccinia Ankara (rMVA) expressing VP2 and NS1 proteins. In the present work, we selected potential CD8 T cell epitopes (MHC-class I binding peptides) for the 129 mouse strain from the VP2 and NS1 proteins of AHSV-4, using a combination of four epitope prediction algorithms (SYFPEITHI, BYMAS, NetMHC I and NetMHCpan). ELISPOT and Intracellular Cytokine Staining (ICS) analysis showed that the VP2-720 (MSLLNFGAV), VP2-1044 (YTFGNKFLL), and NS1-83 (CVIKNADYV) peptides elicited IFN-γ production in splenocytes of MVA-VP2 and MVA-NS1 immunized mice and were identified as CD8(+) T cell epitopes. In addition, these three MHC-class I-binding peptides induced the expression of CD107a in CD8(+) T cells, an indirect marker of cytotoxic activity. Importantly, VP2-1044 and NS1-83 epitopes are conserved among all nine AHSV serotypes. These data demonstrate the activation of AHSV specific T-cell epitopes during vaccination with rMVAs expressing VP2 and NS1. Furthermore, the characterization of these CD8(+) T-cell epitopes provides information useful for the design of novel marker multiserotype vaccines against AHSV.
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Affiliation(s)
- Francisco de la Poza
- Centro de Investigación en Sanidad Animal, INIA-CISA, Valdeolmos, 28130 Madrid, Spain
| | - Alejandro Marín-López
- Centro de Investigación en Sanidad Animal, INIA-CISA, Valdeolmos, 28130 Madrid, Spain
| | | | | | - Javier Ortego
- Centro de Investigación en Sanidad Animal, INIA-CISA, Valdeolmos, 28130 Madrid, Spain.
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Weyer CT, Joone C, Lourens CW, Monyai MS, Koekemoer O, Grewar JD, van Schalkwyk A, Majiwa PO, MacLachlan NJ, Guthrie AJ. Development of three triplex real-time reverse transcription PCR assays for the qualitative molecular typing of the nine serotypes of African horse sickness virus. J Virol Methods 2015; 223:69-74. [DOI: 10.1016/j.jviromet.2015.07.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 07/14/2015] [Accepted: 07/27/2015] [Indexed: 11/25/2022]
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Consensus Sequence of 27 African Horse Sickness Virus Genomes from Viruses Collected over a 76-Year Period (1933 to 2009). GENOME ANNOUNCEMENTS 2015; 3:3/5/e00921-15. [PMID: 26358586 PMCID: PMC4566168 DOI: 10.1128/genomea.00921-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We announce the complete consensus genome sequence of 27 African horse sickness viruses, representing all nine African horse sickness virus (AHSV) serotypes from historical and recent isolates collected over a 76-year period (1933 to 2009). The data set includes the sequence of the virulent Office International des Epizooties AHSV reference strains which are not adapted to cell culture.
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Kanai Y, van Rijn PA, Maris-Veldhuis M, Kaname Y, Athmaram TN, Roy P. Immunogenicity of recombinant VP2 proteins of all nine serotypes of African horse sickness virus. Vaccine 2014; 32:4932-7. [PMID: 25045805 PMCID: PMC4148702 DOI: 10.1016/j.vaccine.2014.07.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/19/2014] [Accepted: 07/08/2014] [Indexed: 12/02/2022]
Abstract
African horse sickness (AHS) is an equine disease with a mortality of up to 90% for susceptible horses. The causative agent AHS virus (AHSV) is transmitted by species of Culicoides. AHSV serogroup within the genus Orbivirus of the Reoviridae family consists of nine serotypes that show no or very limited cross-neutralization. Of the seven structural proteins (VP1-VP7) of AHSV, VP2 is the serotype specific protein, and the major target for neutralizing antibodies. In this report, recombinant VP2 proteins of all nine serotypes were expressed individually by the baculovirus expression system and the immunogenicity of each was studied by immunization of guinea pigs with single VP2 as well as with cocktails of VP2 proteins. Homologous neutralizing antibodies measured by 50% plaque reduction assay showed varying degrees (from 37 to 1365) of titers for different VP2 proteins. A low cross-neutralizing antibody titer was found for genetically related AHSV serotypes. Immunization with VP2 cocktails containing equal amounts of each of the VP2 proteins also triggered neutralizing antibodies albeit to lower titers (4-117) to each of the serotypes in the cocktail. This study is a first step to develop a VP2 subunit vaccine for AHS and our results indicate that VP2 subunit vaccines are feasible individually or in a multi-serotype cocktail.
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Affiliation(s)
- Yuta Kanai
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Piet A van Rijn
- Department of Virology, Central Veterinary Institute of Wageningen University (CVI), PO Box 65, 8200 AB Lelystad, The Netherlands; Department of Biochemistry, Centre for Human Metabonomics, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa
| | - Mieke Maris-Veldhuis
- Department of Virology, Central Veterinary Institute of Wageningen University (CVI), PO Box 65, 8200 AB Lelystad, The Netherlands
| | - Yuki Kaname
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - T N Athmaram
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Polly Roy
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom.
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Bachanek-Bankowska K, Maan S, Castillo-Olivares J, Manning NM, Maan NS, Potgieter AC, Di Nardo A, Sutton G, Batten C, Mertens PPC. Real time RT-PCR assays for detection and typing of African horse sickness virus. PLoS One 2014; 9:e93758. [PMID: 24721971 PMCID: PMC3983086 DOI: 10.1371/journal.pone.0093758] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 03/05/2014] [Indexed: 12/25/2022] Open
Abstract
Although African horse sickness (AHS) can cause up to 95% mortality in horses, naïve animals can be protected by vaccination against the homologous AHSV serotype. Genome segment 2 (Seg-2) encodes outer capsid protein VP2, the most variable of the AHSV proteins. VP2 is also a primary target for AHSV specific neutralising antibodies, and consequently determines the identity of the nine AHSV serotypes. In contrast VP1 (the viral polymerase) and VP3 (the sub-core shell protein), encoded by Seg-1 and Seg-3 respectively, are highly conserved, representing virus species/orbivirus-serogroup-specific antigens. We report development and evaluation of real-time RT-PCR assays targeting AHSV Seg-1 or Seg-3, that can detect any AHSV type (virus species/serogroup-specific assays), as well as type-specific assays targeting Seg-2 of the nine AHSV serotypes. These assays were evaluated using isolates of different AHSV serotypes and other closely related orbiviruses, from the ‘Orbivirus Reference Collection’ (ORC) at The Pirbright Institute. The assays were shown to be AHSV virus-species-specific, or type-specific (as designed) and can be used for rapid, sensitive and reliable detection and identification (typing) of AHSV RNA in infected blood, tissue samples, homogenised Culicoides, or tissue culture supernatant. None of the assays amplified cDNAs from closely related heterologous orbiviruses, or from uninfected host animals or cell cultures.
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Affiliation(s)
| | - Sushila Maan
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Javier Castillo-Olivares
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Nicola M. Manning
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Narender Singh Maan
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Abraham C. Potgieter
- Deltamune (Pty) Ltd, Lyttelton, Centurion, South Africa
- Department of Biochemistry, Centre for Human Metabonomics, North-West University, Private Bag X6001, Potchefstroom, South Africa
| | - Antonello Di Nardo
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Geoff Sutton
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Carrie Batten
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Peter P. C. Mertens
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
- * E-mail:
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Cooper E, Anbalagan S, Klumper P, Scherba G, Simonson RR, Hause BM. Mobuck virus genome sequence and phylogenetic analysis: identification of a novel Orbivirus isolated from a white-tailed deer in Missouri, USA. J Gen Virol 2014; 95:110-116. [DOI: 10.1099/vir.0.058800-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The genus Orbivirus includes a diverse group of segmented dsRNA viruses that are transmitted via arthropods, have a global distribution and affect a wide range of hosts. A novel orbivirus was co-isolated with epizootic haemorrhagic disease virus (EHDV) from a white-tailed deer (Odocoileus virginianus) exhibiting clinical signs characteristic of EHDV. Using antiserum generated against EHDV, a pure isolate of the novel non-cytopathic orbivirus was obtained in Aedes albopictus cell culture. Genomic sequencing and phylogenetic analysis of predicted ORFs showed that eight of the ten ORFs were most homologous to Peruvian horse sickness virus (PHSV), with amino acid identities of 44.3–73.7 %. The remaining two ORFs, VP3 and VP5, were most similar to Middle Point orbivirus (35.9 %) and Yunnan orbivirus (59.8 %), respectively. Taxonomic classification of orbiviruses is largely based on homology of the major subcore structural protein VP2(T2), encoded by segment 2 for mobuck virus. With only 69.1 % amino acid identity to PHSV, we propose mobuck virus as the prototype of a new species of Orbivirus.
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Affiliation(s)
- Elyse Cooper
- Newport Laboratories, 1520 Prairie Drive, Worthington, MN 56187, USA
| | | | - Patricia Klumper
- Newport Laboratories, 1520 Prairie Drive, Worthington, MN 56187, USA
| | - Gail Scherba
- Department of Pathobiology and the Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Illinois, Urbana, IL 61801, USA
| | - Randy R. Simonson
- Newport Laboratories, 1520 Prairie Drive, Worthington, MN 56187, USA
| | - Ben M. Hause
- Newport Laboratories, 1520 Prairie Drive, Worthington, MN 56187, USA
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Cowled C, Melville L, Weir R, Walsh S, Gubala A, Davis S, Boyle D. Persistent and recrudescent infection in cattle following natural infection with Middle Point orbivirus. Arch Virol 2012; 157:1161-5. [PMID: 22415142 DOI: 10.1007/s00705-012-1277-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 02/06/2012] [Indexed: 11/28/2022]
Abstract
Middle Point orbivirus (MPOV) is a recently described Australian arbovirus, related to Yunnan orbivirus from China. Analysis of genetic variation within the major serotype gene of MPOV isolates collected from sentinel cattle has identified eight co-circulating strains. The pattern of strain isolation from individual animals during the study period was consistent with an interpretation of persistent MPOV infection of up to five months, featuring episodes of quiescence (below levels required for virus isolation) followed by viral recrudescence. This is significant with regard to current interpretations of infection, persistence and recrudescence during natural infections of orbiviruses, including bluetongue virus.
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Affiliation(s)
- Christopher Cowled
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, VIC, Australia.
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12
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Serotype specific primers and gel-based RT-PCR assays for 'typing' African horse sickness virus: identification of strains from Africa. PLoS One 2011; 6:e25686. [PMID: 22028787 PMCID: PMC3197586 DOI: 10.1371/journal.pone.0025686] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 09/08/2011] [Indexed: 11/19/2022] Open
Abstract
African horse sickness is a devastating, transboundary animal disease, that is ‘listed’ by the Office International des Epizooties (OIE). Although attenuated, inactivated and subunit vaccines have been developed for African horse sickness virus (AHSV), these are serotype-specific and their effective deployment therefore relies on rapid and reliable identification of virus type. AHSV serotype is controlled by the specificity of interactions between neutralising antibodies, and components of the outer-capsid, particularly protein VP2 (encoded by AHSV genome segment 2 (Seg-2)). We report the development and evaluation of novel gel based reverse transcription-PCR (RT–PCR) assays targeting AHSV Seg-2, which can be used to very significantly increase the speed and reliability of detection and identification (compared to virus neutralisation tests) of the nine serotypes of AHSV. Primer sets were designed targeting regions of Seg-2 that are conserved between strains within each of the AHSV serotype (types 1 to 9). These assays were evaluated using multiple AHSV strains from the orbivirus reference collection at IAH (www.reoviridae.org/dsRNA_virus_proteins/ReoID/AHSV-isolates.htm). In each case the Seg-2 primers showed a high level of specificity and failed to cross-amplify the most closely related heterologous AHSV types, or other related orbiviruses (such as bluetongue virus (BTV), or equine encephalosis virus (EEV)). The assays are rapid and sensitive, and can be used to detect and type viral RNA in blood, tissue samples, or cultivated viral suspensions within 24 h. They were used to identify AHSV strains from recent outbreaks in sub-Saharan African countries. These methods also generate cDNAs suitable for sequencing and phylogenetic analyses of Seg-2, identifying distinct virus lineages within each virus-type and helping to identify strain movements/origins. The RT-PCR methods described here provide a robust and versatile tool for rapid and specific detection and identification of AHSV serotypes 1 to 9.
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13
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In vivo cross-protection to African horse sickness Serotypes 5 and 9 after vaccination with Serotypes 8 and 6. Vaccine 2010; 28:6505-17. [PMID: 20638456 DOI: 10.1016/j.vaccine.2010.06.105] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 06/08/2010] [Accepted: 06/30/2010] [Indexed: 11/23/2022]
Abstract
The polyvalent African horsesickness (AHS) attenuated live virus (AHS-ALV) vaccine produced at Onderstepoort Biological Products incorporates 7 of the 9 known serotypes circulating in southern Africa. Serological cross-reaction has been shown in vitro to Serotypes 5 and 9 by Serotypes 8 and 6 respectively, but the degree of in vivo cross-protection between these serotypes in vaccinated horses has not previously been reported. Due to the increasing incidence of AHS Serotypes 5 and 9 in the field, over the last 3-4 seasons of AHS in South Africa, and the absence of Serotypes 5 and 9 in the AHS-ALV vaccine, it was necessary to conduct a vaccination-challenge study to determine in vivo cross-protection of vaccine-incorporated Serotypes 8 and 6 respectively. Groups of horses were vaccinated with either the polyvalent AHS-ALV vaccine or a monovalent Serotype 6 (vAHSV6) or 8 (vAHSV8) vaccine to determine the cross-protection of vaccinated horses following challenge with virulent AHS virus (AHSV) of either Serotype 5, 6, 8 or 9. Serial vaccination of naive horses with the polyvalent AHS-ALV vaccine generated a broad neutralizing antibody response to all vaccine strains as well as cross-neutralizing antibodies to Serotypes 5 and 9. Booster vaccination of horses with monovalent vaccine vAHSV6 or vAHSV8 induced an adequate protective immune response to challenge with homologous and heterologous virulent virus. In vivo cross-protection between AHSV6 and AHSV9 and AHSV8 and AHSV5 respectively, was demonstrated.
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Koekemoer J. Serotype-specific detection of African horsesickness virus by real-time PCR and the influence of genetic variations. J Virol Methods 2008; 154:104-10. [DOI: 10.1016/j.jviromet.2008.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 08/11/2008] [Accepted: 08/15/2008] [Indexed: 10/21/2022]
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First Report of an Outbreak of African Horsesickness Virus Serotype 2 in the Northern Hemisphere. J Equine Vet Sci 2008. [DOI: 10.1016/j.jevs.2008.01.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Cowled C, Melville L, Weir R, Walsh S, Hyatt A, Van Driel R, Davis S, Gubala A, Boyle D. Genetic and epidemiological characterization of Middle Point orbivirus, a novel virus isolated from sentinel cattle in northern Australia. J Gen Virol 2008; 88:3413-3422. [PMID: 18024911 DOI: 10.1099/vir.0.83231-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Middle Point orbivirus (MPOV) was isolated in 1998 from a healthy cow pastured at Beatrice Hill farm, Middle Point (formerly Coastal Plains Research Station), 50 km east of Darwin in Australia's Northern Territory. The isolate could not be identified by using conventional serological tests, and electron microscopy indicated that it belongs to the family Reoviridae, genus Orbivirus. Genetic sequencing of segments 2 and 3 revealed that this virus is related to Yunnan orbivirus, an orbivirus known only from China and not previously associated with a vertebrate host. A real-time RT-PCR test was developed to study the epidemiology of this virus in the field. Over 150 previously unidentified viruses isolated from cattle between 1994 and 2006 were positively identified as isolates of MPOV. Serology was used to demonstrate the development of antibody responses to MPOV in cattle from multiple locations across the Northern Territory.
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Affiliation(s)
- Chris Cowled
- CSIRO Livestock Industries, Australian Animal Health Laboratory, East Geelong, Victoria 3220, Australia
| | - Lorna Melville
- Northern Territory Department of Primary Industries, Fisheries and Mines, Berrimah Veterinary Laboratories, Berrimah, Northern Territory 0801, Australia
| | - Richard Weir
- Northern Territory Department of Primary Industries, Fisheries and Mines, Berrimah Veterinary Laboratories, Berrimah, Northern Territory 0801, Australia
| | - Susan Walsh
- Northern Territory Department of Primary Industries, Fisheries and Mines, Berrimah Veterinary Laboratories, Berrimah, Northern Territory 0801, Australia
| | - Alex Hyatt
- CSIRO Livestock Industries, Australian Animal Health Laboratory, East Geelong, Victoria 3220, Australia
| | - Rosey Van Driel
- CSIRO Livestock Industries, Australian Animal Health Laboratory, East Geelong, Victoria 3220, Australia
| | - Steven Davis
- Northern Territory Department of Primary Industries, Fisheries and Mines, Berrimah Veterinary Laboratories, Berrimah, Northern Territory 0801, Australia
| | - Aneta Gubala
- CSIRO Livestock Industries, Australian Animal Health Laboratory, East Geelong, Victoria 3220, Australia
| | - David Boyle
- CSIRO Livestock Industries, Australian Animal Health Laboratory, East Geelong, Victoria 3220, Australia
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Koekemoer JJO, Dijk AAV. African horsesickness virus serotyping and identification of multiple co-infecting serotypes with a single genome segment 2 RT-PCR amplification and reverse line blot hybridization. J Virol Methods 2005; 122:49-56. [PMID: 15488620 DOI: 10.1016/j.jviromet.2004.08.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Revised: 07/30/2004] [Accepted: 08/09/2004] [Indexed: 11/28/2022]
Abstract
Since protection against African horsesickness (AHS) is serotype-specific, rapid serotyping of AHSV is crucial to identify the correct vaccine serotype for efficient control of the spread of AHS outbreaks, especially when they occur in non-endemic regions. This paper describes the first one-day serotyping procedure that requires only a single RT-PCR and hybridization and which can identify multiple serotypes in mixed infections in one assay. The same region of genome segment 2 of all nine AHSV serotypes is amplified in a single RT-PCR. A universal primer set, designed to amplify the 5'-terminal 521-553bp of genome segment 2 of all of the nine AHSV serotypes with one reaction, was used to generate serotype-specific probes from dsRNA prepared from infected tissue cultures or organ samples. These probes hybridized serotype-specifically with immobilized genome segment 2 cDNA of the nine AHSV reference serotypes in a checkerboard reverse line blot format. All nine AHSV reference and the seven vaccine strains and field viruses isolated up to 28 years apart could be serotyped accurately within a day. The sensitivity of the method is 1pg dsRNA which is sufficient to serotype AHSV directly from lung and spleen specimens of infected horses.
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Affiliation(s)
- J J O Koekemoer
- Biochemistry Division, Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa.
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Koekemoer JJO, Paweska JT, Pretorius PJ, van Dijk AA. VP2 gene phylogenetic characterization of field isolates of African horsesickness virus serotype 7 circulating in South Africa during the time of the 1999 African horsesickness outbreak in the Western Cape. Virus Res 2003; 93:159-67. [PMID: 12782364 DOI: 10.1016/s0168-1702(03)00076-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We present the first VP2-gene phylogenetic analysis of African horsesickness (AHS) viruses within a serotype. Thirteen AHSV 7 isolates were obtained from cases that occurred in South Africa during 1998-1999, and three were historical AHSV 7 isolates. The goals were to start a database of isolates of known location and time of isolation and to determine if we could identify the origin of an AHS outbreak in the surveillance area in the Western Cape. We prepared full-length cDNA copies of the VP2-genes of the isolates. Nucleic acid sequence data of a 786 bp region was used to characterize the genetic relationships between the isolates. The nucleic acid identities between the isolates ranged from 95.5 to 100%. Isolates from common geographical regions grouped together. Characterization of field isolates revealed the presence of two AHSV 7 lineages in South Africa during this period. The grouping of the viruses into two clades accurately reflected the geographical groupings of the isolates. The average nucleic acid divergence between the clades was 4.3%. Within the clades the divergence was 0.5 and 0.1%, respectively. The data suggests that the AHS outbreak in the Western Cape could have been an incursion from the Kwazulu Natal Province.
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Affiliation(s)
- J J O Koekemoer
- Onderstepoort Veterinary Institute, Private Bag X5, 0110, Onderstepoort, South Africa
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