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Ashby M, Moore R, King S, Newbrook K, Flannery J, Batten C. Designing a Multiplex PCR-xMAP Assay for the Detection and Differentiation of African Horse Sickness Virus, Serotypes 1-9. Microorganisms 2024; 12:932. [PMID: 38792762 PMCID: PMC11124020 DOI: 10.3390/microorganisms12050932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/26/2024] Open
Abstract
African horse sickness is a severe and often fatal disease affecting all species of equids. The aetiological agent, African horse sickness virus (AHSV), can be differentiated into nine serotypes. The identification of AHSV serotypes is vital for disease management, as this can influence vaccine selection and help trace disease incursion routes. In this study, we report the development and optimisation of a novel, molecular-based assay that utilises multiplex PCR and microsphere-based technology to expedite detection and differentiation of multiple AHSV serotypes in one assay. We demonstrated the ability of this assay to identify all nine AHSV serotypes, with detection limits ranging from 1 to 277 genome copies/µL depending on the AHSV serotype. An evaluation of diagnostic sensitivity and specificity revealed a sensitivity of 88% and specificity of 100%. This method can serotype up to 42 samples per run and can be completed in approximately 4-6 h. It provides a powerful tool to enhance the rapidity and efficiency of AHSV serotype detection, thereby facilitating the generation of epidemiological data that can help understand and control the incidence of AHSV worldwide.
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Affiliation(s)
- Martin Ashby
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK; (R.M.); (S.K.); (K.N.); (C.B.)
| | - Rebecca Moore
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK; (R.M.); (S.K.); (K.N.); (C.B.)
| | - Simon King
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK; (R.M.); (S.K.); (K.N.); (C.B.)
| | - Kerry Newbrook
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK; (R.M.); (S.K.); (K.N.); (C.B.)
| | - John Flannery
- Department of Pharmaceutical Sciences and Biotechnology, Technological University of the Shannon, Athlone Campus, N37HD68 Athlone, Ireland;
| | - Carrie Batten
- The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, UK; (R.M.); (S.K.); (K.N.); (C.B.)
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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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Calvo-Pinilla E, Jiménez-Cabello L, Utrilla-Trigo S, Illescas-Amo M, Ortego J. Cytokine mRNA Expression Profile in Target Organs of IFNAR (-/-) Mice Infected with African Horse Sickness Virus. Int J Mol Sci 2024; 25:2065. [PMID: 38396742 PMCID: PMC10888608 DOI: 10.3390/ijms25042065] [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: 01/04/2024] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
African horse sickness (AHS) is a highly severe disease caused by a viral etiological agent, African horse sickness virus (AHSV). It is endemic in sub-Saharan Africa, while sporadic outbreaks have occurred in North Africa, Asia, and Europe, with the most recent cases in Thailand. AHSV transmission between equines occurs primarily by biting midges of the genus Culicoides, especially C. imicola, with a wide distribution globally. As research in horses is highly restricted due to a variety of factors, small laboratory animal models that reproduce clinical signs and pathology observed in natural infection of AHSV are highly needed. Here, we investigated the expression profile of several pro-inflammatory cytokines in target organs and serum of IFNAR (-/-) mice, to continue characterizing this established animal model and to go deep into the innate immune responses that are still needed.
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Affiliation(s)
- Eva Calvo-Pinilla
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), 28130 Valdeolmos, Spain; (L.J.-C.); (S.U.-T.); (M.I.-A.); (J.O.)
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4
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Durán-Ferrer M, Villalba R, Fernández-Pacheco P, Tena-Tomás C, Jiménez-Clavero MÁ, Bouzada JA, Ruano MJ, Fernández-Pinero J, Arias M, Castillo-Olivares J, Agüero M. Clinical, Virological and Immunological Responses after Experimental Infection with African Horse Sickness Virus Serotype 9 in Immunologically Naïve and Vaccinated Horses. Viruses 2022; 14:v14071545. [PMID: 35891525 PMCID: PMC9316263 DOI: 10.3390/v14071545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/30/2022] [Accepted: 07/13/2022] [Indexed: 11/16/2022] Open
Abstract
This study described the clinical, virological, and serological responses of immunologically naïve and vaccinated horses to African horse sickness virus (AHSV) serotype 9. Naïve horses developed a clinical picture resembling the cardiac form of African horse sickness. This was characterized by inappetence, reduced activity, and hyperthermia leading to lethargy and immobility–recumbency by days 9–10 post-infection, an end-point criteria for euthanasia. After challenge, unvaccinated horses were viremic from days 3 or 4 post-infection till euthanasia, as detected by serogroup-specific (GS) real time RT-PCR (rRT-PCR) and virus isolation. Virus isolation, antigen ELISA, and GS-rRT-PCR also demonstrated high sensitivity in the post-mortem detection of the pathogen. After infection, serogroup-specific VP7 antibodies were undetectable by blocking ELISA (b-ELISA) in 2 out of 3 unvaccinated horses during the course of the disease (9–10 dpi). Vaccinated horses did not show significant side effects post-vaccination and were largely asymptomatic after the AHSV-9 challenge. VP7-specific antibodies could not be detected by the b-ELISA until day 21 and day 30 post-inoculation, respectively. Virus neutralizing antibody titres were low or even undetectable for specific serotypes in the vaccinated horses. Virus isolation and GS-rRT-PCR detected the presence of AHSV vaccine strains genomes and infectious vaccine virus after vaccination and challenge. This study established an experimental infection model of AHSV-9 in horses and characterized the main clinical, virological, and immunological parameters in both immunologically naïve and vaccinated horses using standardized bio-assays.
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Affiliation(s)
- Manuel Durán-Ferrer
- Laboratorio Central de Veterinaria (LCV), Ministry of Agriculture, Fisheries and Food, Ctra. M-106, pk 1,4, 28110 Algete, Spain; (M.D.-F.); (R.V.); (J.-A.B.); (M.-J.R.)
| | - Rubén Villalba
- Laboratorio Central de Veterinaria (LCV), Ministry of Agriculture, Fisheries and Food, Ctra. M-106, pk 1,4, 28110 Algete, Spain; (M.D.-F.); (R.V.); (J.-A.B.); (M.-J.R.)
| | - Paloma Fernández-Pacheco
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Ctra. M-106, pk 8,1, 28130 Valdeolmos, Spain; (P.F.-P.); (M.-Á.J.-C.); (J.F.-P.); (M.A.)
| | | | - Miguel-Ángel Jiménez-Clavero
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Ctra. M-106, pk 8,1, 28130 Valdeolmos, Spain; (P.F.-P.); (M.-Á.J.-C.); (J.F.-P.); (M.A.)
- CIBER of Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain
| | - José-Antonio Bouzada
- Laboratorio Central de Veterinaria (LCV), Ministry of Agriculture, Fisheries and Food, Ctra. M-106, pk 1,4, 28110 Algete, Spain; (M.D.-F.); (R.V.); (J.-A.B.); (M.-J.R.)
| | - María-José Ruano
- Laboratorio Central de Veterinaria (LCV), Ministry of Agriculture, Fisheries and Food, Ctra. M-106, pk 1,4, 28110 Algete, Spain; (M.D.-F.); (R.V.); (J.-A.B.); (M.-J.R.)
| | - Jovita Fernández-Pinero
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Ctra. M-106, pk 8,1, 28130 Valdeolmos, Spain; (P.F.-P.); (M.-Á.J.-C.); (J.F.-P.); (M.A.)
| | - Marisa Arias
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Ctra. M-106, pk 8,1, 28130 Valdeolmos, Spain; (P.F.-P.); (M.-Á.J.-C.); (J.F.-P.); (M.A.)
| | - Javier Castillo-Olivares
- Laboratory of Viral Zoonotics, Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK;
| | - Montserrat Agüero
- Laboratorio Central de Veterinaria (LCV), Ministry of Agriculture, Fisheries and Food, Ctra. M-106, pk 1,4, 28110 Algete, Spain; (M.D.-F.); (R.V.); (J.-A.B.); (M.-J.R.)
- Correspondence:
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Duan YL, Yang ZX, Bellis G, Li L. Isolation of Tibet Orbivirus from Culicoides jacobsoni (Diptera, Ceratopogonidae) in China. Parasit Vectors 2021; 14:432. [PMID: 34454575 PMCID: PMC8401062 DOI: 10.1186/s13071-021-04899-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 07/27/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tibet Orbivirus (TIBOV) is a recently discovered Orbivirus known to infect cattle, Asian buffalo and goats in south-western China. It was first isolated from mosquitoes and subsequently from biting midges (Culicoides spp.) in Yunnan, China, indicating that it is an arbovirus. Little is known of its potential to cause disease, but the economic importance of related viruses promoted an investigation of potential Culicoides spp. vectors of TIBOV. METHODS Biting midges were collected approximately once per week between May and December 2020, at a cattle farm in Wulong village, Shizong County, Yunnan Province, China. Approximately 3000 specimens of nine species were subsequently used in attempts to isolate virus, and a further 2000 specimens of six species were tested for the presence of bluetongue virus (BTV) and TIBOV using a RT-qPCR test. RESULTS Virus isolation attempts resulted in the isolation of three viruses. One isolate from a pool of Culicoides jacobsoni was identified as TIBOV, while the other two viruses from C. orientalis and C. tainanus remain unidentified but are not BTV or TIBOV. RT-qPCR analysis did not detect BTV in any specimens, but a single pool containing five specimens of C. jacobsoni and another containing five specimens of C. tainanus produced PCR quantification cycle (Cq) values of around 28 that may indicate infection with TIBOV. CONCLUSIONS The isolation of TIBOV from C. jacobsoni satisfies one criterion required to prove its status as a vector of this virus. This isolation is supported by a low Cq value produced from a different pool of this species in the RT-qPCR test. The low Cq value obtained from a pool of C. tainanus suggests that this species may also be able to satisfy this criterion. Both of these species are widespread throughout Asia, with C. jacobsoni extending into the Pacific region, which raises the possibility that TIBOV may be more widespread than is currently known.
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Affiliation(s)
- Ying Liang Duan
- Yunnan Tropical and Subtropical Animal Virus Diseases Laboratory, Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan China
| | - Zhen Xing Yang
- Yunnan Tropical and Subtropical Animal Virus Diseases Laboratory, Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan China
| | - Glenn Bellis
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, NT Australia
- Department of Agriculture, Water and the Environment, Darwin, NT Australia
| | - Le Li
- Yunnan Tropical and Subtropical Animal Virus Diseases Laboratory, Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan China
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6
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Toh X, Wang Y, Rajapakse MP, Lee B, Songkasupa T, Suwankitwat N, Kamlangdee A, Judith Fernandez C, Huangfu T. Use of nanopore sequencing to characterize african horse sickness virus (AHSV) from the African horse sickness outbreak in thailand in 2020. Transbound Emerg Dis 2021; 69:1010-1019. [PMID: 33682298 DOI: 10.1111/tbed.14056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 03/03/2021] [Accepted: 03/03/2021] [Indexed: 12/01/2022]
Abstract
African horse sickness (AHS) is a highly infectious and deadly disease despite availability of vaccines. Molecular characterization of African horse sickness virus (AHSV) detected from the March 2020 Thailand outbreak was carried out by whole-genome sequencing using Nanopore with a Sequence-Independent Single Primer Amplification (SISPA) approach. Nucleotide sequence of the whole genome was compared with closest matching AHSV strains using phylogenetic analyses and the AHSV-1 virus shared high sequence identity with isolates from the same outbreak. Substitution analysis revealed non-synonymous and synonymous substitutions in the VP2 gene as compared to circulating South African strains. The use of sequencing technologies, such as Nanopore with SISPA, has enabled rapid detection, identification and detailed genetic characterization of the AHS virus for informed decision-making and implementation of disease control measures. Active genetic information sharing has also allowed emergence of AHSV to be better monitored on a global basis.
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Affiliation(s)
- Xinyu Toh
- Center for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Singapore
| | - Yifan Wang
- Center for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Singapore
| | | | - Bernett Lee
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), Singapore
| | - Tapanut Songkasupa
- Virology section, Department of Livestock Development, National Institute of Animal Health, Bangkok, Thailand
| | - Nutthakarn Suwankitwat
- Virology section, Department of Livestock Development, National Institute of Animal Health, Bangkok, Thailand
| | - Attapon Kamlangdee
- Faculty of Veterinary Medicine, Kasetsart university, Kamphaengsean, Thailand
| | - Charlene Judith Fernandez
- Center for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Singapore
| | - Taoqi Huangfu
- Center for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Singapore
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7
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Castillo‐Olivares J. African horse sickness in Thailand: Challenges of controlling an outbreak by vaccination. Equine Vet J 2021; 53:9-14. [PMID: 33007121 PMCID: PMC7821295 DOI: 10.1111/evj.13353] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 08/27/2020] [Indexed: 12/20/2022]
Affiliation(s)
- Javier Castillo‐Olivares
- Laboratory of Viral ZoonoticsDepartment of Veterinary MedicineUniversity of CambridgeCambridgeUK
- School of Veterinary Medicine and ScienceUniversity of NottinghamLoughboroughLeicsUK
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Alonso C, Utrilla-Trigo S, Calvo-Pinilla E, Jiménez-Cabello L, Ortego J, Nogales A. Inhibition of Orbivirus Replication by Aurintricarboxylic Acid. Int J Mol Sci 2020; 21:ijms21197294. [PMID: 33023235 PMCID: PMC7582255 DOI: 10.3390/ijms21197294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/28/2020] [Accepted: 09/30/2020] [Indexed: 12/19/2022] Open
Abstract
Bluetongue virus (BTV) and African horse sickness virus (AHSV) are vector-borne viruses belonging to the Orbivirus genus, which are transmitted between hosts primarily by biting midges of the genus Culicoides. With recent BTV and AHSV outbreaks causing epidemics and important economy losses, there is a pressing need for efficacious drugs to treat and control the spread of these infections. The polyanionic aromatic compound aurintricarboxylic acid (ATA) has been shown to have a broad-spectrum antiviral activity. Here, we evaluated ATA as a potential antiviral compound against Orbivirus infections in both mammalian and insect cells. Notably, ATA was able to prevent the replication of BTV and AHSV in both cell types in a time- and concentration-dependent manner. In addition, we evaluated the effect of ATA in vivo using a mouse model of infection. ATA did not protect mice against a lethal challenge with BTV or AHSV, most probably due to the in vivo effect of ATA on immune system regulation. Overall, these results demonstrate that ATA has inhibitory activity against Orbivirus replication in vitro, but further in vivo analysis will be required before considering it as a potential therapy for future clinical evaluation.
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King S, Rajko-Nenow P, Ashby M, Frost L, Carpenter S, Batten C. Outbreak of African horse sickness in Thailand, 2020. Transbound Emerg Dis 2020; 67:1764-1767. [PMID: 32593205 DOI: 10.1111/tbed.13701] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 06/21/2020] [Indexed: 12/12/2022]
Abstract
African horse sickness was confirmed in horses in Thailand during March 2020. The virus was determined to belong to serotype 1 and is phylogenetically closely related to isolates from South Africa. This is the first incidence of African horse sickness occurring in South East Asia and of serotype 1 outside of Africa.
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Dennis SJ, Meyers AE, Hitzeroth II, Rybicki EP. African Horse Sickness: A Review of Current Understanding and Vaccine Development. Viruses 2019; 11:E844. [PMID: 31514299 PMCID: PMC6783979 DOI: 10.3390/v11090844] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/30/2019] [Accepted: 09/04/2019] [Indexed: 01/05/2023] Open
Abstract
African horse sickness is a devastating disease that causes great suffering and many fatalities amongst horses in sub-Saharan Africa. It is caused by nine different serotypes of the orbivirus African horse sickness virus (AHSV) and it is spread by Culicoid midges. The disease has significant economic consequences for the equine industry both in southern Africa and increasingly further afield as the geographic distribution of the midge vector broadens with global warming and climate change. Live attenuated vaccines (LAV) have been used with relative success for many decades but carry the risk of reversion to virulence and/or genetic re-assortment between outbreak and vaccine strains. Furthermore, the vaccines lack DIVA capacity, the ability to distinguish between vaccine-induced immunity and that induced by natural infection. These concerns have motivated interest in the development of new, more favourable recombinant vaccines that utilize viral vectors or are based on reverse genetics or virus-like particle technologies. This review summarizes the current understanding of AHSV structure and the viral replication cycle and also evaluates existing and potential vaccine strategies that may be applied to prevent or control the disease.
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Affiliation(s)
- Susan J Dennis
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
| | - Ann E Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
| | - Inga I Hitzeroth
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
| | - Edward P Rybicki
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, Cape Town, 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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12
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Durán-Ferrer M, Agüero M, Zientara S, Beck C, Lecollinet S, Sailleau C, Smith S, Potgieter C, Rueda P, Sastre P, Monaco F, Villalba R, Tena-Tomás C, Batten C, Frost L, Flannery J, Gubbins S, Lubisi BA, Sánchez-Vizcaíno JM, Emery M, Sturgill T, Ostlund E, Castillo-Olivares J. Assessment of reproducibility of a VP7 Blocking ELISA diagnostic test for African horse sickness. Transbound Emerg Dis 2019; 66:83-90. [PMID: 30070433 PMCID: PMC6378617 DOI: 10.1111/tbed.12968] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/22/2018] [Accepted: 07/02/2018] [Indexed: 11/26/2022]
Abstract
The laboratory diagnosis of African horse sickness (AHS) is important for: (a) demonstrating freedom from infection in a population, animals or products for trade (b) assessing the efficiency of eradication policies; (c) laboratory confirmation of clinical diagnosis; (d) estimating the prevalence of AHS infection; and (e) assessing postvaccination immune status of individual animals or populations. Although serological techniques play a secondary role in the confirmation of clinical cases, their use is very important for all the other purposes due to their high throughput, ease of use and good cost-benefit ratio. The main objective of this study was to support the validation of AHS VP7 Blocking ELISA up to the Stage 3 of the World Animal Health Organization (OIE) assay validation pathway. To achieve this, a collaborative ring trial, which included all OIE Reference Laboratories and other AHS-specialist diagnostic centres, was conducted in order to assess the diagnostic performance characteristics of the VP7 Blocking ELISA. In this trial, a panel of sera of different epidemiological origin and infection status was used. Through this comprehensive evaluation we can conclude that the VP7 Blocking ELISA satisfies the OIE requirements of reproducibility. The VP7 Blocking ELISA, in its commercial version is ready to enter Stage 4 of the validation pathway (Programme Implementation). Specifically, this will require testing the diagnostic performance of the assay using contemporary serum samples collected during control campaigns in endemic countries.
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Affiliation(s)
| | | | - Stephan Zientara
- UMR, Laboratoire de Santé Animale, ANSES, INRA, ENVA, Maisons-Alfort, France
| | - Cécile Beck
- UMR, Laboratoire de Santé Animale, ANSES, INRA, ENVA, Maisons-Alfort, France
| | - Sylvie Lecollinet
- UMR, Laboratoire de Santé Animale, ANSES, INRA, ENVA, Maisons-Alfort, France
| | - Corinne Sailleau
- UMR, Laboratoire de Santé Animale, ANSES, INRA, ENVA, Maisons-Alfort, France
| | | | - Christiaan Potgieter
- Deltamune, Pretoria, South Africa.,Department of Biochemistry, Centre for Human Metabolomics, North-West University, Potchefstroom, South Africa
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13
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Manning NM, Bachanek-Bankowska K, Mertens PPC, Castillo-Olivares J. Vaccination with recombinant Modified Vaccinia Ankara (MVA) viruses expressing single African horse sickness virus VP2 antigens induced cross-reactive virus neutralising antibodies (VNAb) in horses when administered in combination. Vaccine 2017; 35:6024-6029. [DOI: 10.1016/j.vaccine.2017.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/27/2017] [Accepted: 04/04/2017] [Indexed: 12/11/2022]
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14
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Fowler VL, Howson ELA, Flannery J, Romito M, Lubisi A, Agüero M, Mertens P, Batten CA, Warren HR, Castillo-Olivares J. Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of African Horse Sickness Virus. Transbound Emerg Dis 2016; 64:1579-1588. [PMID: 27484889 PMCID: PMC5600106 DOI: 10.1111/tbed.12549] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Indexed: 12/24/2022]
Abstract
African horse sickness (AHS) is a disease of equids caused by African Horse Sickness Virus (AHSV) and is transmitted by Culicoides midges. AHS is endemic in sub‐Saharan Africa, but during the past century, outbreaks of significant economic importance and elevated mortality have been recorded in Northern African countries, the Iberian and Arabian Peninsula, the Middle East and the Indian subcontinent. Effective control combines the application of early warning systems, accurate laboratory diagnosis and reporting, animal movement restrictions, suitable vaccination and surveillance programs, and the coordination of all these measures by efficient veterinary services. Conventional reverse‐transcriptase (RT) PCR (RT‐PCR) and real‐time RT‐PCR (rRT‐PCR) assays have improved the sensitivity and rapidity of diagnosing AHS, resulting in the adoption of these methods as recommended tests by the World Organisation for Animal Health (OIE). However, currently these assays are only performed within laboratory settings; therefore, the development of field diagnostics for AHS would improve the fast implementation of control policies. Loop‐mediated isothermal amplification (LAMP) is an isothermal, autocycling, strand‐displacement nucleic acid amplification technique which can be performed in the field. LAMP assays are attractive molecular assays because they are simple to use, rapid, portable and have sensitivity and specificity within the range of rRT‐PCR. This study describes the development of a novel RT‐LAMP assay for the detection of AHSV. The AHSV RT‐LAMP assay has an analytical sensitivity of 96.1% when considering an rRT‐PCR cut‐off value of CT > 36, or 91.3% when no rRT‐PCR cut‐off is applied. Diagnostic sensitivity and specificity were 100%. This assay provides for a rapid and low cost AHS diagnostic for use in the field.
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Affiliation(s)
- V L Fowler
- The Pirbright Institute, Pirbright, Woking, Surrey, UK
| | - E L A Howson
- The Pirbright Institute, Pirbright, Woking, Surrey, UK
| | - J Flannery
- The Pirbright Institute, Pirbright, Woking, Surrey, UK
| | - M Romito
- ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - A Lubisi
- ARC-Onderstepoort Veterinary Institute, Onderstepoort, South Africa
| | - M Agüero
- Laboratorio Central de Veterinaria-Sanidad Animal, Algete (Madrid), Spain
| | - P Mertens
- The Pirbright Institute, Pirbright, Woking, Surrey, UK
| | - C A Batten
- The Pirbright Institute, Pirbright, Woking, Surrey, UK
| | - H R Warren
- OptiGene Limited, Horsham, West Sussex, UK
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15
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Robin M, Page P, Archer D, Baylis M. African horse sickness: The potential for an outbreak in disease-free regions and current disease control and elimination techniques. Equine Vet J 2016; 48:659-69. [PMID: 27292229 DOI: 10.1111/evj.12600] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 06/09/2016] [Indexed: 11/26/2022]
Abstract
African horse sickness (AHS) is an arboviral disease of equids transmitted by Culicoides biting midges. The virus is endemic in parts of sub-Saharan Africa and official AHS disease-free status can be obtained from the World Organization for Animal Health on fulfilment of a number of criteria. AHS is associated with case fatality rates of up to 95%, making an outbreak among naïve horses both a welfare and economic disaster. The worldwide distributions of similar vector-borne diseases (particularly bluetongue disease of ruminants) are changing rapidly, probably due to a combination of globalisation and climate change. There is extensive evidence that the requisite conditions for an AHS epizootic currently exist in disease-free countries. In particular, although the stringent regulations enforced upon competition horses make them extremely unlikely to redistribute the virus, there are great concerns over the effects of illegal equid movement. An outbreak of AHS in a disease free region would have catastrophic effects on equine welfare and industry, particularly for international events such as the Olympic Games. While many regions have contingency plans in place to manage an outbreak of AHS, further research is urgently required if the equine industry is to avoid or effectively contain an AHS epizootic in disease-free regions. This review describes the key aspects of AHS as a global issue and discusses the evidence supporting concerns that an epizootic may occur in AHS free countries, the planned government responses, and the roles and responsibilities of equine veterinarians.
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Affiliation(s)
- M Robin
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK
| | - P Page
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - D Archer
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK
| | - M Baylis
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, UK
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Sergeant ES, Grewar JD, Weyer CT, Guthrie AJ. Quantitative Risk Assessment for African Horse Sickness in Live Horses Exported from South Africa. PLoS One 2016; 11:e0151757. [PMID: 26986002 PMCID: PMC4795756 DOI: 10.1371/journal.pone.0151757] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 03/03/2016] [Indexed: 11/30/2022] Open
Abstract
African horse sickness (AHS) is a severe, often fatal, arbovirus infection of horses, transmitted by Culicoides spp. midges. AHS occurs in most of sub-Saharan Africa and is a significant impediment to export of live horses from infected countries, such as South Africa. A stochastic risk model was developed to estimate the probability of exporting an undetected AHS-infected horse through a vector protected pre-export quarantine facility, in accordance with OIE recommendations for trade from an infected country. The model also allows for additional risk management measures, including multiple PCR tests prior to and during pre-export quarantine and optionally during post-arrival quarantine, as well as for comparison of risk associated with exports from a demonstrated low-risk area for AHS and an area where AHS is endemic. If 1 million horses were exported from the low-risk area with no post-arrival quarantine we estimate the median number of infected horses to be 5.4 (95% prediction interval 0.5 to 41). This equates to an annual probability of 0.0016 (95% PI: 0.00015 to 0.012) assuming 300 horses exported per year. An additional PCR test while in vector-protected post-arrival quarantine reduced these probabilities by approximately 12-fold. Probabilities for horses exported from an area where AHS is endemic were approximately 15 to 17 times higher than for horses exported from the low-risk area under comparable scenarios. The probability of undetected AHS infection in horses exported from an infected country can be minimised by appropriate risk management measures. The final choice of risk management measures depends on the level of risk acceptable to the importing country.
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Affiliation(s)
- Evan S. Sergeant
- AusVet Animal Health Services, Canberra, Australian Capital Territory, Australia
- * E-mail:
| | - John D. Grewar
- Veterinary Services, Western Cape Department of Agriculture, Elsenburg, South Africa
| | - Camilla T. Weyer
- Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Alan J. Guthrie
- Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
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17
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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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18
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Study of the virulence of serotypes 4 and 9 of African horse sickness virus in IFNAR(-/-), Balb/C and 129 Sv/Ev mice. Vet Microbiol 2014; 174:322-332. [PMID: 25458420 DOI: 10.1016/j.vetmic.2014.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 11/23/2022]
Abstract
African horse sickness virus (AHSV) is a double-stranded RNA virus which belongs to the family Reoviridae, genus Orbivirus. Recent studies have focused on the interferon-α/β receptor knock-out mice (IFNAR(-/-)) as a small animal laboratory for the development of AHSV vaccines. The aim of this work was to study in vivo the virulence of two strains of AHSV and to compare the outcome of the infection of three mouse strains. To address this, AHSV serotypes 4 (AHSV-4) and 9 (AHSV-9) were inoculated subcutaneously (SC) and intranasally (IN) in two immunocompetent mouse strains (Balb/C and 129 Sv/Ev (129 WT)) as well as IFNAR(-/-) mice (on 129 Sv/Ev genetic background). In IFNAR(-/-) mice, fatality up to 50% was measured and significantly more clinical signs were observed in comparison with SC inoculated immunocompetent mice. The observed clinical signs were significantly more severe after AHSV-4 infection, in particular in immunocompetent mice inoculated by IN route. Considering RNAemia, significantly higher viral loads were measured following AHSV-4 infection. In the organs of 129 WT inoculated by IN route, significantly higher viral loads were detected after AHSV-4 infection. Together the results support a higher virulence for AHSV-4 compared to AHSV-9 and a higher clinical impact following infections in IN inoculated mice, at least in the investigated strains. The study also brought indirect evidences for type I IFN involvement in the control of AHSV infection.
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19
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Alberca B, Bachanek-Bankowska K, Cabana M, Calvo-Pinilla E, Viaplana E, Frost L, Gubbins S, Urniza A, Mertens P, Castillo-Olivares J. Vaccination of horses with a recombinant modified vaccinia Ankara virus (MVA) expressing African horse sickness (AHS) virus major capsid protein VP2 provides complete clinical protection against challenge. Vaccine 2014; 32:3670-4. [PMID: 24837765 PMCID: PMC4061461 DOI: 10.1016/j.vaccine.2014.04.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/01/2014] [Accepted: 04/14/2014] [Indexed: 11/15/2022]
Abstract
A recombinant modified Vaccinia Ankara virus expressing VP2 of African horse sickness virus serotype 9 was generated. Four horses were vaccinated on days 0 and 20. Three unvaccinated controls were used. Vaccinated and control horses were challenged intravenously with 107.4TCID50 of AHSV-9 on day 34 of the study. At challenge, vaccinates had virus neutralising antibodies but were negative for antibodies to AHSV-VP7. All vaccinates were completely protected against clinical signs of African horse sickness.
African horse sickness virus (AHSV) is an arthropod-borne pathogen that infects all species of equidae and causes high mortality in horses. Previously, a recombinant modified vaccinia Ankara (MVA) virus expressing the protein VP2 of AHSV serotype 4 was shown to induce virus neutralising antibodies in horses and protected interferon alpha receptor gene knock-out mice (IFNAR −/−) against virulent AHSV challenge. This study builds on the previous work, examining the protective efficacy of MVA-VP2 vaccination in the natural host of AHSV infection. A study group of 4 horses was vaccinated twice with a recombinant MVA virus expressing the major capsid protein (VP2) of AHSV serotype 9. Vaccinated animals and a control group of unvaccinated horses were then challenged with a virulent strain of AHSV-9. The vaccinated animals were completely protected against clinical disease and also against viraemia as measured by standard end-point dilution assays. In contrast, all control horses presented viraemia after challenge and succumbed to the infection. These results demonstrate the potential of recombinant MVA viruses expressing the outer capsid VP2 of AHSV as a protective vaccine against AHSV infection in the field.
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Affiliation(s)
- Berta Alberca
- Zoetis-Spain, Ctra de Comprodon, Finca La Riba, 17813 Vall de Bianya, Girona, Spain
| | | | - Marta Cabana
- Zoetis-Spain, Ctra de Comprodon, Finca La Riba, 17813 Vall de Bianya, Girona, Spain
| | - Eva Calvo-Pinilla
- The Pirbright Institute, Ash Road, Pirbright, Woking GU24 0NF, Surrey, UK
| | - Elisenda Viaplana
- Zoetis-Spain, Ctra de Comprodon, Finca La Riba, 17813 Vall de Bianya, Girona, Spain
| | - Lorraine Frost
- The Pirbright Institute, Ash Road, Pirbright, Woking GU24 0NF, Surrey, UK
| | - Simon Gubbins
- The Pirbright Institute, Ash Road, Pirbright, Woking GU24 0NF, Surrey, UK
| | - Alicia Urniza
- Zoetis-Spain, Ctra de Comprodon, Finca La Riba, 17813 Vall de Bianya, Girona, Spain
| | - Peter Mertens
- The Pirbright Institute, Ash Road, Pirbright, Woking GU24 0NF, Surrey, UK
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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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21
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Rathogwa NM, Quan M, Smit JQ, Lourens C, Guthrie AJ, van Vuuren M. Development of a real time polymerase chain reaction assay for equine encephalosis virus. J Virol Methods 2013; 195:205-10. [PMID: 24161811 DOI: 10.1016/j.jviromet.2013.10.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/06/2013] [Accepted: 10/08/2013] [Indexed: 11/24/2022]
Abstract
Equine encephalosis virus (EEV) is the cause of equine encephalosis. The disease is similar to mild forms of African horse sickness (AHS) and the two diseases are easily confused. Laboratory identification and serotyping of EEV is based on viral isolation in BHK-21 cells and a viral plaque inhibition neutralisation test. These procedures are time-consuming and therefore a more rapid diagnostic assay for EEV that can distinguish EEV from African horse sickness virus (AHSV) infections was developed. The S7 (VP7) gene from 38 EEV isolates representing all seven serotypes was amplified and sequenced. A conserved region at the 5' end of the gene was identified and used to design group-specific EEV primers and a TaqMan(®) MGB™ hydrolysis probe. The efficiency of the EEV real-time RT-PCR assay was 81%. The assay was specific, as it did not detect any of the nine serotypes of AHSV, nor 24 serotypes of bluetongue virus (BTV) and sensitive, with a 95% limit of detection of 10(2.9) TCID50/ml blood (95% confidence interval: 10(2.7) to 10(3.3)). The real-time format was selected because of its convenience, sensitivity and ability to produce results rapidly.
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Affiliation(s)
- N M Rathogwa
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
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22
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Guthrie AJ, MacLachlan NJ, Joone C, Lourens CW, Weyer CT, Quan M, Monyai MS, Gardner IA. Diagnostic accuracy of a duplex real-time reverse transcription quantitative PCR assay for detection of African horse sickness virus. J Virol Methods 2013; 189:30-5. [DOI: 10.1016/j.jviromet.2012.12.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
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Rapid molecular detection methods for arboviruses of livestock of importance to northern Europe. J Biomed Biotechnol 2011; 2012:719402. [PMID: 22219660 PMCID: PMC3246798 DOI: 10.1155/2012/719402] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/14/2011] [Accepted: 10/25/2011] [Indexed: 11/18/2022] Open
Abstract
Arthropod-borne viruses (arboviruses) have been responsible for some of the most explosive epidemics of emerging infectious diseases over the past decade. Their impact on both human and livestock populations has been dramatic. The early detection either through surveillance or diagnosis of virus will be a critical feature in responding and resolving the emergence of such epidemics in the future. Although some of the most important emerging arboviruses are human pathogens, this paper aims to highlight those diseases that primarily affect livestock, although many are zoonotic and some occasionally cause human mortality. This paper also highlights the molecular detection methods specific to each virus and identifies those emerging diseases for which a rapid detection methods are not yet developed.
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A new duplex real-time RT-PCR assay for sensitive and specific detection of African horse sickness virus. Mol Cell Probes 2011; 25:87-93. [PMID: 21315146 DOI: 10.1016/j.mcp.2011.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 01/18/2011] [Accepted: 01/21/2011] [Indexed: 11/23/2022]
Abstract
A new real-time reverse transcription-polymerase chain reaction (RT-PCR) assay for a simple and rapid diagnosis of African Horse Sickness (AHS) was developed. Primers and FAM-labeled TaqMan-MGB probes specific for African horse sickness virus (AHSV) were selected from the consensus sequence of the segment 8 of all 9 serotypes of AHSV reference strains. For the determination of the analytical sensitivity, an in vitro transcript (AHS_ns2T7) of the target region was constructed and tested. Furthermore, the AHS_ns2T7 transcript was used either as positive control or as a standard for quantifying target copies. A commercial heterologous Armored RNA was used as an internal positive control (IPC) for both RNA isolation and RT-PCR steps. The qRT-PCR AHS_ns2 was able to amplify the target sequence up to 0.71 copies/reaction. Its flexibility allowed to amplify a wide dynamic range of RNA copies from 1.5 to 0.001fg. Within this range, the Ct values varied from 18 to 38 cycles with SD values always lower than 0.5 confirming their strong and constant linear correlation with the RNA target. Furthermore the newly designed duplex real-time RT-PCR proved to be strictly AHSV-specific as it did not amplify close related viruses.
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Quan M, Lourens CW, MacLachlan NJ, Gardner IA, Guthrie AJ. Development and optimisation of a duplex real-time reverse transcription quantitative PCR assay targeting the VP7 and NS2 genes of African horse sickness virus. J Virol Methods 2010; 167:45-52. [PMID: 20304015 DOI: 10.1016/j.jviromet.2010.03.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 03/01/2010] [Accepted: 03/08/2010] [Indexed: 10/19/2022]
Abstract
Nucleotide sequences of 52 South African isolates of African horse sickness virus (AHSV) collected during 2004-2005 and including viruses of all nine AHSV serotypes, were used to design and develop a duplex real-time reverse transcription quantitative PCR (RT-PCR) assay targeting the VP7 (S8) and NS2 (S9) genes of AHSV. The assay was optimized for detection of AHSV in fresh and frozen blood of naturally infected horses. Assay performance was enhanced using random hexamers rather than gene-specific primers for RT, and with denaturation of double-stranded RNA in the presence of random hexamers. The assay was efficient with a linear range of at least five orders of magnitude. The analytical sensitivity of the assay was 132 copies of the target genes (4125 copies per ml of blood), and the assay was at least 10-fold more sensitive than virus isolation on BHK-21 cells. The assay was also highly specific because it did not detect related orbiviruses, such as bluetongue and equine encephalosis viruses.
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Affiliation(s)
- M Quan
- Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
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26
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Boinas F, Calistrib P, Domingo M, Avilés MM, López BM, Sánchez BR, Sánchez‐Vizcaíno JM. Scientific review on African Horse Sickness. ACTA ACUST UNITED AC 2009. [DOI: 10.2903/sp.efsa.2009.en-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Fernando Boinas
- Faculdade de Medicina Veterinaria, Universidade Técnica de Lisboa, (FMV‐UTL)
| | - Paolo Calistrib
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise “G. Caporale” (IZSA&M)
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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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