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Fairbanks EL, Brennan ML, Mertens PPC, Tildesley MJ, Daly JM. Re-parameterisation of a mathematical model of African horse sickness virus using data from a systematic literature search. Transbound Emerg Dis 2021; 69:e671-e681. [PMID: 34921513 PMCID: PMC9543668 DOI: 10.1111/tbed.14420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 11/26/2022]
Abstract
African horse sickness (AHS) is a vector‐borne disease transmitted by Culicoides spp., endemic to sub‐Saharan Africa. There have been many examples of historic and recent outbreaks in the Middle East, Asia and Europe. However, not much is known about infection dynamics and outbreak potential in these naive populations. In order to better inform a previously published ordinary differential equation model, we performed a systematic literature search to identify studies documenting experimental infection of naive (control) equids in vaccination trials. Data on the time until the onset of viraemia, clinical signs and death after experimental infection of a naive equid and duration of viraemia were extracted. The time to viraemia was 4.6 days and the time to clinical signs was 4.9 days, longer than the previously estimated latent period of 3.7 days. The infectious periods of animals that died/were euthanized or survived were found to be 3.9 and 8.7 days, whereas previous estimations were 4.4 and 6 days, respectively. The case fatality was also found to be higher than previous estimations. The updated parameter values (along with other more recently published estimates from literature) resulted in an increase in the number of host deaths, decrease in the duration of the outbreak and greater prevalence in vectors.
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Affiliation(s)
- Emma L Fairbanks
- School of Veterinary Medicine and Science, University of Nottingham, Loughborough, LE12 5RD, UK
| | - Marnie L Brennan
- School of Veterinary Medicine and Science, University of Nottingham, Loughborough, LE12 5RD, UK
| | - Peter P C Mertens
- School of Veterinary Medicine and Science, University of Nottingham, Loughborough, LE12 5RD, UK
| | - Michael J Tildesley
- The Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research, School of Life Sciences and Mathematics Institute, University of Warwick, Coventry, CV4 7AL, UK
| | - Janet M Daly
- School of Veterinary Medicine and Science, University of Nottingham, Loughborough, LE12 5RD, UK
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Karamalla ST, Gubran AI, Adam IA, Abdalla TM, Sinada RO, Haroun EM, Aradaib IE. Sero-epidemioloical survey on African horse sickness virus among horses in Khartoum State, Central Sudan. BMC Vet Res 2018; 14:230. [PMID: 30068335 PMCID: PMC6090883 DOI: 10.1186/s12917-018-1554-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 07/24/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND African horse sickness virus (AHSV) is an infectious non contagious insect-transmitted double-stranded (ds) RNA orbivirus of the family Reoviridae. AHSV causes an often fatal hemorrhagic infection with high mortality among selected breeds of Arabian horses. This study was conducted to avail some information with regard to the prevalence and associated risk factors of AHSV among ecotype breeds of horses in central Sudan. METHODS Sera were collected from 320 horses, which were selected randomly from four localities and employed in the study. A competitive enzyme-linked immunosorbent assay (cELISA) was used to screen sampled sera for AHSV-specific immunoglobulin G (Ig G) antibodies. RESULTS Seropositivity to AHSV Ig G was detected in 275 out of the 320 horse sera, thus accounting for a prevalence rate of 85.9%. Potential risk factors to AHSV infection were reported to be associated with horse breed (OR = 5.0, CI = 0.07-2.104, p-value = 0.039) and activity of the horse (OR = 3.21, CI = 0.72-1.48, p- value = 0.008). CONCLUSIONS The high prevalence of AHSV in Khartoum State of Central Sudan necessitates the need for continuous surveillance for AHSV infection to prevent a possible disease outbreak in this region of the African continent.
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Affiliation(s)
- Siham T. Karamalla
- Molecular Biology Laboratory (MBL), Department of Clinical Medicine, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Ahmed I. Gubran
- Molecular Biology Laboratory (MBL), Department of Clinical Medicine, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Ibrahim A. Adam
- Molecular Biology Laboratory (MBL), Department of Clinical Medicine, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Tamadur M. Abdalla
- Molecular Biology Laboratory (MBL), Department of Clinical Medicine, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Reem O. Sinada
- Molecular Biology Laboratory (MBL), Department of Clinical Medicine, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Eltahir M. Haroun
- Scientific Research Directorate, Al-Mughtaribeen University, Khartoum, Sudan
| | - Imadeldin E. Aradaib
- Molecular Biology Laboratory (MBL), Department of Clinical Medicine, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
- Scientific Research Directorate, Al-Mughtaribeen University, Khartoum, Sudan
- EBH Scientific Research Laboratory, Zamzam University College (ZUC), Khartoum, Sudan
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Mathebula EM, Faber FE, Van Wyngaardt W, Van Schalkwyk A, Pretorius A, Fehrsen J. B-cell epitopes of African horse sickness virus serotype 4 recognised by immune horse sera. ACTA ACUST UNITED AC 2017; 84:e1-e12. [PMID: 28281773 PMCID: PMC6238682 DOI: 10.4102/ojvr.v84i1.1313] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/27/2016] [Accepted: 09/29/2016] [Indexed: 01/07/2023]
Abstract
Identifying antigenic proteins and mapping their epitopes is important for the development of diagnostic reagents and recombinant vaccines. B-cell epitopes of African horse sickness virus (AHSV) have previously been mapped on VP2, VP5, VP7 and NS1, using mouse, rabbit and chicken monoclonal antibodies. A comprehensive study of the humoral immune response of five vaccinated horses to AHSV-4 antigenic peptides was undertaken. A fragmented-genome phage display library expressing a repertoire of AHSV-4 peptides spanning the entire genome was constructed. The library was affinity selected for binders on immobilised polyclonal immunoglobulin G (IgG) isolated from horse sera collected pre- and post-immunisation with an attenuated AHSV-4 monovalent vaccine. The DNA inserts of binding phages were sequenced with Illumina high-throughput sequencing. The data were normalised using pre-immune IgG-selected sequences. More sequences mapped to the genes coding for NS3, VP6 and VP5 than to the other genes. However, VP2 and VP5 each had more antigenic regions than each of the other proteins. This study identified a number of epitopes to which the horse’s humoral immune system responds during immunisation with AHSV-4.
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Affiliation(s)
| | | | | | | | | | - Jeanni Fehrsen
- New Generation Vaccines Programme, Agricultural Research Council - Onderstepoort Veterinary Institute; Department of Veterinary Tropical Diseases, University of Pretoria.
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Chiam R, Sharp E, Maan S, Rao S, Mertens P, Blacklaws B, Davis-Poynter N, Wood J, Castillo-Olivares J. Induction of antibody responses to African horse sickness virus (AHSV) in ponies after vaccination with recombinant modified vaccinia Ankara (MVA). PLoS One 2009; 4:e5997. [PMID: 19543394 PMCID: PMC2694985 DOI: 10.1371/journal.pone.0005997] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 05/23/2009] [Indexed: 11/18/2022] Open
Abstract
Background African horse sickness virus (AHSV) causes a non-contagious, infectious disease in equids, with mortality rates that can exceed 90% in susceptible horse populations. AHSV vaccines play a crucial role in the control of the disease; however, there are concerns over the use of polyvalent live attenuated vaccines particularly in areas where AHSV is not endemic. Therefore, it is important to consider alternative approaches for AHSV vaccine development. We have carried out a pilot study to investigate the ability of recombinant modified vaccinia Ankara (MVA) vaccines expressing VP2, VP7 or NS3 genes of AHSV to stimulate immune responses against AHSV antigens in the horse. Methodology/Principal Findings VP2, VP7 and NS3 genes from AHSV-4/Madrid87 were cloned into the vaccinia transfer vector pSC11 and recombinant MVA viruses generated. Antigen expression or transcription of the AHSV genes from cells infected with the recombinant viruses was confirmed. Pairs of ponies were vaccinated with MVAVP2, MVAVP7 or MVANS3 and both MVA vector and AHSV antigen-specific antibody responses were analysed. Vaccination with MVAVP2 induced a strong AHSV neutralising antibody response (VN titre up to a value of 2). MVAVP7 also induced AHSV antigen–specific responses, detected by western blotting. NS3 specific antibody responses were not detected. Conclusions This pilot study demonstrates the immunogenicity of recombinant MVA vectored AHSV vaccines, in particular MVAVP2, and indicates that further work to investigate whether these vaccines would confer protection from lethal AHSV challenge in the horse is justifiable.
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Affiliation(s)
- Rachael Chiam
- Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, United Kingdom
| | - Emma Sharp
- Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, United Kingdom
| | - Sushila Maan
- Institute for Animal Health, Pirbright Laboratory, Pirbright, Surrey, United Kingdom
| | - Shujing Rao
- Institute for Animal Health, Pirbright Laboratory, Pirbright, Surrey, United Kingdom
| | - Peter Mertens
- Institute for Animal Health, Pirbright Laboratory, Pirbright, Surrey, United Kingdom
| | - Barbara Blacklaws
- Cambridge Infectious Diseases Consortium, Department of Veterinary Medicine, Cambridge, United Kingdom
| | - Nick Davis-Poynter
- Sir Albert Sakzewski Virus Research Centre, University of Queensland, Herston, Queensland, Australia
| | - James Wood
- Cambridge Infectious Diseases Consortium, Department of Veterinary Medicine, Cambridge, United Kingdom
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Martínez-Torrecuadrada JL, Langeveld JP, Venteo A, Sanz A, Dalsgaard K, Hamilton WD, Meloen RH, Casal JI. Antigenic profile of African horse sickness virus serotype 4 VP5 and identification of a neutralizing epitope shared with bluetongue virus and epizootic hemorrhagic disease virus. Virology 1999; 257:449-59. [PMID: 10329555 DOI: 10.1006/viro.1999.9680] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
African horse sickness virus (AHSV) causes a fatal disease in horses. The virus capsid is composed of a double protein layer, the outermost of which is formed by two proteins: VP2 and VP5. VP2 is known to determine the serotype of the virus and to contain the neutralizing epitopes. The biological function of VP5, the other component of the capsid, is unknown. In this report, AHSV VP5, expressed in insect cells alone or together with VP2, was able to induce AHSV-specific neutralizing antibodies. Moreover, two VP5-specific monoclonal antibodies (MAbs) that were able to neutralize the virus in a plaque reduction assay were generated. To dissect the antigenic structure of AHSV VP5, the protein was cloned in Escherichia coli using the pET3 system. The immunoreactivity of both MAbs, and horse and rabbit polyclonal antisera, with 17 overlapping fragments from VP5 was analyzed. The most immunodominant region was found in the N-terminal 330 residues of VP5, defining two antigenic regions, I (residues 151-200) and II (residues 83-120). The epitopes were further defined by PEPSCAN analysis with 12mer peptides, which determined eight antigenic sites in the N-terminal half of the molecule. Neutralizing epitopes were defined at positions 85-92 (PDPLSPGE) for MAb 10AE12 and at 179-185 (EEDLRTR) for MAb 10AC6. Epitope 10AE12 is highly conserved between the different orbiviruses. MAb 10AE12 was able to recognize bluetongue virus VP5 and epizootic hemorrhagic disease virus VP5 by several techniques. These data will be especially useful for vaccine development and diagnostic purposes.
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