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Home / Equine Research Bank / PLoS One / Quantitative Risk Assessment for African Horse Sickness in L...
PloS one2016; 11(3); e0151757; doi: 10.1371/journal.pone.0151757

Quantitative Risk Assessment for African Horse Sickness in Live Horses Exported from South Africa.

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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Publication Date: 2016-03-17 PubMed ID: 26986002PubMed Central: PMC4795756DOI: 10.1371/journal.pone.0151757Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research discusses a risk assessment model for evaluating the probability of exporting a horse infected with African Horse Sickness (AHS) from South Africa, where this disease is endemic. This model considers various risk management measures, including multiple PCR tests and quarantine facilities, to reduce the risk of disease transmission.

Objective of the Research

The main objective of the study was to develop a stochastic risk model for estimating the probability of accidentally exporting a horse from South Africa that’s infected with African Horse Sickness (AHS) but remains undetected. Specifically, it looked at how the application of additional risk mitigation strategies, such as pre-export and post-arrival PCR tests and quarantine measures, affects this probability.

About African Horse Sickness

  • AHS is a severe viral infection that can be fatal to horses.
  • The disease is transmitted by Culicoides species midges and is prevalent in most regions of Sub-Saharan Africa.
  • Since the disease is widespread in South Africa, it poses substantial challenges to the export of live horses from the country.

Key Findings of the Research

  • The model estimated that if one million horses were exported from a low-risk area without post-arrival quarantine, the median number of infected horses would be around 5.4.
  • The annual probability of exporting an infected horse is 0.0016 if 300 horses are exported per year from a low-risk area.
  • An additional PCR test during vector-protected post-arrival quarantine could reduce this risk by approximately 12-fold.
  • For horses exported from an area where AHS is endemic, the probabilities were much higher, approximately 15 to 17 times higher than for horses from the low-risk area under similar scenarios.

Implications of the Research

  • The research indicates that the risk of undetected AHS infection in horses exported from an infected country can be significantly reduced through appropriate risk management measures.
  • These measures include multiple PCR tests before and during pre-export quarantine, as well as during post-arrival quarantine, if necessary.
  • The selection of appropriate risk management measures depends largely on the level of risk the importing country deems acceptable.

Cite This Article

APA
Sergeant ES, Grewar JD, Weyer CT, Guthrie AJ. (2016). Quantitative Risk Assessment for African Horse Sickness in Live Horses Exported from South Africa. PLoS One, 11(3), e0151757. https://doi.org/10.1371/journal.pone.0151757

Publication

PloS one
ISSN: 1932-6203
NlmUniqueID: 101285081
Country: United States
Language: English
Volume: 11
Issue: 3
Pages: e0151757

Researcher Affiliations

Sergeant, Evan S
  • AusVet Animal Health Services, Canberra, Australian Capital Territory, Australia.
Grewar, John D
  • Veterinary Services, Western Cape Department of Agriculture, Elsenburg, South Africa.
Weyer, Camilla T
  • Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
Guthrie, Alan J
  • Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.

MeSH Terms

  • African Horse Sickness / diagnosis
  • African Horse Sickness / epidemiology
  • African Horse Sickness / transmission
  • African Horse Sickness Virus / isolation & purification
  • Animals
  • Horses
  • Insect Vectors / virology
  • Quarantine
  • Risk Assessment
  • Seasons
  • South Africa / epidemiology

Conflict of Interest Statement

Competing Interests: The authors have the following interests: The participation of ES in this research was funded by private donors through the Equine Health Fund of South Africa, a division of Wits Health Consortium (Pty) Ltd (http://www.equinehealthfund.co.za/Home.aspx). The Equine Research Centre is supported by South African horse industry funding, through the Equine Health Fund. ES is employed by AusVet Animal Health Services. There are no patents, products in development or marketed products to declare. This does not alter the authors\' adherence to all the PLOS ONE policies on sharing data and materials.

References

This article includes 22 references
  1. OIE. African horse sickness. Technical Disease Cards 2013.
  2. Mellor PS, Hamblin C. African horse sickness. Vet Res 2004;35(4):445–66.
    doi: 10.1051/vetres:2004021pubmed: 15236676google scholar: lookup
  3. Coetzer JAW, Guthrie AJ. African hose sickness. Infectious Diseases of Livestock 2004.
  4. OIE. African horse sickness. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals 2012.
  5. Guthrie AJ, Quan M, Lourens CW, Audonnet J-C, Minke JM, Yao J. Protective immunization of horses with a recombinant canarypox virus vectored vaccine co-expressing genes encoding the outer capsid proteins of African horse sickness virus. Vaccine 2009;27(33):4434–8.
    doi: 10.1016/j.vaccine.2009.05.044pubmed: 19490959google scholar: lookup
  6. OIE. African horse sickness. Terrestrial Animal Health Code 2014.
  7. OIE. Bluetongue. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals 2014 2014.
  8. Grewar JD, Weyer CT, Guthrie AJ, Koen P, Davey S, Quan M. The 2011 outbreak of African horse sickness in the African horse sickness controlled area in South Africa. J S A Vet Assoc 2013;84(1):Art. #973, 7 pages.
  9. OIE. OIE-Listed diseases, infections and infestations in force in 2015. 2015.
  10. Sinclair M, Buhrmann G, Gummow B. An epidemiological investigation of the African horsesickness outbreak in the Western Cape Province of South Africa in 2004 and its relevance to the current equine export protocol. J S A Vet Assoc 2006;77(4):191–6.
    pubmed: 17458343
  11. R-Core-Team. R: A language and environment for statistical computing. 2014.
  12. Maja M. Standard for the registration of vector-protected equine quarantine facility for export. 2014.
  13. Page PC, Labuschagne K, Venter GJ, Schoeman JP, Guthrie AJ. Efficacy of alphacypermethrin-treated high density polyethylene mesh applied to jet stalls housing horses against Culicoides biting midges in South Africa. Vet Parasitol 2015;210(1–2):84–90.
    doi: 10.1016/j.vetpar.2015.02.007pubmed: 25794942google scholar: lookup
  14. Guthrie AJ, MacLachlan NJ, Joone C, Lourens CW, Weyer CT, Quan M. Diagnostic accuracy of a duplex real-time reverse transcription quantitative PCR assay for detection of African horse sickness virus. J Virol Methods 2013;189(1):30–5.
    doi: 10.1016/j.jviromet.2012.12.014pubmed: 23291102google scholar: lookup
  15. Sergeant ESG. Epitools epidemiological calculators. 2013.
  16. de Vos CJ, Hoek CA, Nodelijk G. Risk of introducing African horse sickness virus into the Netherlands by international equine movements. Prev Vet Med 2012;106(2):108–22.
    doi: 10.1016/j.prevetmed.2012.01.019pubmed: 22341773google scholar: lookup
  17. Faverjon C, Leblond A, Hendrikx P, Balenghien T, de Vos CJ, Fischer EAJ. A spatiotemporal model to assess the introduction risk of African horse sickness by import of animals and vectors in France. BMC Veterinary Research 2015;11(1):1–15.
    doi: 10.1186/s12917-015-0435-4pmc: PMC4455332pubmed: 26040321google scholar: lookup
  18. Nomikou K, Hughes J, Wash R, Kellam P, Breard E, Zientara S. Widespread Reassortment Shapes the Evolution and Epidemiology of Bluetongue Virus following European Invasion. PLoS Pathogens 2015;11(8):e1005056.
    doi: 10.1371/journal.ppat.1005056pmc: PMC4529188pubmed: 26252219google scholar: lookup
  19. Lee CC, Zhu H, Huang PY, Peng L, Chang YC, Yip CH. Emergence and evolution of avian H5N2 influenza viruses in chickens in Taiwan. Journal of virology 2014;88(10):5677–86.
    doi: 10.1128/jvi.00139-14pmc: PMC4019133pubmed: 24623422google scholar: lookup
  20. Aguero M, Gomez-Tejedor C, Angeles Cubillo M, Rubio C, Romero E, Jimenez-Clavero A. Real-time fluorogenic reverse transcription polymerase chain reaction assay for detection of African horse sickness virus. Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc. 2008;20(3):325–8.
    pubmed: 18460619
  21. Weyer CT, Quan M, Joone C, Lourens CW, MacLachlan NJ, Guthrie AJ. African horse sickness in naturally infected, immunised horses. Equine Vet J 2013;45(1):117–9.
    doi: 10.1111/j.2042-3306.2012.00590.xpubmed: 22612775google scholar: lookup
  22. EFSA. Risk of Bluetongue Transmission in Animal Transit: Scientific Opinion of the Panel on Animal Health and Welfare. EFSA J 2008;2008(795):1–56.

Citations

This article has been cited 7 times.
  1. Marques ARP, Gonzalez Villeta L, Simons R, Horigan V, de Vos C, Conrady B. Quantitative risk assessment for infectious disease introduction in animal populations: a comprehensive review. Front Vet Sci 2025;12:1648695.
    doi: 10.3389/fvets.2025.1648695pubmed: 41142563google scholar: lookup
  2. Amenu K, McIntyre KM, Moje N, Knight-Jones T, Rushton J, Grace D. Approaches for disease prioritization and decision-making in animal health, 2000-2021: a structured scoping review. Front Vet Sci 2023;10:1231711.
    doi: 10.3389/fvets.2023.1231711pubmed: 37876628google scholar: lookup
  3. Nelson E, Thurston W, Pearce-Kelly P, Jenkins H, Cameron M, Carpenter S, Guthrie A, England M. A Qualitative Risk Assessment for Bluetongue Disease and African Horse Sickness: The Risk of Entry and Exposure at a UK Zoo. Viruses 2022 Feb 28;14(3).
    doi: 10.3390/v14030502pubmed: 35336912google scholar: lookup
  4. Grewar JD, Kotze JL, Parker BJ, van Helden LS, Weyer CT. An entry risk assessment of African horse sickness virus into the controlled area of South Africa through the legal movement of equids. PLoS One 2021;16(5):e0252117.
    doi: 10.1371/journal.pone.0252117pubmed: 34038466google scholar: lookup
  5. Bessell PR, Auty HK, Roberts H, McKendrick IJ, Bronsvoort BMC, Boden LA. A Tool for Prioritizing Livestock Disease Threats to Scotland. Front Vet Sci 2020;7:223.
    doi: 10.3389/fvets.2020.00223pubmed: 32391390google scholar: lookup
  6. Porphyre T, Grewar JD. Assessing the potential of plains zebra to maintain African horse sickness in the Western Cape Province, South Africa. PLoS One 2019;14(10):e0222366.
    doi: 10.1371/journal.pone.0222366pubmed: 31671099google scholar: lookup
  7. Durr PA, Graham K, van Klinken RD. Sellers' Revisited: A Big Data Reassessment of Historical Outbreaks of Bluetongue and African Horse Sickness due to the Long-Distance Wind Dispersion of Culicoides Midges. Front Vet Sci 2017;4:98.
    doi: 10.3389/fvets.2017.00098pubmed: 28775987google scholar: lookup
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