African horse sickness in naturally infected, immunised horses.
Abstract: To determine whether subclinical cases, together with clinical cases, of African horse sickness (AHS) occur in immunised horses in field conditions, whole blood samples were collected and rectal temperatures recorded weekly from 50 Nooitgedacht ponies resident in open camps at the Faculty of Veterinary Science, University of Pretoria, Onderstepoort, during 2008-2010. The samples were tested for the presence of African horse sickness virus (AHSV) RNA by a recently developed real-time RT-PCR. It was shown that 16% of immunised horses in an AHS endemic area were infected with AHSV over a 2 year period, with half of these (8%) being subclinically infected. The potential impact of such cases on the epidemiology of AHS warrants further investigation.
© 2012 EVJ Ltd.
Publication Date: 2012-05-21 PubMed ID: 22612775DOI: 10.1111/j.2042-3306.2012.00590.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article investigates the prevalence of the African horse sickness virus (AHSV) in immunised horses, with a focus on identifying both clinical and subclinical infections.
Objective of the Research
- The research’s main objective was to determine whether immunized horses in field conditions could contract AHSV, both clinically and subclinically. This was to provide more insight into potential risks and implications associated with AHS immunization programs.
Methodology
- The study involved 50 Nooitgedacht ponies that resided in open camps at the University of Pretoria’s Faculty of Veterinary Science.
- These ponies were observed between 2008 – 2010, during which whole blood samples were collected weekly, and rectal temperatures were recorded.
- The samples were then examined for the presence of the AHSV RNA utilising a recently developed real-time RT-PCR (Reverse Transcription Polymerase Chain Reaction). This cutting-edge technology is capable of identifying the genetic material of the virus within the samples.
Results and Findings
- The study’s findings revealed that 16% of the immunised horses were infected with AHSV over the two-year period. This indicated that despite being immunized, horses could still contract the virus under certain conditions.
- Moreover, half of the infected horses (8%) were found to be subclinically infected. This underlines the presence of AHSV infection even without visible or noticeable symptoms, raising important questions about detection and containment strategies.
Conclusion and Future Work
- The research concludes that there is a significant prevalence of both clinical and subclinical AHSV infections among immunized horses in field conditions. This underscores the need for enhanced monitoring, testing, and control measures in AHS immunization programs.
- The researchers further suggest that the potential implications of such subclinical cases on the overall epidemiology of African Horse Sickness warrant further investigation. This implies that future studies could focus more on understanding the role of subclinically infected horses in disease transmission, developing efficient detection methods, and devising more effective public health interventions.
Cite This Article
APA
Weyer CT, Quan M, Joone C, Lourens CW, MacLachlan NJ, Guthrie AJ.
(2012).
African horse sickness in naturally infected, immunised horses.
Equine Vet J, 45(1), 117-119.
https://doi.org/10.1111/j.2042-3306.2012.00590.x Publication
Researcher Affiliations
- Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
MeSH Terms
- African Horse Sickness / blood
- African Horse Sickness / immunology
- African Horse Sickness / virology
- African Horse Sickness Virus / isolation & purification
- Animals
- Horses
- Incidence
- RNA, Viral / blood
- RNA, Viral / isolation & purification
- Reverse Transcriptase Polymerase Chain Reaction / veterinary
- Viral Vaccines / immunology
Citations
This article has been cited 12 times.- de Klerk JN, Gorsich EE, Grewar JD, Atkins BD, Tennant WSD, Labuschagne K, Tildesley MJ. Modelling African horse sickness emergence and transmission in the South African control area using a deterministic metapopulation approach. PLoS Comput Biol 2023 Sep;19(9):e1011448.
- 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 Jul 15;14(7).
- Sullivan E, Lecollinet S, Kerviel A, Hue E, Pronost S, Beck C, Dumarest M, Zientara S, Roy P. Entry-competent-replication-abortive African horse sickness virus strains elicit robust immunity in ponies against all serotypes. Vaccine 2021 May 27;39(23):3161-3168.
- Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Depner K, Drewe JA, Garin-Bastuji B, Gonzales Rojas JL, Gortázar Schmidt C, Herskin M, Michel V, Miranda Chueca MÁ, Pasquali P, Roberts HC, Sihvonen LH, Spoolder H, Ståhl K, Velarde A, Viltrop A, Winckler C, De Clercq K, Klement E, Stegeman JA, Gubbins S, Antoniou SE, Broglia A, Van der Stede Y, Zancanaro G, Aznar I. Scientific Opinion on the assessment of the control measures of the category A diseases of Animal Health Law: African Horse Sickness. EFSA J 2021 Feb;19(2):e06403.
- Castillo-Olivares J. African horse sickness in Thailand: Challenges of controlling an outbreak by vaccination. Equine Vet J 2021 Jan;53(1):9-14.
- Calvo-Pinilla E, Marín-López A, Utrilla-Trigo S, Jiménez-Cabello L, Ortego J. Reverse genetics approaches: a novel strategy for African horse sickness virus vaccine design. Curr Opin Virol 2020 Oct;44:49-56.
- Dennis SJ, Meyers AE, Hitzeroth II, Rybicki EP. African Horse Sickness: A Review of Current Understanding and Vaccine Development. Viruses 2019 Sep 11;11(9).
- Dennis SJ, Meyers AE, Guthrie AJ, Hitzeroth II, Rybicki EP. Immunogenicity of plant-produced African horse sickness virus-like particles: implications for a novel vaccine. Plant Biotechnol J 2018 Feb;16(2):442-450.
- Weyer CT, Grewar JD, Burger P, Rossouw E, Lourens C, Joone C, le Grange M, Coetzee P, Venter E, Martin DP, MacLachlan NJ, Guthrie AJ. African Horse Sickness Caused by Genome Reassortment and Reversion to Virulence of Live, Attenuated Vaccine Viruses, South Africa, 2004-2014. Emerg Infect Dis 2016 Dec;22(12):2087-2096.
- 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(3):e0151757.
- de la Poza F, Calvo-Pinilla E, López-Gil E, Marín-López A, Mateos F, Castillo-Olivares J, Lorenzo G, Ortego J. Ns1 is a key protein in the vaccine composition to protect Ifnar(-/-) mice against infection with multiple serotypes of African horse sickness virus. PLoS One 2013;8(7):e70197.
- Lo Iacono G, Robin CA, Newton JR, Gubbins S, Wood JL. Where are the horses? With the sheep or cows? Uncertain host location, vector-feeding preferences and the risk of African horse sickness transmission in Great Britain. J R Soc Interface 2013 Jun 6;10(83):20130194.
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