Japanese encephalitis in a racing thoroughbred gelding in Hong Kong.
Abstract: A horse in Hong Kong that had been vaccinated against Japanese encephalitis suffered a pyrexic episode that culminated in a hyperexcitable state and self-inflicted trauma. Japanese encephalitis was diagnosed on the basis of clinical, pathological and serological observations, and confirmed by the detection of genomic sequences of the virus in spinal cord tissue. Phylogenetic analyses of E gene and NS5-3'UTR sequences revealed divergent clustering of these segments with previously described genotypes, suggesting the possibility that the horse might have been infected with a recombinant between genotype I and genotype II viruses. Horses are considered to be dead-end hosts for the disease, but the occurrence of an infected horse in a population may have implications for the health status of the national herd. The effect that this case had on the horse industry in Hong Kong is discussed with specific reference to the movement of horses and the vaccination programme for Japanese encephalitis.
Publication Date: 2005-08-09 PubMed ID: 16085723DOI: 10.1136/vr.157.6.168Google Scholar: Lookup
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Summary
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The research indicates that a horse in Hong Kong, which had been vaccinated against Japanese encephalitis, still contracted the disease. This raises questions about the potential impact on the horse industry, the movement of horses, and the effectiveness of the Japanese encephalitis vaccination program.
Diagnosis of Japanese Encephalitis
- The horse in Hong Kong displayed a high fever, extreme excitability, and self-inflicted physical harm. Despite being vaccinated, it had contracted Japanese encephalitis.
- The diagnosis was based on clinical, pathological, and serological observations, including detection of the genomic sequences of the virus in its spinal cord tissue.
Evidence of New Virus Genotype
- The researchers conducted phylogenetic analyses of E gene and NS5-3’UTR sequences to understand the genetic makeup of the virus.
- The result revealed that the segments analysed varied significantly from previously described genotypes. This suggests that the horse might have been infected with a new recombinant type that includes aspects of both genotype I and genotype II viruses.
Implications for the Horse Industry
- Normally, horses are seen as dead-end hosts for the disease, meaning they can carry the virus but do not spread it.
- However, one infected horse in a population can potentially impact the overall health status of the entire national herd.
- The researchers discuss the effects this case might have on the horse industry in Hong Kong, specifically in terms of horse movements and the effectiveness of the Japanese encephalitis vaccination program. It could mean heightened scrutiny on horse transfers and reconsideration of the vaccination protocols, as one vaccinated horse still acquired the disease.
Cite This Article
APA
Lam KH, Ellis TM, Williams DT, Lunt RA, Daniels PW, Watkins KL, Riggs CM.
(2005).
Japanese encephalitis in a racing thoroughbred gelding in Hong Kong.
Vet Rec, 157(6), 168-173.
https://doi.org/10.1136/vr.157.6.168 Publication
Researcher Affiliations
- Department of Veterinary Clinical Services, Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin, New Territories, Hong Kong.
MeSH Terms
- Animals
- Antibodies, Viral / blood
- Antibodies, Viral / cerebrospinal fluid
- Brain / pathology
- Cell Line
- Encephalitis Virus, Japanese / classification
- Encephalitis Virus, Japanese / genetics
- Encephalitis Virus, Japanese / immunology
- Encephalitis, Japanese / diagnosis
- Encephalitis, Japanese / veterinary
- Encephalitis, Japanese / virology
- Enzyme-Linked Immunosorbent Assay
- Fever / veterinary
- Genotype
- Hong Kong
- Horse Diseases / diagnosis
- Horse Diseases / virology
- Horses
- Immunohistochemistry
- Male
- Mice
- Phylogeny
- Reverse Transcriptase Polymerase Chain Reaction
- Spinal Cord / virology
- Vaccination / veterinary
- Vaccines, Inactivated / administration & dosage
- Viral Vaccines / administration & dosage
Citations
This article has been cited 12 times.- Wang S, Yang K, Li C, Liu W, Gao T, Yuan F, Guo R, Liu Z, Tan Y, Hu X, Tian Y, Zhou D. 4-Phenyl-butyric Acid Inhibits Japanese Encephalitis Virus Replication via Inhibiting Endoplasmic Reticulum Stress Response. Viruses 2023 Feb 14;15(2).
- Furlong M, Adamu AM, Hoskins A, Russell TL, Gummow B, Golchin M, Hickson RI, Horwood PF. Japanese Encephalitis Enzootic and Epidemic Risks across Australia. Viruses 2023 Feb 6;15(2).
- Mackenzie JS, Williams DT, van den Hurk AF, Smith DW, Currie BJ. Japanese Encephalitis Virus: The Emergence of Genotype IV in Australia and Its Potential Endemicity. Viruses 2022 Nov 9;14(11).
- Mulvey P, Duong V, Boyer S, Burgess G, Williams DT, Dussart P, Horwood PF. The Ecology and Evolution of Japanese Encephalitis Virus. Pathogens 2021 Nov 24;10(12).
- Knox A, Beddoe T. Isothermal Nucleic Acid Amplification Technologies for the Detection of Equine Viral Pathogens. Animals (Basel) 2021 Jul 20;11(7).
- Kumar B, Manuja A, Gulati BR, Virmani N, Tripathi BN. Zoonotic Viral Diseases of Equines and Their Impact on Human and Animal Health. Open Virol J 2018;12:80-98.
- Yun SI, Lee YM. Early Events in Japanese Encephalitis Virus Infection: Viral Entry. Pathogens 2018 Aug 13;7(3).
- Bielefeldt-Ohmann H, Prow NA, Wang W, Tan CS, Coyle M, Douma A, Hobson-Peters J, Kidd L, Hall RA, Petrovsky N. Safety and immunogenicity of a delta inulin-adjuvanted inactivated Japanese encephalitis virus vaccine in pregnant mares and foals. Vet Res 2014 Dec 17;45(1):130.
- Gulati BR, Singha H, Singh BK, Virmani N, Kumar S, Singh RK. Isolation and genetic characterization of Japanese encephalitis virus from equines in India. J Vet Sci 2012 Jun;13(2):111-8.
- Gulati BR, Singha H, Singh BK, Virmani N, Khurana SK, Singh RK. Serosurveillance for Japanese encephalitis virus infection among equines in India. J Vet Sci 2011 Dec;12(4):341-5.
- Levesque ZA, Walsh MG, Webb CE, Zadoks RN, Brookes VJ. A scoping review of evidence of naturally occurring Japanese encephalitis infection in vertebrate animals other than humans, ardeid birds and pigs. PLoS Negl Trop Dis 2024 Oct;18(10):e0012510.
- Harrison JJ, Nguyen W, Morgan MS, Tang B, Habarugira G, de Malmanche H, Freney ME, Modhiran N, Watterson D, Cox AL, Yan K, Yuen NKY, Bowman DH, Kirkland PD, Bielefeldt-Ohmann H, Suhrbier A, Hall RA, Rawle DJ, Hobson-Peters J. A chimeric vaccine derived from Australian genotype IV Japanese encephalitis virus protects mice from lethal challenge. NPJ Vaccines 2024 Jul 31;9(1):134.
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