Equine viral encephalitis.
Abstract: The most important neurotropic viral infections of the horse are the arthropod-borne encephalitides. These include Venezuelan encephalitis (VE), eastern encephalitis (EE) and western encephalitis (WE), which are found in the Americas, and Japanese B encephalitis which occurs in the Far East. All the viruses cause encephalitis in man. Between 1969 and 1972 an epidemic of VE occurred in Central America. In 1971 the disease was reported in Texas, where it was brought under control by the vaccination of susceptible horses with an attenuated live virus vaccine and by the reduction of the mosquito population with insecticides sprayed from aircraft. A high titre viraemia occurs with VE virus in the horse and epidemics are maintained by a mosquito/horse cycle; infection of man and other species is incidental. EE and WE have been recognised as separate diseases since 1933 and in the U.S.A. horses are protected by routine vaccination. Epidemics of these diseases are routine vaccination. Epidemics of these diseases are now uncommon. In contrast with VE, both EE and WE viruses are maintained by a bird/mosquito cycle. The viraemia in the horse is generally considered insufficient to infect mosquito vectors; the horse is a "dead end host". Several species of mosquito can act as vectors of VE, WE and EE. The extension of other arthropod-borne diseases to areas originally outside their geographical distribution (e.g. bluetongue in sheep) serves to illustrate the potential of VE, WE and EE to cause disease on other continents.
Publication Date: 1976-04-01 PubMed ID: 4301DOI: 10.1111/j.2042-3306.1976.tb03293.xGoogle Scholar: Lookup
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- Journal Article
- Review
- Alphavirus
- Arboviruses
- Disease control
- Disease Outbreaks
- Disease Prevention
- Disease Transmission
- Encephalitis
- Encephalomyelitis
- Epidemiology
- Equine Diseases
- Equine Health
- Horses
- Infectious Disease
- Mosquito-borne Diseases
- Public Health
- Vaccination
- Vector-borne disease
- Veterinary Medicine
- Virology
- Western Equine Encephalitis
Summary
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This research article discusses the neurotropic viral infections that affect horses, including Venezuelan, Eastern, and Western encephalitis, as well as Japanese B encephalitis. The study details how these are controlled and how they could potentially spread.
Encephalitis infections in horses
- Arthropod-borne encephalitides represent the primary neurotropic viral infections in horses. These include Venezuelan encephalitis (VE), eastern encephalitis (EE), and western encephalitis (WE).
- These infections have also been identified in humans and are prevalent in regions such as the Americas and the Far East.
- Between 1969 and 1972, a VE epidemic was reported in Central America, and it eventually reached Texas by 1971. Despite this, the disease was brought under control.
Control measures
- An effective mechanism to control the spread of the VE virus in Texas involved the vaccination of susceptible horses and reduction of the mosquito population. This was achieved by spraying insecticides from aircraft and using an attenuated live virus vaccine.
- EE and WE have been acknowledged as distinct diseases since 1933. In the U.S.A., these are managed by routine vaccination, thereby reducing the frequency of epidemics.
- Different species of mosquitoes act as transmitters of VE, WE, and EE, contributing to the proliferation of these diseases.
Transmission cycle and potential spread
- VE viruses result in a high viraemia in horses, facilitating the sustainment of epidemics through a mosquito/horse cycle. In contrast, EE and WE are maintained via a bird/mosquito cycle.
- Other species, including humans, are incidentally infected. Unlike VE, the viraemia generated in horses by EE and WE viruses is generally inadequate to infect mosquito vectors, making the horse a “dead end host”.
- Fears around the potential spread of VE, WE, and EE to other continents are highlighted, driven by the observation that other arthropod-borne diseases have extended their reach beyond their original geographical distribution.
Cite This Article
APA
Gibbs EP.
(1976).
Equine viral encephalitis.
Equine Vet J, 8(2), 66-71.
https://doi.org/10.1111/j.2042-3306.1976.tb03293.x Publication
Researcher Affiliations
MeSH Terms
- Animals
- Borna Disease / veterinary
- Culicidae / microbiology
- Encephalitis Virus, Eastern Equine
- Encephalitis Virus, Venezuelan Equine / immunology
- Encephalitis Virus, Western Equine
- Encephalitis, Japanese / veterinary
- Encephalomyelitis, Equine / epidemiology
- Encephalomyelitis, Equine / etiology
- Encephalomyelitis, Venezuelan Equine / epidemiology
- Encephalomyelitis, Venezuelan Equine / immunology
- Herpesvirus 1, Equid
- Horse Diseases / epidemiology
- Horse Diseases / immunology
- Horses
- Ticks / microbiology
- Viral Vaccines
References
This article includes 26 references
Citations
This article has been cited 6 times.- Patroca da Silva S, Barbosa de Almeida Medeiros D, Ribeiro Cruz AC, Marques França AF, Diniz Nunes BT, Guerreiro Rodrigues DS, Pinto da Silva EV, Almada GL, Neves Casseb LM, Correia Rodrigues da Cunha MA, Dias Pestana Santos MG, Dilcher M, Britto SG, Martins Romano AP, Chiang JO, Martins LC. Co-infection of Peruvian horse sickness virus and West Nile virus associated with neurological diseases in horses from Brazil. Heliyon 2022 Dec;8(12):e12097.
- Boghdeh NA, Risner KH, Barrera MD, Britt CM, Schaffer DK, Alem F, Brown JA, Wikswo JP, Narayanan A. Application of a Human Blood Brain Barrier Organ-on-a-Chip Model to Evaluate Small Molecule Effectiveness against Venezuelan Equine Encephalitis Virus. Viruses 2022 Dec 15;14(12).
- Nunes JDSDSS, Casseb LMN, Guimarães RJPS, Reis WDM, de Barros BCV, Ferreira MS, Chiang JO, Pinheiro HHC, Vasconcelos PFDC, Cruz ACR. Serological evidence of Eastern equine encephalitis circulation in equids in Pará state, Brazil. Braz J Vet Med 2021;43:e001720.
- Urakova N, Kuznetsova V, Crossman DK, Sokratian A, Guthrie DB, Kolykhalov AA, Lockwood MA, Natchus MG, Crowley MR, Painter GR, Frolova EI, Frolov I. β-d-N(4)-Hydroxycytidine Is a Potent Anti-alphavirus Compound That Induces a High Level of Mutations in the Viral Genome. J Virol 2018 Feb 1;92(3).
- Frolov I, Kim DY, Akhrymuk M, Mobley JA, Frolova EI. Hypervariable Domain of Eastern Equine Encephalitis Virus nsP3 Redundantly Utilizes Multiple Cellular Proteins for Replication Complex Assembly. J Virol 2017 Jul 15;91(14).
- Onmaz AC, Beutel RG, Schneeberg K, Pavaloiu AN, Komarek A, van den Hoven R. Vectors and vector-borne diseases of horses. Vet Res Commun 2013 Mar;37(1):65-81.
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