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Journal of clinical microbiology1975; 2(3); 198-205; doi: 10.1128/jcm.2.3.198-205.1975

Laboratory studies of Venezuelan equine encephalitis virus in equines, Texas, 1971.

Abstract: During the summer and fall of 1971, epizootic and epidemic Venezuelan equine encephalitis was detected in Texas. Isolates of epizootic (IB) and vaccine (TC-83) strains were distinguished by virulence of the former for guinea pigs. Vaccine virus was isolated from 1 to 14 days after vaccination and neutralization tests demonstrated the appearance of antibody about a week after vaccination. Viremia titers of subtype IB in horses ranged from 2.2 to 8.3 log10 suckling mouse intracranial 50% lethal doses per ml. Of 101 equines from which Venezuelan equine encephalitis virus (IB or TC-83) strains were isolated, 87 had no neutralizing antibody against Venezuelan, eastern or western equine encephalitis viruses.
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Publication Date: 1975-09-01 PubMed ID: 1176627PubMed Central: PMC274171DOI: 10.1128/jcm.2.3.198-205.1975Google Scholar: Lookup
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  • Journal Article

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.

This research article explores studies on the Venezuelan equine encephalitis virus (VEEV) in horses in Texas during 1971. The study revealed that both epizootic (IB) and vaccine (TC-83) strains of VEEV were present and the former showed a high virulence in guinea pigs. The virus was isolated up to 14 days after vaccination and the appearance of antibodies could be detected roughly a week following vaccination.

Virus Strains

  • The study identified the presence of both epizootic (IB) and vaccine (TC-83) strains of the Venezuelan equine encephalitis virus (VEEV) in horses.
  • The IB strain proved to be highly virulent when tested in guinea pigs. The virulence of a virus refers to its ability to infect and cause disease in a host organism.

Vaccine Efficacy

  • Virus of the vaccination strain (TC-83) was still capable of being isolated from the horses anywhere from 1 to 14 days after they had been vaccinated.
  • This suggests that the vaccination does not immediately clear the virus from the system. However, it initiates an immune response leading to the production of antibodies against the VEEV. The presence of these antibodies could be confirmed about a week after vaccination.

Viremia and Antibody Production

  • Viremia, the presence of viruses in the blood, resulted in titers of subtype IB ranging between 2.2 to 8.3 log10 suckling mouse intracranial 50% lethal doses per ml. This shows the potency and capacity of the virus to cause disease.
  • Out of 101 horses from which the virus was isolated, 87 did not have any neutralizing antibodies against VEEV or related eastern or western equine encephalitis viruses.
  • Neutralizing antibodies are critical in viral infection control as they prevent viruses from being able to infect cells. Their absence could lead to increased susceptibility to the diseases.

Cite This Article

APA
Calisher CH, Maness KS. (1975). Laboratory studies of Venezuelan equine encephalitis virus in equines, Texas, 1971. J Clin Microbiol, 2(3), 198-205. https://doi.org/10.1128/jcm.2.3.198-205.1975

Publication

Journal of clinical microbiology
ISSN: 0095-1137
NlmUniqueID: 7505564
Country: United States
Language: English
Volume: 2
Issue: 3
Pages: 198-205

Researcher Affiliations

Calisher, C H
    Maness, K S

      MeSH Terms

      • Animals
      • Antigens, Viral / analysis
      • Disease Outbreaks / veterinary
      • Encephalitis Virus, Venezuelan Equine / immunology
      • Encephalitis Virus, Venezuelan Equine / isolation & purification
      • Encephalitis Virus, Venezuelan Equine / pathogenicity
      • Encephalomyelitis, Equine / veterinary
      • Encephalomyelitis, Venezuelan Equine / microbiology
      • Encephalomyelitis, Venezuelan Equine / veterinary
      • Guinea Pigs
      • Horse Diseases / microbiology
      • Horses
      • Mice
      • Texas
      • Vaccination
      • Viral Vaccines
      • Virulence

      References

      This article includes 10 references
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      Citations

      This article has been cited 1 times.
      1. Bowen GS, Calisher CH. Virological and serological studies of Venezuelan equine encephalomyelitis in humans. J Clin Microbiol 1976 Jul;4(1):22-7.
        doi: 10.1128/jcm.4.1.22-27.1976pubmed: 956360google scholar: lookup
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