Quantification by real-time PCR of the magnitude and duration of leucocyte-associated viraemia in horses infected with neuropathogenic vs. non-neuropathogenic strains of EHV-1.
Abstract: Neurological disease in horses caused by infection with certain 'paralytic' strains of equine herpesvirus-1 (EHV-1) is a potentially devastating condition the pathogenesis of which is poorly understood. Preliminary observations in both experimentally induced and naturally occurring cases of the central nervous system disease have revealed a more robust cell-associated viraemia in horses infected with paralytic isolates of EHV-1, relative to horses infected with abortigenic isolates. To investigate further this pathogenesis-relevant question, the present study was performed using a greater number of horses and a more precise method for quantification of EHV-1 DNA present in viraemic leucocytes. Objective: To compare the magnitude and duration of leucocyte-associated viraemia in seronegative, age-matched foals following infection with paralytic vs. abortigenic isolates of EHV-1. Methods: Peripheral blood mononuclear cells (PBMC) were collected from 20 weanling foals at 2, 4, 7, 9, 11, 14 and 21 days after intranasal inoculation with either paralytic or abortigenic isolates of EHV-1. The amount of EHV-1 DNA present in each PBMC sample was measured by real-time quantitative PCR. Results: Foals inoculated with paralytic strains of EHV-1 developed both a greater magnitude and longer duration of PBMC-associated viraemia than foals inoculated with abortigenic strains of the virus. Conclusions: Both the higher magnitude and longer duration of cell-associated viraemia contribute to the risk for development of neurological signs in horses infected with paralytic strains of EHV-1. Conclusions: Our results provide empirically derived, scientific data that contributes to a better understanding of the pathogenetic basis for the differing abilities of paralytic and abortigenic strains of EHV-1 to cause post infection central nervous system disease in the horse. The findings identify the importance of minimising the quantitative burden of viraemic leucocytes that follows exposure to the virus, by the use of effective therapeutic antiviral drugs and efficacious prophylactic vaccines that stimulate cytotoxic immune responses against EHV-1 infected cells.
Publication Date: 2006-05-19 PubMed ID: 16706281DOI: 10.2746/042516406776866453Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigates the differences in how paralytic and abortigenic strains of the equine herpesvirus-1 (EHV-1) affect horses, specifically by analyzing the intensity and length of viraemia in white blood cells, known as leucocytes.
Study Objective
The main purpose of this study was to unravel the discrepancies in the magnitude and duration of white blood cell (leucocyte)-linked viraemia in horses following exposure to either the paralytic or abortigenic forms of the EHV-1 virus. The researchers intended to extend their initial observations regarding the prevalence of a stronger cell-related viraemia in horses struck with paralytic forms, compared to those with abortigenic varieties of EHV-1.
Methods
- The researchers deliberately exposed 20 young, seronegative foals to either paralytic or abortigenic forms of EHV-1 through intranasal inoculation.
- The research team then collected peripheral blood mononuclear cells (PBMC) samples from these foals 2, 4, 7, 9, 11, 14, and 21 days after the inoculation.
- Finally, the team utilized real-time quantitative PCR to measure the amount of EHV-1 DNA present in each PBMC sample.
Results
The findings suggested that foals exposed to paralytic EHV-1 strains developed a grander magnitude and longer duration of PBMC-associated viraemia compared to foals exposed to abortigenic strains of the virus.
Conclusions
The results pointed to the higher intensity and longer period of cell-related viraemia as factors that contribute to increasing the risk of neurological symptoms in horses infected with paralytic strains of EHV-1. The researchers concluded that their data provide significant insights into the varying ability of paralytic and abortigenic EHV-1 strains to cause post-infection central nervous system disease in horses. These results highlight the relevance of reducing the quantitative load of viraemic leucocytes following exposure to EHV-1, possibly through the application of effective antiviral drugs and prophylactic vaccines that trigger immune responses against EHV-1 infected cells.
Cite This Article
APA
Allen GP, Breathnach CC.
(2006).
Quantification by real-time PCR of the magnitude and duration of leucocyte-associated viraemia in horses infected with neuropathogenic vs. non-neuropathogenic strains of EHV-1.
Equine Vet J, 38(3), 252-257.
https://doi.org/10.2746/042516406776866453 Publication
Researcher Affiliations
- Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, Kentucky 40546-0099, USA.
MeSH Terms
- Animals
- DNA, Viral / analysis
- Female
- Herpesviridae Infections / diagnosis
- Herpesviridae Infections / veterinary
- Herpesviridae Infections / virology
- Herpesvirus 1, Equid / isolation & purification
- Herpesvirus 1, Equid / pathogenicity
- Horse Diseases / diagnosis
- Horse Diseases / virology
- Horses
- Leukocytes, Mononuclear / virology
- Male
- Polymerase Chain Reaction / methods
- Polymerase Chain Reaction / veterinary
- Viremia / diagnosis
- Viremia / veterinary
- Viremia / virology
Citations
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