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Home / Equine Research Bank / Pathogens / Investigation of an EHV-1 Outbreak in the United States Caus...
Pathogens (Basel, Switzerland)2021; 10(6); doi: 10.3390/pathogens10060747

Investigation of an EHV-1 Outbreak in the United States Caused by a New H752 Genotype.

Abstract: Here we report on an EHV-1 outbreak investigation caused by a novel genotype H752 (histidine in amino acid position 752 of the ORF 30 gene). The outbreak involved 31 performance horses. Horses were monitored over a period of 35 days for clinical signs, therapeutic outcome and qPCR results of EHV-1 in blood and nasal secretions. The morbidity of the EHV-1 outbreak was 84% with 26 clinically infected horses displaying fever and less frequently anorexia and distal limb edema. Four horses showed mild transient neurological deficits. Clinically diseased horses experienced high viral load of EHV-1 in blood and/or nasal secretions via qPCR, while subclinically infected horses had detectable EHV-1 mainly in nasal secretions. The majority of infected horses showed a rise in antibody titers to EHV-1 during the outbreak. All 31 horses were treated with valacyclovir, while clinically infected horses further received flunixin meglumine and sodium heparin. This investigation highlights various relevant aspects of an EHV-1 outbreak caused by a new H752 genotype: (i) importance of early detection of EHV-1 infection; (ii) diagnostic challenge to assess H752 genotype; (iii) apparent benefit of valacyclovir use in the early stage of the outbreak; and (iv) weekly testing of blood and nasal secretions by qPCR in order to monitor individual infection status and lift quarantine.
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Publication Date: 2021-06-13 PubMed ID: 34199153PubMed Central: PMC8231618DOI: 10.3390/pathogens10060747Google Scholar: Lookup
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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.

The research discusses an outbreak of EHV-1, a disease affecting horses, caused by a new H752 genotype. The outbreak, which affected 31 performance horses, was monitored and investigated over a duration of 35 days.

About the Outbreak and the H752 Genotype

  • The outbreak investigated in this study was caused by EHV-1, an equine virus, and was novel in that it was linked to a new H (histidine) genotype located in amino acid position 752 of the enzyme gene.
  • The outbreak had a high morbidity rate with 84% of the 31 performance horses examined showing clinical signs of the infection.
  • The clinical signs included fever, anorexia, distal limb edema, and less frequently observed mild and transient neurological deficits.

Monitoring and Testing:

  • The horses were monitored over a period of 35 days for several factors, including clinical signs, therapeutic outcomes, and results of quantitative Polymerase Chain Reaction (qPCR) tests for EHV-1 in the horses’ blood and nasal secretions.
  • Clinically sick horses experienced a high viral load of EHV-1 detected in their blood and/or nasal secretions using qPCR.
  • Horses that were subclinically infected, which means they were infected but not displaying symptoms, had mainly detectable EHV-1 in their nasal secretions.

Therapeutic approach and Challenges:

  • All 31 horses were treated with an antiviral drug called Valacyclovir.
  • Horses that displayed clinical symptoms received additional treatments of non-steroidal anti-inflammatory drugs (Flunixin Meglumine) and blood thinners (Sodium Heparin).
  • Most of the horses showed an increase in antibodies to EHV-1, indicating an immune response to the infection.
  • The study raises a diagnostic challenge due to the difficulty to detect and diagnose the new H genotype.

Significance of the Study:

  • The study’s findings are crucial because they underline the importance of early detection of the EHV-1 infection, especially within outbreaks triggered by new genotypes like this one.
  • The study also notes the apparent benefit of using Valacyclovir in the early stages of the outbreak, as well as the importance of weekly testing of horses’ blood and nasal secretions using qPCR to monitor individual infection status and to guide decisions for lifting quarantine.

Cite This Article

APA
Pusterla N, Barnum S, Miller J, Varnell S, Dallap-Schaer B, Aceto H, Simeone A. (2021). Investigation of an EHV-1 Outbreak in the United States Caused by a New H752 Genotype. Pathogens, 10(6). https://doi.org/10.3390/pathogens10060747

Publication

Pathogens (Basel, Switzerland)
ISSN: 2076-0817
NlmUniqueID: 101596317
Country: Switzerland
Language: English
Volume: 10
Issue: 6

Researcher Affiliations

Pusterla, Nicola
  • Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Barnum, Samantha
  • Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Miller, Julia
  • Alliance Equine Health Care, Glenmoore, PA 19343, USA.
Varnell, Sarah
  • Alliance Equine Health Care, Glenmoore, PA 19343, USA.
Dallap-Schaer, Barbara
  • Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348, USA.
Aceto, Helen
  • Department of Clinical Studies, New Bolton Center, University of Pennsylvania, Kennett Square, PA 19348, USA.
Simeone, Aliza
  • Pennsylvania Department of Agriculture, Bureau of Animal Health, Collegeville, PA 17110, USA.

Conflict of Interest Statement

The authors declare no conflict of interest.

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