Strain impact on equine herpesvirus type 1 (EHV-1) abortion models: Viral loads in fetal and placental tissues and foals

David W. Gardiner, David P. Lunn, Lutz S. Goehring, Yu Wei Chiang, Corey Cook, Nikolaus Osterrieder, Patrick McCue, Fabio Del Piero, Stephen B. Hussey, Gisela Soboll Hussey

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Equine herpesvirus-1 (EHV-1) continues to cause both sporadic and epidemic abortions despite extensive vaccination. Lack of progress in the development of protective vaccines may be hindered by the lack of equine abortion models that employ contemporary EHV-1 strains. The objective of our experiments was to compare a contemporary EHV-1 strain with a previously described challenge strain, and to quantify EHV-1 loads in various maternal and fetal tissues. Infection experiments were performed in two groups of 7 pregnant pony mares at 270-290 days of gestation with a contemporary EHV-1 strain (University of Findlay 2003 isolate - OH03) or an EHV-1 strain isolated over 30 years ago, and previously described in abortion models (Ab4). All mares in both groups exhibited nasal viral shedding and viremia. Infection with OH03 resulted in 1/7 abortion and infection with Ab4 resulted in 5/7 abortions. In the OH03 challenge, placentas of foals delivered at term showed little detectable virus, while the aborted fetus expressed high levels of virus infection in the spleen and liver, lower levels in the lung and thymus, and lowest levels in the chorioallantois. After Ab4 challenge, high viral loads were detected in fetal and placental tissues in abortions. In the two normal deliveries, the chorioallantois contained virus levels comparable with the chorioallantois of aborted foals and both foals shed EHV-1 starting on day 4 of life, but were clinically healthy. Our results demonstrate the continued importance of strain selection for abortion models, and this study is the first report of viral load quantification using contemporary methods. Extremely high EHV-1 loads in decidua from abortions illustrate the infection risk posed to other horses.

Original languageEnglish
Pages (from-to)6564-6572
Number of pages9
Issue number46
StatePublished - Oct 12 2012

Bibliographical note

Funding Information:
The authors would like to thank Diane Hathaway, Xueyan Li, Sherri Dolecheck, Dr. Rob Shipley and Dr. Norman Wonderlich for their technical assistance during Experiment 2. The work was funded by Fort Dodge Animal Health .


  • Abortion
  • Equine herpesvirus-1
  • Horses

ASJC Scopus subject areas

  • Molecular Medicine
  • General Immunology and Microbiology
  • General Veterinary
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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