The Molecular Detection of Equine Herpesviruses 2 and 5 in Genital Swabs From Clinically Normal Thoroughbred Mares in South Korea.
Authors: Lee Sang-Kyu, Lee Inhyung
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: EHV-2 and EHV-5 Detection in Reproductive Tract Swabs Equine herpesviruses 2 and 5 are increasingly implicated in reproductive disease, yet their presence in genital tissues of asymptomatic mares remains poorly characterised. Lee and colleagues screened 430 genital swabs from clinically normal Korean Thoroughbreds using glycoprotein B-specific PCR, detecting EHV-2 DNA in 2.3% of samples and EHV-5 in 2.6%, establishing baseline prevalence data for these pathogens in the reproductive tract. Phylogenetic analysis of positive sequences revealed substantial strain diversity, with nucleotide identity ranging from 92.57–100% amongst Korean EHV-2 isolates and 98.07–100% for EHV-5, though both showed variable homology (88–100% and 96–100% respectively) to international strains. Whilst the relatively low detection rates in asymptomatic animals suggest these viruses may be carried without causing clinical signs, the genetic variation identified warrants further investigation into whether specific strains or co-infections correlate with subfertility or pregnancy loss—information practitioners will need before interpreting positive genital swabs in clinically affected mares.
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Practical Takeaways
- •EHV-2 and EHV-5 are present in genital samples of clinically normal mares at low prevalence (2.3-2.6%), suggesting subclinical shedding may occur
- •Practitioners should remain alert to the potential association between these viruses and reproductive disorders, though causation has not yet been established
- •Further research linking viral presence to clinical reproductive disease is needed before screening protocols can be recommended for routine practice
Key Findings
- •EHV-2 DNA detected in 2.3% (10/430) of genital swabs from clinically normal mares
- •EHV-5 DNA detected in 2.6% (11/430) of genital swabs from clinically normal mares
- •Korean EHV-2 strains showed nucleotide sequence identity ranging from 92.57% to 100%, indicating marked genetic diversity
- •Korean EHV-5 strains showed nucleotide sequence identity ranging from 98.07% to 100% compared to international strains at 95.96% to 100%