Genome-wide association study for host genetic factors associated with equine herpesvirus type-1 induced myeloencephalopathy.
Authors: Dunuwille Wangisa M B, YousefiMashouf Navid, Balasuriya Udeni B R, Pusterla Nicola, Bailey Ernest
Journal: Equine veterinary journal
Summary
# Equine Herpesvirus-1 Myeloencephalopathy: Genetic Susceptibility Factors Equine herpesvirus type-1 (EHV-1) causes neurological disease in only a proportion of infected horses, suggesting underlying genetic variation influences disease outcome; this genome-wide association study aimed to identify host genetic markers predisposing horses to myeloencephalopathy (EHM) rather than subclinical or respiratory infection. Using DNA genotyping across the entire equine genome, researchers compared horses that developed EHM with matched controls following EHV-1 exposure, with particular focus on chromosome 6 where previous work had indicated potential disease associations. The study identified significant genetic markers on equine chromosome 6 (ECA6) associated with EHM susceptibility, suggesting that specific genetic variants influence an individual horse's risk of developing neurological rather than other manifestations of EHV-1 infection. These findings have practical implications for breeding programmes and prognostic assessment: identifying at-risk genotypes could inform selection decisions and potentially help predict which horses in an outbreak may develop the more severe neurological form of disease. Further validation of these markers across diverse horse populations and breeds will be necessary before implementation in clinical or breeding contexts, but this work provides a biological foundation for understanding why EHM appears sporadically within herds despite widespread EHV-1 exposure.
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Practical Takeaways
- •Genetic testing may eventually help identify horses at higher risk of developing EHM following EHV-1 infection, informing management and biosecurity decisions
- •Understanding host genetic factors could support selective breeding to reduce EHM susceptibility in horse populations
- •Not all EHV-1 infected horses develop myeloencephalopathy; genetic screening may help predict which individuals require more intensive monitoring
Key Findings
- •Genome-wide association study identified genetic markers on equine chromosome 6 (ECA6) associated with EHM occurrence
- •Sporadic presentation of EHM in horse herds suggests a host genetic component to disease susceptibility
- •Genetic variation influences whether EHV-1 infected horses develop neurological clinical signs