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Equine Arteritis Virus Resistance

Equine arteritis virus resistance (EAVR)


Gene or region:  ECA11: 49.57 Mb – 49.64 Mb

Reference alleles: AACACATC

Mutant alleles: GGGGAGGT

Affected Breeds: Thoroughbred, Saddlebred, Standardbred, Quarter Horse


Research Confidence:                          Experimental, association was present in multiple breeds with strong candidate genes in the region



What it does:  


Equine viral arteritis is an infectious disease with a broad range of symptoms, though most horses will not display any overt signs. However, infection with EAV can result in abortions in pregnant mares, and some stallions persistently shed the virus through their semen. Infection prevalence has been reported to vary among breeds, indicating a genetic component to resistance/susceptibility.


The measured SNPs were reported to be associated with susceptibility of CD3+ lymphocytes to EAV infection. When all four studied breeds were grouped together, the “GGGGAGGT” group of alleles was present in 73% of susceptible horses and 16% of resistant horses. Thus, a horse that genotypes homozygous for all 8 of these SNPs are classified as at a higher risk for susceptibility to infection. As this region contains 5 genes, further research is warranted to refine the association.




Go YY et al., “Genome-wide association study among four horse breeds identifies a common haplotype associated with in vitro CD3+ T cell susceptibility/resistance to equine arteritis virus infection.” (2011) J Virol. 85: 13174-84.  PMID: 21994447


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