Equine Viral Arteritis

What is Equine Viral Arteritis? 

Equine viral arteritis (EVA) is a contagious viral disease of equids. Serological evidence of indicates exposure to the virus in equine populations in many countries. The disease is frequently confused with other illnesses that produce similar clinical signs.

Clinical Signs: Depending on the viral strain and size of the inoculum, infection can vary from inapparent to fulminant clinical disease in young foals. The majority of acute EAV infections are subclinical or inapparent. Presentation is variable (similar to any infectious agent that causes vasculitis) but most commonly includes:

  • Fever (up to 106° F or 41.1° C)
  • depression, anorexia 
  • Edema: limbs, ventrum, peri or supraorbital region, scrotum/prepuce (male), mammary glands (female) 
  • Conjunctivitis 
  • Epiphora 
  • Rhinitis 
  • Urticaria 
  • Leukopenia 
  • Abortion- can be associated with ‘abortion storms’ 
  • Temporary subfertility in stallions 
  • Fatal pneumonitis or pneumo-enteric syndrome in neonatal/young foals

Diagnosis: Diagnosis is based clinical signs and laboratory testing by virus isolation and PCR on serum.  is problematic due to the wide array of clinical signs, the similarity of presentation to those of certain other diseases, and the frequency of inapparent infection/horses mildly affected with disease.

Treatment: No specific antiviral treatment for EVA is currently available. Most 

Prevention: Control measures include restricting viral spread in breeding operations and identifying carrier stallions.


September 19, 2023
Queen, PE
Ongoing Investigation