Equine Herpes Abortion (EHA) is a complication of the respiratory form of Equine Herpes Virus-1 (EHV-1) disease. To completely understand EHA you must also understand the respiratory form of this disease so this is a companion article to Rhinopneumonitis: Equine Herpes Virus (EHV-1/4) which expands on many of the aspects of EHV infection in the horse.

The Equine Herpes Virus is one of the most common causes of infectious abortions in horses and may account for 15% of all mare abortions that occur during the last six months of pregnancy. Most abortions are due to EHV-1. EHV-4 has caused abortions in some cases. This article discusses how horses contract this disease, clinical signs, diagnosis, but emphasizes prevention of EHV abortion.

With the complete characterization of the EHV genome we are learning important new facts about the virus almost monthly. Most importantly coming out of this research is the recognition that different serotypes have remarkably different virulence and the ability to test for the serotype makes prognosis for complications possible. This may lead to more effective vaccines against the most serious forms of the disease. The most common cause of abortion is the EHV-1 strains Ab4 and Army-184 while the V592 strain is only rarely associated with abortion or neurological disease.