Could ERAV be affecting your respiratory health management program?

What is Equine Rhinitis A Virus (ERAV)?

ERAV was originally classified as a part of the Rhinovirus genus and was previously known as equine rhinovirus 1. The first recognized serotype was reclassified in the genus Aphthovirus and is now called Equine Rhinitis A Virus.

ERAV may cause mild to severe respiratory tract disease in horses, affecting both the upper and lower airways. It may be a contributing or exacerbating factor of inflammatory airway disease (IAD) and recurrent airway obstruction (RAO or heaves).1, 2

ERAV clinical signs may include:

  • Fever
  • Serous nasal discharge
  • Coughing
  • Abnormal lung sounds
  • Anorexia
  • Pharyngitis
  • Lymphadenitis
  • Increased tracheal mucus production, and
  • Occasionally leg edema
No abortion, neurological disease, or latent infections have been reported. Viremia consistently developed at 3–7 days following infection and lasted for 4–5 days with disappearance of virus from the blood coinciding with the onset of antibody production.3

ERAV should NOT be confused with rhinopneumonitis (equine herpesvirus 1 and 4), which is often referred to as "rhino." ERAV is also different from equine influenza virus. In the horse, clinical signs of ERAV may be indistinguishable from EHV (1 and 4) and equine influenza.

How is ERAV diagnosed?

ERAV has been isolated from nasal swabs, blood, feces and urine samples. ERAV can be detected from horses with acute, respiratory disease using virus isolation, PCR or serum virus neutralization assay testing (paired serological tests).

At the present time, it would be best to specifically request diagnostic testing for ERAV when sending respiratory samples to diagnostic laboratories.


1 Hodgson JL, Hodgson D R: Inflammatory Airway Disease. In Equine Respiratory Diseases. ed Lekeux P (IVIS) August 2002.
2 Loving NS: Equine Rhinitis in Respiratory Infection Cases. The Horse, Article # 19482, January 2012.
3 Plummer G, Kerry JB: Studies on an equine respiratory virus, Vet Rec 74: 967 – 970, 1962.

For more information:

  • Boehringer Ingelheim Vetmedica, Inc.

    Equine Division

    3902 Gene Field Road
    St. Joseph, Missouri 64506

    • Phone 866-638-2226
    • Fax 816-326-9167