Equine herpesvirus

From Dog
Electron microscopy of EHV-1

Equine herpesvirus is a mosquito-borne varicellovirus (rhadinovirus; F: Herpesviridae) which can cause disease in dogs, and is closely related to canine herpesvirus.

Horses are considered the natural vector of this virus and experience little or no clinical signs when infected[1].

Although few reports of natural infections exist, experimentally-infected dogs show clinical symptoms including weight loss, pyrexia, anorexia, pneumonia and neurologic signs characteristic of encephalitis.

Histopathologically, postmortem findings were primarily with lymphoid necrosis and a fulminant nonsuppurative encephalitis with severe neuronal degeneration and loss, with intranuclear inclusions, slight glial reactions, perivascular cuffing, and multifocal hemorrhage. The olfactory bulb and the frontal and temporal lobes are predominantly affected[2].

Diagnosis is based on immunohistochemistry or PCR identification of viral antigens.

Treatment is usually non-specific and supportive.


  1. Taniguchi A et al (2000) Pathogenicity of a new neurotropic equine herpesvirus 9 (gazelle herpesvirus 1) in horses. J Vet Med Sci 62:215–218
  2. Yanai T et al (2003) Experimental infection of equine herpesvirus 9 in dogs. Vet Pathol 40(3):263-267