The protective properties of vaccination against equine herpesvirus 1-induced viremia, abortion and nervous system disorders

Equine herpesvirus (EHV) 1 is an important pathogen of horses. Upon infection, the virus replicates in the upper respiratory tract. Then it spreads to internal organs via a cell-associated viremia. Local replication in internal organs may result in abortion and nervous system disorders. The currently designed vaccines are not able to induce significant protection against EHV1-induced viremia. However, several vaccines are able to induce a significant level of protection against either abortion or nervous system disorders. Which immune responses correlate with this protection is so far unknown. Besides vaccination, management will remain a crucial factor in the prevention of EHV1-induced clinical signs. Management measures include the vaccination of all horses on the premises to reduce infection pressure; the separate housing of young horses, adult horses and pregnant mares; strict hygiene measures and strict control of contact with horses from outside the premises. If, despite vaccination and thorough management, an outbreak of EHV1-induced disease occurs, treatment with antiviral agents may be useful.