Efficacy of a live equine herpesvirus-1 (EHV-1) strain C147 vaccine in foals with maternally-derived antibody: protection against EHV-1 infection.
BACKGROUND
Currently, there is no recommended immunoprophylaxis against febrile respiratory diseases due to equine herpesvirus-1 (EHV-1) and -4 (EHV-4) in horses below age 5-6 months. This is because of interference by maternally-derived antibody (MDA) of vaccines.


OBJECTIVE
Unweaned equine foals are an important reservoir of EHV-1 transmission; therefore, we experimentally assessed the efficacy of a live EHV-1 vaccine in foals age 1.4-3.5 months with MDA.


METHODS
Following vaccination and challenge, parameters assessed were virus shedding in nasal mucus, leucocyte-associated viraemia, circulating virus neutralising antibody activity and clinical reactions.


RESULTS
Controlled challenge showed that a single intranasal dose of the vaccine afforded partial but significant protection against febrile respiratory disease, virus shedding and viraemia due to EHV-1 infection, despite virus-neutralising MDA.


CONCLUSIONS
The prospective vaccine would be a significant step forward in reducing the incidence of the disease caused by EHV-1 infection.
Patel
J R
JR
Intervet UK Ltd., The Elms, Thicket Road, Houghton, Huntingdon, Cambridgeshire PE28 2BQ, UK.
Didlick
S
S
Bateman
H
H
D000281:Administration, Intranasal; D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D000914:Antibodies, Viral / Q000097:blood*; D005260:Female; D006566:Herpesviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D004861:Herpesvirus 1, Equid / Q000276:immunology*; D023141:Herpesvirus 4, Equid / Q000276:immunology*; D022283:Herpesvirus Vaccines; D006734:Horse Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D006736:Horses; D007112:Immunity, Maternally-Acquired; D008297:Male; D009093:Mucus / Q000821:virology; D009297:Nasal Mucosa / Q000821:virology; D009500:Neutralization Tests / Q000662:veterinary; D016896:Treatment Outcome; D014766:Viremia / Q000662:veterinary; D017201:Virus Shedding
D000914:Antibodies, Viral; D022283:Herpesvirus Vaccines