title: Further studies on the efficacy of an inactivated African horse sickness serotype 4 vaccine.
abstract: The immunity induced by two inoculations of a commercial inactivated African horse sickness (AHS) serotype 4 (AHSV-4) vaccine was studied. No adverse reaction was observed in five horses following vaccination. Following challenge-inoculation, no clinical signs attributable to AHS, no viraemia indicating infection, and no anamnestic response was observed in the vaccinated ponies. Two control ponies developed clinical signs typical of AHS, high levels of viraemia, and died 7 and 8 days postchallenge-inoculation. The quality of immunity induced by the two-dose regimen was compared with a one-dose regimen from a previous study; in the one-dose study following challenge-inoculation, six of nine ponies were protected from clinical signs of AHS, seven of the nine vaccinated ponies developed an anamnestic response, and one pony had a viraemia about 10(3) 50% mouse lethal dose of AHSV-4 per ml of blood for 3 days following challenge-inoculation. The utility of an efficacious inactivated AHS vaccine in the control and eradication of AHS from a non-endemic area is discussed. The lack of viraemia following vaccination with an inactivated vaccine and the prevention of vector infection by animals exposed to field virus are important in the eradication of AHS.
authors.affiliation: USDA, Foreign Animal Disease Diagnostic Laboratory, Plum Island, NY 11944.
authors.forename: J A
authors.initials: JA
authors.lastname: House
authors.forename: M
authors.initials: M
authors.lastname: Lombard
authors.forename: P
authors.initials: P
authors.lastname: Dubourget
authors.forename: C
authors.initials: C
authors.lastname: House
authors.forename: C A
authors.initials: CA
authors.lastname: Mebus
mesh_terms: D000355:African Horse Sickness / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D000356:African Horse Sickness Virus / Q000145:classification / Q000276:immunology* / Q000302:isolation & purification; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D006736:Horses; D008297:Male; D009500:Neutralization Tests; D012703:Serotyping; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D014766:Viremia / Q000209:etiology / Q000517:prevention & control
chemical_list: D000914:Antibodies, Viral; D015164:Vaccines, Inactivated; D014765:Viral Vaccines