title: Comparison of the humoral response between sheep vaccinated with a killed-virus vaccine and those vaccinated with a modified-live virus vaccine against bluetongue virus serotype 17.
abstract: OBJECTIVE To compare the humoral response between sheep vaccinated with a killed-virus (KV) vaccine and those vaccinated with a modified-live virus (MLV) vaccine against bluetongue virus (BTV) serotype 17. DESIGN Randomized clinical trial followed by a field trial. ANIMALS 30 yearling crossbred ewes (phase 1) and 344 sheep from 7 Wyoming farms (phase 2). PROCEDURES In phase 1, ewes seronegative for anti-BTV antibodies received sterile diluent (control group; n = 10) or an MLV (10) or KV (10) vaccine against BTV-17 on day 0. Ewes in the KV group received a second dose of the vaccine on day 21. Ewes were bred 5 months after vaccination and allowed to lamb. Anti-BTV antibodies were measured in ewes at predetermined times after vaccination and in their lambs once at 5 to 10 days after birth. In phase 2, 248 commercial sheep were screened for anti-BTV antibodies and vaccinated with a KV vaccine against BTV-17 on day 0. Sheep seronegative for anti-BTV antibodies on day 0 (n = 90) underwent follow-up serologic testing on day 365 along with 96 unvaccinated cohorts (controls). RESULTS In phase 1, all vaccinated ewes developed anti-BTV antibodies by 14 days after vaccination and remained seropositive for 1 year; all of their lambs were also seropositive. All control ewes and lambs were seronegative. In phase 2, the prevalence of vaccinated sheep with anti-BTV antibodies 1 year after vaccination was 93% and 76% as determined by a serum neutralization assay and competitive ELISA, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Both vaccines induced antibodies against BTV-17 that persisted for at least 1 year and provided passive immunity for lambs and may be a viable option to protect sheep against disease.
authors.forename: Kelsie L
authors.initials: KL
authors.lastname: Speiser
authors.forename: Brant A
authors.initials: BA
authors.lastname: Schumaker
authors.forename: Walter E
authors.initials: WE
authors.lastname: Cook
authors.forename: Todd E
authors.initials: TE
authors.lastname: Cornish
authors.forename: Kristi M
authors.initials: KM
authors.lastname: Cammack
authors.forename: Myrna M
authors.initials: MM
authors.lastname: Miller
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood; D001819:Bluetongue / Q000276:immunology / Q000517:prevention & control*; D001820:Bluetongue virus / Q000276:immunology*; D005260:Female; D007112:Immunity, Maternally-Acquired; D007700:Kinetics; D008297:Male; D011446:Prospective Studies; D012756:Sheep / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000276:immunology* / Q000592:standards; D015164:Vaccines, Inactivated / Q000276:immunology* / Q000592:standards; D014765:Viral Vaccines / Q000145:classification / Q000276:immunology* / Q000592:standards
chemical_list: D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated; D014765:Viral Vaccines