title: Protection of Brucella abortus RB51 revaccinated cows, introduced in a herd with active brucellosis, with presence of atypical humoral response.
abstract: It is a dogma, that RB51 vaccination does not induce antibodies that interfere with Brucellosis diagnosis, therefore any animal positive to serological test is considered as an infected animal. To determine protection against Brucellosis virulent field strain, 35 pregnant cows from a free-Brucellosis herd, previously vaccinated as calves with 1 x 10(10) CFU of RB51, were revaccinated with RB51 reduced dose, and then introduced into a herd with an active outbreak. Seventeen cows resulted positive in card test after revaccination. All 35 pregnant revaccinated cows had normal parturition; nevertheless, RB51 vaccine strain was isolated from milk and vaginal exudates from two cows after delivery at day 120 post-revaccination. At 150 days post-revaccination, two cows were positives to card and rivanol test and the field virulent strain was isolated. Revaccination with a reduced dose of RB51 in endemic zones did not cause abortion and protected 94% of animals against field infection, but caused an atypical response to conventional serological tests.
authors.affiliation: Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Av. Primero de mayo s/n, Cuautitlán Izcalli, Estado de México 54740, Mexico.
authors.forename: Marisela
authors.initials: M
authors.lastname: Leal-Hernandez
authors.forename: Efrén
authors.initials: E
authors.lastname: Díaz-Aparicio
authors.forename: Rafael
authors.initials: R
authors.lastname: Pérez
authors.forename: Laura Hernández
authors.initials: LH
authors.lastname: Andrade
authors.forename: Beatriz
authors.initials: B
authors.lastname: Arellano-Reynoso
authors.forename: Edgar
authors.initials: E
authors.lastname: Alfonseca
authors.forename: Francisco
authors.initials: F
authors.lastname: Suárez-Güemes
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D002004:Brucella Vaccine / Q000008:administration & dosage / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology; D002007:Brucellosis, Bovine / Q000517:prevention & control*; D002417:Cattle; D005260:Female; D007117:Immunization, Secondary / Q000379:methods / Q000662:veterinary; D008892:Milk / Q000382:microbiology; D011247:Pregnancy; D014621:Vagina / Q000382:microbiology
chemical_list: D000907:Antibodies, Bacterial; D002004:Brucella Vaccine