标题：Evaluation of Vaccination with Brucella abortus RB51 Strain in Herds Naturally Infected with Brucellosis in Productive Systems Found in Tropical Climate
摘要：In this study, the efficacy of vaccination with Brucella abortus RB51 strain as a measure for bovine brucellosis control was evaluated by a clinical assay in double purpose cattle that are naturally infected under tropical conditions. A herd with eight reactors to rivanol test with an initial serum reaction of 5% was selected. Confirmation of infected herd was carried out by isolation and identification of Brucella abortus from reactor animals, using bacteriological procedures. Also, the milk samples were analyzed by PCR technique whereby Brucella abortus infection was corroborated. Vaccinated and non-vaccinated groups were formed with 88 females each. Reactors were not eliminated nor segregated from the population. During 18 months of monitoring three new cases happened in the vaccinated group and therefore the initial serum reaction rate increased from 10 to 12.5%. The rate of vaccinated group remained at 0% due to 100% of protective efficacy that RB51 strain provided to the total vaccinated population (RR = 0; C.I. 95% 0-0). The conclusion is that under extensive double purpose livestock rearing conditions tropical climate, strain RB51 is a biological product efficacious for brucellosis control in infected herds with a prevalence of 6%.
