Brucella melitensis Rev. 1 and Brucella abortus 45/20 Vaccines in Goats: Immunity

SUMMARY The living attenuated Brucella melitensis Rev. 1 vaccine in reduced dose and the nonliving Brucella abortus 45/20 adjuvant vaccine were examined for suitability in protecting possibly pregnant, adult goats against B. melitensis infection. The immunizing ability of the 2 vaccines was compared with that of the normal dose of Rev. 1 vaccine given to young goats. Thirteen and one-half months after vaccination, the vaccinated and nonvaccinated goats were given graded doses of virulent B. melitensis via the conjunctival route, and their tissues were examined for brucellar organisms 4 to 8 weeks later. The normal and reduced doses of Rev. 1 provided similar effective protection in terms of recovery of organisms from selected tissues, whereas the 45/20 adjuvant vaccine was clearly less efficacious.