Protection against brucellosis in goats, five years after vaccination with reduced-dose Brucella melitensis Rev 1 vaccine.

The protection conferred by the reduced-dose Rev 1 Brucella melitensis vaccine in goats that had been immunized 5 years previously was evaluated. Sixteen goats vaccinated 5 years before with Rev 1 (1 x 10(5) cfu) and 5 non-vaccinated goats were challenged with B. melitensis 16M (4 x 10(5) cfu) using the conjunctival route. After giving birth or aborting, the goats were sacrificed and tissue samples were taken for bacteriological study. The challenge strain was recovered in 12%, of the animals from the vaccinated group, and in (80% of the control group. It is concluded, therefore that the use of reduced-dose Rev 1 protects goats vaccinated in endemic areas for at least 5 years after immunization.