Experimental infection of dogs with Brucella abortus: effect of exposure dose on serologic responses and comparison of culture methods.

Two studies of experimentally induced Brucella abortus infections in dogs are reported. Twenty dogs in experiment 1 were fed approximately 4.8 X 10(10) colony forming units of B. abortus strain 2308 (BA 2308), and 11 dogs in experiment 2 were fed approximately 3.4 X 10(14) BA 2308. Serum samples from each infected dog and noninfected control were tested on the day of infection and at weekly and biweekly intervals post-infection (PI) for antibodies to B. abortus. The standard tube agglutination (STA) and rivanol (RIV) mean log-titers of the infected dogs in the 2 experiments were compared statistically on the day of infection and on PI days 7, 14, 21, 35, 42 and 49. The STA and RIV titers of the infected dogs in experiment 2 were significantly higher than were those of the dogs in experiment 1. Brucella abortus was isolated from 29 infected dogs in experiments 1 and 2 including 10 dogs, which were seronegative when cultured.