Post-exposure serological and bacteriological responses of water buffalo (Bubalus bubalis) to Brucella abortus biovar 1 following vaccination with Brucella abortus strain RB51.

摘要

The serological and bacteriological responses to Brucella abortus biovar 1 after vaccination with B. abortus strain RB51 (RB51) were examined in 30 domestic water buffalo (Bubalus bubalis) that were randomly divided into five treatment groups. Group I, II, III, IV and V were treated with the recommended dose (RD) of RB51 vaccine once, RD twice at four weeks interval, double RD once, double RD twice at four weeks interval and saline once (control), respectively. Results revealed that vaccination did not produce any serological response. Experimental animals released after 27 weeks post initial inoculation (27 PIIW) into a brucellosis-positive herd failed to seroconvert after 29 weeks. Experimental challenge commenced at 57 PIIW. All animals received B. abortus biovar 1 intraconjunctivally at 0, 5 and 9 weeks post experimental exposure (PEEW). Serum samples collected at 4, 8 and 13 PEEW were negative. At 16 PEEW all animals received B. abortus biovar 1 subcutaneously (SC), and all seroconverted by 20 PEEW. Five of 26 animals were positive for Brucella infection on bacterial culture. Brucella abortus biovar 1 was isolated from three animals, while B. abortus RB51 was isolated from two. Treatment group, age and sex had no effect on the isolation of Brucella (P>0.05).