Abstract: Brucellosis is a zoonosis which is caused by Brucella species and pruduces severe economic losses and a public health problem. At present, the diagonsis of Brucella infection mainly depends on serological tests to detect antibodies in sera and the animal brucellosis is prevented via vaccine. In this study, the kinetics and cross-reactivity of antibodies in sera were evaluated in Small Tail Han sheep (Ovis arie) infected with a virulent field strain of Brucella melitensis (BmF) and ones inoculated with a vaccine strain S2 of B. suis under laboratory conditions. Serum samples were collected at 0, 3, 7, 14, 21, 30, 40, 44, 50, 60 and 75 days post-challenge (dpc) and were analyzed by Rose Bengal Plate Agglutination Test (RBPT) and indirect Enzyme-Linked Immunosorbent Assay (iELISA). Sera samples of BmF-challenged and S2-challenged sheep groups at 40, 44, 50, 60 and 75 dpc were tested positive to Brucella by the RBPT, nevertheless the earliest positive reaction results were observed in sera at 21 dpc by iELISA. The virulent field strain BmF initiated a higher level of antibody titer than vaccine strain S2 without statistic significant difference (p>0.05). The cross-reactivities with the virulent and the vaccine stains were confirmed in serum antibodies between the BmF-challenged group and the S2-challenged group. The results indicated that the serodiagnosis is hard to distinguish the brucella-infected sheep from the vaccine-inoculated sheep. Diagnosis methods of identifying between the healthy and the infected animals need to further be studied in future.
Feng Tang, Hong-Lin Ren, Yun-Ming Xu, De-Ying Zou, Nan-Nan Liu, Yan-Song Li, Yu Zhou, Jie Song, Zhao-Hui Li, Yuan-Yuan Zhang, Shi-Ying Lu and Zeng-Shan Liu, 2012. Kinetics and Cross-Reactivity of the Antibody in Sheep Inoculated with Virulent and Avirulent Brucella. Journal of Animal and Veterinary Advances, 11: 1564-1569.