Comparison of dot enzyme-linked immunosorbent assay (dot-ELISA) with other serological tests for the detection of Brucella antibodies in bovine sera.

A dot Enzyme-linked Immunosorbent Assay (dot-ELISA), using whole cell Brucella abortus antigen dotted on the nitrocellulose membrane bound to a plastic strip (dipstick) was employed for the detection of Brucella antibodies in bovine sera. The results were compared with that of serum agglutination (SAT), Rose Bengal plate agglutination (RBPT) and Complement Fixation test (CFT). All the four tests gave negative reaction in 127 sera obtained from a brucellosis free herd. Testing of 549 sera from a chronically infected herd revealed 57 positive and 447 negative animals in all the four assays. Of the remaining 45 sera, 34 were positive in dot-ELISA. Six of these cases were independently detected by dot-ELISA while 28 showed positive reactions in combination with other tests. When serum samples from 158 aborted cases were subjected to dot-ELISA, 79 were found positive. Of these dot-ELISA positive cases, 71 gave positive reaction in SAT, 72 in RBPT and 78 in CFT. B. abortus biotype 3 was isolated from 34 of the 98 aborted fetuses examined.