Studies on the use of Yersinia enterocolitica 09 antigens in rapid quantitative plate tests for the differentiation of Brucella and Yersinia infections in cattle and the diagnosis of bovine brucellosis

The use of the rapid quantitative plate agglutination test (QPAT) utilizing triphenyltetrazolium chloride (TTC) stained antigen for the differentiation of bovine brucellosis and yersiniosis is described. It was found with experimental laboratory animals and cattle, that titres against homologous antigen tended to exceed titres against heterologous antigen and that this reaction together with measurement of the Yersinia OH agglutinin titre could be used for purposes of differentiation. It was, however, not possible to differentiate these infections in serum from cattle with naturally-occurring antibodies. It was also shown that Brucella 0 agglutination in the QPAT was very weak in some sera with high titred anti-Brucella antibodies by serum agglutination, while Yersinia 0 agglutination was not. The QPAT, using Yersinia 0 antigen, therefore correlated well with the results obtained using Brucella 0 antigen in serum agglutination tests. It is suggested that Yersinia 0 antigen may be a suitable antigen for use in rapid agglutination tests because of this relative insusceptibility to false negative results.