Serologic response of pigs to experimental infection with Yersinia enterocolitica serotype O9 and Brucella abortus.

Groups of young pigs were inoculated with either Brucella abortus or Yersinia enterocolitica O:9 and their serum was analyzed to identify techniques by which infections with these organisms could be distinguished. Yersinia enterocolitica was capable consistently of inducing a significant anti-Brucella agglutinin response. By means of microplate agglutination, it was shown that homologous titers usually exceeded or were equal to heterologous titers. This technique was also capable of detecting Yersinia flagellar agglutinins. When a group of serum samples from healthy pigs was surveyed, it was found that none of the techniques tested were capable of unequivocally distinguishing between the 2 infections.