An agglutination test with the use of
formalin-killed
antigen of the cell carrying the
capsule was developed and used for the detection of antibody in swine naturally infected with Bordetella bronchiseptica. Under optimum
antigen concentration and reaction temperature 210 or 60% of 342 serum samples tested from 42 conventional swine herds were positive for
Bordetella infection. In contrast, only 34 or 10% of 342 nasal swabs from the same animals were positive for Bordetella by culture technique. The test was relatively free of cross-reactivity to related organism. However, 2.7 and 13.0% of sera from growing pigs and mature hogs, respectively, reacted with
antigen of Pasteurella multocida. Because of this, only
agglutinin reactions in 1:20 dilutions or higher to Bordetella were considered positive. The bulk of the antibody activity of selected sera tested from various age ranges of swine was
mercaptoethanol sensitive, suggesting that serum antibody in
Bordetella infection may be associated with
immunoglobulin IgM. Because of the high agglutinability and stability of
formalin-killed
antigen the test may be useful as an auxiliary aid for the diagnosis of
Bordetella infection where the organism cannot be identified by culture means.