Bordetella agglutinating antibody in swine. A herd survey

An agglutination test with killed Bordetella bronchiseptica, suspended in 0.85% saline, standardized photometrically to contain approximately 20 billion microorganisms per ml as antigen, was used to detect naturally-occurring antibody against this bacterium in the sera of 451 pigs ranging in age from one month to over 36 months. Agglutinating antibody was demonstrated in 32.8% of 201 sera of pigs one to six months old, 61.5% of 52 pigs six to 12 months old, 83.8% of 62 pigs 13 to 18 months old, 92.3% of 39 pigs 19 to 24 months old and 100% of 97 adults older than 24 months. Nasal swab cultures did not reliably detect the carrier state of subclinically infected pigs, however, detection of agglutinating antibody against B. bronchiseptica may be useful for diagnosing infection in swine herds.