Abstract
In the previous investigation, the authors established an agglutination procedure, which they called the "bouillon method", for the diagnosis of atrophic rhinitis (AR) in naturally infected swine. The present experiment was carried out to study the significance of the agglutination (AG) reaction and a possibility of applying it to 400 field specimens, in comparison with bacteriological and pathological findings. The results obtained are as follows. 1. Positive responses were observed in 218 samples (54.5%) out of 400 in the AG test at a titer of 1:20 or higher. It was suggested that Bordetella infections might have occurred in a piggery or a farm as a unit, spreading from the sow to her young or from one pig to another. 2. Bordetella bronchiseptica was isolated at a high rate during the first stage of infection (1 to 3 months after birth). The isolation rate decreased gradually after the second stage (4 to 5 months) with the advance in age. AG antibody became detectable at 12 or 20 weeks of age. It seemed that at the same time the isolation rate of the causative organism from the nasal cavity might begin to decrease. 3. Comparison of three diagnostic methods, i.e., serological (agglutination test), pathological (gross lesion examination), and bacteriological (B. bronchiseptica isolation) tests, revealed that the results were not always coincidental among the three tests, Lesions were found in 85 (91.4%) out of 93 serologically positive pigs. Of 110 pathologically positive cases, 85 (77.3%) showed a positive reaction in the AG test. From these results, it was concluded that the serological test was available for the diagnosis of B. bronchiseptica infection among pigs in the field.
