A study of chronic pneumonia in a guineapig colony with enzootic Bordetella bronchiseptica infection.

Three types of lesion were present in the lungs of guineapigs with chronic pneumonia - pulmonary interstitial fibrosis, perivascular lymphoid hyperplasia and foreign body granulomas. Bordetella bronchiseptica was present in the nasopharynx, trachea and lungs of a high proportion of animals from 4 weeks old, and antibodies to this organism were also found. Animals removed at 4 days old and reared in isolation from the main colony and free from B. bronchiseptica developed similar lung lesions, so that B. bronchiseptica appeared to have no causative role in these forms of chronic pneumonia.