Chlamydophlla spp. Infection

Chlamydophila species include C. psittaci and C. pneumo­niae, both of which can infect domestic rabbits. The prevalence of natural infection and infecting species among domestic rabbits is unknown, since infection is usually subclinical.

Cilia-Associated Respiratory (CAR) Bacillus Infection

Colonization of the apices of ciliated epithelial cells lining the larynx, trachea, and bronchi with CAR bacil­lus has been observed in laboratory rabbits (Fig 6.27). The bacilli have been demonstrated both in silver- stained preparations and by electron microscopy, in which bacteria were aligned perpendicularly within the surface of ciliated bronchial epithelium. The animals were without clinical signs. 16S rRNA analysis indicated that the rabbit isolate belongs to a different genus than

FIG. 6.27. Lung of a rabbit naturally infected with cilia-associated respiratory (CAR) bacillus. This organism colonizes the epithelium of the larynx, trachea, and bronchi in the rabbit. Note the prominent peribronchiolar lymphocytic infiltration (Warthin-Starry stain). (Source: D. Imai, University of California, Davis, CA. Reproduced with permission from D. Imai. )

the rat CAR bacillus. Furthermore, rabbits developed rhinitis following inoculation with a rabbit isolate, but not with a rat isolate. Mild to moderate peribronchial lymphoid hyperplasia and hyperplasia of epithelial cells lining airways were described. One study examined 3-month-old rabbits raised for meat production, and found that 30-100% of rabbits from different rabbitries were infected, based upon Warthin-Starry-stained tis­sues. No gross lesions were found, but a significant number of rabbits had mild inflammatory lesions in the respiratory tract, particularly bronchi, in association with CAR bacillus.

Corynebacterium bovis Infection

Testicular and pulmonary abscesses were observed in a laboratory rabbit, and C. bovis was isolated from both sites. Experimental infection of another rabbit repro­duced a similar disease.