Pathogenesis of feline gastric chlamydial infection.

Studies were conducted to determine whether the gastric chlamydiae that have been observed recently in cats are of pathologic significance. Chlamydiae were isolated in mouse L cell cultures from the homogenized pooled gastric mucosa of 3 cats that had been identified, by histopathologic examination, to have gastric chlamydiosis. Ten specific-pathogen-free kittens were exposed by aerosol and oral inoculation to the harvested feline gastric chlamydiae cell-culture media. In general, the clinical signs and lesions were conjunctivitis, rhinitis, and mild gastritis. The clinical signs and lesions were most severe in 2 chlamydia-infected kittens that had received methylprednisolone acetate (50 mg/kg of body weight). Chlamydiae were demonstrated in epithelial cells of conjunctival and nasal smears in 10 of 10 infected kittens from postexposure days 7 through 35. In addition, chlamydiae were isolated in L cell cultures from a variety of antemortem and postmortem specimens from infected kittens. The present study provided evidence that feline gastric chlamydiae, under appropriate conditions, were capable of inducing, in cats, clinical signs and lesions similar to those induced by the feline pneumonitis agent.