Isolation of a chlamydial agent from Rocky Mountain bighorn sheep.

A total of 53 clinical specimens from both healthy and diseased Rocky Mountain bighorn sheep (Ovis canadensis) were examined for Chlamydia. An agent consistently lethal for chicken embryos was recovered from a nasal swab taken from a normal ewe. This agent, designated BHS-15, possesses antigens which fix complement in the presence of anti-chlamydial serum, is susceptible to chlortetracycline, and is resistant to sodium sulfadiazine and streptomycin. Attempts to culture the isolate in quality control media, including blood agar, thioglycolate broth, and PPLO broth and agar were unsuccessful. A recommendation is made for classification of agent BHS-15 as a member of the species Chlamydia psittaci. The possible relationship of the isolate to the pneumonia complex in bighorn sheep is discussed.