Properties and Frequency of Isolation of Chlamydiae from Eyes of Lambs with Conjunctivitis and Polyarthritis

Abstract

SUMMARY Eye infections were studied among lambs of 6 different flocks affected with follicular conjunctivitis. Ten to 25% of the lambs in 5 of the flocks also had polyarthritic signs and in the 6th flock more than 85% of the lambs had polyarthritis. Ocular samples for microbial culture were collected by expressing conjunctival follicles. Chlamydiae were isolated in developing chicken embryos from conjunctival samples of 27 of 64 lambs examined (42.2%). Identification of the isolates as chlamydiae was based on biological and antigenic properties, growth characteristics in chicken embryos, and ultrastructural morphologic features. Nine of the isolates were resistant to 1 mg. of sulfadiazine per chicken embryo, which is a property of strains of the species Chlamydia psittaci . Complement-fixing antibody titers of 1:16 or greater against chlamydial group antigen were detected in serum samples of 28 of 64 lambs examined (43.8%).