Clinical conditions associated with positive complement fixation serology for Chlamydiae.

The hospital records of 242 patients with diagnostic chlamydial complement fixation (CF) titres (seroconversion and/or titre greater than or equal to 64) found among 60,000 patients screened for suspected viral illnesses were reviewed to study the clinical conditions associated with positive CF serology for Chlamydiae. After excluding typical genital C. trachomatis infections, the majority of the remainder were considered to represent C. psittaci infections. Respiratory symptoms were the most common clinical manifestations of chlamydial infections detectable by CF, but the majority (58%) of the patients did not have pneumonia. Abdominal, neurological as well as urinary tract symptoms were common. Cutaneous, joint, cardiac, genital and ocular manifestations were also noted. Fever (greater than or equal to 38.5 degrees C) was present in 62% of the patients. The ESR was raised (greater than or equal to 20 mm/h) in the majority of the patients (83%), but the leucocyte count was usually (86%) within normal limits. Because the clinical spectrum of C. psittaci infections is apparently broad, serological tests for detecting antibodies to C. psittaci (e.g. CF) should be used widely in various clinical conditions and not for patients with pneumonia alone.