UTILITY OF COMPLEMENT-FIXATION AND MICROIMMUNOFLUORESCENCE ASSAYS FORDETECTING SEROLOGIC RESPONSES IN PATIENTS WITH CLINICALLY DIAGNOSED PSITTACOSIS

The serodiagnosis of human psittacosis was considerably improved by a microimmunofluorescence (MTF) assay that uses selected strains of Chla mydia psittaci, C. pneumoniae, and C. trachomatis as antigens. The 78 patients examined in the study were clinically diagnosed as having psi ttacosis on the basis of compatible clinical symptoms following exposu re to sick birds. The conventional complement fixation (CF) test ident ified 36 patients, or 46% (36 of 78) of the total, as positive. Antibo dy responses to C. psittaci were demonstrated by the MIF test in all 3 6 CF-positive patients. The MIF test also detected antibody responses to C. psittaci in 12 patients (15% of the total) whose sera were negat ive or anticomplementary in the CF test. Seven patients, or 9% (7 of 7 8) of the total, were identified by the MIF test as having C. pneumoni ae infections. About 30% of the study patients (23 of 78) showed no se rologic evidence of either C. psittaci or C. pneumoniae infection by b oth the CF and the MIF tests. Four distinctive serologic reaction patt erns were observed in the study patients. Recognition of these reactio n patterns and judicious corroboration of serologic responses to the c hlamydial species by the MIF test with epidemiologic and clinical info rmation will increase the efficiency and accuracy of serodiagnosis for human psittacosis.