DIAGNOSTIC SEROLOGIC TESTING OF CAGE AND AVIARY BIRDS FOR CHLAMYDIOSIS AND SUGGESTED CONFIRMATORY TESTING

A 2 x 2 contingency table was constructed to demonstrate the relations hips between detectable chlamydial antibody activity and clinical heal th status of tested birds. The table revealed that 65.5% of clinically ill birds were antibody positive by elementary body agglutination (EB A) (greater than or equal to 10 titers) and 59.0% were antibody positi ve by latex agglutination (LA). Thus, EBA was slightly more sensitive than LA in detecting antibody activity. Of the clinically normal birds , 96.7% were antibody negative (<10 titers) by EBA and 98.3% were anti body negative by LA, Individual serum or plasma samples from a group o f mixed types of psittacine birds and cockatiels were tested as a sepa rate group, and relationships between EBA-detectable antibody activity and health status were obtained from a 2 x 2 contingency table. Sixty -six percent of birds clinically ill with signs of chlamydiosis in the mixed-type group were antibody positive, whereas only 32.3% of clinic ally ill cockatiels were antibody positive. Statistical analysis of th e contingency table using a chi-square test demonstrated that the EBA test differentiates between individual birds on the basis of health st atus (P < 0.001). When testing paired serum or plasma samples by EBA, LA, and direct complement fixation (DCF), the highest percentage of si gnificant (greater than or equal to 4-fold change) titer decreases was detected by LA, and the highest percentage of significant titer incre ases was detected by DCF. Examples of EBA, LA, and DCF titers in paire d and multiple serum or plasma samples are presented to show the varie ty of responses that can occur. Results reflected variations seen in i ndividual testing of birds with titer variability seen in the first sa mple tested. Additional types of testing believed necessary for confir ming or ruling out an infectious process in birds are outlined. The cu rrent interpretations of serologic results are given.