Comparison of procedures to detect Chlamydia psittaci antibodies in cockatiels (Nymphicus hollandicus).

Diagnostic serologic procedures for psittacine chlamydiosis were evaluated using experimentally inoculated cockatiels (Nymphicus hollandicus). Chlamydia psittaci was recovered from subjects on day 16 postinoculation. Seroconversion was confirmed by the direct complement fixation (DCF) test. The blocking enzyme-linked immunosorbent assay was demonstrated to be the most sensitive of three serodiagnostic procedures evaluated from inoculation until day 24 postinfection, with 92% sensitivity and 73% specificity. The DCF test was progressively more sensitive over the duration of the experiment, attaining 100% sensitivity and specificity on the day 24 postinfection. This study confirms the ability of the DCF procedure to adequately detect C. psittaci antibodies. Limitations relating to reproducibility of serologic results under clinical conditions found in this study indicate that a further refinement of tests is required to consistently detect and quantify antibodies.