Evaluation of an immunofluorescence test on direct smears of conjunctival and urogenital swabs taken from koalas for the detection of Chlamydia psittaci

The Chlamydia-Cel Vet IF Test (CCVIT), a commercially available immunofluorescence test for use on direct smears of clinical specimens, was evaluated in a colony of 43 captive koalas. The test is based on a monoclonal antibody directed against the chlamydial common group specific lipopolysaccharide antigen. Swabs were taken from conjuncitva and penis or urogenital sinus and used for direct smear evaluation and cell culture isolation. Compared with isolation of the organism in cell culture, the CCVIT on direct smears of conjunctival swabs presented a sensitivity of 88%, a specificity of 100%, a positive predictive value (PV+) of 100% and a negative predictive value (PV-) of 97%. The CCVIT on direct smears of urogenital swabs presented a sensitivity of 90%, a specificity of 84%, a PV+ of 86% and a PV- of 89%. The overall sensitivity was 89% (95% confidence interval [CI] of 71% to 97%), the specificity 94% (95% CI of 84% to 98%), the PV+ 89% and the PV- 94%. It was concluded that the CCVIT on direct smears was suitable as a diagnostic screening test for the detection of Chlamydia psittaci in koalas.