A comparative study of detecting Chlamydophila psittaci in pet birds using isolation in embryonated egg and polymerase chain reaction

Abstract

This study, for the first time in Turkey, investigated the existence of Chlamydophila psittaci and determined the prevalence of its disease, chlamydiosis, in pet birds. Polymerase chain reaction (PCR) was compared with other testing methods that have been typically used in the diagnosis of C psittaci. Fecal specimens (n = 96) of avian origin were tested by PCR and two identification methods, modified Gimenez staining (mGS) and direct fluorescein-conjugated monoclonal antibody staining (FA). The identification methods were implemented by staining the yolk sacs of embryonated chicken eggs inoculated at 6 days of age and harvested between 3 and 10 days after inoculation. Fecal specimens from pet birds were randomly collected from pet shops and homes. These specimens were then used to isolate C psittaci and to detect its specific DNA. The inocula that were prepared from fecal specimens were then inoculated into yolks of 6-day-old embryonated chicken eggs. The preparations from egg yolk sacs were examined with mGS and direct FA after three blind passages. The PCR method was used to detect specific DNA in feces. In 96 fecal specimens, 33 (34.4%) were positive with PCR, 21 (21.9%) were positive with mGS, and 29 (30.2%) were positive with FA. Among 33 positive specimens with PCR, 28 specimens were positive with FA, and 20 specimens were positive with mGS. The sensitivity and specificity were 59% and 94% between FA and mGS, and 97% and 93% between FA and PCR, respectively.