COMPARISON OF POLYMERASE CHAIN-REACTION, DIRECT IMMUNOFLUORESCENCE, CELL-CULTURE AND ENZYME-IMMUNOASSAY FOR THE DETECTION OF CHLAMYDIA-PSITTACI IN BULL SEMEN

The polymerase chain reaction (PCR), direct immunofluorescence (DIF; J MAGEN Chlamydia, DAKO Diagnostics, UK), cell culture (CC) and enzyme i mmunoassay (ELA; Syva MicroTrak) were evaluated for detection of Chlam ydia psittaci in bull semen. Three specimens were collected from each of 47 bulls at 3-6 month intervals (134 samples). Judging by the numbe r of samples tested (n=134), PCR showed a sensitivity of 90.9%, DIF of 93.9%, CC of 72.7% and EIA of 81.8%. PCR, DIF, CC and EIA were 100% s pecific, respectively. Of the 47 bulls the maximum number of chlamydia -positive animals (n=14) was revealed when repeated tests were made by PCR. PCR detected 21.4% more positives than DIF and CC and 35.7% more than ELA. Although CC was less sensitive judging by the number of sam ples tested, it was as sensitive as DIF (78.6%) when judged by the num ber of bulls investigated. All bulls found to be chlamydia-positive re mained so throughout the investigation, which lasted 18 months.