AN INDIRECT MICROIMMUNOFLUORESCENCE TEST FOR DETECTION OF CHLAMYDIAL ANTIBODIES IN OVINE FETAL FLUIDS

The objective of this study was to evaluate an indirect microimmunoflu orescence test (IMIF) for detection of chlamydial antibodies in serum and/or thoracic fluids of aborted ovine fetuses. One hundred eighty-tw o ovine fetuses, including 64 fetuses from 40 ewes that were experimen tally infected with an ovine abortion strain of Chlamydia psittaci at gestation days 90-100, 10 fetuses from 6 normal ewes, and 108 fetuses selected from those received at the Iowa Veterinary Diagnostic Laborat ory, were evaluated in this study. Fetuses from experimentally infecte d ewes were examined 4-60 days after inoculation. The IMIF findings we re compared with the results of complement fixation serology for chlam ydiae and concentrations of immunoglobulin (IgG). Chlamydiae-specific antibodies were detected by IMIF in 28 of 38 fetuses infected with C. psittaci. Elevated levels of IgG and IMIF titers greater-than-or-equal -to 1:8 were consistent findings in ovine fetuses infected with chlamy diae for more than 24 days. IgG levels and titers of chlamydial antibo dies increased with maturity of the fetus and duration of chlamydial i nfection. Chlamydial antibodies were not detected with the complement fixation test. Fluids from ovine fetuses aborted as a result of other causes also were examined, and IMIF results were negative. The results of this study indicate that the IMIF is a useful and relatively rapid test for identification of chlamydial antibodies in ovine fetuses.