Detection of Chlamydophila (Chlamydia) abortus and Toxoplasma gondii in smears from cases of ovine and caprine abortion by the streptavidin-biotin method.

Fetal membranes from 59 cases of ovine and six of caprine abortion from a total of 52 flocks or herds were collected. Immunohistochemical examination of cotyledons fixed in formalin and embedded in paraffin wax detected Chlamydophila abortus in 44 (68%) cases. Immunocytochemical examination of smears made from the surface of fetal membranes detected the organism in 37 (57%) cases. Light microscopical examination of such smears stained by Stamp's method detected C. abortus in 26 (40%) cases. The streptavidin-biotin method described proved to have 100% specificity and 84% sensitivity in the detection of C. abortus in cotyledon smears. Sensitivity could probably be increased still further by the simultaneous examination of smears made from the cut surface of several cotyledons. In five cases Toxoplasma gondii was detected in the cotyledons by immunohistochemical examination. In three of these cases the presence of T. gondii was revealed also by immunocytological examination. In four cases, simultaneous C. abortus and T. gondii infection of the cotyledons was observed. The two pathogens and the lesions caused by them occurred in separate locations.