EN
Epizootic bovine abortion (EBA), described by Schoop and Kauker (13) in 1955, and afterwards by other authors (1, 2, 3, 4, 5, 6, 11, 17), is caused by organisms of the Psittacosis-Lymphogranuloma-Venerum group which were assigned to the genus Chlamydia in 1966 (10). It was demonstrated also that the organisms are a cause of EBA in experimentally infected pregnant cows (8, 14, 15, 16). A detailed characteristic of the organisms was presented previously (12, 18). The present report describes the investigations on the occurrence of Chlamydia organisms in cows which aborted and in aborted foetuses. The investigations ensued from a previous exclusion of Brucella and Vibrio foetus as etiologic agents.