Abortion in small ruminants in Switzerland: Investigations during two lambing seasons with special regard to Chlamydiae

Abortion cases of 144 goats and 86 sheep were investigated etiologically during 2 lambing seasons (1996/1997, 1997/1998). Macroscopic inspection of fetus and placenta was completed by histopathology and bacteriological isolation of agents. In, addition, immunohistologically the following antigens were labeled in formalin-fixed and paraffin-embedded tissue sections: Toxoplasma gondii, Neospora caninum, Chlamydophila abortus (formerly Chlamydia psittaci serovar 1) and Border Disease Virus. From farms with abortions caused by Chlamydophila abortus specific data were recorded. In 75% of abortion cases in sheep and in 59% of cases in goats an etiologic diagnosis could be substantiated. Chlamydophila abortus is the most commonly involved agent in the etiology of caprine and ovine abortion (sheep 39%, goats 23%), followed by Toxoplasma gondii (sheep 19%, goats 15%) and Coxiella burnetti (sheep 1%, goats 10%). All other agents are of minor importance. An infectious cause of abortion based on histopathologic findings without isolation of agents was observed in sheep (10%) and goats, (21%). Malformation occured in sheep (2%) and goats (3%) and lesions suggestive for Vitamin E/Selenium deficiency were seen in goats only (2%).