[Ovine enzootic abortion: seroprevalence in Switzerland using a competitive enzyme-linked immunosorbent assay...

The present study gives an overview over the seroprevalence of ovine enzootic abortion in Switzerland. 639 sheep flocks out of eight cantons in Switzerland were examined by a competitive enzyme linked immunosorbent assay (cELISA) for antibodies against Chlamydophila abortus (Chlamydia psittaci serotype 1), the agent causing ovine enzootic abortion. The eight cantons included Aargau, Bern, Zürich, Appenzell-Ausserrhoden, Appenzell-Innerrhoden and Fribourg, the Vallais and the Graubünden. They were representative for 57% of the Swiss sheep flocks and for 60% of Swiss sheep population. In total, almost 19% (118) of the examined flocks were seropositive. Seroprevalence was the highest in Graubünden with 41%; this requires further examination and the evaluation of the need for a monitoring and controlling program. The examination of pooled sera made it possible to test a large number of samples with a reasonable amount of work. Higher sensitivity (92.9%) and specificity (97.6%) than the complement fixation test (CFT) in combination with testing of pooled sera makes the cELISA to be an usuable tool for serological screening on flock level.