Detection methods for Salmonella abortus ovis and examinations in sheep flocks in northern Baden-Württemberg

Abstract

Investigations into the incidence of Salmonella abortus ovis (S. abortus ovis) infections should not be neglected in diagnosis of ovine abortion cases. For detection of this pathogen agent, direct cultivation, as well as pre-enrichment combined with enrichment procedures in tetrathionate or Rappaport-Vassiliadis medium, should be performed with respect to the features of S. abortus ovis. The detection limit of S. abortus ovis using pre-enrichment and enrichment media could be determined using 6.5 x 10(3)-6.5 x 10(4) bacteria. For subsequent cultivation of S. abortus ovis Gassner, XLD or Rambach agar are suitable. In infected sheep showing no excretion of S. abortus ovis, the pathogen can be detected by serological studies using microagglutination or the ELISA test. The ELISA test proved to be more sensitive than the microagglutination test, detecting antibodies against S. abortus ovis in 17% of the 814 sheep tested. The microagglutination test revealed positive results in only 2% of the sheep tested.