A Salmonella abortusovis inactivated vaccine protects mice from abortion after challenge.

Two types of Salmonella abortusovis vaccines were prepared, one with aluminium hydroxide (vaccine A) and the other with water in oil (vaccine B) adjuvants. They were compared in a pregnant mouse model, aiming at protecting them from abortions after challenge with a virulent strain of S. abortusovis. The protection for vaccine A was from 74% to 77.6% and that for vaccine B from 71% to 79.6%. Abortions occurred 5-10 days post challenge and S. abortusovis was isolated from all aborted fetuses and from the liver and the spleen of their mothers at the end of the experiment (18 days post challenge). The presence of salmonella in the liver and the spleen of vaccinated non-pregnant but challenged mice was studied in a separate experiment. The bacterium was isolated from one out of 12 vaccinated mice 6 days post challenge as well as from the six controls.