A Salmonella abortusovis inactivated vaccine protects mice from abortion after challenge

Two types of Salmonella abortusovis vaccines were prepared, one with alumin ium hydroxide (vaccine A) and the other with water in oil (vaccine B) adjuv ants. They were compared in a pregnant mouse model, aiming at protecting th em 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, abort usovis was isolated from all aborted fetuses and from the liver and the spl een 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-p regnant but challenged mice was studied in a separate experiment. The bacte rium was isolated from one out of 12 vaccinated mice 6 days post challenge as well as from the six controls. (C) 1999 Elsevier Science B.V. All rights reserved.