Vaccinal efficacy of Toxoplasma gondii S48 strain tested in anexperimental trial in goats. [French]

摘要

Toxoplasmosis due to Toxoplasma gondii represents the second cause of abortion of dairy goats in France. A live vaccine (S48 strain, Ovilis Toxovax (R)) approved in sheep was tested in experimental conditions in goats. Goats were inoculated intramuscularly with vaccine 1 mont before mating. Two groups of vaccinated (n=17) and unvaccinated (n=16) goats were defined and challenged with 10,000 oocysts on day 90 of pregnancy. The evolution was quite different according to the initial level of ELISA antibody titers. In animals having very low low antibody titers, vaccination induced an increase of rectal temperature and of serological titers with large individual variations. After challenge, a rise in rectal temperature was recorded only in unvaccinated animals whereas both vaccinated and unvaccinated goats showed a dramatic increase in antibody titers. Percentages of abortion and stillbirth were respectively 0 and 25% in the vaccinated group and 25 and 12.5% in the unvaccinated one. In animals exhibiting higher initial antibody titers, rectal temperature and serological responses to vaccination and challenge were less clear.