A ten year's experience with inactivated vaccine against listeriosis of sheep.

Efficacy of preventive use of an inactivated vaccine was controlled through several years in 24 farms on 32,124 vaccinated and 35,880 unvaccinated (control) sheep. Death due to listeriosis was 273 (0.85%) in the vaccinated and 462 (1.29%) in the non-vaccinated groups. Vaccination in the acute phase of the disease was performed in 5 flocks, on 10,303 animals, leaving 9,781 as unvaccinated controls. In most flocks, deaths due to listeriosis ceased or became minimized 7-10 days post-vaccination. In total 59 (0.57%) of the vaccinated and 251 (2.56%) of the non-vaccinated animals died as a result of listeriosis.