[Immune reactivity of piglets vaccinated at an early age with a live vaccine against erysipelas].

Studies were carried out on the immune response in pigs that had been treated at various intervals following birth with a live vaccine against erysipelothrix rhusiopathiae. The pigs originated from sows that had been vaccinated against the disease on the 80th day of pregnancy. Both biologic and morphologic investigation were performed. It was found that passive immunity protected the small pigs against an experimental infection up to the age of 45 days, inhibiting during this period being the action of the vaccine applied. The young pigs built up an active immunity against swine erysipelas after their vaccination at the age of 2 months, which protected them against control challenging, while the nonvaccinated animals reacted with a rise in temperature and reddening at the site of scarification. The morphologic studies confirmed the results of the biologic experiments.