[Immunoprophylaxis of listeriosis in sheep with a killed vaccine].

Experiments were carried out with 20 young ewes, 20 rabbits, 20 guinea pigs, and 10000 sheep and lambs, using a killed vaccine of Listeria 1 and 4c with heat under the protection of antidenaturation agents. Bacteriologic, histologic, and histochemical investigations and lung macrophage cultures were used to establish the changes in untreated, vaccinated, and challenged vaccinated animals. Listeria organisms from the challenged animals were isolated in sporadic cases from the barin and viscera, while from untreated and infected animals such organisms were isolated during the entire period of investigation. The use of cultures demonstrated the part played by cell immunity as early as the 3rd to 7th day following vaccination. It was found that the vaccine inhibited the development of pathologic lesions of intoxication in the body and led to the immunologic rebuild of animals. The vaccination of both sheep and lambs in herds with listeriosis suppressed the disease and the mortality thereof.