[Seasonal dynamics and the prevention of the meningoencephalitic form of listeriosis in lambs].

The seasonal dynamics of the meningoencephalitic form of listeriosis in lambs was followed up. The peak values in the disease course were found to be in the months of February and March. It is likely that outbreaks coincide with the start in feeding the lambs with roughage.

[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.

[Effect of levamisole on the formation of agglutinins against salmonellosis in weaned lambs].

In order to follow up the effect of levamizol on the titer of agglutinins a killed vaccine of Salmonella abortus ovis; S. enteritidis, and S. typhimurium strains was used under protection of antidenaturating agents (80 per cent sac charose) and levamizol ICI at the rate of 10 mg per kg body mass.

[Effect of several biologically active substances on the reactivity and immune response of the body].

Experiments were carried out with a total of 140 guinea pigs to study the effect of a tissue emulsion of swine embryos on some of the general defense reactions, the cell and humoral immunity of the organism in the treatment with an intact and a killed (with 3 per cent formalin) vaccine produced with two strains of Salmonella abortus ovis. Investigated were the phagocytic activity of the lung macrophages and the immobile cells of the reticulo-endothelial system in the spleen and the liver, the protein spectrum, the blood serum level of properdine, and the histologic changes in the parenchymal organs of the test animals. It was found that the application of a tissue emulsion simultaneously with the injection of the animals with an anti-Salmonella vaccine raised the unspecific reactivity of the organism.

[Hematologic and histochemical changes in the bodies of sheep experimentally infected with listeriae].

Hematologic and histologic investigations were carried out on forty experimentally infected young ewes to which the infection was introduced through venous, intratracheal, and oral route as well as along the branches of nervus trigeminus parallel to the study of 3 control sheep, 12 albino mice, and other four young sheep that were injected with a water-extractive antigen obtained from Listeria. It was established that the leukocyte count rose in the first days following infection along with neutrophilia, lymphopenia, and monocytosis of a varying degree in the different animals, depending on the way of infection. Most indifferent with regard to the hematologic indices proved animals that were orally inoculated.