Oral immunisation of wild boar against classical swine fever: concluding analysis of the recent field trials in Germany.

The recent oral immunisation trials in wild boar against classical swine fever (CSF) in Germany are described and evaluated in summary. After the first field study in Lower Saxony from 1993-1995 further immunisation trials started in Mecklenburg-Western Pomerania, Brandenburg, Lower Saxony, Baden-Württemberg and Saxony-Anhalt. The immunisation strategies and the size of the vaccination zones were different in the individual federal states. In principle, the bait vaccine based on the CSF virus strain "C" were laid out by hand. Later also the aerial distribution was carried out in selected areas of Mecklenburg-Western Pomerania. The application of baits by plane was introduced at the beginning of the immunisation measures in Saxony-Anhalt apart from the manual distribution. Up to now, the field trials show that the oral immunisation can be an additional tool for CSF control by increasing of herd immunity and reduction of the CSFV prevalence. However, the immunisation was not sufficient enough for young boars in the most field studies. Based on the evaluation of the immunisation experiments an improved immunisation procedure is recommended.

The effects of intramuscularly administered vitamin D3, 25- and 1 alpha-hydroxycholecalciferol in cows on plasma mineral content, plasma 25-hydroxycholecalciferol and on mineral deposits in soft tissues.

The investigations were carried out to evaluate potential side effects of a prophylaxis with high doses of vitamin D3 and vitamin D metabolites in parturient paresis. For this reason, 10(7) IU vitamin D3 (= 250 mg), 4 mg 25-OHD3 or 420 micrograms 1 alpha-OHD3 were applied to non-gravid dairy cows at the end of lactation. The application was repeated 3 times at one week intervals and the changes of the mineral concentration and 25-OHD were measured in the plasma. The pathomorphological changes in the cardio-vascular system and other organs were examined macro- and microscopically. The application of vitamin D3 and 25-OHD3 led to an immediate and continuous increase of the 25-OHD concentration in the plasma. On the other hand, administration of 1 alpha-OHD3 resulted in a decrease of the 25-OHD level. After the application of vitamin D3 and 1 alpha-OHD3, the Ca and Pi concentration increased significantly. After 25-OHD3, the Ca concentration decreased below the initial level in the second week. The administration of all 3 compounds led to a significant decrease of the Mg concentration after the first injection. The administration of vitamin D3 and 1 alpha-OHD3 resulted in a significantly more pronounced calcinosis of inner organs while after the application of 25-OHD3 only occasionally calcium deposits were observed in the vascular system.

[Acute toxoplasmosis outbreak in rabbit flocks]. / Akute Toxoplasmose-Ausbrüche in Kaninchenbeständen.

Acute toxoplasmosis occurred in 2-18 month old domestic rabbits of 15 flocks entailing losses of 3-66%. Pathomorphological examinations of 49 rabbits revealed lesions of a generalized granulomatous-necrotizing toxoplasmosis with spleen, liver, lungs and lymphonodes mainly affected. Similarities existed to pseudotuberculosis. The spleen was massively packed with pseudocysts and cysts of Toxoplasma. Electronmicroscopic examinations of organ specimens fixed in formalin assured the identity of Toxoplasma and serological tests (CFT, SFT, IFAT) as well as the mouse test confirmed it.

[Attempts to influence birth in swine with dexamethasone. 2. Effect of DXMS on adrenal mass and cell nuclear volume of the fascicular zone in piglets]. / Versuche zur Beeinflussung der Geburt beim Schwein mittels Dexamethason. 2. Mitteilung: Der Einfluss von DXMS auf die Nebennierenmasse und die Zellkernvolumina der Zona fascieulata der Ferkel.

The adrenal weights of spontaneously born piglets, immediately after parturition, were significantly higher than those of piglets from sows in whom parturition had been induced by DXMS. The differences between mean values went down with DXMS treatment started later in advanced pregnancy. Mean absolute and relative adrenal weights of the DXMS groups came closer to those of the untreated controls on the tenth day of piglet age. Cell nucleus volumes of the zona fasciculata were normal in all groups and did not reveal any influence of DXMS treatment in any of the newborn piglets. The mean values were 89.9 micron3 in the control group and 87.6 micron3 in experimental group V (75 mg DXMS per animal and die on 109th through 111th days of pregnancy).

[Studies on Salmonellosis in the calf. 5. Clinical testing of Smd-Salmonella-dublin vaccine for oral administration]. / Untersuchungen zur Salmonellose des Kalbes. 5. Mitteilung: Klinische Erprobung des oral zu verabreichenden Smd-Salmonella-dublin-Impfstoffes.

The oral vaccine, prepared on the basis of streptomycindependent mutants for administration to control S.-dublin infection, was clinically tested on 2,210 calves of 22 herds. The experimentally obtained findings regarding good tolerance and sufficient effectiveness of oral live vaccines were thus confirmed under field conditions. Good effectiveness of the oral vaccine was reflected in the recorded decline of clinical salmonellosis cases and of calf losses due to salmonellosis, and it was established also by bacteriological identification of S. dublin in faecal samples, histological sections, and material obtained from emergency slaughter carcasses. A comparison between this oral vaccine and "Mellavax" an imported vaccine for subcutaneous adminstration with good effectiveness, revealed superiority of the oral vaccine by almost all criteria of action. Particular importance was attributed to the significant reduction of the number of Salmonella-excreting animals (faeces) following oral immunisation. The oral vaccine against Dublin salmonellosis of calf was disembargoed for production in 1975 under the name of "Salmonella-dublin Live Vaccine Dessau".

[Studies on calf salmonellosis. 4. Oral and parenteral immunization with live (Smd) and killed antigens]. / Untersuchungen zur Salmonellose des Kalbes 4. Mitteilung: Orale und parenterale Immunisierung mit Lebend- (Smd-) und Totantigen

Reported are results obtained from studies into oral and parenteral immunisation of calf. The approaches had included the use of live (Smd) or dead antigen from Salmonella (S.) dublin and a combination of the two immunisation methods. Live antigen (Smd) was superior to thermally activated dead antigen, when the oral route was used to prevent S.-dublin injection of calves. The above findings were supported by results from analogous studies in which S. typhimurium and S. dublin or live antigen (Smd) or dead antigen, made of the two, had been applied to mice. (One single subcutaneous) parenteral administration did hardly reveal any difference in favour of live vaccine (Smd). Parenteral administration of live or dead antigen proved to be less effective than repeated oral immunisation, particularly when live vaccine (Smd) was used. Immunity not less than up to six months of age against S. dublin wild strain infection can be provided for young calves by oral immunisation, with Smd vaccine (5. 1010 to 1. 1011 live germs/d) being given on ten consecutive days. Calves orally immunised with live antigen (ten repetitive applications of Smd mutants) are likely to develop an antibody titre (H-agglutinins) against S. dublin. Parenteral boostering,using live antigen, has been accompanied by sensitisation due to oral live antigen administration as well as by dose dependence, as was seen from the bactericidal values. Sensitisation was established from orally immunised calves up to three months old (typical booster reaction). Some of it was attributabale to confrontation with wild strains of Salmonella. The H-agglutinin titres of animals aged threemonths in a calf herd with salmonelloses in which all animals had been orally Smd-immunised were close to those recorded from calves in stocks with no salmonellosis occurrence. Under the conditions of oral immunisation, there had obviously been no action of the wild strain which might have triggered intensive antibody formation.