The synergism of Actinobacillus pleuropneumoniae and influenza A virus in experimentally-infected mice

Models for infecting mice with Influenza A-Virus (A/PR 8/34, H0N1) and Actinobacillus pleuropneumoniae (serotype 9) were developed in Han: NMRI-mice. After infecting mice with sublethal doses of one of the infectious agents, or both together as a mixed infection, animals were subsequently exsanguinated and the lungs washed by bronchoalveolar lavage. Clinical symptoms were recorded daily, examination of lung lavage fluid and sera as well as histology of the lungs were done. An increase in mortality, weight reduction and total cell yield of lung lavage fluid was observed after mixed infection. Compared to mixed infections total protein content and elastase in sera and lung lavage fluid after singular ones were raised not as much. In lung lavage fluid the total cell yield was increased more marked. These alterations indicate a synergistic effect of viruses and bacteria, developed by mixed infection as well as a bacterial infection on top of a viral one. Histopathologically the lung alterations were found to depend on the infectious agent and the mode of infection.     

Isolation of Chlamydia psittaci and Moraxella bovis from infectious keratoconjunctivitis in lambs

Out of 189 lambs in the flock, 25 animals suffered from bilateral or unilateral conjunctivitis, or keratoconjunctivitis. By serological examination (RVK), positive levels of antibodies to the group-specific antigen of Chl. psittaci were found in three out of six lambs examined by laboratory methods. Bacteriological examination of eye smears of six lambs showed in four cases the infection by microorganisms of Moraxella bovis. Smears from the conjunctivas of these lambs were after preparation instilled in the yolk sacs of six to seven days old chicken embryos. One strain of Chlamydia psittaci was isolated from the same material as Moraxella bovis.     

Determination of zearalenone in grains using high pressure liquid chromatography

The determination of zearalenone content in cereals (maize, wheat and barley) was performed by means of liquid chromatography using the Czechoslovak-made apparatus. This method enables to determine this mycotoxin up to the concentration of 8 micrograms per 1 kg of grain with the accuracy exceeding +/- 9%.     

Ascorbic acid levels in the bronchopneumonia of calves]

The level of ascorbic acid in the blood plasma of 59 calves was determined. The age of the calves ranged between two and three months and the samples of blood were collected in January. The first group of calves included 30 animals displaying no clinical symptoms of disease: the average ascorbic acid level was 0.50 +/- 0.18 mg per 100 ml. In the second group, consisting of 19 calves, the blood of the animals was collected three weeks after the termination of the acute stage of bronchopneumonia; the average value of ascorbic acid was 0.30 +/- 0.14 mg per 100 ml. The lowest average value of ascorbic acid was obtained in the calves at an acute stage of bronchopneumonia, reaching 0.18 +/- 0.11 mg per 100 ml. The differences of results between groups I and II and between groups I and III were found to be statistically significant. A conspicuous drop of ascorbic acid level was ascertained in calves suffering from bronchopneumonia-this problem needs deeper scrutiny, owing to the fact that bronchopneumonia is responsible for considerable economic losses in large-capacity calf houses.     

Studies of bovine mycoplasma mastitis. 1. Review of literature on the occurrence of bovine mastitis with Mycoplasma involvement]

The clinical pattern as well as the pathologico-anatomic or histological changes due to mycoplasma mastitis are neither specific nor pathognomic. Mastitis pathogens so far described included M. bovis, M. bovigenitalium, A. laidlawii, A. axanthum, M. alkalescens, M. canadense, M. dispar, M. bovirhinis, strains of Group 7 according to Leach, strain ST 6, and ureaplasma strains. In the GDR, enzootic mastitis has been confined to A. laidlawii and A. axanthum.