INVESTIGATIONS ON THE INFLUENCE OF A BORDETELLA LIVE VACCINE UPON OCCURRENCE AND SIGNIFICANCE OF RHINITIS ATROPHICAN SUUM AND THE INFECTION PRESSURE BY FIELD STRAINS OF THE CAUSAL AGENT

A field study was carried out in a large scale unit for swine breeding and fattening with the object to influence the high morbidity rate of Atrophic Rhinitis and pneumonia with the help of a Bordetella live vaccine. The results show that it is possible to decrease the infectious pressure by B. bronchiseptica and to reduce the pathomorphological signs of Atrophic Rhinitis in consequence of the application of the live vaccine. The pathologic-anatomical investigations of nasal turbinates in immunized slaughtered fattening pigs show a significant lower morbidity concerning Atrophic Rhinitis and a higher persentage of pigs without changes at conchae nasales and septum nasi. We find also a lower contamination of the air with B. bronchiseptica field strains during vaccine application. The results also explain that a high infectious pressure by B. bronchiseptica and the possibility of communication between unvaccinated and vaccinated groups of pigs counteract a better efficiency of the vaccine. The decrease of the morbidity rate of Atrophic Rhinitis appears so much more important because toxinogenious Pasteurella multocida strains were isolated from nasal swabs of vaccinated pigs during the investigations. But these strains influenced the Atrophic Rhinitis frequency only accidentally. All results as a whole point out that in pig houses with a high animal density one has to pay more attention to virulent B. bronchiseptica strains than it was been done till now.