[Experimental Pasteurella multocida infection of swine. A contribution to the etiology of enzootic porcine pneumonia].

Pasteurella can be isolated from about 50 per cent of pneumonically changed pig lungs. Isolation, however, is possible also from intact lungs of conventional or secondary SPF animals. The authors of this paper used the positive hyaluronidase test and identified exclusively Pasteurella multocida, with predominance of capsular type A. Most of the Pasteurella strains tested in this context caused pneumonia in SPF animals, particularly, following intratracheal application. No correlations were found to exist with murine virulence, the serological type or the origin of the strains from affected or intact lungs. Apart from virulence differences between the strains, host reactivity was found to depend primarily on high germ counts and, under natural conditions, on environmental stresses. Pasteurella multocida, hence, can be considered as one of the potential pathogens of porcine pneumonia. Pneumonia foci with transduced localised fibrinous pleuritis are characteristic and constitute a process of purulent inflammation with early involvement of fibrin.