OCCURRENCE AND POSSIBLE ROLE OF MORAXELLA SPECIES IN PIGS

Bacteriological examination of material from 4500 post mortem examined suckling pigs from 17 herds resulted in the isolation of a haemolytic Moraxella species in 81 cases (1.8 per cent). In 43 instances Moraxella was isolated in pure culture and 34 pigs apparently succumbed to a generalized Moraxella infection. Mixed infections occurred in 11 pigs and 27 isolations were from mucous membranes. A tendency to a prevalence among pigs born by primiparae was found. Seasonal variation with the highest frequency in the winter-months was obvious. The infections occurred sporadically in 13 out of 17 herds. The Moraxella was predominantly found among pigs less than one week old, 73 of all the isolates and 94 per cent of the generalized infections were found in this age group. Besides generalized infections, Moraxella was isolated from four cases of catarrhal pneumonia, three cases of arthritis and three abscesses. The morphology and the biochemical properties of the isolated strains are described. In a preliminary inoculation-experiment with gnotobiotic pigs the employed Moraxella-strain was able to establish itself in the pharynx, but no clinical symptoms or pathological lesions were produced. It is concluded, that the described Moraxella species like some other gram-negative related species can act as an opportunistic pathogen in pigs and occasionally cause generalized or localized infections in piglets—mainly among predisposed and debilitated individuals.