Environment, incidence, aetiology, epizootiology and immunoprophylaxis of soil-borne diseases in north-east Mexico.

Within the framework of an extensive research programme, the socio-economic and environmental conditions which influence the emergence of soil-borne diseases in north-eastern Mexico were analysed. Furthermore, specimens collected from carcasses in the field were bacteriologically examined and the causal organisms of soil-borne diseases differentiated by means of gas chromatographic analysis of their metabolic products and the long-chained fatty acids contained in the cell. With experimental clostridial vaccines prepared with the Goettingen Bioreactor Technique, trials to protect cattle and guinea-pigs against gas gangrene were carried out. It was found that the farm structure and the dry climate as well as the specific soil conditions and plant cover favour the emergence of soil-borne diseases. Causal organisms B. anthracis, C. perfringens, C. sordellii, C. haemolyticum, C. chauvoei/septicum, C. novyi A, C. botulinum and site-specific field strains of clostridia were detected. Experimental site-specific vaccines proved to be highly efficient in protecting cattle and guinea pigs.

[Bacteriological studies of the problem "Epidemic losses in hares and deer in habitats with high cultivation of 00-rapeseed"]. / Bakteriologische Untersuchungen zur Frage "Seuchenhafte Verluste bei Hasen und Rehen an Standorten mit Hoher Anbaudichte von 00-Raps".

Within the scope of the research work for possible reasons of the so-called "wildlife mortality" more than 900 specimens of 440 animals (183 hares, 153 deer, 14 rabbits found dead, and 98 hares and 6 deer shot by hunters) were checked for the presence of Clostridia in inner organs. The results show that in 40.3% of the animals found dead but only in 13.3% of the hunted hares Clostridia were to be found. Out of the isolated Clostridia strains 24.4% could not be identified; potentially pathogenic species were found in 78.3% of isolates of hares, 81.7% of those of deer and in 9.2% of those of hunted hares. 23.9% of the isolates were C. perfringens. Considering the known epizootiology of clostridioses it can be concluded that clostridia certainly play a role in losses of wildlife, as well in hares as in deer. Triggering factors could lie in the kind of feed which is available for animals in modern agrarian landscape. During the critical period in autumn and winter there are mainly crop plants like rapeseed, wheat and barley only available for wildlife.