Yersinia enterocolitica and Yersinia like microbes isolated from mammals and water in Norway and Denmark.

Data pertaining to 149 strains belonging to genus Yersinia are summarized in this paper. Yersinia enterocolitica (Y.e.) was isolated from the faeces of 31 of 305 small rodents and from 5 of 31 shrews (Soricidae) trapped at five localities in Norway and one locality in Denmark. Isolations were obtained from 9 of 29 water samples collected within the trapping areas. Three of 25 red foxes (Vulpes vulpes) from one locality in Norway harbored Y.e. in their faeces. Y.e. serotype 16 was isolated from one zoologist suffering from diarrhoea. A total of 85 strains from small rodents, shrews, water and foxes showed biochemical properties intermediate to Y.e. and Y. pseudotuberculosis. Another three strains were classified as Y. pseudotuberculosis on biochemical basis. They were obtained from small rodents in Denmark. Serological examination of 59 small rodents naturally infected with Y.e. and related microbes, revealed two cases of low antibody titres (80) against homologous isolates. Pathological examination of 44 of these animals gave a negative result. Strains antigenically related to the same serotypes were frequently isolated from both terrestrial ecosystems and adjacent freshwater. Strains related to serotype 6 dominated both in red fox and in their small rodent prey. No evidence was found for a dynamical significance of Y.e. in populations of small rodents. The results indicate that Y.e. and Yersinia like microbes have a broad occurrence in terrestial ecosystems.