[Seasonal isolation of Yersinia enterocolitica and Yersinia pseudotuberculosis from tonsils of healthy slaughter pigs (author's transl)].

45 strains of Yersinia (Y.) enterocolitica from which 36 respectively 9 belonged to O-group I or V and 28 strains of Y. pseudotuberculosis from which 15 respectively 13 isolates belonged to serotype I or II were isolated from 70 tonsils of 480 examined, clinically healthy slaughter pigs. In the tonsils of three animals were found both species together. Y. enterocolitica was isolated during the whole year, but especially in the months of November (17.5%) and December (32.5%). Y. pseudotuberculosis was found during the time of winter and spring, most frequently in the months of January (30%) and December (17.5%). The bacteriological findings and the possible significance for human infections are discussed.