[Yersinia enterocolitica serotype O:8 infections at the Hirosaki district in Aomori Prefecture from 1984 to 1991].

During the period from January 1984 to December 1991, 118 strains of Yersinia enterocolitica were isolated from the specimens which were requested for bacterial examination from various medical practitioners. The results of bacteriological examination of these isolates showed that 11 of Y. enterocolitica serotype O:8 sporadic infections were confirmed at Hirosaki district in Aomori Prefecture. Of the eleven isolated strains, nine were from feces, two were from contents of extracted appendix. These strains were biovar (Wauters) 1, harboring 42 megadalton virulence plasmid, positive for autoagglutination and calcium dependency. Patients were under fifteen years old except one case of a 45 year old. Seven patients were living in the inter-mountain area, three in the urban area and one in the plain area. The infectious source was not found.