Human infections with Yersinia enterocolytica.

In 1964 a pathogenic organism that had been named Pasteurella X by Daniels (1963) was transferred to the genus Yersinia as Y. enterocolytica by Frederiksen (1964). This genus comprised already Y. pestis and Y. pseudotuberculosis. Since then the organism has been studied extensively by a group of research workers in Maim6 (Winblad, Carlsson, Nilehn, SjOstr~Sm and others). The symptoms in humans vary from diarrhoea with fever to the development of an acute or subchronical condition low down on the right side of the abdomen, resembling appendicitis. During operation an appendicitis is seldom found, but instead, a more or less pronounced inflammation of the iliocoecal region and tile regional lymphnodes. Especially an acute terminal ileitis seems to be characteristic. The recent isolation of Y. enterocolytica in three patients in Rotterdam proves that this infection occurs also in The Netherlands, as might be expected since typical cases have already been found in several Et, ropean countries. Two of our patients had the typical ileocoecal syndrome. Y. enterocolytica was isolated from the faeces, and in both patients a high sero-agglutination titre against the isolated strain developed. The third patient was an eleven years old boy who was operated on for appendicitis with high fever (40 C). A mildly inflamed appendix was found. The faeces were found to contain Y. enterocolytica. A few weeks after the operation a positive serotitre against his own strain was found. Epidemiologically this case is interesting because his brother (one of the two typical cases) was operated one week later; the Y. enterocolytica strains of the two brothers belonged to the same serotype. The other patient harboured another serotype.