Intestinal yersiniosis. Clinical importance, epidemiology, diagnosis, and prevention

Yersinia enterocolitica and Y. pseudotuberculosis are causative agents of yersiniosis in humans and animals that have to be separated from Y. pestis, the causative agent of plague, representing a separate clinical and epidemiological entity. Intestinal yersiniosis may manifest in humans as (1) enteritis, (2) terminal ileitis, mesenteric lymphadenitis, or pseudoappendicitis, and (3) septicemia leading to focal abscesses in spleen and liver. The intestinal infection may be followed by reactive arthritis in a number of cases. Y. enterocolitica and Y. pseudotuberculosis are distributed worldwide but occur mainly in moderate or subtropical climates. The most important reservoirs are rodents, lagomorphs, and birds for Y. pseudotuberculosis and domestic animals, especially pigs, for Y. enterocolitica. All Y. pseudotuberculosis isolates may be considered as pathogenic whereas Y. enterocolitica strains can be subdivided into pathotypes of different virulence. The differentiation of pathotypes by determination of the biovar and demonstration of the 75-kb virulence plasmid is therefore of diagnostic importance. Preventive measures include avoidance of direct infection by contact with infected reservoir animals and practice of good hygiene during slaughtering as well as in food production and preparation of meals.