Any person with at least one of the following five:
Fever
Diarrhoea
Vomiting
Abdominal pain (pseudoappendicitis)
Tenesmus
Isolation of human pathogenic Yersinia enterocolitica or Yersinia pseudotuberculosis from a clinical specimen
At least one of the following four epidemiological links:
Human to human transmission
Exposure to a common source
Animal to human transmission
Exposure to contaminated food
Any person meeting the clinical criteria and with an epidemiological link
Any person meeting the clinical and the laboratory criteria