Reporting Obligations

Individuals with suspect or confirmed cases must be reported to the Thunder Bay District Health Unit by the next working day by fax, phone or mail.

  • Fax: (807) 625-4822
  • Phone: 625-5930 or toll-free at 1-888-294-6630, ext. 5930
  • Mail: 999 Balmoral Street, Thunder Bay, ON P7B 6E7


Aetiologic Agent:

Yersiniosis is caused by a Gram-negative enterobacteriacae of the genus Yersinia. Two species, Y. entercolitica (most common in Canada) and Y. pseudotuberculosis, are the causative agents of yersiniosis.

Clinical Presentation:

Y. entercolitica infections typically manifest as fever and diarrhea in young children. Stool often contains leukocytes, blood and mucus. In older children and adults a pseudoappendicitis syndrome, with fever, abdominal pain, tenderness in the right lower quadrant of the abdomen and leukocytosis predominates.

Y. pseudotuberculosis presents with fever, scarlatini-form rash and abdominal symptoms and acute pseudo-appendicieal abdominal pain is common. Clinical features can mimic those of Kawasaki disease.

Complications include post infection arthritis and systemic infections.

Modes of transmission:

Fecal-oral transmission via contaminated food and water or by contact with infected people or animals such as puppies and kittens; raw pork and pork products are known sources of infection.

Incubation Period:

Probably 3-7 days, generally less than 11 days.

Period of Communicability:

Secondary transmission appears rare; fecal shedding occurs as long as symptoms persist, usually 2-3 weeks; if untreated, persons may shed 2-3 months; prolonged asymptomatic carriage has been reported.


Risk Factors/Susceptibility

Diarrhea is more severe in children; complications in adolescents and older adults are more severe and septicemia occurs more often in people with iron overload or immunosuppression.

  • Consumption of raw/unpasteurized milk/milk products
  • Consumption of potentially contaminated water
  • Consumption of raw/undercooked pork/pork products
  • Animal contact (pets, farm animals, petting zoos)
  • Failure to wash hands after handling raw pork/meat
  • Poor hand hygiene
  • Travel outside the province/country


Diagnosis & Laboratory Testing

Diagnosis is usually made through stool culture. Stool cultures generally are positive during the rst two weeks of illness.

Y. entercolitica and Y. pseudotuberculosis can be recovered from stool, throat swabs, mesenteric lymph nodes, peritoneal fluid, and blood. Y. entercolitica also has been isolated from synovial fluid, bile, urine, cerebrospinal fluid, sputum and wounds.

Testing Information & Requisition


Treatment & Case Management

Treatment is under the direction of the attending health care provider. Contact precautions are indicated for diapered or incontinent children and hospitalized cases for the duration of diarrheal illness.

Provide personal preventative measures (thorough cooking and safe handling of meats; proper hand hygiene practices after toileting, handling meat or animals; only consume pasteurized milk and milk products).

Inform patients that symptomatic cases will be excluded from conducting activities in high-risk settings such as the food industry, healthcare, or daycare until at least 24 hours after cessation of diarrhea or 48 hours after completion of antibiotic therapy.

Advise household members who are symptomatic to seek medical care.


Patient Information

Patient Fact Sheet



1. Ministry of Health and Long Term Care, Infectious Diseases Protocol - Appendix 1 (2022) Yersiniosis.


Additional Resources

Public Health Ontario.. "Yersiniosis"

Heymann, D.L. Control of Communicable Disease Manual (20th Ed.). Washington, American Public Health Association, 2015


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