Yersiniosis is an intestinal infection that causes diarrhea. In humans, the infection is most often caused by bacteria called Yersinia enterocolitica or Yersinia pseudotuberculosis. Yersiniosis is found worldwide, with cases most often occurring in children and young adults.

How is yersiniosis spread?

Yersiniosis is usually caused by eating or drinking food or water contaminated with Yersinia bacteria or by coming in contact with a person or animal infected with Yersinia. People can become sick after eating raw or undercooked pork or pork products or raw (unpasteurized) dairy products. The preparation of raw pork intestines (chitterlings or chitlins) can be particularly risky. Poor sanitation, improper food storage or poor food handling practices (allowing for a risky food to cross-contaminate what should be a safe food) may also be a source of infection.

When Yersinia bacteria grow in food that is already cooked, the bacteria last longer than in raw foods. Yersinia can grow at refrigeration temperatures, for example, in refrigerated seafood and vacuum-packed meats, boiled eggs, boiled fish, pasteurized liquid eggs, pasteurized whole milk, cottage cheese and tofu.

Animals other than pigs can also carry strains of Yersinia that cause human illness including rodents, rabbits, sheep, cattle, horses, dogs and cats.

What are the symptoms of yersiniosis?
In most cases, symptoms start 3 to 7 days (up to 10 days) after ingesting the bacteria. In children under 5 years, symptoms include fever, abdominal pain and diarrhea; stool often contains pus, blood and mucous. Diarrhea commonly lasts for over 2 weeks. In older children and adults there may be pain in the lower right abdomen which may be mistaken for appendicitis. The bacteria can also get into the blood stream and infect other parts of the body. Reactive arthritis (painful joints) and a red, nodular rash (little swellings) may occur as complications beginning within one month after the onset of the first symptoms.
What is the treatment for yersiniosis?

In general, people only require rest and fluids to replace water lost through diarrhea. Most people recover in a few days without treatment. People with severe symptoms or symptoms that last a long time should seek care from their health care provider.

Are there any restrictions or special considerations for people ill with yersiniosis?

Persons who are ill with yersiniosis should stay at home while they have symptoms. People who work preparing or handling food, people who provide child care or health care, and children who attend daycare cannot return to these settings until the diarrhea has stopped for at least 24 hours.

How can I protect myself against yersiniosis?

To prevent becoming ill with yersiniosis:

  • Cook meats (especially pork), poultry pieces and egg products to 74°C (165°F)
  • Do not eat raw pork or pork products
  • Wash hands well for at least 15 seconds before preparing food and when hands become soiled with meat, poultry, fish or eggs, as well as before eating, after using the toilet, after changing a diaper, after touching animals and anytime hands might be dirty
  • Do not eat or drink raw (unpasteurized) milk or dairy products
  • Clean counters where food is prepared with warm soapy water, and sanitize utensils, cutting boards and surfaces that may have been contaminated with raw meat or poultry
  • Use one cutting board for raw meat and another cutting board for fresh produce to prevent cross-contamination
  • Avoid food preparation or serving food or drinks to others if you have diarrhea
What is Ottawa Public Health’s role?

All cases of yersiniosis must be reported to public health. Once a laboratory report of this illness is received, Ottawa Public Health (OPH) investigates all cases to potentially determine the cause or exposure, provide education, and follow up with their healthcare providers where appropriate. If a common source of illness is identified, OPH will provide follow-up investigation.

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