Although Yersinia enterocolitica are primarily found in northern Europe and North America, worldwide, 1 to 3 percent of diarrhea illnesses are caused by these bacteria.
A Yersinia enterocolitica infection is most often acquired by eating contaminated food, especially raw or undercooked pork products. Occasionally, infection occurs after contact with infected animals, passing from the stools or soiled fingers of one person to the mouth of another person.
Symptoms of infection can vary, depending on the age of the person infected. Infections occur most often in young children. Common symptoms of a Yersinia enterocolitica infection in children include:
- Abdominal pain (stomach pain)
- Diarrhea, which in 5 percent of children is bloody.
In older children and adults, right-sided abdominal pain and fever may be the most common symptoms, and may be confused with appendicitis. In a small number of cases, complications can occur, such as:
- Erythema nodosum
- Joint pains
- Spread of bacteria to the bloodstream (known as septicemia).
Septicemia from Yersinia enterocolitica is more common in people with:
- Graves' disease (a common form of hyperthyroidism)
- Cirrhosis (the destruction of an organ)
- Hemochromatosis (a metabolic disorder)
- Severe anemia (a deficiency of red blood cells).
Yersinia pseudotuberculosis is the closest genetic relative to Yersinia pestis, but can be distinguished from it by the symptoms it causes and by laboratory test results.
Neither of these bacteria frequently infect humans, in contrast to Yersinia enterocolitica, which accounts for 1 to 3 percent of diarrhea cases caused by bacteria. When Yersinia pseudotuberculosis does infect humans, it can cause symptoms similar to Yersinia enterocolitica. Such infections are more common in females and during winter months.