Because it is uncommon, many laboratories do not routinely perform the specific tests needed to identify it. The yersinia germ is spread by eating or drinking contaminated food or water or by contact with an infected person or animal. Infected people may experience mild or severe diarrhea, fever and abdominal cramps. Sometimes yersinia infection may mimic appendicitis. Symptoms generally appear three to seven days after exposure.
Animals are the main source of yersinia.
Fecal wastes from animals may contaminate water, milk and foods and become a source of infection for people or other animals. The germ has been found in raw milk, lakes and streams, ice cream, improperly pasteurized chocolate milk, tofu, shellfish and wild and domestic animals. The germ is passed in the feces during the time the person is experiencing diarrhea and in some cases for a few weeks or months afterward. For this reason, infected people must be very careful to thoroughly wash their hands after each toilet visit. Most cases recover on their own without treatment.