Yersiniosis is an intestinal disease found mostly in children and young adults that is caused by bacteria in the genus Yersinia. In the United States, the rod-shaped bacterium Yersinia enterocolitica causes the most illness from yersiniosis, primarily in young children. This bacterium is found in the feces of infected humans and animals and in some foods. The infectious disease is characterized by intestinal pain and by symptoms that resemble appendicitis.
According to the Foodborne Diseases Active Surveillance Network (FoodNet), as monitored by the Centers for Disease Control and Prevention (CDC), about one Y. enterocolitica infection occurs for every 100,000 persons annually in the United States. Children are infected at higher rates than adults. The infection is more common in the colder months of the year because the bacteria prefer cooler temperatures.
Adults most often acquire yersiniosis when they don't practice proper hygiene, especially handwashing. Other activities that can lead to transmission of Y. enterocolitica include eating contaminated foods, such as undercooked or raw pork (especially chitterlings, which are made from the large intestines of pigs). Sometimes, humans contract the disease after coming in contact with the feces or urine of infected animals. Handling contaminated soil or contaminated human feces can also cause the infection. Although commonly assumed, yersiniosis does not originate from the mouths of infected humans.
Children can acquire the infection from drinking contaminated milk that is not pasteurized or untreated water. Babies acquire the infection when adults carelessly handle raw pork and do not wash their hands before handling the baby or objects in contract with the baby, such as bottles, clothing, and toys.
Infants are especially susceptible to yersiniosis. A medical professional should be consulted as soon as symptoms appear in an infant in order to assure that health complications do not result. It is especially important that infants younger than three months be immediately treated if suspected of being infected with yersiniosis because bacteremia (a blood infection) can result. An infant with bacteremia is often treated in a hospital or major medical facility due to the seriousness of this condition.
Yersiniosis can cause numerous symptoms, which primarily depend on the age of the patient. Most symptoms appear within three to seven days of being infected. They often last one to three weeks, but sometimes longer. In young children, common symptoms include abdominal pain, watery diarrhea often containing blood or mucus, and fever. In older children and adults, common symptoms include abdominal pain on the right portion of the body (similar to symptoms reported for appendicitis) and fever. Other symptoms include nausea and vomiting. Some people do not have noticeable symptoms, but they still excrete the bacteria in their stool and can infect others. Complications from yersiniosis can include joint pain, skin rashes, and spread of the bacteria into the bloodstream.
Yersiniosis is found worldwide, but it more prevalent in areas where wild or domesticated animals, primarily pigs, are found. The bacterium that causes yersiniosis is found worldwide, however, the infection itself is more likely to be found in areas with poor sanitary conditions and among people with poor personal hygiene. For the most part, yersiniosis is a relatively uncommon bacterial infection in the United States.
Diagnosis of yersiniosis is generally performed through detection of the organism in the stools (feces) of infected people. The organism can also be detected through culture samples taken from the bile, blood, joint fluid, lymph nodes, or urine of patients. Stool samples can also distinguish between yersiniosis and appendicitis.
Treatment is usually not necessary when cases are uncomplicated. However, treatment is needed when cases become complicated, such as when severe symptoms occur or bacteria enter in the bloodstream. Then, antibiotics, such as aminoglycosides, fluoroquinolones, or tirmethoprim/sulfamethoxazole, are often prescribed.
Long-term problems caused by lack of treatment can result. Joint pain in the ankles, knees, or wrists sometimes occurs. Such pain often develops about one month after diarrhea occurs. A skin rash sometimes appears on the legs and trunk; women more frequently develop this complication than do men.
Yersiniosis can be prevented by eating only thoroughly cooked meats and, especially, and by staying away from raw or undercooked pork. Pork and other meats should be cooked to an internal temperature of at least 150°F (66°C). In addition, people should only consume pasteurized milk and milk products to avoid yersiniosis.
Prevention can be maximized by washing hands after handling raw meat, going to the bathroom, changing diapers (and promptly throwing away soiled diapers), and touching animals. Hands should be washed thoroughly with soap and water before playing with infants or touching their toys, bottles, or other such objects. Kitchen countertops, cutting boards, and other utensils should be cleaned regularly, especially after raw meat is prepared. Animal and human feces should be disposed of in a sanitary manner. Water supplies should be protected from human and animal wastes.
Chitterlings (pig intestines) is a traditional holiday food in some parts of the world, such as the United States. The preparation of chitterlings is a long and messy process that is a primary source of yersiniosis infection. Fecal matter is sometimes contained in the pork intestines, posing a health concern to those in direct contact with the contaminated intestines, and to children and infants who may be exposed to Y. enterocolitica by adult caregivers who have handled the contaminated intestines. The CDC states that public awareness campaigns are mounted each year in an attempt to eliminate such contamination. However, for the most part, these campaigns have been unsuccessful. Measures are continuing to be developed and implemented to prevent this disease among people who perform what the CDC considers a high-risk health activity.
WORDS TO KNOW
BACTEREMIA: Bacteremia occurs when bacteria enter the bloodstream. This condition may occur through a wound or infection, or through a surgical procedure or injection. Bacteremia may cause no symptoms and resolve without treatment, or it may produce fever and other symptoms of infection. In some cases, bacteremia leads to septic shock, a potentially life-threatening condition.
PASTEURIZATION: Pasteurization is a process where fluids such as wine and milk are heated for a predetermined time at a temperature that is below the boiling point of the liquid. The treatment kills any microorganisms that are in the fluid but does not alter the taste, appearance, or nutritive value of the fluid.
SURVEILLANCE: The systematic analysis, collection, evaluation, interpretation, and dissemination of data. In public health, it assists in the identification of health threats and the planning, implementation, and evaluation of responses to those threats.
Several U.S. federal agencies are involved in the control and prevention of yersiniosis. The CDC monitors yersiniosis through its FoodNet and also conducts surveillance and investigations whenever outbreaks of the disease occur. This agency also uses public awareness campaigns to publicize the dangers associated with yersiniosis. The U.S. Food and Drug Administration (FDA) inspects food and milk processing plants and restaurants in order to assure safe products are consumed by all U.S. citizens.
The United States Department of Agriculture (USDA) monitors the health of domesticated animals raised for food. It inspects food slaughtering and processing plants to ensure that the human food supply is not contaminated. The U.S. Environmental Protection Agency (EPA) monitors and regulates the safety of U.S. drinking water to prevent the transmission of yersiniosis and other infectious diseases through the water supply.
Bannister, Barbara A. Infection: Microbiology and Management. Malden, MA: Blackwell Publishing, 2006.
Centers for Disease Control and Prevention. “Yersinia enterocolitica.” October 25, 2005. <http://www.cdc.gov/ncidod/dbmd/diseaseinfo/yersinia_g.htm> (accessed April 7, 2007).
Food Safety and Inspection Service, U.S. Department of Agriculture. “Yersiniosis and Chitterlings: Tips to Protect You and Those You Care for from Foodborne Illness.” February 2, 2007. <http://www.fsis.usda.gov/Fact_Sheets/Yersiniosis_and_Chitterlings/index.asp> (accessed April 9, 2007).