Yersinia

General Information

What is yersiniosis?

Yersiniosis is an infectious disease caused by a bacterium of the genus Yersinia. In the United States, most human illness is caused by one species, Y. enterocolitica. Infection with Y. enterocolitica can cause a variety of symptoms depending on the age of the person infected. Infection with Y. enterocolitica occurs most often in young children. Common symptoms in children are fever, abdominal pain, and diarrhea, which is often bloody. Symptoms typically develop 4 to 7 days after exposure and may last 1 to 3 weeks or longer. In older children and adults, right-sided abdominal pain and fever may be the predominant symptoms, and may be confused with appendicitis. In a small proportion of cases, complications such as skin rash, joint pains, or spread of bacteria to the bloodstream can occur.

What sort of germ is Y. enterocolitica?

Y. enterocolitica belongs to a family of rod-shaped bacteria. Other species of bacteria in this family include Y. pseudotuberculosis, which causes an illness similar to Y. enterocolitica, and Y. pestis, which causes plague. Only a few strains of Y. enterocolitica cause illness in humans. The major animal reservoir for Y. enterocolitica strains that cause human illness is pigs, but other strains are also found in many other animals including rodents, rabbits, sheep, cattle, horses, dogs, and cats. In pigs, the bacteria are most likely to be found on the tonsils.

How do people get infected with Y. enterocolitica?

Infection is most often acquired by eating contaminated food, especially raw or undercooked pork products. The preparation of raw pork intestines (chitterlings) may be particularly risky. Infants can be infected if their caretakers handle raw chitterlings and then do not adequately clean their hands before handling the infant or the infant’s toys, bottles, or pacifiers. Drinking contaminated unpasteurized milk or untreated water can also transmit the infection. Occasionally Y. enterocolitica infection occurs after contact with infected animals. On rare occasions, it can be transmitted as a result of the bacterium passing from the stools or soiled fingers of one person to the mouth of another person. This may happen when basic hygiene and handwashing habits are inadequate. Rarely, the organism is transmitted through contaminated blood during a transfusion.

How common is infection with Y. enterocolitica?

Y. enterocolitica is a relatively infrequent cause of diarrhea and abdominal pain. Based on data from the Foodborne Diseases Active Surveillance Network (FoodNet), which measures the burden and sources of specific diseases over time, approximately one culture-confirmed Y. enterocolitica infection per 100,000 persons occurs each year. Children are infected more often than adults, and the infection is more common in the winter.

How can Y. enterocolitica infections be diagnosed?

Y. enterocolitica infections are generally diagnosed by detecting the organism in the stools. Many laboratories do not routinely test for Y. enterocolitica,so it is important to notify laboratory personnel when infection with this bacterium is suspected so that special tests can be done. The organism can also be recovered from other sites, including the throat, lymph nodes, joint fluid, urine, bile, and blood.

How can Y. enterocolitica infections be treated?

Uncomplicated cases of diarrhea due to Y. enterocolitica usually resolve on their own without antibiotic treatment. However, in more severe or complicated infections, antibiotics such as aminoglycosides, doxycycline, trimethoprim-sulfamethoxazole, or fluoroquinolones may be useful.

Are there long-term consequences of Y. enterocolitica infections?

Most infections are uncomplicated and resolve completely. Occasionally, some persons develop joint pain, most commonly in the knees, ankles or wrists. These joint pains usually develop about 1 month after the initial episode of diarrhea and generally resolve after 1 to 6 months. A skin rash, called "erythema nodosum," may also appear on the legs and trunk; this is more common in women. In most cases, erythema nodosum resolves spontaneously within a month.

What can be done to prevent the infection?

1. Avoid eating raw or undercooked pork.
2. Consume only pasteurized milk or milk products.
3. Wash hands with soap and water before eating and preparing food, after contact with animals, and after handling raw meat.
4. After handling raw chitterlings, clean hands and fingernails scrupulously with soap and water before touching infants or their toys, bottles, or pacifiers. Someone other than the foodhandler should care for children while chitterlings are being prepared.
5. Prevent cross-contamination in the kitchen: -Use separate cutting boards for meat and other foods. -Carefully clean all cutting boards, counter-tops, and utensils with soap and hot water after preparing raw meat.
6. Dispose of animal feces in a sanitary manner.

What are public health agencies doing to prevent or control yersiniosis?

The Centers for Disease Control and Prevention (CDC) monitors the frequency of Y. enterocolitica infections through the foodborne disease active surveillance network (FoodNet). In addition, CDC conducts investigations of outbreaks of yersiniosis to control them and to learn more about how to prevent these infections. CDC has collaborated in an educational campaign to increase public awareness about prevention of Y. enterocolitica infections. The U.S. Food and Drug Administration inspects imported foods and milk pasteurization plants and promotes better food preparation techniques in restaurants and food processing plants. The U.S. Department of Agriculture monitors the health of food animals and is responsible for the quality of slaughtered and processed meat. The U.S. Environmental Protection Agency regulates and monitors the safety of our drinking water supplies.