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Over the past 30 years, Yersinia enterocolitica, Yersinia pseudotuberculosis, and minor Yersinia species have been increasingly recognized as important pathogens. Yersinia pestis, the agent that causes plague, is discussed in Chapter 147: Plague.
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The reported incidence of yersiniosis varies geographically; in the United States, Y. enterocolitica accounts for approximately 92% of speciated infections,1 whereas in other countries, such as Japan and Russia, Y. pseudotuberculosis is the most commonly reported Yersinia species. In parts of northern Europe, Japan, and Canada, Yersinia have been reported as a leading cause of bacterial gastroenteritis, in contrast to other countries in Africa, Asia, and South America where Yersinia are less often reported. Because of the complexity in culturing the organism, the incidence of Yersinia may be an underestimate, particularly in resource-limited settings. In the United States, Yersinia are less commonly reported than other bacterial pathogens such as Campylobacter, Salmonella, Shigella, or Shiga toxin-producing Escherichia coli, but their incidence is rising due, in part, to increased detection as a result of culture-independent diagnostic testing (CIDT).2 Most cases occur in the cold months, and incidence of reported infections is highest in children.1
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A wide variety of animals, including domestic dogs, cats, sheep, cattle, and pigs, have been found to be asymptomatically infected with Y. enterocolitica. Although Yersinia has been isolated from a variety of foods, most of these isolates are nonpathogenic. In northern Europe, pathogenic strains of Yersinia have been frequently found in the pharynx of pigs, and in raw pork and pork products. These foods have often been implicated as a source of human disease.3,4 The ability of Yersinia species to grow at 4ºC may contribute to the frequency with which raw or partly cooked refrigerated meats cause sporadic cases and outbreaks.5 In the United States, illness in black infants has been associated with pork chitterlings (intestines) being prepared in the infant’s home,3 although in recent years there has been a decline in these infections, possibly as a result of reduced contamination, educational efforts, or both.6 Outbreaks have been associated with ingestion of milk, tofu, produce, and other foods.7–9 Cases have also been associated with ill pets including dogs.10 Few cases have been associated with water, even though this organism has been found in rivers, lakes, and drinking water.7,11 Secondary cases are rare, but nosocomial and intrafamilial transmission have been reported.7
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Y. pseudotuberculosis is widespread in the environment, and is also found in many animal species, especially rodents and other small mammals, and can cause illness in deer and other ruminants.
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CLINICAL CHARACTERISTICS
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Most Yersinia enterocolitica infections present as gastroenteritis, characterized by a febrile illness with diarrhea with abdominal pain. The diarrhea can be bloody, especially in children less than 5 years old. Y. pseudotuberculosis and other minor ...