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Public Health - Seattle & King County


Yersinia enterocolitica, and less commonly other Yersinia species, are bacteria that cause acute diarrhea. Infection is usually spread by food or water contaminated by feces or urine from infected humans, animals or pets, and raw pork or pork products. Rarely, blood products contaminated with Yersinia from an infected donor cause transfusion-associated infection. Yersiniosis is likely underdiagnosed because in many laboratories it is not included in routine stool culture for gastrointestinal pathogens.

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Yersiniosis in King County

Purpose of surveillance:

  • To identify common source outbreaks
  • To identify and eliminate sources of transmission

Yersiniosis case data

Local epidemiology:

Twenty-two cases of yersiniosis were reported in 2012, which represents an increase over previous years. Beginning in early 2011, laboratories were required to report positive results for yersiniosis, which may account for some of the increase. Seven of the cases were hospitalized, and none died. Sixteen cases were exposed in King County, one was exposed during travel to Africa, and five cases had undetermined places of exposure. Eleven cases reported consumption of pork during their exposure period.

No common source outbreaks of yersiniosis have been identified in King County in the past 20 years.

Each year in Washington state there are between 15 and 30 cases reported.