skip to main content

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. Yersiniosis is likely underdiagnosed because in many laboratories it is not included in routine stool culture for gastrointestinal pathogens.

Resources for the general public
Resources for health care providers
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 cases of yersiniosis were reported in 2014, compared to a five-year average of 12 cases per year. Beginning in early 2011, laboratories were required to report positive results for yersiniosis, which typically leads to an increase in the number of reports. Eight of the cases were hospitalized, and none died. Sixteen cases were exposed in King County, one was exposed during travel to Mexico, and three cases had undetermined places of exposure.

While most cases reported are typically Y. enterocolitica, 4 Y. pseudotuberculosis cases were reported in 2014, three of which were reported in December. A source has not yet been identified. Europe has reported numerous outbreaks of Y. pseudotuberculosis associated with consumption of produce – including iceburg lettuce and carrots – that has undergone prolonged cold storage.

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

Each year in Washington state between 20 and 40 cases are reported.