BACKGROUND ON INVESTIGATION
The Pennsylvania Department of Health (PADOH) and the Pennsylvania Department of Agriculture is investigating an outbreak of cases of yersiniosis in northeastern Pennsylvania focused in Wayne County. Milk from Creamworks Creamery in Waymart, PA is suspected as the source and control measures are being implemented. At present, PADOH is investigating 17 laboratory-confirmed illnesses due to Yersinia enterocolitica, and numerous additional reports of gastroenteritis. Known illness onsets range from June 17 through July 15, but it is possible the problem existed prior to June 17.
WHEN TO CONSIDER YERSINOSIS FOR YOUR PATIENT
Yersiniosis is a relatively infrequent cause of foodborne illness and outbreaks have been rare in Pennsylvania. Therefore, clinicians may be unfamiliar with the signs and symptoms of yersiniosis. PADOH encourages health care providers and laboratories in northeastern Pennsylvania to consider Yersinia enterocolitica in the differential diagnosis for patients who present with gastroenteritis or with an apparent acute abdomen.
Clinical manifestations most commonly include:
- Diarrhea (sometimes bloody)
- Abdominal pain
- Fever
Yersinia infection can mimic appendicitis, and complications of Yersinia can include perforated bowel or ulcerating ileitis and colitis, as well as a variety of extra-intestinal manifestations such as septic arthritis. Pharyngitis is also sometimes seen, as the organism has a predilection for lymphatic tissue.
Incubation period:
- Typically 4–7 days (range 1–14 days)
Duration of illness:
- 1–3 weeks or longer
The onset of yersiniosis can be more insidious than other foodborne pathogens, and patients may not present for care until several days into illness. Post-infectious sequelae can include erythema nodosum and reactive arthritis.
LABORATORY TESTING FOR YERSINIA ENTEROCOLITICA
If laboratories are conducting PCR testing on stool, any Yersinia positive samples should be reflexed to culture for confirmation. Isolates should be sent to public health authorities for further investigation.
Routine stool or blood cultures may not detect Yersinia, since it grows poorly on the media typically used for pathogens such as Salmonella, Shigella, and Campylobacter.
Selective growth medium and incubation temperatures may be necessary to isolate or identify Yersinia species. Therefore, stool culture requests should specifically include Yersinia testing when indicated. Yersinia grow best at an incubation temperature of 25 degrees Celsius.
REPORTING TO PADOH
PADOH requests that any suspected cases of Yersinia infection be reported to your local health department or the Pennsylvania Department of Health (1-877-PA-HEALTH). In addition, any isolate of Y. enterocolitica from Northeastern PA should be forwarded to the Pennsylvania Department of Health Bureau of Laboratories for confirmation and further identification.
A fact sheet regarding yersiniosis epidemiology, diagnosis, and treatment can be found at https://www.health.pa.gov/topics/Documents/Diseases%20and%20Conditions/Yersinia%20enterocolitica.pdf and https://www.cdc.gov/yersinia/index.html.
Originally released by the Pennsylvania Department of Health on July 19, 2019
