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Gastroenteritis Outbreak Investigative Guidelines

Investigation Method

1) Collect preliminary data, specifically

  • are there > 2 non-householders with gastroenteritis?
  • what are the percentages of:
    • vomiting?
    • diarrhea?
    • severe abdominal cramps?
    • fever?
  • where did the > 2 non-householders eat?
  • when did they eat (date and time)?
  • when did they start vomiting or experiencing diarrhea (date and time)?
  • what did they eat?
  • with whom did they eat?
  • did they share other meals in the past week?

2) Call ACDP at 971-673-1111 for referral, if indicated, to the ACDP Urgent Epidemiologic Response Team (UERT).

3) Specimens

  • Give outbreak-affected persons Instructions for Collecting Stools for Viral Culture and PCR (pdf)
  • Use secure, leak-proof containers with screw tops, not flip tops, labeled with name, collection date, and outbreak number.
  • Collect specimens of walnut-size stool, 3 tbsp of diarrheal stool (or vomitus) or 3-4 rectal swabs from six outbreak-affected persons up to four days after onset. Collecting >6 does not increase the chance of finding something.
  • Use proper containers for shipping stool and include OSPHL Virology/Immunology Request Form. Keep fresh stool specimens cold from the time they are produced until the time they reach OSPHL. (See Instructions for Stool Collection (pdf). )
  • Remember that two positives are required to "confirm" the microbial cause of an outbreak. The Oregon State Public Health Laboratory will not test just a single specimen.
  • Also send OSPHL scoops of fecal matter plopped into Cary Blair transport media (for bacteriology testing if norovirus tests are negative and include the Microbiology Request Form.

4) Paperwork

Special Situations

Refer to the Investigative Guidelines below for:


Definition, suspect foodborne outbreak

  • > 2 non-householders who develop gastroenteritis (acute onset vomiting, diarrhea or both) at about the same time after eating food from the same source

Investigative authority

  • ORS 333-018-0015 authorizes local health departments to investigate foodborne and other common source outbreaks by requiring health care providers to report all such suspected outbreaks immediately.  
  • ORS 333-019-0010 imposes work restrictions on persons who work at food service facilities whilst in a communicable stage of any illness accompanied by diarrhea or vomiting.
  • ORS 6-24-080 authorizes local health departments to collect stool specimens from food handlers.

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