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Investigating Foodborne Outbreaks


  • 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.

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

Investigation method

    • 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?
    • Call ACDP (971-673-1111) for referral, if indicated, to the ACDP Urgent Epidemiologic Response Team (UERT).
      • Conduct a conference call in accordance with the Outbreak Communication Agreement and following the Outbreak Conference Call Agenda if the outbreak is in Clackamas, Multnomah, or Washington counties.
      • Get patron information and menus from the restaurant using the Foodborne Outbreak Restaurant Checklist (which can and should be used for evaluating other food service establishments).
      • Expand the investigation with ACDP/UERT assistance and in accordance with Outbreak Investigation guidelines. 
    • Specimens
      • Give outbreak-affected persons Instructions for Collecting Stools for Viral Culture and PCR
      • 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. (Instructions for Stool Collection.)
      • Also send OSPHL scoops of fecal matter plopped into Clair Blair transport media (for bacteriology testing if norovirus tests are negative and include the Microbiology Request Form.


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