Suzanne Wilson, MPHSuzanne Wilson, MPHFood and Waterborne Disease EpidemiologistFood and Waterborne Disease Epidemiologist

WVDHHR-Division of Infectious Disease WVDHHR-Division of Infectious Disease EpidemiologyEpidemiology

November 17, 2010November 17, 2010

Definition of a Foodborne Outbreak Preparation steps for an outbreak

investigation Initial action steps for an outbreak

investigation Conducting good interviews

Two or more persons who Two or more persons who experience a similar illness after experience a similar illness after ingestion of a common foodingestion of a common food

Identify Members of Investigation TeamIdentify Members of Investigation Team Nurse/Epi, Environmental, LaboratoryNurse/Epi, Environmental, Laboratory

Delineate roles/activities for team Delineate roles/activities for team membersmembers

Know how to obtain additional Know how to obtain additional resourcesresources

Maintain a network and list of key Maintain a network and list of key contactscontacts

Be educated on clinical features of Be educated on clinical features of specific foodborne illness and the specific foodborne illness and the specific factors that contribute to these specific factors that contribute to these illnesses – stay current!illnesses – stay current!

Establish a system for intake and Establish a system for intake and review of complaints and illness reportsreview of complaints and illness reports

Know your baseline- How many of these Know your baseline- How many of these do we “normally” get?do we “normally” get?

Record informationRecord information Signs and symptomsSigns and symptoms Date and time of onsetDate and time of onset Obtain 72 hour food historyObtain 72 hour food history Any other people who are illAny other people who are ill How many people at the activityHow many people at the activity Any medical treatment or testingAny medical treatment or testing

If random complaintIf random complaint check complaint log for similar reportscheck complaint log for similar reports

If reporting on an event (i.e. banquet, If reporting on an event (i.e. banquet, wedding)wedding) Obtain information on event organizerObtain information on event organizer Contact information for attendeesContact information for attendees

Contact others on list to identify other potential cases

Systematically look at information to determine plausibility of an outbreak Are reported symptoms consistent Any common exposures

USE A LINELIST TO DO THIS!

Keeps all information in one place Allows for systematic evaluation of cases Used to make an epicurve

Sample can be found at: http://www.wvidep.org/AZIndexofInfectiousDiseases/OutbreaksorClustersofAnyIllness/tabid/1535/Default.aspx

Gastroenteritis in Nursing Home

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2

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10

12

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18

Onset Time

Nu

mb

er

of

ca

se

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Staff

Residents

Person-to-Person

Point-source

Develop a case definitionDevelop a case definition Conduct hypothesis generating Conduct hypothesis generating

interviewsinterviews In depth and detail orientedIn depth and detail oriented About 8 to 10 cases About 8 to 10 cases

Develop questionnaireDevelop questionnaire Broad range of exposuresBroad range of exposures

If outbreak is centered around an event If outbreak is centered around an event or locationor location Conduct a risk assessment of the facility Conduct a risk assessment of the facility

and processesand processes Embargo any leftover foodEmbargo any leftover food Track food flow through the facilityTrack food flow through the facility Look for what went wrongLook for what went wrong

““When you have a foodborne When you have a foodborne outbreak, more than one thing went outbreak, more than one thing went

wrong.”wrong.”Dr. Frank Bryan, CDCDr. Frank Bryan, CDC

Handout

Collect Information on Line listing Determine transmission mode Develop case definition Hypothesis Generating Interviews

Can be used for : Verifying outbreak Searching for additional cases Determining if cases are associated Collecting data to determine possible sources

A good interview is a MUST!

Be consistent in interviews Do your homework to minimize repeat

contacts Target questions to greatest degree

possible

Be prepared-conduct training if needed Select form to be used

Establish rapport Identify self, organization, and reason

for investigation Start with easy questions

Demographics, etc. Let them know you may be need to re-

contact them

When they cannot remember meals: Ask about food preferences Can rule in/out some foods Identify key days and dates to jog memory

(use a calendar) Review receipts or checkbook

Buffets-need to clearly describe each food item

Recall is better for items from a menu

Last Meal Bias Take multi day food history Explain that pathogens may take days to

cause illness Ask if leftovers are available for testing Don’t forget the details

Exact restaurant locations

Ask questions as written on form Review form before ending interview Ask if individuals have

Unanswered questions Additional information

Thank them for their time!!

Break up into groups of three Interviewer Interviewee Observer