Table 1 A summary of the focus group participants’ key findings based on the study framework for an enteric disease investigation

Preparation for contacting the case

● Have good working knowledge of the pathogen incubation period, common sources of infection, modes of transmission and control measures.

● Review demographic information pertaining to the case such as gender, age, and residence.

Contacting the case

● Use voice-mail or text-messaging strategically to make contact with cases of particular demographics who do not answer the phone.

Building rapport

● Ensure that cases are comfortable during the interview process. Attempt to relieve any anxiety the case may have.

● Explain the role of public health, the purpose of the interview, and that confidentiality will be maintained.

● Allow cases to tell their story.

● Be empathetic, and be respectful of culture and religious differences as well as language barriers.

Identifying the source

● Educate the case in regard to the pathogen incubation period, modes of transmission and common sources to assist with identifying the source.

● Have the case use a calendar to remember dates, regular weekly activities, and special events close to the date of onset of symptoms.

● Use questionnaires with common risk factors specific to the pathogen and with open and closed-ended questions to assist the case’s recall.

Education

● Use education to assist with identifying the source of the illness (as per above).

● If the source of the illness is identified, education targeted at the identified source can assist with preventing further illness.

● Be sensitive, neutral and non-judgemental when providing education pertaining to high-risk behaviours, sexual practices, and cultural practices

Exclusion

● Identifying a case that requires exclusion from working in a food premise, healthcare setting, or working in/attending a childcare setting can create tension in the interview. It is better to identify if exclusion is required closer to the end of the interview to avoid the loss of any rapport that was built.

Linking cases

● Communication with other enteric disease investigators, public health inspectors, epidemiologists, data entry clerks, and staff in other jurisdictions is useful in attempting to link cases to a common source or food premise.

● Processes that actively attempt to link cases such as the single interviewer approach, a point person in a co-ordinator role, routine meetings of case investigators, and data analysis using spreadsheets or other software tools are useful in attempting to link cases to a common source or food premises.