BACKGROUND: In July 2016, the Austin Public Health Department (APH) started to receive an influx of laboratory confirmed cyclosporiasis cases from local laboratories. Travis County received the highest number of cases (n=27) reported by any county in Texas during a 3-month period for the second year in a row. This case study details a local health department’s quick response to a another outbreak associated with a restaurant involving case interviews and initial traceback investigation utilizing lessons learned from the 2015 cyclosporiasis outbreak.
METHODS: An outbreak investigation was initiated to identify clusters of illness and potential food vehicles. All cases were interviewed using a state supplied case investigation form for cyclosporiasis and food histories were collected. Applying the same investigative approach as the 2015 outbreak, a restaurant line list was generated and common meal items were analyzed to identify a restaurant cluster of illness. Restaurant site visit with the manager helped hone in on specific fresh produce ingredients by reviewing recipes and supplier invoices.
RESULTS: Twenty-five confirmed cases and 2 probable cases of cyclosporiasis that had onsets of illness between June 13, 2016 and August 13, 2016 were investigated. A cluster of illness was identified at a local restaurant with 6 separate dining parties and 3 employees. Trace back investigation converged on two produce suppliers focusing in on carrots and green cabbage, ingredients in a coleslaw salad used in several dishes.
CONCLUSIONS: Through initial trace back investigation conducted by state agencies, it was determined the suspect food vehicles for this outbreak may have had Mexico origin. Though the FDA import ban placed on cilantro in 2015 significantly reduced the amount of cyclosporiasis cases nationally and statewide, this investigation potentially identified two new produce items that have not been linked to domestically acquired cyclosporiasis. This outbreak it is important reminder to remain vigilant for other sources of contamination for domestically acquired cyclosporiasis cases.