Multiple Outbreaks of Cyclosporiasis Arrive in the U.S. – Federal Perspective on the Cyclospora Investigation

BACKGROUND: During the summer of 2013, the Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and state and local partners investigated clusters of illnesses associated with Cyclospora cayetanensis. Extensive epidemiological and traceback analysis performed by CDC, FDA, and states identified at least two separate common source Cyclospora outbreaks: one associated with bagged salad mix and one with fresh cilantro.

METHODS: Cases were defined as persons with laboratory-confirmed Cyclospora cayetanensis infection with symptom onset (reported or estimated) between June 1 and August 31, 2013 with no known travel prior to illness onset. FDA field offices, in conjunction with state partners, collected product distribution records in order to identify products and firms potentially associated with case patient illnesses.

RESULTS: A total of 631 cases, with 49 hospitalizations and no deaths, from 25 states were ultimately investigated. The Iowa Department of Public Health (IDPH) and Nebraska Department of Health and Human Services (NDHHS) identified bagged salad mix as the vehicle for IA/NE cases associated with exposure to multiple locations of Restaurant Chain A and B; this product was ultimately traced to a common distribution center.  FDA and state partners continued traceback activities, identifying Taylor Farms de Mexico as the producer of the implicated product.  An Environmental Assessment (EA) was performed jointly by FDA, CDC and Mexican officials in cooperation with the firm at Taylor Farms de Mexico’s processing facility in Guanajuato, Mexico and five farms associated with the production of salad mix components. All samples collected during the EA were negative for Cyclospora and conditions and practices observed at these facilities at the time of the assessment were in accordance with known food safety protocols. Epidemiologic analysis of multiple TX clusters by CDC, TX state and local health authorities identified cilantro as a common suspect vehicle. FDA and state partners performed a traceback investigation and identified farms/growers of interest in Puebla, Mexico.

CONCLUSIONS: Epidemiologic information combined with traceback findings led FDA to increase surveillance sampling of produce imported from Mexico. As a result of the EA, Taylor Farms de Mexico implemented additional safety control measures at their facilities. Deficiencies in laboratory techniques and poor food history recall from case patients were some of the challenges faced during this investigation. Despite these challenges, strong collaboration between federal, state, and local public health and regulatory officials led to the identification of at least two separate outbreaks of cyclosporiasis.