Cyclosporiasis Surveillance — United States, 2011–2015

• Published in: MMWR. Surveillance summaries 2019-04, Vol.68 (3), p.1-12
• Main Authors: Casillas, Shannon M., Hall, Rebecca L., Herwaldt, Barbara L.
• Format: Article
• Language: English
• Subjects: Surveillance Summaries
• ISSN: 1546-0738; 1545-8636
• DOI: 10.15585/mmwr.ss6803a1

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis, which is transmissible by ingestion of fecally contaminated food or water. Cyclosporiasis is most common in tropical and subtropical regions of the world. In the United States, foodborne outbreaks of cyclosporiasis have been linked to various types of imported fresh produce (e.g., basil, raspberries, and snow peas). Validated molecular typing tools, which could facilitate detection and investigation of outbreaks, are not yet available for C. cayetanensis. 2011-2015. CDC has been conducting national surveillance for cyclosporiasis since it became a nationally notifiable disease in January 1999. As of 2015, cyclosporiasis was a reportable condition in 42 states, the District of Columbia, and New York City (NYC). Health departments voluntarily notify CDC of cases of cyclosporiasis through the National Notifiable Diseases Surveillance System and submit additional case information using the CDC cyclosporiasis case report form or the Cyclosporiasis National Hypothesis Generating Questionnaire (CNHGQ). For the 2011-2015 surveillance period, CDC was notified by 37 states and NYC of 2,207 cases of cyclosporiasis, including 1,988 confirmed cases (90.1%) and 219 probable cases (9.9%). The annual number of reported cases ranged from 130 in 2012 to 798 in 2013; the annual population-adjusted incidence rate ranged from 0.05 cases per 100,000 persons in 2012 to 0.29 in 2013. A total of 415 patients (18.8%) had a documented history of international travel during the 14 days before illness onset, 1,384 (62.7%) did not have a history of international travel, and 408 (18.5%) had an unknown travel history. Among the 1,359 domestically acquired cases with available information about illness onset, 1,263 (92.9%) occurred among persons who became ill during May-August. During 2011-2015, a total of 10 outbreaks of cyclosporiasis associated with 438 reported cases were investigated; a median of 21 cases were reported per outbreak (range: eight to 162). A food vehicle of infection (i.e., a food item or ingredient thereof) was identified (or suspected) for at least five of the 10 outbreaks; the food vehicles included a berry salad (one outbreak), cilantro imported from Mexico (at least three outbreaks), and a prepackaged salad mix from Mexico (one outbreak). Cyclosporiasis continues to be a U.S. public health concern, with seasonal increases in reported cases during spring and summer months. The