Domestically Acquired Cases of Cyclosporiasis — United States, May–August 2018

Last Updated OCTOBER 1, 2018 4:00 PM EDT

Highlights

• Read more in CDC’s MMWR: Multiple Cyclosporiasis Outbreaks—United States, 2018.
• Cyclospora cayetanensis is a single-celled parasite that causes an intestinal infection called cyclosporiasis.
• In 2018, multiple outbreaks of cyclosporiasis were identified and found to be linked to different produce items. Previous U.S. outbreaks of cyclosporiasis have been linked to various types of imported fresh produce (e.g., basil, cilantro, mesclun lettuce, raspberries, and snow peas).
• As of October 1, 2018, 2,299 laboratory-confirmed cases of cyclosporiasis were reported to CDC by 33 states in people who became ill during May–August without a history of international travel during the 14-day period before illness onset.

• • The median illness onset date was July 1, 2018 (range: May 1–August 30, 2018).
  • Fifty-six percent (56%) of sick people were female.
  • The median age among sick people was 49 years (range: <1–103 years).
  • At least 160 people were hospitalized; no deaths were reported.
• The overall number of domestically acquired cases reported to date for May–August 2018 (i.e., 2,299) is markedly higher than the numbers of cases reported for the same period in 2016 and 2017. Multiple large outbreaks were reported during May–August this year. In addition to these multiple large outbreaks, this increase may also be due, in part, to changes in diagnostic testing practices—namely, increased use of a multiplex molecular assay to examine stool specimens. CDC is working with state public health partners to determine whether and to what extent changes in testing practices may have contributed to increased case detection and reporting.
• Approximately one-third of ill people were associated with either of the following two large multistate outbreaks in the Midwest:
  • An outbreak linked to prepackaged vegetable trays (containing broccoli, cauliflower, and carrots) sold at a convenience store chain. Read more about this outbreak investigation.
  • An outbreak linked to salads (containing carrots, romaine, spinach, kale, and varietal red leaf lettuce) sold at a fast food chain. Read more about this outbreak investigation.
• In addition, the following clusters of cases associated with other types of fresh produce, including basil and cilantro, were investigated by state public health authorities, CDC, and FDA:
  • Two basil-associated clusters of eight confirmed cases each were identified among people in two different states (in the West and Midwest) who became ill during June.
    • FDA traceback investigations of the basil associated with these two clusters are ongoing.
  • Multiple cilantro-associated clusters were identified, including three clusters associated with unrelated Mexican-style restaurants in the Midwest. CDC received reports of 53 confirmed cases in people who became ill during May–August and were associated with these three clusters.
    • FDA traceback investigations of the cilantro from the three restaurant clusters are ongoing.
• Many cases of cyclosporiasis could not be directly linked to an outbreak, in part because of the lack of validated molecular typing tools for C. cayetanensis.