Domestically Acquired Cases of Cyclosporiasis — United States, May–August 2020

Last Updated SEPTEMBER 24, 2020 5:00 PM EDT

While cyclosporiasis cases are reported year-round in the United States, cyclosporiasis acquired in the United States (i.e., “domestically acquired”, or cases of cyclosporiasis that are not associated with travel to a country that is considered endemic for Cyclospora) is most common during the spring and summer months. The exact timing and duration of U.S. cyclosporiasis seasons can vary, but reports tend to increase starting in May. In previous years the reported number of cases peaked between June and July, although increased activity can last as late as September. The overall health impact (e.g., number of infections or hospitalizations) and the number of identified clusters of cases (i.e., cases that can be linked to a common exposure) also vary from season to season. 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).

At a Glance
  • States reporting cases: 34
  • Deaths: 0
  • Hospitalizations: 90


CDC, along with state and federal health and regulatory officials, monitor cases of cyclosporiasis in the United States in the spring and summer months to try to detect outbreaks linked to a common food source. However, many cases of cyclosporiasis cannot be directly linked to an outbreak, in part because of the lack of validated laboratory methods needed to link cases of Cyclospora infection. Officials use questionnaires to interview sick people to determine what they ate in the 14-day period before illness onset. If a commonality is found, CDC and partners work quickly to determine if contaminated product is still available in stores or in peoples’ homes and issue advisories.

Final Update

  • In 2020, multiple outbreaks of cyclosporiasis were identified and found to be linked to different produce items.
  • As of September 23, 2020, 1,241 laboratory-confirmed cases of cyclosporiasis in people who had no history of international travel during the 14-day period before illness onset have been reported to CDC by 35 jurisdictions, including 34 states and New York City, since May 1, 2020.
    • The median illness onset date is June 13, 2020 (range: May 1–August 31, 2020).
    • At least 90 people have been hospitalized; no deaths have been reported.
    • Multiple clusters of cases associated with different restaurants or events were investigated by state public health authorities, CDC, and FDA.

September 24, 2020

Geographic Distribution of Reported Cases of Domestically Acquired Cyclosporiasis—Onset May – August, 2020*



*Data are current as of 9/23/2020 (1:00 PM EDT).  States/jurisdictions highlighted on the map have each reported at least one case. New York State includes case reports from New York City. Data are preliminary and subject to change.  For questions related to the number of cases reported in each state, please contact that state’s health department.

Previous Updates

Page last reviewed: September 24, 2020