Before the federal Centers for Disease Control and Prevention (CDC) in Atlanta said the Cyclosporiasis season was over for another year, it added 156 cases from September to the yearly totals.

As of Sept. 28, CDC counted 1,020 laboratory-confirmed cases of cyclosporiasis in people who had no history of international travel during the 14-day period before illness onset. The infections were reported from 37 jurisdictions, including 36 states and New York City, since May 1.

At least 70 people have been hospitalized; no deaths have been reported.

Cyclospora has been coming off a recent peak from 2018-19 when the number of non-travel related patient counts came in at 2,299 in 2018 and 2,418 cases in 2019. The fall-off came in 2020 when the case count fell to 1,241.

In 2021, multiple outbreaks of cyclosporiasis cases associated with different restaurants or events were investigated by state public health authorities, CDC, and the Food and Drug Administration (FDA).

The CDC investigated two large multistate outbreaks of cyclosporiasis one including 40 illnesses and one with 130 illnesses, in which ill people reported eating various types of leafy greens. State officials and FDA conducted traceback investigations for these two outbreaks, but a specific type or grower of leafy greens was not identified as the source of either outbreak.

“The exact timing and duration of these seasonal increases in domestically acquired cyclosporiasis can vary, but reports tend to increase starting in May. In previous years the reported number of cases peaked between June and July, although activity can last as late as September,” CDC’s final report says.

“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,” it adds.

 Previous U.S. outbreaks of cyclosporiasis have been linked to various types of fresh produce, including basil, cilantro, mesclun lettuce, raspberries and snow peas.

Between 33 and 37 states have annually reported cyclosporiasis illnesses.  Domestically acquired Cyclospora usually occurs during the spring and summer months.

The 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 detect outbreaks linked to a common food source.

 However, the agency says many cases of cyclosporiasis cannot be directly linked to an outbreak, in part because of the lack of validated laboratory “fingerprinting” 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 commonality is found, CDC and partners work quickly to determine if a contaminated food product is still available in stores or in peoples’ homes and issue advisories.

In 2021, consumers were told to continue to enjoy fresh produce as part of a well-balanced diet.

The Food and Drug Administration and CDC both recommend washing fresh fruits and vegetables with clean running water; but did caution that washing, including the use of routine chemical disinfection or sanitizing methods, is unlikely to kill Cyclospora cayetanensis. 

Cyclospora cayetanensis is a parasite composed of one cell, too small to be seen without a microscope. This parasite causes an intestinal infection called cyclosporiasis.

Cyclospora is spread by people ingesting something — such as food or water — that was contaminated with microscopic particles of feces. Good hand washing practices help control the spread of the parasite.

Cyclospora needs time, typically, at least 1 to 2 weeks, after being passed in a bowel movement to become infectious for another person. Therefore, it is unlikely that Cyclospora is passed directly from one person to another

People with a diarrheal illness that lasts for more than 3 days or who have any other concerning symptoms should see a health care provider if they think they might have become ill from eating contaminated food.

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