Outbreak of Cyclospora May Be Linked to Imported Broccoli

An outbreak of cyclosporiasis in the US has resulted in 210 cases reported as of June 22, 2023.  While the source has not been definitively determined at this point, "FDA and state and local partners conducted traceback investigations and determined that the broccoli was imported. However, FDA investigators were unable to confirm the specific type or producer of the imported broccoli as the source of the outbreak. This outbreak appears to be over and there is no indication at this time that broccoli continues to be a source of illness for other cases of cyclosporiasis being reported in the United States."

One of the main issues for determining the source is the long time between consumption and symptoms, which can range from one to two weeks. 

Cyclospora is an issue in fresh produce.  "C. cayetanensis is a parasite that must live inside a human host for part of its life cycle, as well as living outside the host during an environmental phase. Although there are many species of Cyclospora, only C. cayetanensis has been known to cause illness in humans, an infection called cyclosporiasis. A person can become infected after ingesting food or water contaminated with the parasite."

Will heating destroy Cyclospora, such as with blanching?  These does not seem to be any history for survival at elevated temperatures, but there are limited studies.

https://www.cdc.gov/parasites/cyclosporiasis/outbreaks/2023/index.html
Cyclosporiasis Illnesses in the United States, 2023
LAST UPDATED JUNE 22, 2023

Fast Facts
Illnesses: 210
Hospitalizations: 30
Deaths: 0
States reporting cases: 22

Investigation status: Active (first posted on May 25, 2023)
2023 Outbreaks:

CDC, FDA, and state and local partners investigated an outbreak of cyclosporiasis cases in Georgia and Alabama linked to raw broccoli that included 20 illnesses. People reported eating broccoli in the 14 days before they got sick. FDA and state and local partners conducted traceback investigations and determined that the broccoli was imported. However, FDA investigators were unable to confirm the specific type or producer of the imported broccoli as the source of the outbreak. This outbreak appears to be over and there is no indication at this time that broccoli continues to be a source of illness for other cases of cyclosporiasis being reported in the United States.

What are the symptoms of cyclosporiasis?

Symptoms usually start within 2 weeks after eating food contaminated with Cyclospora.

People typically experience watery diarrhea. They may also experience loss of appetite, cramping, bloating, increased gas, nausea, and fatigue.

Symptoms can persist for several weeks to a month or more. If untreated, symptoms may get better for a while and then return, and this pattern may repeat.

For more information about Cyclospora, see the Cyclospora Frequently Asked Questions.

https://pubmed.ncbi.nlm.nih.gov/16729675/

Effects of temperature and different food matrices on Cyclospora cayetanensis oocyst sporulation

Lakshmi Sathyanarayanan 1, Ynes Ortega

Affiliations expand

PMID: 16729675 DOI: 10.1645/GE-630R.1

Abstract

Effects of temperature on the sporulation of the parasite Cyclospora cayetanensis were studied in 2 food substrates, dairy and basil. Unsporulated Cyclospora oocysts were subjected to freezing and heating conditions for time periods ranging from 15 min to 1 wk. Oocysts were then removed from the food substrates and placed in 2.5% potassium dichromate for 2 wk to allow viable unsporulated oocysts to differentiate and fully sporulate, and to determine the percentage sporulation as an indicator of viability. Sporulation occurred when oocysts resuspended in dairy substrates were stored within 24 hr at -15 C. When oocysts were placed in water or basil, sporulation occurred after incubation for up to 2 days at -20 C, and up to 4 days at 37 C. Few oocysts sporulated when incubated for 1 hr at 50 C. Sporulation was not observed in basil leaves or water at -70 C, 70 C, [for 15 minutes] *and 100 C. Sporulation was not affected when incubated at 4 C and 23 C for up to 1 wk, which was the duration of the experiment in both of the tested substrates.