Should We Be Worried About Cyclosporiasis?
1Q1A — where we ask one question and an expert gives one answer
Story by:
- Sara Bock
–
sbock@ucsd.edu
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Published Date
July 16, 2026
Story by:
- Sara Bock
–
sbock@ucsd.edu
Article Content
Few people had heard of cyclosporiasis a week ago. Now it’s one of the latest public health topics dominating headlines and social media feeds — and it’s not exactly the summer conversation anyone was hoping to have
Recent reports of cases in California come as a growing number of illnesses have been reported across the country, fueling questions about fresh produce, food safety and whether people should change what they’re eating. The illness, caused by the parasite Cyclospora, can trigger prolonged bouts of explosive diarrhea and is most commonly linked to contaminated fresh produce
To help separate fact from fear, we turned to a UC San Diego expert who studies parasites for a living
Conor Caffrey is a parasitologist and pharmaceutical scientist, professor in the Skaggs School of Pharmacy and Pharmaceutical Sciences and director of UC San Diego’s Center for Discovery and Innovation in Parasitic Diseases. He and his colleagues in the center develop new treatments for neglected parasitic diseases and study the biology of parasites more broadly, helping advance research that informs drug development, diagnostics and public health preparedness around the world
What should people know about cyclosporiasis, and should they be worried?
Conor Caffrey: “After COVID, and hot on the heels of the recent hantavirus episode on a cruise ship, the public and media are now much more sensitized to what’s going on in their environment. So, in the case of cyclosporiasis, it’s very understandable that people are asking questions about this latest disease.
Cyclospora is an intestinal parasite that spreads differently than many people assume. It isn’t passed directly from person to person. Instead, infected people shed the parasite in their feces, but it isn’t immediately infectious. It has to spend time in the environment — typically in warm, humid conditions, where it matures before it becomes capable of infecting another person, typically through contaminated food or water. That’s why outbreaks are linked to contaminated fresh produce rather than casual contact.
The hallmark symptom is persistent, sometimes explosive, watery diarrhea that can be quite severe. People often think they’re getting better, only to relapse because they’re still carrying the parasite. If symptoms persist, staying hydrated is especially important — particularly for children and older adults — and it’s important to seek medical care and receive a proper diagnosis. There are effective treatments available once the infection is identified
Cyclospora is a very resilient parasite. People ask whether washing produce is enough, and while washing may reduce contamination, it doesn’t reliably remove or kill Cyclospora. Cooking produce or peeling fruits and vegetables when appropriate are the most effective ways to protect yourself. Avoiding fruits and vegetables altogether is the wrong message
One of the things we’ve learned from studying parasites is that there are common themes across many of the diseases they cause. Basic food and water hygiene is one concept that can help reduce the risk of many infectious diseases, as well as the continued need for robust and adaptive local and national public health surveillance systems.Cyclospora thrives in warm, humid conditions, so these outbreaks tend to become more common during the warmer months. Indeed, as temperatures continue to rise in general, we’ll need to stay ahead of the curve by identifying outbreaks early and being ready to respond.”
