Overview of Cyclosporiasis: the science, risks and red flags
This NPR Short Wave episode explains the recent U.S. outbreak of cyclosporiasis, a parasitic intestinal infection caused by Cyclospora. The conversation covers what the illness is, how it spreads, why this summer’s outbreak is unusually large, who is most at risk, and what people can do to protect themselves while investigators work to identify the source.
What cyclosporiasis is
- Cyclosporiasis is an intestinal infection caused by Cyclospora parasites.
- It can cause foul gastrointestinal symptoms, including:
- gas
- abdominal cramping
- watery diarrhea, sometimes severe or explosive
- The parasite infects the small intestine, reproduces there, and is eventually passed in stool.
Why this outbreak is notable
- The CDC had confirmed 1,645 domestic cases at the time of reporting, with thousands more suspected.
- Experts interviewed on the show said this is likely the largest known Cyclospora outbreak in the U.S.
- Although cases are linked to multiple states, the exact nationwide source is still unclear.
- The FDA and CDC had linked some cases in several states to a possible lettuce source associated with Taco Bell, but that explanation does not account for all cases.
How it spreads
- Cyclosporiasis is commonly spread through contaminated water.
- People can become infected by:
- drinking contaminated water
- eating food washed with contaminated water
- consuming produce grown with contaminated water
- Historically, outbreaks have often been linked to fresh produce.
- Past culprits mentioned in the episode include:
- lettuce
- raspberries
- basil
- cilantro
- snow peas
- salad from McDonald’s in a prior outbreak
Who should be most cautious
- Most healthy adults will likely have a self-limited illness and may recover without treatment.
- Extra caution is advised for:
- older adults
- young children
- immunocompromised people
- These groups are more likely to need evaluation or treatment.
Red flags and when to see a doctor
Symptoms that should prompt concern
- Diarrhea lasting more than a few days
- Diarrhea that goes away and then comes back
- Signs of dehydration, such as not being able to keep fluids down
Why testing matters
- Seeing a doctor is useful not only for treatment, but also for public health tracking.
- Confirmed cases help officials:
- count the outbreak accurately
- identify the source faster
- prevent additional infections
Treatment and recovery
- There is an antibiotic that can help in some cases:
- trimethoprim-sulfamethoxazole
- also known as Bactrim or Septra
- It is generally used more often for people who are more vulnerable or immunocompromised.
- For many healthy people, the infection may resolve on its own.
- Hydration is important if diarrhea develops.
How to reduce your risk
- Check the FDA recall website for recalled produce.
- Wash hands with soap and water before handling fruits and vegetables.
- Wash produce with clean, uncontaminated water.
- Cooking kills the parasite.
- The episode notes that:
- vinegar
- and other popular chemical produce washes
do not reliably kill Cyclospora.
- One expert suggested that, until the outbreak is better understood, it may be reasonable to temporarily avoid raw salads and some fresh produce, especially if you are in a higher-risk group.
Main takeaway
The episode’s core message is that cyclosporiasis is a serious but usually preventable parasite infection tied to contaminated produce and water. While the outbreak source is still being investigated, the best defenses are careful produce handling, attention to recalls, hydration if symptoms appear, and medical evaluation for persistent or recurring diarrhea.