Cyclospora (Cyclosporiasis) is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

What Is Cyclospora?

Cyclospora cayetanensis is a single-celled parasite that infects the small intestine. It is not a virus or bacteria. The parasite is shed in human feces as oocysts (protective shells), which need time (days to weeks) in the environment to become infectious. This is why direct person-to-person spread is rare.

Get the Drinking Water Guide

How Cyclospora Lands in the Food System

Contamination usually occurs when human feces pollute water used for irrigation, washing produce, or during harvesting/processing — most often in tropical or subtropical regions where the parasite is endemic. The parasite then clings to the surface of fresh produce.

It is not typically spread by animals or in the U.S. domestic supply chain in the same way as some bacterial outbreaks. Most U.S. cases are linked to imported fresh produce.

Commonly linked foods in outbreaks (historical and recent):

• Raspberries
• Basil
• Cilantro
• Snow peas
• Mesclun lettuce and other salad mixes/leafy greens
• Occasionally other herbs or fresh produce

Recent outbreaks (including 2026) have frequently been associated with lettuce and salad mixes.

Effects on Humans

Healthy people:

• Symptoms usually start about 1 week after infection (range: 2 days to 2+ weeks).
  
  
• Main symptoms: Watery diarrhea (often frequent/explosive), loss of appetite, weight loss, stomach cramps, bloating, gas, nausea, and significant fatigue.
  
  
• Less common: Vomiting, low-grade fever, body aches, headache.
  
  
• Illness can last from a few days to over a month if untreated. Symptoms may improve then relapse. It is debilitating but rarely life-threatening. Most people eventually recover, though fatigue can linger.

Immunocompromised people: (e.g., HIV/AIDS, organ transplant recipients, chemotherapy patients, or those on immunosuppressive drugs):

• Symptoms are often more severe and prolonged.
  
  
• Higher risk of chronic or relapsing diarrhea, significant weight loss, malabsorption, and complications.
  
  
• May require longer treatment courses.

Some infected people (especially in endemic areas) may have mild or no symptoms.

Treatment (Getting Rid of It in the Body)

The standard treatment is the antibiotic trimethoprim-sulfamethoxazole (TMP-SMX, brand names Bactrim, Septra, or Cotrim), usually for 7–10 days. Immunocompromised patients may need longer courses.

Supportive care includes rest and staying hydrated. See a healthcare provider if you have prolonged diarrhea (especially during May–August, the peak U.S. season). Diagnosis requires specific lab testing for Cyclospora.

What Kills or Removes Cyclospora on Produce

• Regular washing with water: Helps reduce risk but does not reliably remove or kill the parasite. The oocysts are sticky and resistant.
  
  
• Commercial produce washes, chlorine, or sanitizers: Generally not effective against Cyclospora oocysts.
  
  
• Vinegar soak (e.g., 1 part white vinegar to 3 parts water, soak and swish for a few minutes): May help mechanically dislodge some parasites but does not kill them.
  
  
• Heat (cooking): The only reliable method to kill Cyclospora. Cook produce to an internal temperature of at least 158°F (70°C) or boil it.

Best consumer practices:

• Wash all fruits and vegetables thoroughly under running water before eating or preparing (even pre-washed items). Separate leaves of leafy greens and herbs.
  
  
• Scrub firm produce with a clean brush.
  
  
• Peel when possible.
  
  
• Refrigerate cut or peeled produce promptly.

High-Risk Produce to Be Cautious With (Especially During Outbreaks)

These have been repeatedly linked to outbreaks and are often eaten raw:

Lower risk (generally safer when raw if washed well): Most other fruits and vegetables not listed above, especially those typically cooked or peeled (e.g., carrots, cucumbers, melons — though always wash).

Frozen produce is generally considered lower risk because freezing and processing often reduce parasite viability.

Practical Tips to Keep Your Family Safe

• During active outbreaks (often May–August), consider cooking high-risk produce (lettuce, herbs, berries) instead of eating raw.
  
  
• Buy from trusted sources and check for any recalls or outbreak notices from CDC/FDA.
  
  
• Practice excellent hand hygiene when handling produce.
  
  
• For immunocompromised family members: Be extra cautious — prioritize cooked versions of high-risk items or well-washed produce from known safe sources.
  
  
• Thorough washing + cooking when possible offers the best protection.

Note: Most fresh produce is safe when handled properly, but Cyclospora is particularly resistant to standard washing. Heat is your best defense for susceptible items.

References

1. Centers for Disease Control and Prevention (CDC)
   About Cyclosporiasis
   https://www.cdc.gov/cyclosporiasis/about/index.html
   (Published/updated July 14, 2026)
   
   
2. Centers for Disease Control and Prevention (CDC)
   Symptoms of Cyclosporiasis
   https://www.cdc.gov/cyclosporiasis/signs-symptoms/index.html
   
   
3. Centers for Disease Control and Prevention (CDC)
   Preventing Cyclosporiasis
   https://www.cdc.gov/cyclosporiasis/prevention/index.html
   
   
4. U.S. Food and Drug Administration (FDA)
   Cyclospora
   https://www.fda.gov/food/foodborne-pathogens/cyclospora
   (Updated information as of 2022–2026)
   
   
5. Centers for Disease Control and Prevention (CDC)
   Surveillance of Cyclosporiasis
   https://www.cdc.gov/cyclosporiasis/php/surveillance/index.html
   (Includes 2026 case data and outbreak information)