If you have been following the news this summer, you may have noticed reports about a growing outbreak of a parasitic illness sweeping through multiple states. Here is a clear, science-backed breakdown of what is happening, why it matters, and what you can do right now.
Key Takeaways
- Health officials in multiple U.S. states (including Michigan, Illinois, and New York) have confirmed rising explosive diarrhea parasite cases caused by Cyclospora cayetanensis.
- This parasitic infection spreads through contaminated food or water, especially raw fresh produce like basil, cilantro, mixed greens, and berries.
- The main symptom is prolonged, sometimes explosive, watery diarrhea that can last weeks if untreated, potentially causing dehydration and nutrient loss.
- Carefully washing fresh produce, monitoring health alerts, and seeing a healthcare provider if diarrhea lasts more than a few days are the most practical steps you can take.
How Big Is The Current Explosive Diarrhea Parasite Problem?
Since late spring 2026, the Centers for Disease Control have tracked a higher-than-average number of cases of cyclosporiasis across the country. Here is what the numbers look like:
- By June 16, 2026, at least 145 reported cases were confirmed in 17 states, including Michigan, Illinois, Texas, and New York.
- The Michigan Department of Health and Human Services documented over 700 cases within a few weeks, with Southeast Michigan counties hit hardest. Michigan normally sees about 50 cases of cyclosporiasis annually.
- Illinois health officials and the Illinois Department of Public Health have flagged sharp rises compared with previous summer months.
- For context, in 2019, 4,703 cyclosporiasis infections were reported in the U.S., with at least 2,400 people sickened in a single large outbreak.
- Official counts are likely an underestimate. Many people with mild symptoms never seek care, and Cyclospora requires a special stool test that standard panels often miss.
- These outbreaks tend to cluster during spring and summer months and typically link back to contaminated food rather than international travel.
Meet The Culprit: What Is This "Explosive Diarrhea Parasite"?
Cyclosporiasis is caused by the Cyclospora cayetanensis parasite, a microscopic single-celled organism that invades the lining of your small intestine. Think of it as a tiny intruder that hijacks the cells meant to absorb your nutrients.
- This is a parasitic infection, not a typical bacterial food poisoning or a virus like norovirus.
- The parasite belongs to the same broad family of infectious diseases as the organisms causing malaria and toxoplasmosis (the Apicomplexa group).
- The infection is most common in tropical and subtropical regions, but contaminated imported produce carries it into subtropical regions, the United States, and Europe.
- Cyclospora oocysts (think of them as microscopic eggs) are shed in human feces, enter soil or water, and then contaminate crops. The parasite is hardy, and normal chlorine levels or quick rinsing may not fully eliminate it.
How The Diarrhea Parasite Spreads: Food, Water And Not Other People
One important fact: you cannot catch this explosive diarrhea parasite directly from another person. Infections do not spread from human to human because freshly shed oocysts are not yet infectious. Cyclospora takes 1 to 2 weeks in warm, moist environments to become infectious outside the body.
- The fecal-oral route is key. Fields or irrigation systems become water contaminated with human feces, and crops growing there pick up the parasite.
- Contaminated water used to wash or process food or water used for drinking can also be a source.
- Past outbreaks have been linked to basil, cilantro, and raspberries, as well as snow peas, green onions, bagged salad mixes, and other salad mixes.
- Explosive diarrhea outbreaks are typically due to fecal contamination of food or water. Contaminated food usually looks and smells completely normal.
- Other parasites like Giardia and Cryptosporidium also cause explosive diarrhea outbreaks, but this growing outbreak is specifically about Cyclospora in contaminated food.
Symptoms: Why It Feels So Sudden And "Explosive"
Recognizing symptoms early helps you act before dehydration sets in. Symptoms usually appear 2 to 14 days after eating food contaminated with the parasite, which makes connecting a specific meal to illness difficult.
- The most commonly reported symptom (and main symptom) is severe, watery "explosive" diarrhea, with frequent bowel movements that can wake people at night.
- Other common symptoms include stomach cramps, bloating, nausea, loss of appetite, body aches, fatigue, and weight loss, often with other flu-like symptoms and a general flu-like feeling.
- Low-grade fever is a less common but possible gastrointestinal symptom.
- Symptoms can last from a few days to over a month without treatment. They may come in waves, seeming to improve then returning, which is a hallmark of this gastrointestinal illness.
- This prolonged illness occurs because the parasite irritates the intestinal lining, reducing absorption of water, salts, and nutrients, and can become life-threatening in vulnerable groups through severe dehydration.
Diagnosis, Treatment And When To Call A Doctor
Do not ignore persistent explosive diarrhea. If watery diarrhea lasts longer than 2 to 3 days, is very severe, or comes with dizziness or extreme thirst, contact your healthcare provider.
- Diagnosis requires a stool test specifically ordered for Cyclospora or "ova and parasite" testing. Standard bacterial stool cultures alone will miss it. Some patients need to test positive on multiple samples because shedding can be intermittent.
- Cyclosporiasis is typically treated with the prescription antibiotic trimethoprim-sulfamethoxazole (TMP-SMX) for 7 to 10 days. Antibiotics are used to treat Cyclospora infections, with trimethoprim-sulfamethoxazole being the most common choice. People allergic to sulfa drugs need alternative management.
- For nutrition support during recovery: small, frequent sips of oral rehydration solutions, broths, bananas, rice, and toast help replace fluids and electrolytes.
- Most people with healthy immune systems recover fully. However, older adults, young children, pregnant individuals, and immunocompromised people face higher risk of complications from this parasitic illness and should seek care sooner.
Everyday Prevention: Handling Produce Safely During An Outbreak
Prevention is about reducing risk through smart habits rather than achieving perfect sterility. Here are practical steps, especially during an active explosive diarrhea parasite outbreak:
- Wash hands with soap and running water for at least 20 seconds before and after preparing raw fruits, vegetables, and herbs.
- Rinse raw produce thoroughly under running water. Scrub firm fruits and vegetables like cucumbers and melons with a clean produce brush. Cut away damaged or bruised areas before consuming food.
- Wash fruits and vegetables with clean running water. Soak delicate herbs like basil and cilantro before use, gently agitating them in clean water.
- Commercial produce washes may remove some contamination but are not guaranteed to kill Cyclospora. Practice safe food handling to reduce contamination risk.
- When explosive diarrhea parasite cases are rising, consider cooking higher-risk items. Cooked fruits and vegetables are safer than raw fruits during active outbreaks. Avoid eating contaminated fresh produce during summer months by checking sourcing.
- Pay attention to your local health department or CDC alerts about recalled produce. The Food and Drug Administration and disease control and prevention agencies investigate clusters and publish recall notices.
- Avoid consuming unfiltered water to prevent infection, especially when traveling to tropical and subtropical regions.
Nutrition, Recovery And Long-Term Gut Health After Infection
Several weeks of explosive diarrhea can temporarily lower your absorption of fluids, electrolytes (sodium, potassium), vitamin B12, folate, and fat-soluble vitamins. Here is how to support recovery:
- Start with easy-to-digest, lower-fat meals: rice, potatoes, bananas, yogurt with live cultures, well-cooked vegetables, and simple soups.
- Gradually reintroduce fiber from fresh fruits, vegetables, and whole grains once diarrhea improves. Adding fiber back too early may worsen symptoms.
- Fermented foods like yogurt and kefir may support beneficial gut bacteria, though scientific evidence on specific probiotics after Cyclospora infection remains limited.
- If you experience ongoing weight loss, persistent fatigue, or new food intolerances after recovery, seek follow-up care for individualized nutrition support.
Frequently Asked Questions
Below are answers to some of the more specific questions readers commonly ask about this parasitic infection and the current large outbreak accounting for hundreds of cases across multiple states.
Can I catch the explosive diarrhea parasite from a swimming pool or lake?
Cyclospora outbreaks are mainly linked to contaminated food and drinking water rather than treated pools or chlorinated systems. However, other diarrhea parasites like Cryptosporidium often spread in recreational water. Do not swallow pool or lake water, and shower after swimming. If health officials report a water contamination event, follow boil-water advisories.
What should I do if I recently ate produce that was later recalled?
Check recall notices from the CDC, Food and Drug Administration, or your local health department to confirm the brand, lot number, and dates. Discard recalled items and clean surfaces they touched. Monitor yourself for about 2 weeks. If you develop symptoms like explosive or persistent watery diarrhea, severe stomach cramps, or fever, contact a healthcare provider who may order stool testing.
How can I best protect children during an outbreak?
Serve cooked vegetables more often for young children when the explosive diarrhea parasite cases are rising locally, especially with imported raw produce. Emphasize handwashing after bathroom use, diaper changes, and before eating food. Seek medical care quickly if children show signs of dehydration such as dry mouth, fewer wet diapers, or unusual sleepiness.
Do home remedies or "detox" drinks cure this parasitic infection?
Gentle herbal teas and clear broths may help with comfort and hydration, but they do not kill Cyclospora. Research supports targeted antibiotics as the primary treatment for cyclosporiasis. Relying on detox products alone can delay proper care. Discuss any supplements with your healthcare provider before use.
If I have had cyclosporiasis once, am I protected from getting it again?
Current evidence suggests any natural immunity after infection is incomplete. People can get sick again if exposed to contaminated food or water in the future. Safe food handling, careful produce washing, and attention to public health alerts remain important even after recovery, particularly for those who travel often to tropical regions.
References
- Centers for Disease Control and Prevention. (2026). Cyclosporiasis outbreak surveillance data, 2025-2026. Retrieved from https://www.cdc.gov/cyclosporiasis/php/surveillance/index.html
- Centers for Disease Control and Prevention. (2026). Clinical care of cyclosporiasis. Retrieved from https://www.cdc.gov/cyclosporiasis/hcp/clinical-care/index.html
- Centers for Disease Control and Prevention. (2026). DPDx: Cyclosporiasis biology and lifecycle. Retrieved from https://www.cdc.gov/dpdx/cyclosporiasis/index.html
- Haque, R., et al. (2025). Effectiveness of trimethoprim-sulfamethoxazole in cyclosporiasis: A systematic review and meta-analysis. International Journal of Medical Sciences. Retrieved from https://ijms.info/IJMS/article/view/3960
- Casillas, S. M., et al. (2022). Investigation of U.S. Cyclospora cayetanensis outbreaks in 2019 and evaluation of an improved genotyping system. Epidemiology and Infection, Cambridge University Press. Retrieved from https://www.cambridge.org/core/journals/epidemiology-and-infection/article/investigation-of-us-cyclospora-cayetanensis-outbreaks-in-2019
- Ars Technica. (2026, July 7). Michigan sees explosive outbreak of diarrheal parasite with over 700 cases. Retrieved from https://arstechnica.com/health/2026/07/michigan-sees-explosive-outbreak-of-diarrheal-parasite-with-over-700-cases/
- Merck Manual Professional Edition. (2024). Cyclosporiasis: Transmission, symptoms, diagnosis, treatment. Retrieved from https://www.merckmanuals.com/professional/infectious-diseases/intestinal-protozoa-and-microsporidia/cyclosporiasis