US Cyclosporiasis Outbreak: What You Need to Know

The United States is experiencing its largest-ever recorded cyclosporiasis outbreak. The CDC confirmed more than 4,000 cases since May 1, 2026, across 34 states, with thousands more under investigation — surpassing the previous record of roughly 1,500 cases in a single outbreak. Michigan alone has reported over 6,500 cases. No deaths have been reported, but at least 141 people have been hospitalized.

What Is Cyclosporiasis?

Cyclosporiasis is an intestinal illness caused by Cyclospora cayetanensis, a microscopic single-celled parasite. The parasite is not visible to the naked eye and cannot be killed by standard washing — making contaminated fresh produce particularly risky.

The illness is not typically life-threatening in healthy adults, but it can persist for weeks and cause significant dehydration. People with weakened immune systems face a longer and more severe course of illness, according to the CDC.

How Did This Outbreak Start?

Cases began climbing in May 2026, with an unusually steep surge through June and July. The FDA and CDC, working with state health departments, identified a multistate cluster centered in five Midwestern states: Indiana, Kentucky, Michigan, Ohio, and West Virginia.

Traceback investigations pointed to iceberg lettuce served at Taco Bell locations in those states. On July 17, 2026, Taylor Farms de Mexico voluntarily recalled all iceberg lettuce sourced from central Mexico. The recalled shredded product had been distributed between June 29 and July 16 across 27 states, from Michigan to Florida.

An FDA lab initially reported a positive Cyclospora test on a sample of the lettuce. The agency later retracted that finding, calling it a false positive — but the investigation into Taylor Farms lettuce remains active, with FDA still treating the supply chain as the focus of its traceback.

[REVIEWER: add clinical insight here — e.g., how a gastroenterologist or infectious disease specialist approaches cyclosporiasis diagnosis and why it is frequently missed in routine stool tests]

How Many People Have Been Affected?

The scale is unlike anything seen before with this particular parasite.

Michigan's Department of Health and Human Services reported over 6,500 cases within the investigation window — compared to the state's typical annual count of 40 to 50. The CDC confirmed 4,173 cases nationally as of mid-July, with more than 5,100 additional cases pending further analysis. In a single month, the prevalence of Cyclospora in laboratory tests surged from under 3% of gastrointestinal pathogen tests to over 18%, according to tracking data from the biotech firm bioMérieux.

The previous US record for a single cyclosporiasis outbreak was approximately 1,500 cases, linked to raspberries, according to a 2023 USDA Food Safety Inspection Service report. This outbreak has already eclipsed that by several multiples.

What Are the Symptoms?

Symptoms of cyclosporiasis typically begin about one week after a person consumes contaminated food or water — though onset can range from 2 days to over 2 weeks. That lag is part of why the outbreak has been difficult to trace: by the time people fall ill, they may struggle to remember exactly what they ate.

The CDC lists the main symptoms as:

• Watery, sometimes "explosive" diarrhea

• Loss of appetite and weight loss

• Stomach cramping and bloating

• Nausea and fatigue

• Increased gas

Without treatment, symptoms can last anywhere from a few days to more than a month. People who recover may experience relapses.

How Is It Diagnosed and Treated?

This is where many cases fall through the cracks. Routine stool tests do not automatically screen for Cyclospora. Patients and clinicians need to specifically request testing for the parasite — something health officials have been urging labs and physicians to do during this outbreak.

The CDC recommends that people with diarrheal symptoms seek care, especially if they have eaten iceberg lettuce or salad greens in the two weeks before becoming ill.

Cyclosporiasis can be treated with antibiotics. Trimethoprim-sulfamethoxazole (TMP-SMX), sold under brand names such as Bactrim or Septra, is the standard treatment recommended by the CDC. Staying hydrated is critical, particularly for older adults and young children.

[REVIEWER: add clinical insight here — e.g., typical antibiotic course duration, what to expect during recovery, and any cases in which alternative treatment is warranted]

Which Products Were Recalled?

On July 17, 2026, Taylor Fresh Foods recalled all iceberg lettuce sourced from central Mexico distributed by Taylor Farms de Mexico. The recall covers:

• Shredded iceberg lettuce sold at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio, and West Virginia

• Marketside-brand bagged lettuce available at Walmart stores

• Products distributed June 29 – July 16 across 27 states

The company stated that no Taylor Farms–branded products and no products outside the central Mexico iceberg supply are involved. Taylor Farms is no longer sourcing iceberg lettuce from central Mexico for the remainder of the growing season.

What to do: If you purchased recalled iceberg lettuce, do not eat it. Throw it away or return it to the store. Wash surfaces and containers that may have contacted the lettuce with hot soapy water.

How to Reduce Your Risk Right Now

Cyclospora is resistant to standard produce washing. Heat is the only reliable method to kill the parasite. Michigan health officials recommend:

• Cook your produce whenever possible, including greens

• If eating raw lettuce, use a whole head rather than pre-bagged greens

• Remove outer leaves and wash inner leaves thoroughly before eating

• Ask restaurants about the source of iceberg lettuce before ordering salads

For anyone immunocompromised, pregnant, or caring for young children, the CDC recommends extra caution with raw fresh produce until the outbreak is resolved.

FAQ

What is cyclosporiasis and how do you get it? Cyclosporiasis is a diarrheal illness caused by swallowing food or water contaminated with the microscopic parasite Cyclospora cayetanensis. It is most commonly linked to fresh produce like lettuce, herbs, and berries. Person-to-person transmission is not a known route because the parasite needs time outside the body to become infectious.

How long does cyclosporiasis last without treatment? Without antibiotic treatment, symptoms can persist for a few days to over a month, and relapses are common. The CDC recommends seeing a doctor and requesting specific Cyclospora testing if you have ongoing watery diarrhea after eating potentially contaminated produce.

Is the recalled Taylor Farms lettuce still on shelves? No. Taylor Fresh Foods completed the recall on July 17, 2026, removing all iceberg lettuce from central Mexico from the market. If you have any in your home purchased before that date, discard it immediately and do not eat it.

Should I avoid all salads and lettuce right now? The CDC and FDA have not issued a blanket advisory against eating all lettuce. The recall is specific to Taylor Farms de Mexico iceberg lettuce. However, given the ongoing investigation, health officials suggest choosing whole-head lettuce over pre-bagged varieties and cooking produce when possible until the source is fully confirmed.

Who is most at risk of serious illness from cyclosporiasis? Most healthy adults recover fully, though the illness can be prolonged and miserable. People who are immunocompromised — including those living with HIV, cancer patients undergoing chemotherapy, or organ transplant recipients — face longer and more severe illness, according to the CDC.

Practical Takeaway

If you have had watery diarrhea lasting more than a few days — especially after eating fresh salad greens — see a doctor and explicitly ask to be tested for Cyclospora. The infection is treatable with a standard antibiotic course, but it will not go away on its own quickly. Check your refrigerator for recalled iceberg lettuce and discard it. Opt for cooked produce or whole-head lettuce until federal investigators confirm the outbreak source is fully contained.Sources

1. U.S. Centers for Disease Control and Prevention. Cyclospora Outbreak Linked to Iceberg Lettuce (July 2026).

2. U.S. Food and Drug Administration. Investigation of 5-State Outbreak of Cyclospora Illnesses: Iceberg Lettuce (July 2026).

3. Taylor Fresh Foods. Statement Regarding Cyclospora Outbreak.

4. Michigan Department of Health and Human Services (MDHHS). Cyclosporiasis outbreak case count updates, July 2026.

5. USDA Food Safety Inspection Service. Cyclospora Outbreak Historical Context, 2023 report.

6. CIDRAP (Center for Infectious Disease Research and Policy), University of Minnesota. What We Truly Know About the Huge US Cyclospora Outbreak — and What We Don't. July 2026.

7. NBC News / CNN / The Hill — outbreak case count reporting, July 2026, citing CDC media briefing with Gwen Biggerstaff, deputy director, CDC Division of Foodborne, Waterborne, and Environmental Diseases.

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Category

Infectious Disease / Food Safety / Public Health

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