Cyclosporiasis Symptoms: Early Signs, Causes, Treatment, and Prevention

The CDC and FDA have confirmed that shredded iceberg lettuce served at Taco Bell is linked to the worst Cyclospora outbreak on record in the U.S., in a major update to the investigation announced July 16, 2026. As of that date, more than 1,644 illnesses tied to this outbreak are linked to Taco Bell locations in five states — Indiana, Kentucky, Michigan, Ohio, and West Virginia — with 94 hospitalizations. Nationally, nearly 7,000 cases have been confirmed or are under review across at least 34 states, and Michigan alone has reported 4,312 cases. No deaths have been reported. Here’s what’s known about the source, the symptoms, and how to protect yourself.

What Is Cyclospora?

Cyclospora cayetanensis is a microscopic parasite that infects the intestines and causes an illness called cyclosporiasis. It is not a virus or a bacterium. People usually get sick after eating food or drinking water that has been contaminated with feces carrying the parasite.

You do not usually catch Cyclospora directly from another sick person. The infection spreads when contaminated food or water reaches your mouth. Fresh produce is the most common source in outbreaks, including basil, cilantro, green onions, raspberries, snow peas, and leafy greens like iceberg lettuce.

“Lettuce [is] a common product that regularly comes up during the investigation.”

— Dr. Natasha Bagdasarian, Michigan’s chief medical executive, in an official statement

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Why This Summer’s Cyclosporiasis Outbreak Matters

Cyclospora cases rise every summer, but 2026 is now the worst year on record in the U.S., surpassing the previous high of about 4,700 cases set in 2019 — and the season isn’t over yet. Michigan typically sees only about 50 cases a year; as of July 16, the state has reported 4,312 cases and 102 hospitalizations, according to the Michigan Department of Health and Human Services. Nationally, the CDC says nearly 7,000 illnesses have been confirmed or are still under review across at least 34 states since May 1.

The most significant update: on July 16, the CDC and FDA formally linked a large share of this surge to shredded iceberg lettuce served at Taco Bell restaurants in the four Midwestern states first flagged on July 14 — Michigan, Ohio, Kentucky, and West Virginia — plus Indiana. This is the first confirmed food source of the outbreak, not just a suspected one. Cases in other states, like Illinois, appear to be a mix of unrelated clusters; in Illinois specifically, more than half of those infected had recently traveled outside the U.S.

According to the CDC’s Health Alert Network notice, sick people nationally have ranged in age from 2 to 95, with a median age of 44, and 56% have been female. So far, no deaths have been reported, though the diarrhea can become severe and drag on for days or even weeks.

Figures are changing daily. For the most current count, check the Michigan Department of Health and Human Services outbreak page.

Is Taco Bell Linked to the Outbreak? Yes — Here’s What Was Confirmed

As of July 16, 2026, the answer changed from “under investigation” to confirmed. The CDC and FDA say shredded iceberg lettuce served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio, and West Virginia is linked to more than 1,644 illnesses in this outbreak, including 94 hospitalizations. The CDC’s guidance is direct: avoid shredded iceberg lettuce from Taco Bell restaurants in those five states.

An FDA traceback investigation identified a single supplier of iceberg lettuce based in Mexico that supplied the affected Taco Bell locations, though the CDC and FDA haven’t publicly named the supplier. Reporting from CNN and the Washington Post, citing sources familiar with the investigation, identifies the supplier as Taylor Farms — but that detail has not been officially confirmed by federal health agencies as of this writing.

“We are proud to have consistently acted quickly and proactively to protect our guests.”

— Taco Bell, in a statement to ABC News

Taco Bell says it voluntarily removed the potentially affected lettuce from its supply chain nationwide as a precaution and is replacing it with lettuce from a different supplier. No formal recall has been issued as of this update; the investigation remains open, and the CDC says it’s also tracking other cyclosporiasis clusters around the country that are unrelated to the Taco Bell cluster.

Cyclosporiasis Symptoms: The Full List

Cyclosporiasis often starts with sudden, watery diarrhea that can last for a long time if a person doesn’t get treated. According to the CDC’s symptom guidance, the illness can cause anywhere from mild digestive upset to weeks of “frequent and sometimes explosive” bowel movements. Symptoms vary from person to person, and some infected people — especially those from regions where the parasite is common — have no symptoms at all.

Most Common Symptoms

• Watery diarrhea — the most common symptom, sometimes frequent and explosive
• Loss of appetite
• Weight loss
• Stomach cramping
• Bloating
• Increased gas
• Nausea
• Fatigue

Less Common Symptoms

• Vomiting
• Body aches
• Headache
• Low-grade fever
• Other flu-like symptoms

How Long Symptoms Last

Symptoms usually show up about a week after exposure, ranging from as soon as 2 days to 2 weeks or more. That delay makes it hard for people to remember which food caused the infection. Without treatment, symptoms can last anywhere from a few days to a month or longer. Diarrhea can go away and then come back, and fatigue can linger even after the digestive symptoms have stopped.

Getting Tested: What to Know

One important warning: a standard stool test may not detect Cyclospora. If you have ongoing watery diarrhea and your regular test comes back negative, ask your doctor about Cyclospora specifically. Labs often need a special stain or a PCR test, and sometimes more than one stool sample.

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Who Is Getting Sick?

Cases have appeared across a wide age range. Per the CDC’s Health Alert Network notice, nationally reported cases range from age 2 to 95, with a median age of 44, and 56% of patients have been female. Experts also note that cyclospora cases have likely been historically underreported, since some standard food-poisoning tests aren’t built to detect it — part of why 2026’s numbers look so much higher than prior years, alongside a genuine real increase in infections.

How Doctors Treat Cyclosporiasis

The CDC says the treatment of choice is trimethoprim-sulfamethoxazole (TMP-SMX), sold under brand names like Bactrim, typically taken for about 10 days. Most healthy people recover, but the illness can last a long time without treatment.

“If you’re healthy and have a normal immune system, the infection will go away on its own.”

— Dr. Rebecca Schein, infectious disease physician, Michigan State University, to NPR

Supportive care matters too: drink plenty of fluids, replace electrolytes, and rest. People with weakened immune systems may have a harder time recovering and should seek medical care early.

How to Protect Yourself From Cyclospora

You can’t control what happens at the farm or in the food supply chain, but you can lower your risk at home. With the source of one major cluster now confirmed, health officials have sharpened their guidance:

1. Skip shredded iceberg lettuce at Taco Bell in Indiana, Kentucky, Michigan, Ohio, and West Virginia until the investigation closes.
2. Buy whole heads of lettuce instead of pre-washed bagged lettuce or salad kits; discard the outer 2–3 layers and wash the inner leaves under running water.
3. Cilantro and basil: wash thoroughly under running water, separating the leaves. Safest when cooked.
4. Green onions: trim the root end, remove the outer layer, and wash thoroughly. Safest when cooked.
5. Raspberries: their bumpy surface makes them especially hard to clean — the parasite can hide in tiny crevices. Safest cooked (pies, jams); frozen raspberries may reduce but don’t guarantee elimination of risk.
6. Scrub firm produce like melons and cucumbers with a clean produce brush before cutting.
7. Cut away bruised or damaged spots before eating fruits and vegetables.
8. Cook produce when possible — heating food to 158°F (70°C) or higher kills Cyclospora; washing alone reduces but doesn’t eliminate risk.
9. Consider frozen vegetables as a lower-risk alternative — most are commercially blanched (briefly boiled) before freezing, which helps reduce risk.
10. Avoid swallowing water from pools, lakes, rivers, or other untreated sources.
11. Wash your hands before handling food and before eating.
12. See a doctor promptly if you develop watery diarrhea lasting more than a few days, and specifically ask for cyclospora testing.

“Pre-washed” on the package doesn’t guarantee safety, and rewashing bagged lettuce at home is unlikely to fully remove Cyclospora — officials specifically recommend avoiding bagged salad mixes and kits while the investigation continues.

When to Get Medical Help

Get medical care if diarrhea doesn’t improve, if you can’t keep fluids down, or if you show signs of dehydration such as dizziness, a dry mouth, or very little urine. People who are pregnant, older adults, and anyone with a weakened immune system should not wait.

This is now the largest Cyclospora outbreak on record in the U.S. — and for the first time, investigators have confirmed a specific source for one major cluster: shredded iceberg lettuce served at Taco Bell in five states. Case counts are still rising nationally, and the CDC continues to track additional clusters unrelated to the Taco Bell findings. For now, the safest approach is simple: skip shredded iceberg lettuce at Taco Bell in the affected states, buy whole lettuce instead of bagged elsewhere, wash and cook produce when you can, handle food carefully, avoid untreated water, and get checked quickly — with a specific request for cyclospora testing — if you develop long-lasting watery diarrhea.

Medical disclaimer: This article is for general information only and is not a substitute for medical advice, diagnosis, or treatment. If you have symptoms or health concerns, talk to a qualified healthcare professional.