Taco Bell Is Being Investigated for One of the Worst Parasite Outbreaks in Years

Customers at Detroit-area Taco Bell locations in early July 2026 noticed signs posted in the restaurants explaining that lettuce, cilantro, onions, pico de gallo, and guacamole were no longer being served due to a “nationwide recall.” No nationwide recall had been issued. Federal and state health officials had quietly opened an investigation into whether Taco Bell played a role in what has become one of the largest foodborne illness outbreaks the United States has seen in years.

The Taco Bell cyclosporiasis outbreak investigation, as it has come to be known, centers on a microscopic parasite capable of causing weeks of misery – and the evidence trail, so far, leads to lettuce.

Lab-confirmed cases linked to the recent outbreak of cyclosporiasis have risen to 1,645, the CDC noted on Tuesday. The CDC said it is also aware of more than 5,100 additional cases that require further analysis and confirmation. Officials caution the real count may be significantly higher because testing is specialized and reporting often lags. Thirty-four states have reported cases, according to the CDC. Dr. Dean Blumberg, Chief of Pediatric Infectious Diseases at UC Davis Children’s Hospital, told CBS Sacramento that “we believe there’s really an undercounting of the number of cases because not all cases are being tested.”

What the Taco Bell Cyclosporiasis Outbreak Investigation Involves

Public health officials are investigating whether lettuce served at Taco Bell restaurants played a role in the outbreak, after Detroit-area Taco Bell locations posted signs that they were “currently unable to sell Lettuce, Cilantro Onion, Pico de Gallo, and Guacamole due to a nationwide recall.” The company told media outlets it had “temporarily and voluntarily” removed unspecified ingredients at select restaurants while officials reviewed the causes of the outbreak.

Taco Bell issued a formal statement: “The health and safety of our guests is our top priority,” Taco Bell Corp said. “Public health officials have not confirmed a link to Taco Bell or any specific ingredient, supplier, restaurant or retailer,” Taco Bell said.

Yum Brands, Taco Bell’s parent company, felt the fallout quickly. The Taco Bell probe impacted Yum Brands’ share price, which fell more than 3% in the 24 hours after the probe became public. Taco Bell makes up nearly 40% of Yum’s total operating profit.

Michigan health officials first flagged lettuce and salad greens as a potential source based on interviews with people who tested positive. So far, no produce, grower, or supplier has been identified. As of mid-July, no single restaurant, grocer, or distributor has been implicated as the source of the current illnesses, and there have been no recalls.

Michigan Is the Epicenter

Michigan’s Department of Health and Human Services is investigating an outbreak of cyclosporiasis in the state. Available information indicates that lettuce or salad greens may be a potential source of this outbreak, though other food items cannot be completely ruled out. The outbreak was first identified on June 29, when the Monroe County Health Department announced it was investigating a cluster of cases.

Reported cases of cyclosporiasis in Michigan surpassed 3,762, with 44 residents hospitalized as of July 9, 2026. Federal health officials stated at a press conference that they still had not confirmed a source of the outbreak in Michigan.

Michigan typically identifies around 50 cyclosporiasis cases per year, according to the Michigan Department of Health and Human Services. This is the largest outbreak of its kind in Michigan’s recorded history and one of the country’s largest in years, as ABC News noted in its coverage.

Michigan’s chief medical executive, Dr. Natasha Bagdasarian, offered crucial context on the scope of the source problem. “Outbreaks of cyclosporiasis have been occurring across the United States and now here in Michigan,” she said. “Based on the unusual number of cases we have identified in a little over a week, we anticipate additional cases of illness being reported.” Her office’s epidemiological data showed Michigan recorded one peak of cases with symptom onset around June 25, and a second peak with onset around July 7, suggesting two separate batches of contaminated ingredients could be at play.

As of the most recent state health data, New York reported the second-highest number of cases nationally at 470 since May 1, followed by Ohio at 364, according to ABC News’ analysis of state health department reports.

What Cyclospora Cayetanensis Actually Does to the Body

Cyclosporiasis is an intestinal illness caused by a parasite called Cyclospora cayetanensis. It can be contracted by consuming food – typically raw fruits and vegetables – or water contaminated with feces, according to the CDC. It’s mainly known for causing gastrointestinal illness – primarily diarrhea, sometimes explosive – and is often associated with nausea, bloating, and a lot of gas. If you have explosive diarrhea that’s not associated with vomiting, that’s a clue it might be cyclosporiasis, because many other causes of gastrointestinal illness – including norovirus – are associated with vomiting. Cyclosporiasis usually doesn’t cause fever either.

Because it can take up to two weeks for symptoms to develop after exposure, state officials say it takes time to investigate the source. If a person doesn’t realize they’ve been infected, they may not connect their illness to a meal eaten nearly two weeks earlier – which is part of why these outbreaks are so hard to track in real time.

Cyclosporiasis is typically not fatal or life-threatening, but some people with the infection are hospitalized for help managing symptoms. Dr. Blumberg notes that those most at risk are young children and seniors, due to the danger of dehydration.

Left untreated, the illness doesn’t simply resolve quickly. The CDC confirms that if not treated, the illness may last from a few days to over a month, and symptoms can cycle – appearing to improve before returning. One Michigan patient who was hospitalized after testing positive described the experience bluntly: “Immediately get help. Because it’s very dangerous.”

Why Lettuce Is Under the Microscope

Fresh produce has always been the primary vehicle for this parasite in the US. Cyclospora is most commonly found in salad, raspberries, cilantro, basil, and snow peas. The parasite can spread from human feces to products like lettuce through contaminated water or unsafe food handling.

The parasite is resistant to routine chemical disinfection, and washing alone can’t guarantee its removal. Using any chemicals isn’t very useful. Cooking is very useful in terms of reducing the load, but of course, for some things, they’re better eaten fresh. Heating produce to at least 158°F is the most effective way to eliminate the risk entirely.

The FDA’s acting deputy commissioner for food, Donald Prate, acknowledged the lettuce signal during a press conference without confirming it. “We are aware of the signal for lettuce that’s been noted by our Michigan partners,” he said. “What I can say at this point is that we’re continuing our traceback investigation on multiple produce items, including the lettuce.”

The connection to Mexican-style restaurants and fresh herbs is not entirely new. A 2025 paper published in the CDC’s Morbidity and Mortality Weekly Report described a 2023 outbreak in Alabama involving 47 cases of cyclosporiasis among patrons of a Mexican-style restaurant, where investigators identified cilantro as the likely food source after case-control analysis.

Read More: Should You Be Concerned About Eating Pre-Washed Lettuce?

Treatment and What to Expect If You’re Infected

Getting a diagnosis early matters because treatment works. According to a UC Davis Health explainer, cyclosporiasis can be diagnosed with a simple stool test – a gastrointestinal panel using PCR assay – and it’s included on that standard panel. Giving the antibiotic trimethoprim/sulfamethoxazole can shorten the illness. Routine stool cultures don’t always catch this parasite; a specific PCR-based panel or microscopy examination is needed.

This outbreak comes just one year after the CDC scaled back monitoring of cyclospora. Beginning July 2025, tracking it became optional. Dr. Blumberg noted that “the cuts to public health have affected the response and resulted in a larger outbreak than otherwise would’ve occurred.”

Officials anticipate cases of cyclosporiasis will continue increasing in the US, possibly through the end of August, as cyclosporiasis season typically runs from May 1 to August 31. Anyone with persistent watery diarrhea lasting more than a few days – especially if they’ve eaten lettuce, salad greens, cilantro, or fresh herbs recently – should contact a healthcare provider and ask specifically about cyclosporiasis testing.

What to Do Now

The investigation is still open. No single product, restaurant, grocer, or distributor has been identified as the source of the current illnesses, and there have been no recalls issued. That means there is currently no specific item to avoid or discard, which makes individual precautions more important, not less.

Michigan’s Department of Health and Human Services indicates that lettuce or salad greens may be a potential source of this outbreak, though other food items cannot be completely ruled out. Their guidance – available on the Michigan MDHHS outbreak page – recommends buying whole heads of lettuce rather than pre-washed, bagged lettuce or pre-mixed salad kits. Removing the outer two to three leaves before washing the inner ones reduces surface contamination. For herbs like cilantro and basil, washing thoroughly under running water while separating the leaves is advised – and cooking them entirely eliminates the risk. For salad greens, it’s best to have unprocessed salad greens, according to Dr. Blumberg.

Cyclosporiasis is not usually life-threatening, but the scale of this outbreak is unusual enough that anyone experiencing prolonged gastrointestinal symptoms should seek medical attention, name the parasite specifically to their doctor, and not assume the illness will resolve on its own. The antibiotic treatment is straightforward and effective when deployed early. Waiting it out can mean weeks of avoidable suffering.

Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.

AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.

Read More: Lettuce May Be Behind the Cyclosporiasis Outbreak Sickening Thousands Across the U.S.