A Foodborne Parasite Is Spreading at Unprecedented Speed
A parasitic illness that causes prolonged, debilitating diarrhea is spreading across the United States at a pace that federal health officials say is far above anything seen at this point in recent years — and investigators have now identified a troubling new detail: two separate peaks in illness onset dates, suggesting two contaminated food events may be driving the surge simultaneously.
As of July 13, 2026, the Centers for Disease Control and Prevention has confirmed 1,645 laboratory-verified domestic cases of cyclosporiasis in 34 states since May 1, and is aware of more than 5,100 additional cases under review. The combined total approaches 7,000 — compared to just 249 cases reported nationally at the same point last year. That represents a nearly sevenfold increase year over year.
Investigators have yet to confirm a specific food source, but federal and state officials are examining lettuce and salad greens. Taco Bell voluntarily and temporarily removed select ingredients at some locations as a precautionary measure; the company and federal officials have emphasized that no confirmed link to Taco Bell or any specific supplier has been established.
Why This Matters
Cyclospora infections do not spread from person to person. This is not a community transmission situation like COVID-19 or influenza. The risk is tied to what people eat — and because the illness is severely underdiagnosed, tens of thousands of Americans may already be sick without knowing why.
The CDC's Health Alert Network notice specifically warned clinicians that Cyclospora testing must be explicitly ordered — it does not appear on standard stool panels. Without that test, a patient with cyclosporiasis may be sent home with a generic diarrhea diagnosis and no treatment. The illness can last weeks, recur in cycles, and cause significant weight loss.
For most healthy adults, cyclosporiasis is not life-threatening. But it is genuinely debilitating, and for older adults, people with weakened immune systems, and young children, the dehydration and weight loss it causes can require hospitalization. As of July 13, 141 confirmed cases have been hospitalized. No deaths have been reported.
What We Know So Far
The CDC confirmed that 1,645 domestically acquired cases have been laboratory-verified since May 1, with more than 5,100 additional illness reports under analysis to determine whether they qualify as domestically acquired cyclosporiasis. Cases have been reported by 34 states.
Among the 1,645 confirmed patients, the age range spans from 2 to 95 years, with a median age of 44. Fifty-six percent of confirmed cases are female. Of those with clinical information available, 141 — or about 9% — were hospitalized.
Federal officials have identified at least one multistate cluster: the CDC confirmed that more than 400 people in Michigan, Ohio, West Virginia, and Kentucky are epidemiologically linked in a single multistate outbreak, with illness onset dates beginning on or after June 22, 2026. A specific food source for this cluster has not yet been confirmed.
A CDC official noted two separate peaks in illness-onset dates — one around June 25 and another around July 7 — suggesting that two separate batches of a contaminated ingredient may be involved. "We're not seeing a slowdown in cases," the official told NBC News, adding that two peaks suggest two separate contaminated food events could be at play.
Where the Risk Is Highest
Michigan is the clear epicenter. The Michigan Department of Health and Human Services reported more than 3,300 cyclosporiasis cases as of July 14 — far exceeding all other states and accounting for the majority of the national burden. State health officials have conducted more than 1,000 patient interviews, with preliminary results pointing to lettuce or salad greens as a probable vehicle of transmission.
New York State has reported approximately 394 cases since May 1. Ohio confirmed at least 364 cases as of July 10, with more than 171 occurring since late June. Illinois and Texas round out the states with the largest reported case counts.
Previous U.S. outbreaks of cyclosporiasis have been linked to fresh herbs and greens including raspberries, basil, cilantro, snow peas, and lettuce, according to the FDA. Prior outbreaks tied to lettuce imported from Mexico have affected hundreds of Americans, including a 2013 multistate outbreak linked to a salad mix.
What Doctors and Experts Say
Dr. Kawsar Talaat, an infectious disease physician and associate professor at the Johns Hopkins Bloomberg School of Public Health, told NPR that cyclosporiasis can present inconsistently — and that persistence is a warning sign readers should not ignore.
"If your diarrhea persists for more than a couple days, go see your doctor," Talaat said. She noted that a recurring pattern is particularly significant: "If the diarrhea goes away and comes back, that's another sign of a potential Cyclospora infection. And again, go see your doctor."
Talaat also emphasized that getting tested helps public health officials understand the scope of the outbreak and where contamination is originating — an important reminder that seeking care is not just a personal health decision, but a contribution to the broader investigation.
Gwen Biggerstaff, deputy director of the CDC's Division of Foodborne, Waterborne, and Environmental Diseases, emphasized at a press conference that person-to-person spread is not a concern. "The source of this outbreak is what we eat or drink — not casual contact with someone who's sick," she said.
What the Evidence Shows — and What It Does Not
Cyclosporiasis is a well-characterized illness with an established clinical profile, so the scientific picture here is not preliminary. What remains unresolved is the specific food source driving the 2026 surge.
The CDC has not confirmed lettuce or any specific ingredient as the outbreak vehicle. Michigan health officials said lettuce or salad greens appear to be the leading suspected source based on patient interviews — but that conclusion is preliminary and has not been confirmed through environmental or supply-chain testing. Taco Bell's voluntary removal of select ingredients is a precautionary action, not a confirmation of a link.
Cyclospora testing deserves specific attention here: the parasite does not appear on standard stool panels. Physicians must specifically order modified acid-fast staining or PCR-based molecular testing. Patients who have experienced prolonged or recurrent watery diarrhea since late May should specifically ask their doctor to test for Cyclospora.
Who Faces the Greatest Risk
Health officials say the highest-risk groups for severe illness or complications from cyclosporiasis include:
- Adults 65 and older
- Infants and young children
- People with weakened immune systems, including those undergoing chemotherapy or taking immunosuppressant medications
- People with HIV or other conditions affecting immune function
- Anyone who has experienced prolonged diarrhea without seeking care
For the general population, cyclosporiasis is unpleasant and disruptive, but manageable with prompt diagnosis and treatment. The key concern is underdiagnosis — most affected people never get the specific test needed to identify the parasite, and therefore never receive the appropriate antibiotic.
Symptoms and Warning Signs to Watch For
Cyclosporiasis symptoms typically begin about one week after exposure, with a range of two to 14 days after being infected. Key symptoms include:
- Watery diarrhea that may be frequent and explosive
- Loss of appetite
- Weight loss
- Bloating and cramping
- Nausea and fatigue
- Low-grade fever (less common)
- Vomiting (less common)
A key feature of cyclosporiasis is its tendency to relapse. Symptoms may improve and then return — sometimes repeatedly over weeks. Without treatment, the illness can last from a few days to more than a month in a remitting-relapsing cycle.
Severe dehydration, inability to keep fluids down, or symptoms lasting more than several days warrants medical evaluation. Older adults, people with chronic illness, and young children who develop prolonged diarrhea should seek care promptly.
What You Can Do Now
- If you have symptoms : See a doctor and specifically ask to be tested for Cyclospora. Do not assume standard stool tests will catch it — that specific test must be requested.
- Wash all fresh produce under clean running water before eating, even items labeled "pre-washed." The CDC notes that washing alone may not fully eliminate Cyclospora, but it reduces risk when combined with other precautions.
- Cook produce when possible. Heating food to 158°F (70°C) or higher kills the parasite.
- Peel produce when practical. Cyclospora sits on the outer surface of produce items with removable skins.
- Check receipts and food records from late May through mid-July if you become ill. Food investigators may need help identifying common sources — noting where you ate and what you ordered can assist the public health investigation.
- Follow FDA and CDC updates. If a specific product is recalled or identified as the outbreak source, prompt action will be needed to discard affected items.
Cost and Access: What Patients Should Know
Cyclosporiasis is treated with a seven-to-ten-day course of trimethoprim-sulfamethoxazole (TMP-SMX), a generic antibiotic available at most pharmacies. Generic TMP-SMX is low-cost and widely covered by insurance, Medicaid, and Medicare Part D.
Stool testing for Cyclospora requires a laboratory visit or a provider-ordered test — costs vary but are typically covered by insurance when ordered for diagnostic purposes. People without insurance can seek testing and treatment at local health departments or HRSA-funded community health centers, which offer services on a sliding-scale fee basis.
If you believe your illness may be part of the outbreak, reporting to your local health department helps investigators trace the source. Reporting is free and confidential.
What Happens Next
The CDC and FDA investigation is active and ongoing. Investigators are conducting patient interviews, environmental sampling, and supply-chain tracing across the affected states. Additional clusters may be linked to the Michigan-Ohio-West Virginia-Kentucky multistate outbreak as analysis continues.
No specific product recall had been issued as of July 15, 2026. If a food source is confirmed, a recall or advisory is expected to follow quickly. MedicalDaily will update coverage as the investigation develops.
The Bottom Line
A foodborne parasite outbreak is expanding rapidly across the United States — and most of the people who are sick have not yet been diagnosed because their doctors have not ordered the right test. If you or someone you know has experienced prolonged or recurring watery diarrhea since late May, ask for Cyclospora-specific testing. Wash all fresh produce thoroughly, cook when possible, and follow CDC and FDA updates for guidance on any specific food product advisories. The investigation is active, and case counts are expected to continue rising through August.
