US cyclosporiasis outbreak tops 1,600 confirmed cases as Taco Bell pulls fresh ingredients in Michigan

The outbreak's scale

The Centers for Disease Control and Prevention (CDC) has confirmed 1,645 lab-confirmed cases of cyclosporiasis as of Tuesday, with a backlog of more than 5,100 additional cases requiring further analysis and patient interviews. The true number of infections is almost certainly higher, because many people with mild illness recover without seeking medical treatment. Michigan alone reported 3,309 cases as of Tuesday, according to state data, making it the hardest-hit state. Ohio's Toledo-Lucas County recorded 1,119 positive cases in the northwestern part of the state, while New York has registered roughly 470 cases statewide. The CDC said 141 people have been hospitalized nationwide and no deaths have been reported.

We're seeing an unusually high number of cyclosporiasis cases this summer.

Taco Bell under scrutiny

The Washington Post reported that federal and state health officials are investigating whether lettuce served at Taco Bell may be associated with the outbreak. Some affected individuals reported eating at Taco Bell restaurants, though other cases show no connection to the chain. As a precaution, certain Taco Bell locations have temporarily stopped serving fresh ingredients including lettuce, cilantro, avocado, tomato, onion, guacamole, and pico de gallo. Yum Brands shares fell as much as 4.5% on Tuesday following the report.

The health and safety of our customers is our highest priority. Health authorities have not confirmed any link to Taco Bell or to any specific ingredient, supplier, restaurant, or retailer. While authorities continue their broader investigation, Taco Bell has voluntarily and temporarily removed some ingredients at certain restaurants as a precaution.

The epidemiological picture

The CDC announced Tuesday that it has identified a probable epidemiological link between cyclosporiasis cases in Michigan, Ohio, West Virginia, and Kentucky, representing the strongest evidence so far that many patients fell ill from a common contamination source. Natasha Bagdasarian, Michigan's chief medical executive, said early information has shown lettuce as a common product that regularly comes up during the investigation. Health officials expect case counts to continue rising through late August.

Perception matters as much as the facts in the early stages of a food safety investigation. Even an unconfirmed link to a foodborne illness can cause consumers to rethink where they eat.

Why tracing the source is difficult

Cyclospora cayetanensis, the single-cell parasite causing the illness, has a long incubation period of one to two weeks before symptoms appear. Diagnosis and reporting take additional weeks, meaning patients are often asked to recall what they ate six to eight weeks prior. The parasite spreads when contaminated water is used to grow, clean, or wash produce, typically entering the agricultural supply chain. Steven Goldberg, chief medical officer at HealthTrack, noted that the foods most commonly implicated (berries, leafy greens, cilantro, basil) are widely consumed, mixed into salads, and have short shelf lives. Budget cuts to health services have also reduced the number of personnel available to conduct testing.

You're not looking for a needle in a haystack. This is more like looking for a microscopic particle of a needle in a haystack.

Market and consumer impact

Foodborne illness investigations can weigh heavily on restaurant stocks. McDonald's faced scrutiny during a cyclospora outbreak linked to salads in 2018, while Chipotle Mexican Grill endured a series of E. coli and norovirus outbreaks that battered its sales and stock price. The CDC recommends thorough handwashing with soap and water before and after handling raw fruits and vegetables, and washing produce carefully. Infected individuals are advised to take a seven-to-ten-day course of co-trimoxazole, an antibiotic combination. The American Medical Association warned that symptoms can include explosive diarrhea, loss of appetite, weight loss, cramps, flatulence, nausea, fever, and generalized muscle pain, lasting from a few days to more than a month.

What comes next

The CDC anticipates case counts will continue to rise as data are received, and the surge is already outpacing testing labs' capacity, potentially delaying diagnoses. The Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota noted that the true number of cases is unknown because the CDC made cyclospora tracking optional starting in July 2025. Federal health officials said they expect outbreaks to continue through August as they scour the food supply chain for the contamination source. Past outbreaks have been linked to bagged salads, herbs, raspberries, and lettuce imported from Mexico.