Infections from the diarrhea-causing parasite cyclospora are surging, with state-level data suggesting that 2026 is already the nation's worst year for reported cases.
In Florida, the most updated information — as of July 11 — from the Florida Department of Health said that since May 1 the state has received reports of 96 cases of cyclosporiasis. Miami-Dade County now leads the state with 17 cases and Lee County following with 14. Collier and Highlands counties both reported 2 cases since May 1.
More than 30 states have reported infections this year, and current data from them shows the number of infections surpassing the record U.S. mark of about 4,700 set in 2019. The illness is not usually life threatening and is typically treated with antibiotics.
The large multistate outbreak of cyclosporiasis is also occurring in at least four midwestern states. Public health officials are interviewing people linked to this outbreak to find out what foods they ate before getting sick.
U.S. Centers for Disease Control investigators are also collecting as much information as they can to solve the outbreak.
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Health officials have not yet definitively identified what is causing the infections. On Tuesday, federal health officials said there may be different infection patterns in different places, although they believe cases in at least four states — Michigan, Ohio, Kentucky and West Virginia — are linked.
In Michigan — where more than 3,300 cases have been reported — officials say early information points to lettuce or salad greens as a possible culprit.
While no specific item has been pinpointed, on Tuesday, the Taco Bell restaurant chain issued a statement saying it had “voluntarily and temporarily removed limited ingredients at select restaurants as a precautionary measure. We will continue to closely monitor the situation and follow the guidance of public health authorities."
In a call with reporters on Tuesday, federal health officials did not directly respond to a question about whether they are looking at Taco Bell or any specific food vendor or distributor.
“FDA certainly is continuing its traceback investigation on multiple produce items, also including locations that are reported by the case patients before they became sick,” said Donald Prater, The U.S. Food and Drug Administration's Acting Deputy Commissioner for Food, in response.
After conducting more than 1,000 interviews with patients, “early information has shown lettuce as a common product that regularly comes up during the investigation,” said Natasha Bagdasarian, the Michigan health department's chief medical executive.
CDC is concerned about the increase in cases since the start of May. CDC, state, and federal partners are also investigating multiple additional clusters of cyclosporiasis across the United States. Cyclosporiasis is not usually life-threatening, however some people can become very ill and require hospitalization. If you have symptoms of cyclosporiasis, contact your healthcare provider right away.
Key points
CDC is aware that states are likely to report higher case counts of cyclosporiasis than reflected in CDC data and is working closely with states to update numbers as additional cases are confirmed. Since May 1, 2026, CDC has received reports of 1,645 confirmed domestic cases of cyclosporiasis and is aware of more than 5,100 cases that require further analysis to confirm the illness as domestically acquired cyclosporiasis. So far this year, multiple states have reported an increase in cases compared to the same period in 2025.
Cyclospora causes ‘explosive’ diarrhea
Cyclospora is a microscopic, spherical parasite that commonly causes watery diarrhea “with frequent and sometimes explosive bowel movements,” according to the U.S. Centers for Disease Control and Prevention. Outbreaks tend to occur most often in the late spring and summer.
The heat-loving parasite infects the bowels and spreads through feces. In the past, people have been infected by consuming fruits or vegetables that were exposed to feces-contaminated irrigation water.
The illness, called cyclosporiasis, is less common than foodborne illnesses caused by other germs, including salmonella and E. coli. Many cases are never linked to a specific food or other source and, for years, few U.S. cyclospora outbreaks were reported. But the number started rising about a decade ago, with a particularly notable spike in 2018 and 2019.
Experts say it's likely that cyclospora cases historically were underreported, in part because some common tests used to check for food poisoning have not been geared to detect cyclospora. They attribute the increasing trend in cases to climate change and better detection.
2019 was the worst year for infections
The worst year in the U.S. for infections was 2019, when about 4,700 illnesses were reported, according to federal data on confirmed and suspected cases.
The Centers for Disease Control and Prevention keeps those numbers, but they traditionally lag what is posted by individual city and state health departments dealing with local outbreaks in real time. On Tuesday, CDC officials issued a health alert that said that since May 1, the agency is aware of 1,645 confirmed domestic cases and more than 5,100 that require further analysis to confirm whether the infections were acquired in the U.S. The reports come from 34 states, and no deaths have been reported, the CDC said.
The true number of cases is likely larger than what has been reported so far because some people may have milder illnesses that they don't seek care for, said Gwen Biggerstaff, deputy director of CDC’s Division of Foodborne, Waterborne, and Environmental Diseases, in the call with reporters.
It can take days to weeks for someone exposed to the parasite to develop symptoms. It's not clear to what extent people currently are being infected, or whether many of the exposures happened earlier. But Biggerstaff said official expect that case numbers will continue to grow through August.
The CDC also posted information about the investigation of an outbreak affecting the four states.
The federal alert did not detail how many reports came from each state. But Michigan officials have reported more than 3,300 cases, officials in northwest Ohio said they have seen more than 1,100, New York City officials counted more than 400 and Illinois reported more than 200.
Officials do not think all can be tied to a common source. In Illinois, for example, more than half the people with infections said they had traveled outside the United States, and at least some may have been infected elsewhere.
But Michigan officials believe a large share of their total is likely due to a linked domestic outbreak. CDC officials did not go into detail about why they currently think cases in Michigan, Ohio, Kentucky and West Virginia are part of the same outbreak.
Key points
CDC and state and federal partners are working together to investigate several outbreaks of cyclosporiasis. Investigations toidentifyand confirm the sources of the outbreaks are ongoing.
On a regular basis, CDC reports all laboratory-confirmed cases that are received from states. State data may include both probable and confirmed cases, which in turn is likely to reflect a higher case count than the CDC surveillance data because initial case reports have not yet been reported to CDC. The CDC surveillance updates do not include probable cases.
2026 fast facts
As of July 13, 2026:
U.S. cases reported to CDC: 1,645
Hospitalizations: 141
Deaths: 0
States reporting cases: 34
Cyclosporiasis is a gastrointestinal disease caused by the microscopic parasite Cyclospora.
Cyclosporiasis is a nationally notifiable disease and is reportable in 47 states, the District of Columbia, and New York City. Even if it is not reportable in a state, it is important for healthcare providers and the public to inform local health departments about potential cases and clusters of the disease so that they can take appropriate action to prevent additional cases.
Symptoms of cyclosporiasis
See your healthcare provider if you have symptoms of cyclosporiasis, which can include watery diarrhea, loss of appetite, and weight loss. Your provider can test and treat you for cyclosporiasis. Healthcare providers: If your patient has a confirmed case of cyclosporiasis, report the case to your local health department.
WGCU is your trusted source for news and information in Southwest Florida. We are a nonprofit public service, and your support is more critical than ever. Keep public media strong and donate now. Thank you. The Associated Press contributed to this report.
