Michigan health officials suggested lettuce or salad greens could be possible sources. Taco Bell said it had removed some ingredients “as a precautionary measure.”

Nearly 7,000 people nationwide may have cyclosporiasis, a foodborne illness that can cause weeks of severe diarrhea, the Centers for Disease Control and Prevention said Tuesday. The bulk of the cases are in Michigan, which has confirmed 3,309 cases.
In a health alert, the CDC reported that 1,645 people have been sickened by cyclosporiasis across the country, making it one of the largest outbreaks of foodborne illness in the U.S. in years. The CDC urged doctors to be alert for patients with common symptoms of the infection, including watery diarrhea, bloating and nausea.
An additional 5,100 cases are under investigation.
“We’re seeing an unusually high number of cyclosporiasis cases this season,” Gwen Biggerstaff, deputy director of the CDC’s Division of Foodborne, Waterborne, and Environmental Diseases, said during a media call Tuesday. There are usually about 2,700 cases each year, mostly during the summer months.
According to the CDC, 141 people have been hospitalized since illnesses were first reported in May. No deaths have been reported.
The number of cases has spiked in the last two weeks and at least 30 states other than Michigan are reporting clusters of illnesses. The national tally lags behind what states are reporting as the agency must confirm each case.
People who’ve tested positive span generations, the CDC reported, ranging in ages from 2 to 95. More than half, 56%, have been women. All became sick starting on June 22. None had traveled outside of the U.S., the CDC reported.
Lettuce, salad greens flagged as potential source
While Michigan has been hit hardest, the CDC said Tuesday it’s likely that multiple outbreaks, from different sources, are occurring at once. The CDC suspects that at least 400 of the cases across four states — Kentucky, Michigan, Ohio and West Virginia — are connected.
“Those cases may be linked as one multistate outbreak,” the CDC’s Biggerstaff said, but “there are a lot of cases that are not accounted for as part of that multistate outbreak, and there are a number of other investigations that are going on.”
Michigan health officials first flagged lettuce and salad greens as a potential source based on more than 1,000 interviews with people who’ve tested positive.
But as of Tuesday, no single product, restaurant, grocer or distributor has been implicated as the source of the current illnesses. There have been no recalls.
Biggerstaff said it’s likely more cases will be reported through August.
Kelly Leahy, 56, of Charlotte, North Carolina, tested positive for cyclosporiasis Monday after two weeks of illness, which left her dehydrated and light-headed. “Buckle in,” she said. “It’s not a 24-hour bug.”
Leahy said a health department worker called her within hours of testing positive, asking what she’d eaten before she got sick. It was nearly impossible to answer the question, she said.
The incubation period for the parasite to make a person sick is up to two weeks, and Leahy had already been sick for two weeks when she tested positive. That means whatever made her ill was likely consumed a month ago.
The Food and Drug Administration, which typically coordinates food investigations and recalls with the CDC, hasn’t publicly identified a specific field, region or supplier of the produce, or where the foods have been distributed. The FDA’s acting deputy commissioner for food, Donald Prater, said during the briefing Tuesday that the agency “is continuing its state-backed investigation on multiple produce items.” That includes lettuce, he said.
A spokesperson for Taco Bell said Tuesday it had “voluntarily and temporarily removed limited ingredients” at some of its restaurants as a precaution, adding that “public health officials have not confirmed a link to Taco Bell or any specific ingredient, supplier, restaurant or retailer.”
What is cyclosporiasis?
Cyclosporiasis is a foodborne illness caused by cyclospora, a microscopic parasite. That parasite can spread from human feces to products like lettuce through contaminated water or unsafe food handling.
It’s not very common in the U.S., compared to foodborne outbreaks linked to salmonella, norovirus or E. coli.
Previous outbreaks of cyclosporiasis have been linked to raspberries, bagged lettuce or salads, cilantro, basil, green onions and snow peas. If people eat food contaminated with cyclospora, it may take up to two weeks for people to get sick. The illness can begin with flu-like symptoms, such as fatigue, body aches and loss of appetite.
The hallmark symptom is severe diarrhea. The illness is most commonly treated with Bactrim, an antibiotic. If people don’t get treatment, symptoms can linger for weeks.
Tara Rabin, a former FDA spokesperson who concentrated on food, said it’s likely way too early in the investigation to pinpoint the source or sources of the outbreaks.
“There may be a song and dance going on with a suspected supplier(s) on effectuating recalls internally, but that process often takes time until the scientific tests that can link products to outbreaks start to become available,” she said. Rabin helped oversee the FDA’s investigation into applesauce pouches contaminated with lead in 2023.
Michigan’s chief medical executive, Dr. Natasha Bagdasarian, suggested the source of the outbreak is likely larger than one restaurant chain or grocer.
“We know that contamination usually occurs where the produce was grown or processed, and because distributors supply the same produce to multiple types of establishments,” she said, “it’s unlikely for there to be one single place as the exposure for all of our cases.”
Bagdasarian said it’s possible that contaminated produce is already off store shelves because of how long it takes to investigate cases. That doesn’t necessarily mean outbreaks are over, she said.
“We had one peak of cases with onset of symptoms around June 25. Another peak appears to have developed, with onset of symptoms around July 7,” she said. That suggests two batches of ingredients could be at play, she said.
Regardless, “we’re not seeing a slowdown in cases,” she said.
Reducing the risk of illness
Cyclospora are notoriously difficult to remove from produce once they latch on. The CDC recommends washing fresh produce under clean running water before eating.
There’s no evidence that soaking food or dousing it with vinegar or commercial vegetable washes is enough to get rid of them. The parasites need to be scrubbed off or cut off as much as possible.
The Michigan Department of Health and Human Services advises peeling fresh fruit and vegetables after washing because the parasite sits on the outer surfaces. Products labeled “pre-washed” don’t guarantee their safety, according to the department.
Cooking food is the only way to kill the parasite before eating it.
Reprinted from NBC News