Amid a nationwide rise in cases of cyclosporiasis — the illness caused by the “explosive diarrhea” parasite — officials have identified one possible source of an outbreak spanning Michigan and several other states.
On July 16, the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention released statements on their investigations, which have so far pointed to shredded lettuce sourced from Mexico and served at Taco Bell restaurants in five states: Michigan, Ohio, Indiana, West Virginia and Kentucky.
“Additional states may be added to this advisory as more information becomes available,” the FDA said.
However, the FDA and CDC also clarified that this finding, at this point, only applies to the outbreak in those states, currently the largest in the nation. Possible sources of other outbreaks and cyclosporiasis cases around the U.S. are still be investigated.
Taylor Fresh Foods, which supplied the lettuce to Taco Bell, has issued a recall of all of its iceberg lettuce sourced from central Mexico from the U.S. The recalled products were mostly distributed to food service locations, but two items were sold under the brand Marketside at Walmart.
“While the FDA traceback is indicating a specific independent farm, which represents less than 1% of the U.S.’s iceberg lettuce supply, as the potential source of the outbreak, we have removed all iceberg lettuce from the region indefinitely,” the company statement said in part.
Taco Bell also said in a statement on July 17 that the implicated lettuce from Taylor Fresh Foods had been removed from all U.S. restaurants.
Cyclosporiasis and the “diarrhea parasite” have made lots of headlines the last few weeks, but the intestinal infection isn’t new. Rates normally ramp up every summer. However, the country is seeing an unusually high number of cases this season, largely driven by the outbreak in Michigan and nearby states.
So far in 2026, over 6,700 confirmed or probable cases of cyclosporiasis have been reported to the CDC, whereas the U.S. saw 2,700 cases in all of 2025, NBC News reported.
Here’s what to know about where the parasite is surging in the U.S. and how to stay safe during peak fresh produce season.
What Is the ‘Diarrhea Parasite’ Going Around?
Cyclosporiasis is caused by Cyclospora cayetanensis, a microscopic parasite carried in human feces. People become infected by consuming food or water contaminated with particles of feces from an infected person, Kali Kniel, Ph.D., professor of microbial food safety at the University of Delaware, tells TODAY.com.
When ingested, cyclospora infects the small intestine and causes severe gastrointestinal upset. The main symptom of cyclosporiasis is watery, “explosive” diarrhea, which may persist for weeks, per the CDC.
“If you’ve ever had a stomach flu or food poisoning, this is exactly what we’re talking about, but people describe it as being even worse,” NBC medical contributor Dr. John Torres said on TODAY in a July 14 segment.
Cyclosporiasis is usually not life-threatening, and most healthy people recover on their own, Kniel says. However, treatment with a combination antibiotic is highly effective.
After the parasite is shed in stool, it takes one to two weeks living outside the body to mature and become infectious, says Kniel, which makes person-to-person spread highly unlikely.
Cyclospora can get into produce if it’s grown in soil or washed with water contaminated with feces, for example. Fresh fruits and vegetables are common culprits, says Kniel.
“In the last few years, we have seen an increasing number of cases tied to domestic and imported produce,” Gwen Biggerstaff, deputy director of the CDC’s Division of foodborne diseases, told reporters in a briefing on July 14.
Where Are Cyclosporiasis Cases Surging?
As of July 13, nearly 7,000 confirmed and probable cases of cyclosporiasis have been reported in more than half of U.S. states, per the CDC.
The CDC has confirmed 1,645 cases in 34 states since May 1, the start of cyclosporiasis season in the U.S., and is also investigating another 5,100 cases, the agency said in a July 14 health alert.
At least 141 people have been hospitalized with the diarrhea-causing parasite so far. No deaths have been reported.
The majority of cases are in the Midwest, which is experiencing a large, multistate outbreak that began in late June.
Michigan is being hit the hardest. As of July 17, the state has reported 5,002 cyclosporiasis cases and 102 hospitalizations, per the Michigan Department of Health and Human Services.
Ohio has also reported over 1,000 cases, the state’s health department said. Cases have also surpassed 200 in Illinois, Indiana, New York and North Carolina, per local officials.
Beyond the five-state outbreak linked to shredded lettuce, it’s unclear which other clusters of cases in the U.S. may be connected, and investigations are ongoing, the CDC said.
“There may be multiple unrelated outbreaks going on at the same time,” Donald Schaffner, Ph.D., professor of food microbiology in the Department of Food Science at Rutgers University, tells TODAY.com.
The true number of cyclospora infections in the U.S. is likely higher than the numbers currently being reported. That’s because many people who get sick with diarrhea do not go to the doctor or get tested for cyclospora, per the CDC.
“We anticipate continuing to see cases increase, possibly through the end of August,” Biggerstaff said.
What Food Is Driving the Rise in Cyclospora Cases?
So far, U.S. health officials have identified one possible source of illnesses in one of the nation’s outbreaks.
On July 16, the CDC and FDA announced that shredded lettuce supplied to Taco Bell locations in five states had been linked to the outbreak in these states (Michigan, Ohio, Indiana, Kentucky and West Virginia).
“More than 1,644 sick people in this outbreak reported eating at Taco Bell locations in 5 states,” the CDC said, adding that the FDA is investigating if the implicated lettuce was used in other states.
Taco Bell said in a statement on July 17 that it had removed this lettuce from its national supply chain.
The supplier of the lettuce, Taylor Fresh Farms, has also recalled of all of its iceberg lettuce products sourced from central Mexico from the U.S. This impacts mostly food service locations, but two salad items were available at Walmart locations in several states.
During the FDA’s investigation, a sample of shredded iceberg lettuce from Mexico supplied to Taylor Fresh Foods tested positive for cyclospora, but this product was not included in the recall, so the company is “working to identify whether any part of this implicated lot is available in commerce or in consumers homes.”
Investigations into the cyclospora clusters in other parts of the U.S. are ongoing. Schaffner and Kniel both suspect there’s more than one food or water source fueling the outbreaks.
Is Taco Bell a Source of the Diarrhea Outbreak?
While the investigation is ongoing, both the CDC and FDA have issued statements saying the shredded lettuce at Taco Bell locations in five states have been linked to a cyclospora outbreak.
“Do not eat shredded iceberg lettuce from Taco Bell locations in Indiana, Kentucky, Michigan, Ohio, and West Virginia,” the CDC said.
However, it’s possible that there’s also another source driving cases in the U.S. “CDC is also investigating other outbreaks and illnesses of cyclosporiasis nationally that are unrelated to this outbreak,” the agency said.
Taco Bell had removed the implicated lettuce from its national supply chain by July 17, a spokesperson said.
The supplier of the lettuce, Taylor Fresh Farms, has also recalled all of its iceberg lettuce sourced from central Mexico from the U.S.
Tracking Cyclospora Outbreaks
Cyclospora is a particularly challenging parasite to track, food safety experts tell TODAY.com.
“It has a much longer incubation period than most (types) of food poisoning,” explained Torres.
Symptoms may not appear for up to 14 days — then confirming a diagnosis through testing and being interviewed by an epidemiologist to investigate can take weeks or longer, says Schaffner. By that point, the person isn’t likely to remember what they ate that could’ve caused the symptoms.
As a result, only a small portion of cases every year get traced back to a particular food item, Dianna Blau, acting chief of the CDC’s Parasitic Disease Branch, told NBC News.
It’s also worth noting that, in July 2025, the CDC’s foodborne surveillance network made testing for cyclospora optional, which could be impacting the response, Schaffner says.
Foods to Avoid Due to the Cyclosporiasis Outbreak
The only way to prevent cyclosporiasis is to avoid food and water that may be contaminated with feces. So far, one recall has been issued in relation to one of the outbreaks in the U.S.
Taylor Fresh Foods has removed all of its iceberg lettuce products sourced from central Mexico from the U.S. market. While 33 out of the 35 affected products were sent to food service locations, two items were provided to Walmart and sold under the brand Marketside:
- Iceberg Salad: 12 oz., 24 oz.; best if used by July 18-Aug. 3, 2026
- Shredded Lettuce: 8 oz., 16 oz.; best if used by July 18-Aug. 3, 2026
The recalled products were distributed to 27 states: Alabama, Arkansas, Connecticut, Florida, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Michigan, Missouri, Mississippi, North Carolina, New Hampshire, New Jersey, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia and Wisconsin.
The FDA is urging consumers not to eat any of the recalled lettuce, including at Taco Bell or other restaurants. It encourages consumers to ask about the source of iceberg lettuce before ordering it at a restaurant.
As part of the FDA investigation, a sample of shredded iceberg lettuce from Mexico provided to Taylor Fresh Farms tested positive for cyclospora, but this product wasn’t included in the current recall, so the company is assessing whether the tainted lot is available in homes or consumer locations.
Still, experts are urging people not to panic.
“Almost all servings of fresh fruits and vegetables that you can buy on the market today are not linked to this outbreak, and are not any more likely to cause illness because of the outbreak,” says Schaffner.
“We know that fresh (produce is) part of a healthy diet, and I certainly don’t want to discourage that,” adds Schaffner, who still plans to enjoy his favorite fruits and vegetables this summer.
If you want to avoid certain foods out of an abundance of caution, past cyclosporiasis outbreaks in the U.S. have been linked to the following foods:
- Salad greens
- Cilantro
- Basil
- Raspberries
- Geen onions
- Snow peas
How to Prevent Cyclospora
Cooking food to least 158 degrees Fahrenheit is the best way to protect yourself, as heat destroys the parasite. Freezing can also eliminate cyclospora, but it’s not a guarantee.
Washing produce thoroughly can reduce the risk of foodborne illness, but it won’t eliminate cyclospora entirely.
Health authorities have offered a few more tips to prevent cyclospora infection:
- Wash your hands well with soap and hot water before and after handling raw produce.
- Scrub all fresh fruits and vegetables with a produce brush under clean, running water. Do not use soap.
- Remove the outer layer of leaves or the peel, if possible. Run the inner leaves under running water.
- Cut or peel off damaged areas of produce before eating.
People with weakened immune systems may need to take extra precautions and should consult their doctor about how to avoid foodborne illness, says Kniel.
“We are seeing hospitalizations, so if you do get sick, good hydration is critical, and so is getting clinical care because this can be treated,” Kniel adds.
If you develop symptoms of cyclosporiasis, contact your doctor.