As Cyclosporiasis Cases Rise, What Foods Should You Avoid Eating?

In recent weeks, headlines about an “explosive diarrhea” parasite have been seemingly everywhere, causing widespread concern. Cyclosporiasis typically spreads through contaminated food, and it’s been sickening thousands of people across the United States. The intestinal infection, caused by the cyclospora parasite, isn’t new, and rates typically ramp up in the summer. However, the U.S. is seeing an unusually high number of cases this season, along with mysterious clusters in several regions. On July 14, the U.S. Centers for Disease Control and Prevention confirmed a large outbreak affecting four midwestern states — including Michigan, which has recorded over half of all cases in the U.S., per NBC News’ latest tally. The CDC said it is also investigating several potential outbreaks in other states. “The very quick uptick and high numbers of cases, I would say, is unusual,” Kali Kniel, Ph.D., professor of microbial food safety at the University of Delaware, tells TODAY.com. The parasite spreads to people through contaminated food or water, and past outbreaks have been linked to raw produce. Health officials are still racing to identify a potential source. In a statement released on Monday, the Michigan Department of Health and Human Services said early results point to lettuce or salad greens as a potential culprit in the state’s outbreak, but that it still couldn’t rule out other foods. So, where is the parasite surging in the U.S. — and is it safe to enjoy fresh fruits and vegetables this summer? 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, Kniel explains. When ingested, cyclospora infects the small intestine and causes severe gastrointestinal upset. The main symptom of cyclosporiasis is sudden, 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 healthy people usually 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. “Historically, outbreaks have been associated with travel to other countries, but 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 14, nearly 7,000 confirmed and probable cases of cyclosporiasis have been reported in more than half of U.S. states, according to the latest data from 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, it said in a 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. The CDC suspects at least 400 cases in Michigan, Ohio, West Virginia and Kentucky are connected. The source is unknown. Michigan is being hit the hardest. As of July 14, the state has reported 3,309 cyclosporiasis cases and 44 hospitalizations, per the MDHHS. Ohio, New York, North Carolina and Illinois are also seeing cases surge into the hundreds. It’s unclear if these other outbreak clusters are connected, the CDC said, but investigations are ongoing. “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 a 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? The cause of the recent cyclosporiasis outbreaks is still unknown. The CDC is working with the U.S. Food and Drug Administration to investigate a potential source. On July 13, Michigan health officials identified “lettuce or salad greens” as a potential source, but stressed that “other food items cannot be completely ruled out. No specific type of produce, grower or supplier has been identified as the source.” These early findings that point to lettuce only apply to Michigan. The MDHSS has shared instructions for “lettuce-specific safety measures” for people living in affected counties. “Much more likely, there are multiple parallel pathways for people to become infected,” Dr. Trevor Suslow, an expert on food safety and professor at University of California, Davis, tells TODAY.com. Past cyclosporiasis outbreaks in the U.S. have been linked to contaminated salad greens, cilantro, basil and raspberries. However, the experts emphasize that food isn’t the only culprit, and that water could potentially be to blame. Water contaminated with feces can be used to irrigate produce crops, for example. In Michigan and Ohio, some surges are happening in counties that border Lake Erie. “These cases seem to me to be more of a waterborne outbreak rather than a foodborne outbreak because of the geographical clustering,” says Schaffner. Michigan health officials stressed in a statement that “there is currently no evidence linking recreational water activities to this outbreak.” 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. Should You Avoid Certain Produce? The only way to prevent cyclosporiasis is to avoid food and water that may be contaminated with feces. And because no definitive source has been identified, it’s impossible to know which items to keep off your grocery list — but the experts caution 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. So, currently there’s no reason to cut out raw produce, especially during peak season for so many delicious fruits and vegetables. “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 fresh produce this summer. If you live in one of the affected counties in Michigan, the state health department is recommending the following precautions: Purchase whole heads of lettuce instead of pre-washed and packaged salad greens.Throw away the outer two to three layers of the leaves.Wash the inner leaves with clean, running water.If you cook your greens, do so to a temperature of at least 158 degrees Fahrenheit, which is ideal as washing doesn’t guarantee you will kill the parasite. How to Prevent Cyclospora “There are ways to be proactive,” says Kniel. Cooking food to least 158 degrees Fahrenheit is the best way to protect yourself. Freezing can also eliminate cyclospora, but it’s not guaranteed. Washing produce thoroughly can reduce the risk of foodborne illness, but it won’t eliminate cyclospora entirely, Suslow notes. State health departments 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. 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.