Our ‘explosive diarrhea parasite’ future

This year’s spread of Cyclospora — better known as the ‘explosive diarrhea parasite’ — is a symptom of federal budget cuts and a scary vision of how America deals with a health crisis in the future.

This year’s spread of Cyclospora — better known as the ‘explosive diarrhea parasite’ — is a symptom of federal budget cuts and a scary vision of how America deals with a health crisis in the future.

Bryan, a food broker from Michigan, wasn’t sure if he’d be able to make it to urgent care in time. He started feeling off on Thursday, and by Saturday, he was having to use the bathroom every 15 to 30 minutes.

“It’s no joke about the explosive diarrhea,” Bryan, who asked that his last name be withheld for obvious reasons, told me. I met him via Reddit, where I recently spent hours lurking in threads about cyclosporiasis, the explosive diarrhea illness infecting people across the country, and Cyclospora cayetanensis , the microscopic parasite that causes it, which spreads through human fecal contamination. Symptoms — including nausea, loss of appetite, cramping and bloating, and the much-discussed watery, explosive diarrhea — can begin anywhere from two days to two weeks after exposure, and experts say they can wax and wane. The explosive diarrhea may stop for a day or two, only to come back in full force. In extreme cases, patients can end up hospitalized after experiencing severe dehydration. So far, the government reports 141 hospitalizations and no deaths.

As a connoisseur of elaborate salads, I was dismayed by the news that a poop-causing parasite may have found its way into America’s summer produce. I wanted answers — and, it appeared, so did thousands of other people on Reddit, who have taken to crowdsourcing information (and misinformation) in the absence of concrete guidance from the federal government. Health agencies are being cautious about doling out immediate advice, but the gap in information has left suffering, toilet-bound Americans — and those who fear joining their ranks — to their own devices, and even made people a little conspiratorial. Online, people are speculating whether the government is trying to protect farmers or food distributors. The reality is more mundane but no more satisfying: Federal agencies won’t make hasty recommendations until they have more data, and Cyclospora infections are notoriously difficult to pin down.

Though Bryan wasn’t able to get a test to confirm it, he believes he has cyclosporiasis, making him one of more than 5,000 people across the country infected by the parasite. That figure is almost certainly an undercount, since many cases aren’t reported — and cuts to a federal program that tracks foodborne illness may be hindering investigation efforts . The “explosive diarrhea parasite” is a bigger problem than anyone has been able to grasp, though it’s not clear just how big. The Centers for Disease Control and Prevention has confirmed 1,645 cases since May 1st and is aware of at least 5,100 additional cases that require further analysis.

At urgent care, Bryan received “a full battery of tests” except for one — the one that would detect Cyclospora , which isn’t detectable by standard diarrhea tests. “The nurse practitioner said, ‘We can do one of two things: We can wait until Monday, or I can prescribe you Bactrim immediately,’” he explained. “She told me the labs were so backed up in Michigan that they can’t even keep up with the amount of people.”

Michigan has more confirmed cyclosporiasis cases than any other state: 2,640 as of Monday, according to state health officials, who said lettuce and other salad greens are a “potential source for this outbreak, although other food items cannot be completely ruled out.” State health officials haven’t traced the outbreak to a specific type of produce, or to any growers or suppliers. But The Washington Post reports that federal and state officials are investigating Taco Bell after the fast food chain voluntarily recalled lettuce, cilantro, onion, pico de gallo, and guacamole at some of its locations.

Cyclospora outbreaks are among the most challenging foodborne outbreaks to investigate

Janet Hamilton, executive director of the Council of State and Territorial Epidemiologists, explained that a lack of information doesn’t mean a lack of government action.

“Anytime we have large outbreaks like this, it’s important to remember that they take time to solve, and it’s not uncommon that it can take multiple days, especially if there’s more than one product that’s involved,” Hamilton said. “There are a lot of folks who are working on this investigation, and it’s a good demonstration around why we do need epidemiologists and disease detectives to have some support and protect our food supply in the US.”

Even under the best of circumstances, the parasite is a tricky one to track.

“ Cyclospora outbreaks are among the most challenging foodborne outbreaks to investigate,” Rodney E. Rohde, program chair of the Medical Laboratory Science Program at Texas State University, told The Verge . The parasite’s long incubation period — usually about a week — and the short shelf life of most fresh produce make it hard to determine what foods made someone sick. Even when a culprit is identified, testing foods for Cyclospora is difficult.

“Another challenge is that pathogens are often present in very low numbers and may be unevenly distributed throughout a food lot,” Rohde said, so a lab may analyze a 25-gram sample of thousands of pounds of product without getting a conclusive result. And even when a tainted batch is confirmed, Rohde explained, “tracing remains difficult because fresh produce often passes through multiple growers, packers, distributors, and retailers before reaching consumers, and contaminated lots may no longer be available once illnesses are recognized.”

But there are some additional hurdles to that. ProPublica’s Annie Waldman pointed out that the Food and Drug Administration lost more than 240 consumer safety specialists last year amid President Donald Trump’s cuts to federal health agencies. And last July, the CDC scaled back a program that tracked foodborne illnesses in partnership with the FDA, the Department of Agriculture, and state health departments. Before July 2025, the CDC’s Foodborne Diseases Active Surveillance Network (FoodNet) worked with 10 state governments to track Campylobacter , Cyclospora , Listeria , Shigella , Vibrio , Yersinia , Salmonella , and Shiga toxin-producing E. coli . FoodNet stopped requiring state health departments to track most of those pathogens, including Cyclospora .

“Essentially, CDC is backing off on one of their best surveillance systems,” Dr. J. Glenn Morris, director of the Emerging Pathogens Institute at the University of Florida, told NBC News at the time. In a list of talking points provided to the Connecticut Department of Public Health, the CDC said financial constraints had led to the drop in surveillance: “Funding has not kept pace with the resources required to maintain the continuation of FoodNet surveillance for all eight pathogens.”

On a Tuesday press call, CDC officials distinguished between FoodNet and its more robust national surveillance program. “The data that we have for cyclosporiasis for this outbreak is the same as we’ve had for all the other seasons,” said Gwen Biggerstaff, deputy director of CDC’s Division of Foodborne, Waterborne, and Environmental Diseases. “We use the same systems and the same process, so that is unchanged.”

FoodNet was “designed as a sentinel system,” said Hamilton of the Council of State and Territorial Epidemiologists. “It was not designed to be the primary system for detecting outbreaks. The primary way that we detect outbreaks when it comes to Cyclospora or cyclosporiasis is really associated with making it be reportable within states, and it’s that reporting process, and then sharing of data with the CDC, that really allows us to detect Cyclospora infections.”

The CDC has identified an epidemiologic link between four states: Michigan, Ohio, West Virginia, and Kentucky. Cases have been reported in 34 states, though it’s not clear how many of those are linked. The department has not identified the source of the outbreak, and tracing efforts are ongoing. Where does that leave Americans who want to take an abundance of caution? The CDC and FDA aren’t currently recommending that people avoid eating certain foods, and both Hamilton and Rohde stressed the importance of practicing proper food hygiene, including thoroughly washing and drying all fresh produce.

And in light of recent reports suggesting lettuce may be a potential vector for infections, Rohde suggested avoiding it and other products connected with outbreaks in the past, especially if you’re immunocompromised or live in a state with high caseloads.

“Vegetables and fruits are obviously important to a nutritious diet,” he told me via email, “BUT one should be cautious and pay attention to ongoing local, state, and federal health reports for your geographic locale.” And if that means avoiding herbs at the peak of summer, then so be it.

Previous cyclosporiasis outbreaks have been traced to lettuces and other leafy greens. After more than 640 people across 11 states fell ill with cyclosporiasis in 2020, the Food and Drug Administration recalled bagged salads sold at Aldi, Walmart, and other retailers under the names Fresh Express, Giant Eagle, Walmart Marketside, and others. The FDA and the CDC reportedly traced the infections to Fresh Express’ Illinois plant. Other outbreaks have been traced to snow and snap peas, raspberries, and herbs like parsley, basil, and cilantro.

“Ultimately, prevention depends most on reducing contamination during production rather than in the home,” Rohde said.

Desperate for a leafy green, I asked whether farmers market produce is a safe alternative. Rohde’s answer was disappointing but illuminating. He explained that preventing future outbreaks means reducing contamination at the source — that is, in farms and distribution networks. “Farmer’s markets may be non-connected to any type of common agricultural water supply that could be a potential source of contamination. So, in that sense, they may be safer. But, if one is in a ‘hot geographic area,’ I would still be cautious.”

Though expert opinion on the matter is mixed, and will likely remain so until more information about the outbreak emerges, I’m going to avoid raw greens for now, lest I succumb to Bryan’s fate.

Nearly a week in, he’s starting to feel much better, he said — but the road to recovery was a long, bumpy one, punctuated by Preparation H wipes and many, many trips to the bathroom. “I wish this on no one,” he said.