Today, Explained - Parasite (2026)

Episode Date: July 17, 2026

Cyclospora can cause explosive diarrhea that can last a month. But you don’t need to swear off vegetables. This episode was produced by Kelli Wessinger with help from Dustin DeSoto, edited by Amina Al-Sadi, fact-checked by Gabriel Dunatov, engineered by Patrick Boyd, and hosted by Sean Rameswaram. Federal and state health officials are investigating whether lettuce served at some Taco Bell restaurants has led to the widespread outbreak of cyclosporiasis. Photo by Mario Tama/Getty Images. Listen to Today, Explained ad-free by becoming a Vox Member: vox.com/members. New Vox members get $20 off their membership right now. Transcript at ⁠vox.com/today-explained-podcast.⁠ Learn more about your ad choices. Visit podcastchoices.com/adchoices

Today explained here with Dylan Scott from Vox to ask what the bug is cyclospora. So cyclospora is a parasite, and it is a particularly nasty parasite because if a human being consumes it, then that person can experience. And this, I want to be clear, is the terminology that is used by public health authorities. Explosive watery diarrhea. Explosive diarrhea. Frequent diarrhea. Huge gastrointestinal issues. If you get sick with this, it can last for up to a month.

It's just a really unpleasant foodborne illness that is wreaking havoc across the United States and particularly in the Midwest right now. And so we have to talk about it on the show today. Sorry. Recommendations can't be amazing. I mean, maybe someone recommended that TV show you've been obsessed with lately. But when it comes to home projects, it's different. If you don't like a show, you might lose a few minutes.

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I've talked to some people or had people in my life. ask me, like, how big of a deal is this really, like, you know, do I really need to be going out of my way to be safe about this? And my answer is, do you want to have to deal with a month of explosive diarrhea? And personally, my answer to that would be no. And so I have been taking precautions as somebody who lives not too far from the epicenter of this outbreak. But yeah, it's a nasty thing.

Like the good news about this parasite is it doesn't kill people. Like it's not fatal. It doesn't transmit between person to person. It's nothing like that that we have to worry about. But it does cause these really unpleasant gastrointestinal symptoms. And that's what public health authorities, especially in Michigan, are contending with right now. If it doesn't kill people, we can laugh about it. And many people are laughing about it.

My doctor confirmed that I consume enough Miller High Life and hint to, lime tortilla chips to create a digestive environment untenable for the explosive diarrhea parasite. If I got the explosive diarrhea parasite, I probably wouldn't even notice. Just one diarrheal parasite away from my goal weight. But you mentioned the epicenter, Dylan. Where is it? And where else is it?

So the big outbreak right now is in Michigan. The last update that I saw was there are more than 4,300 cases of cyclosporiasis in Michigan right now. That is up from just about 1,500 late last week. And so, like, that's a really rapid growth in cases. And the doctors that I have talked to who are based in Michigan have said, like, that's just the ones we've confirmed with a test. Like, the actual number of cases, and so the actual number of people who are dealing with this really unpleasant diarrhea right now is probably even higher than that. And like, we've seen

outbreaks in the past, you know, maybe a couple hundred people who got sick, like back, you know, in 2018, 2015, 2005. But like, never anything, like the thousands of cases that we're seeing right now in Michigan. And the doctors I've talked to there have said, like, it's probably going to keep going and we may eventually reach like 10,000 cases of this parasite. before it's all said and done. Ugh. What did the United States do to deserve this terrible parasite? Is it the war we started for no reason, or, like, only letting white people in for the

World Cup? So I have to say, like, this isn't anybody's fault. Oh. Like this, like I said before, this is something that we have dealt with in the past. It's getting a lot more attention now, I think, because of how big the outbreak has gotten. But, like, we've dealt with cyclospora before. And if you want to blame anything, there's probably two things to blame. One would be we now have this really globalized food distribution system where like we're getting leafy greens grown all over the world and shipped to plants in the United States and being, you know, packaged into these bag salad kits that I personally love to buy for lunch and sold all over.

And so there's this long chain where produce can. potentially get infected with cyclospora. Like the kind of classic example would be, you know, there's a field in some tropical region of the world where they're growing lettuce. It gets irrigated with water that has been infected by this parasite. And then it's all these weeks later after it's been harvested and packaged into something and put on your grocery shelves

and you've eaten it that then finally you get sick. And so it's more of a kind of byproduct of the way that our food supply has changed, as well as potentially, and I feel like this is an evergreen topic with any kind of disease like this, climate change is probably playing a role too. Like, this parasite tends to thrive or is naturally found in, like, tropical or sub-tropical regions, but we have started to notice it appearing domestically as well. And that's because, like, as the planet starts to get warmer, there are going to be more places with the kind of climate where this parasite could thrive. And therefore, you know, it may not be an accident that we're

dealing with the worst outbreak ever right now. And it may be a preview of things to come. This might be just something that we have to deal with from time to time because of these food systems that we've set up and because of what's happening with the planet. Do we know where this all started for the United States, Dylan? Is there a patient zero or a, I don't know, a Taco Bell zero? or like a, you know, a leafy green farm zero, whatever it might be? So it looks like we're getting closer to figuring that out. For the past week, health officials in Michigan had said, we think this is linked to lettuce or bag salad,

but they hadn't gotten much more specific than that. And then on Thursday evening, the Washington Post reported that CDC and FDA officials were zeroing in, and specifically on iceberg lettuce that had been supplied to Taco Bell by the company Taylor Farms. They thought that that potentially, that specific product and that specific brand being sold at that particular restaurant might be the source of the ongoing diarrhea outbreak. Now, they haven't confirmed this for sure. It is possible, like there's cyclosporic cases all over the country this summer.

It could be that we're dealing with a couple of different outbreaks. But in terms of the big crisis in Michigan and Ohio and a couple of those neighboring states, it appears, according to this preliminary reporting, that if you ate at Taco Bell and got a dish with iceberg lettuce, that might be why you ended up getting sick. Why is Taco Bell always somewhere in these situations? What the heck's going on to Taco Bell? You might have to deal with diarrhea because you're eating Taco Bell for other reasons. Then we don't have to get into that right now.

But it appears that in this case, they just got unlucky. They were sourcing this particular ingredient from this particular company and got a batch that was contaminated with cyclospora. And, you know, it could have ended up at a grocery store or at a different restaurant, but it turned out in this case to end up at Taco Bell. And so, yeah, as best as we know, sitting here today, that seems to be the most likely source for this outbreak. So what do you do if you're like missing Taco Bell this weekend, maybe just like eat a tuna sandwich or something?

There's lots of things like, you know, obviously anything that's not a fruit or vegetable that you could eat. Heat is a really good way to kill this parasite. So like if you want to eat vegetables, maybe you could grill them, stuff like that. And then, you know, I do think in general this whole episode is a really good reminder about how important food hygiene is. Because if you do take careful steps to really thoroughly wash your food, even the green, leafy vegetables that we worry might be contaminated with this parasite, there's a really good chance that you can get rid of it and eat that stuff that is obviously really good for your body's health in general and not have to worry about getting debilitating diarrhea.

That's what we can do. What about the old government, Dylan? What are they doing and what could they be doing in a moment where thousands upon thousands of Americans are getting a violent stomach bug? I will say that, like, the state health departments are definitely taking the lead on this outbreak, which is unusual. You know, usually, especially when you're dealing with, like, a multi-state outbreak, as we seem to be at this point, you would expect the CDC and the federal government to be taking the lead. But like the CDC's case counts have lagged pretty far behind what the states have been reporting at this point. I was told by a hospital epidemiologist in Michigan that last year, the federal government stopped asking states to report cyclospora cases. So that may explain why there's been this lag in federal data.

What? Yeah. And so it's like, again, I'd want to emphasize that like this could have happened no matter what. You know, food surveillance in the United States has been lacking for a long. time, well before, you know, the cuts we've seen to the federal workforce under the Trump administration here in the last couple of years. But at the same time, now that we are dealing with a live, active emergency, it certainly doesn't help to have a CDC and federal health authorities who seem to be a step behind. Doesn't help that the fact that there's, you know,

fewer workers, fewer resources that the CDC and federal government can spend responding to this outbreak. So, you know, the truth is that you know, the truth is. You know, you know, somewhere here and there in the middle where it's like, you know, they're doing what they can, states are taking the lead, you know, this probably would have happened no matter what, because this is just a reality of the food distribution system that we've set up. But at the same time, we are, you know, we've got a federal government that does have one hand tied behind its back when it comes to responding to public health emergencies. And that's probably not helping us, you know, get this over with faster either. And just to be sure here,

You said earlier that no one is really to blame here. But with cuts to monitoring of this particular parasite, can you blame people for rushing to judge this particular administration? No, no. I get – and, like, yeah, that's the sort of, like, unforced error that we've seen a lot in how the Trump administration has been changing public health policy. You know, stopping reporting requirements when there doesn't seem to be a need to do so. Disbanding task force that are dedicated to public health policy. pandemic preparedness. Like, you know, if we had had a more robust CDC, you know, it's possible we would have identified the problem earlier, been able to mount a response faster, moving more

quickly, and all of those things, you know, could have ultimately minimized the number of people who get sick, the number of people who end up in the hospital, and that would have been a good thing. Dylan Scott, thank you so much for joining us to help us understand this bug. And when we get back on today, Explain, we're going to talk about how to be a lot of it. Now, a bunch of powerful people in the White House don't need to worry about catching it because they stopped eating fresh vegetables before this bug necessitated it. The first ever All-Electric 2026 Subaru Trail Seeker is the EV for the Trail Obsessed, with up to 444 kilometers on a full charge and DC fast charging from 10 to 80% in about 30 minutes in ideal conditions. Plus, ample ground clearance and symmetrical all-wheel drive make the 2026 trail seeker

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for free. That's upwork.com to connect with top talent, ready to help your business grow. That's UP-W-R-K.com. Upwork.com. I'm Liz, Esley-White, and I'm a health reporter for the Wall Street Journal. And Liz, as you know, the nation is terrified of a gut parasite at the moment. People are wondering what to eat instead of their leafy greens. And you recently reported that the White House, of all places, might have an idea. What is it? Sourcrow or kimchi or some other fermented vegetable.

What is going on to that White House? What does it smell like? I can't say that I personally have been smelling the White House, But I will say that Health Secretary Robert F. Kennedy Jr. I went to dinner at the Ned last night, and I brought my sauerkraut. Commerce Secretary Howard Lutnik, Transportation Secretary Sean Duffy, and Vice President J.D. Vance are all on this eat a lot of steak and sourcrow diet. And they claim a lot of health benefits.

And actually, you know, fermented foods are recommended by a lot of doctors and scientists, and not just the White House. Is there like a name for this diet, like a la, you know, paleo or whatever else? Kennedy calls it the carnivore diet. I think people mean different things when they say that, but for him it includes a lot of yogurt, a lot of kimchi or sauerkraut, a lot of steak, a lot of eggs. None of these things, I believe, are known to carry the parasite we've been discussing on this show. Exactly. No lettuce.

How widespread is this in the White House? Does it go up all the way to the top to the president? Is he partaking in the carnivore diet? I mean, given what we have seen of his recent public dieting, I don't think so. At the next game, he was eating pizza and french fries and, you know, he still has his Diet Coke button on his desk or he just pushes it and the Diet Coke comes. So he's going to live forever. Yeah, Kennedy said, once said on a podcast about him. I don't know how he's alive.

So anyway, Kennedy now travels with Sourcrow. Like, his wife has said that he has asked her to carry it in her purse for him. And she has said, I actually cannot, which is an amazing phrase. One of the many humiliations of being married to Robert F. Kennedy, Jr. It seems they all think their skin is glowing, too, and people online have commented that J.D. Vance is looking good. And are we sure that? I mean, I have to ask, journalistically. But are we sure it's not Wagovi? We don't have any public knowledge of that, but we do know that he is,

eating eggs, sourcrowp, pickles, blackberries, and raspberries for lunch pretty often. Wow. And beef and lamb with sauerkraut for dinner. And then when he's on Air Force, too, he snacks on beef jerky and maybe eats a hamburger with cheese, no bun, and a side of fermented vegetables. So still no lettuce. But I think the raspberries could have the diarrhea. Well, that's sight.

Now that you're mentioning the full spectrum of, like, J.D. Vance's diet, it's kind of reminding me of their new food pyramid? Is this part of that? Does it fit in? Yeah. Earlier this year, Kennedy and the other health officials like to say they flipped the food pyramid. As Secretary of Health and Human Services,

my message is clear. Eat real food. And they recommended a lot more fruits and vegetables, red meat, which was controversial, and whole grains and whole milk, that kind of thing. They also, and for the first time in the nation's dietary guidelines, recommended fermented foods, which, you know, was something that was actually agreed upon by a lot of people,

and they thought that was a good part of this, even if they had qualms about the red meat recommendations, because those can't introduce more cardiac risk and, you know, risk of bad cholesterol. Does the science back this up or is this some kind of quackery that fernments can make your skin healthier and help you lose weight? Is it correlation or causation? So I don't think there are a lot of good studies that show exactly that sauerkraut can help you lose weight. But there have been a number of studies that have shown health benefits.

Researchers have generally agreed that sauerkraut and other fermented foods can help with digestion, and inflammation. There was a 2025 study from UC Davis that suggested fermented cabbage could protect your gut and protect against illness. Basically, they found that the intestinal cells do better. With sauerkraut, they help maintain the integrity of those intestinal cells.

And in general, that has a lot of other good health effects. Mainstream scientists, dietitians are pro-fermented veggies. This is not something that, you know, is hotly debated. Most people in the scientific community are realizing there's a lot of good fresh science out there about how important your gut really is in your overall health. And the part of the diet that is a little more controversial is the focus on red meat. And, you know, obviously that comes with some cardiac risk and some cholesterol risk. And that is why, you know, when the new dietary guidelines came out and recommended more of that for Americans, that part in particular made some dietitians a little upset.

Who got Robert F. Kennedy Jr. into this, or is this part of his, like, broader fitness regimen? He had a friend who pointed him to this doctor, Sean O'Mara. I am Sean O'Mara, MD, J.D. I'm a retired Army colonel. And by the way, you know, I don't know why I get mostly exclusive conservatives, but they tend to be. But dude, I'm super excited to be chatting with you. So what is your connection, Dr. Sean, to people in the White House eating more fermented foods? Can you tell us that? I take care of a lot of prominent people, and so there was one of my clients I work with, had a 93-year-old mother. She was not talking, hadn't been out of her bed in three years, and they got her off, processed foods and carbohydrates, and they got her eating meat, seafood, and fermented foods.

Just those things. And within three weeks, less than three weeks, she started talking, and she got up out of the bed and started using her walker. So that was raised, got to a cabinet member, you know, who expressed interest in working with me and getting my physician care and helping them become more optimally healthy. So it is anecdotal, but there are a number of studies that show the connection between fermented living probiotic foods that haven't been pasteurized, they have these living species of bacteria and yeast and fungi and a whole host of different life forms living in them, benefiting people and associated with a lower incident of chronic disease.

So this is not something that's novel. It's not something that's fat. It's been around in traditional people for thousands of years. Are there risks to eating too much fermented foods? Well, it has not been studied, but I will say this. It comes up occasionally in some studies where people eat too many pickled foods. which is a different thing than fermented foods. Pickled foods are not probiotic.

They're not living. They're not preserved through bacteria. They're preserved through acetic acid, usually vinegar. That pickling is a chemical process rather than a bacterial biological one. And then as a consequence of all that pickled food, there is a higher incidence for gastric carcinoma. So gastric cancers can be increased

from eating too many pickled foods. But that's not been exclusively seen with fermented foods, but here's the guidance I give. I tell people not to eat too much of the fermented foods and to treat them as a garnish. Do you think fermented foods could help people with this parasite that gives you explosive diarrhea? Yes.

Yes, I really do think so, because what happens is, you know, the way I think of the gastrointestinal track, which is the way the medium through which this particular organism is being spread, they're eating foods that are infected with this particular species of a pathogenic parasite microbe that's on lettuce, they're still trying to figure out the vectors, goes into your stomach. Well, Sean, if you have living within your stomach a healthier microbiome, they will overcome that particular introduction. But typically what happens is,

to people consuming this is they have what's called a dysbiotic microbiome or what is a name in term, a suboptimal microbiome. So what you want is an African safari living with you, a strong diversity of multiple species, zebra, tigers, lions, chimpanzees, orangutans, apes, birds, lizards, frogs, fish, all of that goes into this matrix creating a healthy environment, and then nothing gets out of proportion.

All that talk about eating zebras and chimps left us kind of confused. So we had to ask Wall Street Journal Liz the same question. I personally have not seen any studies on whether fermented foods help with explosive diarrhea, but let me know if you find one. Kelly Wessinger, Aminawana, Sadi, Gabriel Donatav, and Patrick Boyd made the show today with help from Dustin De Soto. The Last of Us, Miranda Kennedy, Jolie Myers, Abishai Artsy, Ariana Spuru, Hadeemaw, Heidi, Miles, Brian, Peter Balin, on Rosen, Danielle Hewitt, Denise Gera,

David Tattachor, and Noel King, who's been thinking deep thoughts about former President Joe Biden while on vacation. It's like they would get him eating ice cream in the most ridiculous, suggestive way imaginable. Today, Explain is distributed by WNYC. The show as a part of the Vox Media Podcast Network. Find more shows at podcasts. Stopvoxmedia.com. Listen to this one, ad free. at Vox.com slash members.

We use music by Breakmaster's cylinder. I'm Sean Ramos firm reminding you to thoroughly wash those leafy greens.