News Flash: Cyclospora Outbreak — What Hospitalists Need to Know

With Special Guest Dr. Scott Curry

In this Inpatient Update News Flash, Dr. Mason Turner is joined by infectious disease physician and hospital epidemiologist Dr. Scott Curry to examine the sharp rise in cyclosporiasis cases across the United States—and what it should change in clinical practice.

Thousands of confirmed cases have been reported across more than 40 states, with hundreds of hospitalizations and additional clusters still under investigation.

So what should hospitalists do differently?

What Is Cyclospora?

Cyclospora is a foodborne parasite that infects the small intestine and commonly causes:

• Prolonged watery diarrhea
• Frequent or urgent bowel movements
• Bloating and gas
• Poor oral intake
• Hypovolemia, AKI, and electrolyte abnormalities

Unlike many other gastrointestinal infections, illness may relapse and persist for a month or longer without treatment.

Person-to-person transmission is not expected because the organism must mature in the environment before becoming infectious.

When Should Hospitalists Suspect It?

Think about cyclosporiasis when a patient has:

• Prolonged or relapsing diarrhea
• Recent consumption of uncooked produce
• Restaurant or grocery-store exposures
• Symptoms lasting longer than expected for viral gastroenteritis
• Hypovolemia, AKI, or hyponatremia associated with ongoing diarrhea

The incubation period may be 7–14 days, so the food history needs to extend well beyond the last meal.

Ask about:

• Fresh produce and salads
• Restaurants and shared meals
• Grocery stores and product brands
• Travel
• Well water
• Whether anyone else who shared the meal became ill

Document those details. They may become important during a public-health investigation.

How Should We Test?

For patients admitted with acute or prolonged gastrointestinal symptoms:

• Order and collect a GI multiplex PCR early, ideally at admission.
• Do not wait until the patient has been hospitalized for several days.
• Interpret results in the context of the clinical syndrome because false positives can occur.

Avoid reflexively ordering a traditional stool ova and parasite examination. It is labor-intensive, low yield, and may miss Cyclospora unless special testing is performed.

A positive result that does not fit the clinical picture should prompt discussion with microbiology or infectious disease rather than automatic treatment.

How Is It Treated?

For an immunocompetent adult with clinically convincing cyclosporiasis:

Trimethoprim-sulfamethoxazole double strength twice daily for 7–10 days

Treatment usually shortens what can otherwise become a prolonged and miserable illness.

Consult infectious disease when the patient:

• Has a serious sulfa allergy
• Is significantly immunocompromised
• Has severe, relapsing, or complicated illness
• Has testing that conflicts with the clinical picture

There is currently no clearly proven, equally effective alternative for patients with a serious sulfa allergy.

Isolation and Reporting

Cyclospora does not require special isolation beyond standard precautions once the diagnosis is known.

However, patients presenting with undifferentiated vomiting or diarrhea should initially be approached with appropriate gown and glove precautions because norovirus and other highly contagious infections remain much more common.

Laboratories generally report confirmed cases to public-health authorities. Clinicians should also consider contacting their health department when a detailed food history suggests a specific restaurant, product, or shared exposure.

Practice-Changing Takeaways

• Take a real food history—and go back up to two weeks.
• Order GI PCR early in the hospitalization when clinically appropriate.
• Stop reflexively ordering stool ova and parasite examinations.
• Treat convincing cyclosporiasis with TMP-SMX.
• Recognize that a positive multiplex PCR does not override a clinical picture that does not fit.
• Call microbiology or ID when the diagnosis or treatment is uncertain.

Bottom Line

The Cyclospora outbreak does not require a completely new approach.

It should sharpen the approach hospitalists already use for gastrointestinal illness:

Ask earlier. Test earlier. Interpret thoughtfully. Treat the patient in front of you.

Transcript

SPEAKER_01 0:19

Hello and welcome to an impatient update newsflash. I'm Mason Turner. In this episode, we'll take a medical issue making headlines and ask Does this affect how I should care for my patients? Today, that issue is the sharp rise in cases of cyclosporitasis across the United States. With the help of infectious disease physician and hospital epidemiologist, Dr. Scott Curry, we'll ask what, if anything, should hospitalist be doing differently? First, the headlines. According to the CDC, cyclosporitis is an intestinal illness caused by the parasite cyclospora. People become infected by consuming food or water contaminated with the parasite. It infects the small intestine and typically causes water diarrhea with frequent and sometimes explosive bowel movements. As of July 20, 2026, the CDC's last report, more than 4,000 laboratory confirmed cases acquired within the United States since May 1st. This spans 41 states and has resulted in 308 hospitalizations and no confirmed deaths. Taylor Farms in Mexico subsequently recalled iceberg lettuce, a source from central Mexico. And you've probably heard about all of this in the news. But that outbreak accounts for only a subset of the national cases. And the CDC is investigating additional clusters and illnesses unrelated to it. So this is what we have. Thousands of cases, hundreds of hospitalizations, a microbe that most of us rarely think about, but many of us will be seeing and treating. Hospitalists evaluate patients with diarrhea, hypovolemia, and all that comes with it on a daily basis. But given the outbreak we're hearing about in the news, what, if anything, should we be doing differently? I put that question to Dr. Scott Curry. Well, hello, Dr. Curry. Thank you for joining me. To start, could you introduce yourself and tell us what you do?

SPEAKER_00 3:20

Sure, Scott Curry. I'm one of the infectious disease specialists at NUSC. I clinically do a lot of transplant infectious diseases and work closely with our clinical micro lab. And my other hat is uh medical director of infection control, so I supervise a group of infection preventionists that help evaluate and prevent the spread of all kinds of illnesses through this place.

SPEAKER_01 3:44

Before we get into practice, can you orient us? What is cyclospora and what should clinicians caring for hospitalized patients understand about the current rise in cases?

SPEAKER_00 3:55

Sure. So cyclospora is not new. We've had our eyes on it for decades. Uh there have been many famous outbreaks, even going back 30 years when I was in medical school. Usually you'd hear about uh, these are mostly imported foodborne illnesses because cyclospora is endemic in in the tropics and in hot parts of the world where they don't get a winter freeze. Uh so this is often brought back by travelers, uh, but it's not spread person to person. It doesn't, it's a parasitic disease where you do shed oocysts, but they don't emerge from people in an infective form. So you've got to try really hard to go person to person with, unlike other parasitic diarrheal illnesses like gyardia and cryptosporidium, where person to person is pretty pretty easy and well documented. So this is almost exclusively a foodborne illness, uh, getting contaminated products, usually imported foods. It's been lots of famous outbreaks uh from berries and things that are hard, you know, things that don't get cooked because it's very heat labile. Uh you don't have to cook food very much to get cyclospora to die. So it's basically uncooked stuff. So hence, you know, we're currently focused on lettuce, but there have been outbreaks associated with spices and basil and raspberries and you know, anything that you don't cook uh and eat fresh. So unfortunately, all the healthiest foods that we're pushing people to eat are probably the highest risk foods. And then, of course, it's until about 20, I'd say 2015-16 is when we started seeing diagnostics that we use day-to-day for diagnosing diarrheal illness, included it as part of a multiplex PCR panel, you know, the so-called famous GI PCR. Uh it was on that. It's always been on that for most of my practice and career. And that's when it really started to be found routinely, kind of by mistake, when you were sending tests for outpatient diarrhea. Uh, so our current diagnostics and most academic medical center labs are going to catch it. Uh, in the older days, you had to really work at it because you'd have to either do special acid fast stains, uh, specifically looking for Cryptosporidium and Sectospora to find it, or a dedicated PCR, which only about two or three reference labs have that uh FDA validated or lab developed testing. So it's really become easy to diagnose, but we didn't see much of it. Every summer you have little pockets of cyclospora, and every summer the FDA and USDA would work with CDC and the food net surveillance system to see if they could track back to where the sources were, but they hardly ever do, mostly because can you remember what you ate two weeks ago? Uh, you know, most of the incubation period is at least seven to ten days, and for many it goes out to two weeks. So that's trying to remember all the fresh things you ate that far back is hard. Uh, and I think one of the reasons we're seeing such a big outbreak this time through is that our food safety surveillance has fallen apart. Uh, this year it's it's in shambles. We don't do any, for example, when we have a hospitalized patient now testing for salmonella, I don't think people know this. We grow salmonella right here in our academic center microlab and we send it to the state. The state will give it a serotype, and it, if there's a bunch of the same, we'll go to CDC for whole genome sequencing to see. And then it traces back to where did the salmonella come from. We stop doing that for everything else. We used to do that for Campylobacter, we don't do that for Campylobacter, and we certainly don't do it for the parasitic diseases. If we have a Cyclospora case, yeah, it's on the list of reportable conditions that DPH in our state requires us to report to the state, but we don't send that physical sample to the lab. There's nobody doing any molecular surveillance at all for this.

SPEAKER_01 7:34

Uh there was we don't send it just because there's no one there to send it to. Right. No one there to look at it.

SPEAKER_00 7:39

No one paying to do it, right? And then and the lab that was talking about starting that up was completely defunded last year. Uh so the government can say to their blue in the face, oh, this is not exploding this way because we don't invest in food safety, but they're lying. Uh it's just it's just not true. The whole food net uh that apparatus, you you go on the CDC website now. Every year I do this because I teach the med students a course on gastrointestinal illness, and I show them here's this last year's salmonella data and all the all the food safety net. It's a shambles. Like you can see that there's maybe a third of the detail we used to get from CDC just on salmonella, which we're still truly trying to do some outbreak, but there's more outbreaks that go completely untraced in salmonella than ever nowadays. Uh, and you know, it's a it's a minor miracle that we ever found what the source was on this, but it happened, it so happened that you know, Michigan's health department that was really dedicated to finding, oh, why do we all of a sudden have hundreds, uh now a thousand excess cases in a state where, you know, just like us, they would usually see 20 to 50 cases in a in a given summer. And it's because of their effort, not CDC, uh, that we have any clue that it was linked back to one restaurant, because that's all gumshoe epidemiology. You've got to call people who are getting these diseases reported to the state, see if they can remember what they had. And of course, that requires a critical mass of people that you're actually doing these tests on, which means that you know, even though 9% of these people are getting sick enough to get hospitalized, there must have been a critical mass of outpatients getting expensive, you know, GIPCRs done on them to find this. As I guarantee you know doctors were just randomly thinking about testing for cyclospora when they had negative stool cultures, which is you know what in our dreams happened, but does doesn't actually happen in real life clinical practice. So I think this this whole thing blew up to be so big because there's nobody nobody watching the store. I think the the key thing about cyclospora as an illness that people aren't uh stressing enough, it's so chronic. It will get better for 95% of people. This does not require treatment, but you will be sick if you don't treat it for a solid month or a month and a half for many people. That's a miserable because it's not there's very little upper GI symptoms in cyclospora. It's just this chronic, remitting, relapsing, uh gassy gastroenteritis where you where you can't be continent fecally for a while, and it's just highly unpleasant. Okay.

SPEAKER_01 10:04

So clinically, as a hospitalist, if I take a case, if I have a 70-something-year-old lady comes in the hospital, very hypovolemic, hyponatriumia, AKI, dry, and reports poor oral intake and diarrhea. We could we see this kind of patient all the time. It's bread and butter of what we admit to the hospital. Should this outbreak be changing how we think about that patient or what nuances of that patient would make us think we need to test?

SPEAKER_00 10:35

I think the chronicity is the biggest clinical clue, right? And that's the same for Giardia, cryptosporidium, some of the some of the things. So I think people need to ask the questions they need to ask of anybody with gastroenteritis are the ones I wish they would have asked in the ER or in the first hospitalist visit, right? Take a food history. Because most gastroenteritis that's acute is fortunately a short incubation period. So the norovirus you ate is whatever you ate about one to three days ago. So at least take a food history going back three days. Can you remember? And you know, what did you eat? Any shared meals with others who are also sick or particularly important. But, you know, in general, what is it you eat? Are you eating high-risk things? Are you drinking raw milk? Are you eating Caesar salad with unpasteurized eggs, stuff like that? And then what restaurants, what are the names of those restaurants? Yeah, put that in your note because we will read that. Like I see, you know, when there is a State Health Department investigation, the first thing they will look at is the HPs and the ER notes, seeing if there's any specifics there that are useful so that you don't have to call the patient up and get it from them. So it's obviously you're closer in time to the exposure, you're less likely to have recall bias and all that. Uh so that's that's important. City water versus well water, always telling our med students to take that history. It's important because you know, well water is an important source of Cryptosporidium. And then obviously with the current outbreak, that food history should focus on what at all are you eating that's fresh. You know, what are you what are and where do you buy it? You know, is it all at restaurants and what are the names of those restaurants, or do you buy it at you know the grocery store and its brand name versus store brand? Even that amount of information can help us in the back end. Uh but again, if you're really gonna want to track back to diseases like this, you've got to go way back in time, up to two weeks back, uh, to get that. And of course, clinically, in a big medical center, you're likely to order a multiplex GIP CR panel, which is gonna cover all of the bases from norovirus to Salmonella to Camphylobacter to GRD cryptosperdium. So, what you do not ever want to do, ever. And I wish I could send this to the to the rooftops and get every hospitalist says, please stop sending OBEN parasite exams. That is perfect.

SPEAKER_01 12:42

That was a question on my list.

SPEAKER_00 12:46

We have local data here. But of the last 250 tests we sent, we have one positive, and it was from a child uh in like our adoption clinic that was an overseas adoptee. And even that wasn't really a significant positive. But if you're not looking for worm eggs, which we don't have endemic, any part of the United States, except for uh pinworms, which is not gonna be found very effectively on a stool oben parasite exam. Uh, and if you don't want to look for strongyloides, which is you're way better to use the blood IgG than you are to use the stool test, there is nothing that you're gonna find that a stool open parasite exam. And it will miss cyclospora because there's no acid fast component. One of the nice, the only nice things I can say about GI multiplex panels is they do at least include the parasitic diseases that are associated with chronic diarrhea illnesses that are endemic to the U.S. So, unless you've got a foreign traveler with bloody diarrhea and there's some other things that won't necessarily be on there, a GIPCR is kind of what you want. And it will catch cyclospora like it will catch many other things. Keep in mind there is a caveat. Uh the diagnostic test manufacturer for the GIPCR kind of has a lock on the market. And the dirty underside of this test is that it has had false positives for years now for reasons that we are just beginning to understand. Uh, and we're talking about all the targets, not just cyclospora can be false positive, but think, you know, there's a target on there for norovirus, the most common cause of gastroenteritis in the US of A. False positives for that are pretty common. And but and you get results that don't make sense, keep that in mind. Is that we have this persistent problem with the currently FDA-approved diagnostic test for gastroenteritis, where there's a lot of false positives out there, and and that should be taken into account when you're seeing a patient where the result you're seeing in front of you doesn't match the clinical scenario in front of the patient you're treating.

SPEAKER_01 14:42

Well, and so if I'm worried about cyclospore, I'm wanting to test for it, I've gotten, you know, a history of more chronic diarrhea, I've gotten my good food food history, I'm I order a GIPCR. But I'm obviously hearing there are there are caveats with that.

SPEAKER_00 14:58

Here's another scenario I can put in front of your audience that they should know. Let's say you have a patient who has what looks like classic norovirus. They're farfing, uh, they're they're vomiting, diarrhea, and then it's like almost completely better by the time you send that test, and you're sitting rounding them on the hospital the next day, they're A-OK, and their test comes back for norovirus and cyclospora. And they're sulfur allergic, and you're saying, Hey, do I need to give them treatment? Well, probably not. This is probably gonna be one of these cases where it is positive for a rare entity that it's false. Uh, in in that scenario, you've got two choices. Just watch, wait, and see, because if it's just norovirus, it's gonna get better or stay better. If they get remitting relapsing disease, okay, you can take that sample and send it on for another method and you can talk to your local microbiology lab. There are many choices. You can sustain it, you can do another dedicated parasite PCR at several different reference labs can be done. Uh, but you know, treat the patient in front of you. If the if the scenario isn't like chronic diarrhea, if there's a lot of upper GI symptoms with it, that that doesn't fit cyclospora and take the take the result you're getting with a grain of salt.

SPEAKER_01 16:08

You mentioned you've been working on this uh inpatient GIPCR stewardship at MUSC. Do you uh mention maybe taking this as an opportunity to talk a little bit more about that? Anything you think our um the audience should know about that initiative?

SPEAKER_00 16:26

Yeah, I think people underestimate what a drag this can be on hospital finances and operations. Be sending a test. I mean, this test is not cheap. Uh it costs us between three to six hundred dollars just to get the cartridge and the patient charge, depending on your insurance, uh, is going to be a somewhere in a thousand dollar range. And if you're testing it on an inpatient, it's not covered by insurance. It's part of your hospital care for most individuals, particularly after day three. The hospital's gonna eat that. So the hospital lab can't have nice things if they're running all these really expensive tests that we're not reimbursed to do, and it's just clinically inappropriate because once you've been in the hospital for three days and you haven't had you know symptoms going on from admission to when you're being tested, the chances that you've got hospital-acquired cyclospora or salmonella or you know, not very high. So in our center, we have begun the process of hard stopping. If you've been here for more than two hospital days and you order one of these, you get hard stops, says, nope, can't have it. Uh, is it directs you to get this GI pre-authorization PCR, and then a microbiologist, and sometimes they page me for backup, will say, What is this about? What do you need this for? Is this an outbreak? Is this a specific, oh, they had chronic diarrhea and we didn't get a sample in the first two days of admission. Tell us why you want this, justify it, please. And if it's justifiable, we let it be done. And if it makes no sense, we will gently deny it and say no. Uh, so that's that's kind of where we are with it. It's not been super popular because people feel like they just want this test and they they eat this test. And we've even had people, there's a little free text thing where we ask them, why do you need the GIPCR? And it says, because my attending said so, or no. No, I tell doctors, look, if we don't police ourselves on stuff like this, Medicare is gonna do it for us. This is this is a huge waste of money. Uh, and uh almost every single one, except I think maybe one of the ones that we've kind of reviewed and allowed to be done have been pan negative. Uh so or or we've directed them to do C diff testing, which is you know one of the things on the panel that sometimes makes some and just do C diff testing way cheaper, way more uh way more logical to test for, and and that's often positive when they do that.

SPEAKER_01 18:39

Okay. So if we do get a patient, we were concerned for cyclospore for all the reasons we've talked about. We test and they are positive, or we're strongly uh concerned. Who should we be treating and how do we treat these patients?

SPEAKER_00 18:57

I mean, if they don't have a cell for allergy, I think everybody should be treated who you have a legit clinical suspicion has it, because this can become truly I mean, it's not life-threatening for most people, but it's truly disgusting and it goes on and on and on before it's before it becomes self-limited. So there is evidence in cyclospora. I will grant you, if you've got cyclosporasis, fine, give the bactrum. Uh, I think that is totally worth it to abbreviate illness, and it usually does so within a couple days. Uh, it's not instantaneous, but two, three days, most people are better. If they got a serious life-threatening sulfur allergy, then I shrug my shoulders and say, I don't know. Uh, you can have us talk to you about some of the iffy data there is for CIPRO and other stuff. Uh, but the the honest answer is we don't know what could be offered to those patients. They should just be counselors. You may be sick for a while. Or you can also dig deep into the sulfur allergy. Usually sulfur allergies are so severe that you wouldn't want to be re-exposing people. But you know, if it was a minor rash as a baby and they've never had a re-exposure as an adult, you could think about uh a challenge or even desensitization if it was a type 1 hypersensitivity reaction. But yeah, like I said, we there's not a lot of evidence for what we do in the context of somebody who needs treatment who's got a sulfur allergy.

SPEAKER_01 20:14

Um if we see this, see these patients and we do are either strongly suspicious they're admitted to the hospital or have a positive GIP CR, should we be calling ID?

SPEAKER_00 20:26

I think I would if they're self-allergic. If they're not self-allergic and not otherwise seriously ill, and you just need to get them out of the hospital, go ahead and treat them. And you know, you can notify them and ask them to have outpatient follow-up if it's some complexity to the case you want us to follow up on. But I don't think it needs to clog up the the discharge line for them just to see us and you know what what will we do that you won't? Not much, other than maybe we'll dig deep and try to get their grocery store receipts and do the old food history into the nth degree. But uh there's not a whole lot else we're gonna add in in most self-limited cases of cyclosporiasis.

SPEAKER_01 21:01

Um Do we need isolation precautions for these patients?

SPEAKER_00 21:05

You actually don't. Standard precautions do the job. Like I said, this is not spread. There's actually no documented, I went looking the other day, no documented hospital outbreaks. Because you basically have to have a farm that your patients are working on, pooping into, uh, and then harvesting fruit and berries and lettuce, serve that lettuce in the hospital, and then you may be able to have a hospital apart outbreak. But until we start doing that, God help me know. Uh yeah, there it's not thought to be possible to have healthcare associated outbreaks of this because it just doesn't come out uh in an infective stage.

SPEAKER_01 21:38

Yeah. Um okay. Good to know.

SPEAKER_00 21:40

Yeah, yeah. Well, the other thing I tell people though is if you are going to see a patient whose chief complaint is cramps or diarrhea or vomiting and and nausea, and you don't put your garbage bag isolation gown and gloves on to see that patient, woe be to you. Because the most Common cause of that in America is norovirus, which is the most contagious thing there is. Except for maybe measles, you go get norovirus if you don't, if you even touch that patient uh and brush up against them and don't wash your hands perfectly. Even if you wash your hands perfectly, there's gonna be enough norovirus virions on your hands that you go get it. Uh so standard precautions has to mean something. If you're seeing somebody with a chief complaint that's in the GI world and you haven't got that test back yet, put your gowns and gloves on because you're gonna regret it uh when you get norovirus.

SPEAKER_01 22:33

Um would we as hospitalists have any reporting responsibilities if we uh get a positive test?

SPEAKER_00 22:43

Not uh directly. So the lab is, of course, required to report to DPH in the state any lab-confirmed infections. Uh they will ask us ultimately for a copy of the of the notes and stuff, and and we're we're good about passing that along in infection control at our institution. Even for low priority stuff like Cyclospora, if you've got uh some advanced knowledge of a potential source, they'd love to hear from you.

SPEAKER_01 23:09

All right. So finally, the what is the single most important thing you would like hospitalists to do differently after hearing this conversation?

SPEAKER_00 23:20

I think take good food histories and test aggressively for patients that are being uh being admitted with a gastroenteritis syndrome, even if it's kind of a minor part of their presentation. You know, people come with chest pain. You know, American hospitals are great at chest pain. They're they exceed expectations when it comes to chest pain. They underwhelm me when it comes to GI illness. They really do. We have patients that come in with weeks of diarrhea from a nursing home and they get missed and they get diagnosed with hospital-acquired C diff because nobody even bothers to take a history about that review of system and send a test until they've been in the hospital for four or five days. So I think aggressively take uh a GI review systems, aggressively test for patients that are being admitted with upper or lower GI symptoms and get those tests ordered and collected quickly before you end up in diagnostic stewardship territory. Uh and if you get something that you've never heard of before on that GIPCR panel, call a microbiologist or an ID doc to help you sort through it because this is not going to be the only weird disease that we're gonna see foodborne outbreaks from. Not the way that public health surveillance is headed nowadays.

SPEAKER_01 24:26

Great. Well, thank you so much, Dr. Curry, for joining me and giving us your time and helping us make sense of all of this.

SPEAKER_00 24:34

Thank you for caring about explosive diarrhea.

SPEAKER_01 24:44

So, my takeaway this outbreak doesn't demand a major new approach on the front end. Instead, it sharpens focus on what we should already be doing when we admit patients with gastrointestinal symptoms. If a patient is being admitted with upper or lower GI symptoms, even if those symptoms are only a minor part of the presentation, order and collect the GI multiplex PCR for all its flaws early, ideally at admission, rather than waiting until they've been sitting in the hospital for four or five days. The patient we should be thinking about the cyclosporiasis in has prolonged diarrhea. If the clinical picture and testing is to support cyclosporiasis, a month of explosive diarrhea is bad enough that we should be treating these folks. For an immunocompetent adult, that means one double strength bactrum twice daily for seven to ten days. If the patient has a severe sulfa allergy, is significantly immunocompromised, or the diagnosis or treatment is otherwise complicated, it's reasonable to consult ID. But for a severe sulfa allergy, recognize that there are not proven and effective alternatives at this time. Thank you again to Dr. Scott Curry for joining me. And this has been an Inpatient Update news flash.