Cyclospora cayetanensis is a microscopic parasite that causes an intestinal illness known as cyclosporiasis. It is not new and has been well-studied for decades. Cases tend to rise in the warmer months, typically May through August. Cyclosporiasis has a favorable outcome and there are no reported long-term health consequences.

What are the symptoms of Cyclospora infection?

Symptoms include watery diarrhea, loss of appetite, weight loss, cramping, bloating, nausea, and fatigue. The illness can last from a few days to a month or more if left untreated. Some people infected with Cyclospora may not have any symptoms.

What should I do if I think I am sick with Cyclospora?

Contact your healthcare provider, who can order a stool test to look for the parasite. Cyclosporiasis is treatable with prescription antibiotics. If you are experiencing symptoms consistent with Cyclospora infection, seek medical attention promptly.

How does Cyclospora spread?

Cyclospora is spread by ingesting food or water contaminated with the parasite. It is not spread directly from person to person because the parasite needs time to become infectious after being passed in a bowel movement. The parasite must mature in the environment before it can cause infection in another person.

How can I reduce my risk of Cyclospora infection?

Follow standard food safety practices: wash your hands thoroughly, rinse fresh produce under running water, and clean food preparation surfaces. Follow public health guidance regarding recreational water quality. These everyday practices help reduce the risk of many foodborne illnesses, including cyclosporiasis.

Has a source of the 2026 Cyclospora outbreak been identified?

No. As of July 2026, no specific food, farm, grower, or supplier has been identified as the source of the outbreak in Michigan and Ohio. IFPA notes potential environmental factors such as municipal sewage overflows impacting Lake Erie and local water quality may be contributing factors.

Why is it difficult to identify the source of a Cyclospora outbreak?

Unlike bacteria, the Cyclospora parasite replicates only in humans, which makes DNA fingerprinting and molecular typing techniques less reliable for tracing the source of an outbreak. This limitation makes it more challenging for investigators to link cases to a specific food or environmental source.

Should consumers stop eating fresh produce because of Cyclospora?

No. Health officials do not recommend that consumers stop eating fresh produce. Standard food safety practices, including washing produce under running water, are advised. Fresh fruits and vegetables remain an essential part of a healthy diet.

Are the 2026 Cyclospora case numbers unusual?

In Michigan and Ohio, yes — the regional cluster is higher than expected and is under active investigation. Across the rest of the United States, national case counts remain within the historical average for this time of year.

Cyclospora Outbreak 2026: FAQs for Consumers

September 14, 2026

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Cyclospora Outbreak: Summer 2026

Last updated: September 14, 2026 / 10:00 AM — Please Note: This page will no longer be updated with information; check federal partner websites for any additional information in the links below.

As of September 11, 2026, CDC has declared this outbreak over.

What began as a handful of unusual case reports out of Michigan in early summer grew into the largest cyclosporiasis outbreak recorded in U.S. history. Over the course of the 2026 season, tens of thousands of people across the country fell ill, most experiencing the watery diarrhea and prolonged gastrointestinal symptoms characteristic of this parasite. Two deaths, both in Michigan and both involving individuals with significant underlying health conditions, were reported in connection with the outbreak.

For weeks, investigators worked without a confirmed source, relying on patient interviews and traceback work while methodically ruling hypotheses in and out, a process this page documented in real time, including the genuine scientific difficulty of pinning down a parasite that can't be cultured in a lab and resists standard water treatment. In mid-July, that work identified a specific subcluster: illnesses linked to shredded iceberg lettuce supplied by Taylor Farms de Mexico and served at Taco Bell locations. Taylor Farms issued a voluntary recall on July 17, and by the time CDC formally closed the outbreak, that confirmed subcluster alone accounted for 12,883 illnesses across 21 states.

FDA's on-site inspections and sample collection at the implicated growers and processing facility in Mexico, conducted in coordination with Mexican officials, have concluded, with results still pending analysis. FDA has stated it remains confident that all recalled product is off the market.

The outbreak itself is over. The work it started is not. While CDC has closed its outbreak designation, FDA's investigation remains ongoing, and the agency will continue collaborating with CDC, state, local, and international partners to complete it. FDA has also launched a dedicated page tracking what comes next: Post-Outbreak Response Activities: Multistate Outbreaks of Cyclospora Illnesses. IFPA will continue to track that work closely, and this page will remain available as a record of what happened and what we learned along the way.

Frequently Asked Questions

What is it and what does it do

What is Cyclospora? Cyclospora cayetanensis is a microscopic, waterborne parasite that can cause an intestinal illness called cyclosporiasis. It's been a known, if uncommon, cause of foodborne illness in the U.S. for decades, with cases typically rising in the warmer months (May – August). It is more common in tropical and subtropical regions of the world.

Infections with Cyclospora are rarely life-threatening, and most people who get sick recover fully, even those with weakened immune systems. Death from cyclosporiasis is uncommon in the United States. As of this writing, we note that Michigan Department of Public Health has reported two individuals who have passed in connection with this outbreak. They note that both individuals had significant underlying health conditions that may have been impacted by cyclosporiasis and dehydration. Both individuals became ill before the July 17 recall.

What are the symptoms? The most common symptom is watery diarrhea, often along with loss of appetite, weight loss, cramping, bloating, nausea, and fatigue. Symptoms can start, on average, about a week after exposure and, without treatment, can last from a few days to a few months. It's treatable with prescription antibiotics, but can also self-resolve.

What should I do if I think I'm sick? Contact your healthcare provider, especially if you have prolonged watery diarrhea. Cyclosporiasis is treatable with prescription antibiotics, and a healthcare provider can confirm diagnosis with a stool test.

Are some people at greater risk than others? Yes. Most healthy adults recover fully with appropriate antibiotic treatment. The illness can be more severe and longer-lasting for people with weakened immune systems, including those living with HIV, organ transplant recipients, or people on immunosuppressive medications. If you or someone in your household is immunocompromised and experiencing symptoms consistent with Cyclospora, it's worth contacting a healthcare provider promptly and specifically asking about Cyclospora testing.

Current outbreak

Was a specific food identified as the source of this outbreak? Yes, for a portion of the broader outbreak. FDA and CDC linked a subcluster of this outbreak, 12,883 confirmed illnesses in its final tally, to iceberg lettuce distributed by Taylor Farms de Mexico across 21 states, with Virginia the last state added before CDC declared the outbreak over on September 11, 2026. The subcluster's final toll included 570 hospitalizations and 2 deaths, with the last reported illness onset on August 17, 2026. On July 17, 2026, Taylor Farms announced a voluntary recall of iceberg lettuce sourced from central Mexico, distributed to 27 states between June 29 and July 16. Taco Bell completed removal of the affected lettuce from its restaurants.

This confirmed subcluster did not account for every reported case, however. Outside of it, no specific food, farm, grower, or supplier was confirmed as the source for the remaining cases nationally. Three smaller, separate Cyclospora outbreak clusters remained without a known food or other source of exposure identified. FDA's onsite inspections and sample collection at the implicated growers and processing facility in Mexico, conducted in coordination with Mexican officials, have since concluded. FDA stated it remained confident that all recalled iceberg lettuce related to this outbreak was off the market.

For the full, current record from federal health authorities, see FDA's investigation page and CDC's outbreak page.

Was any product recalled, and did it test positive for Cyclospora? Yes, product was recalled. On July 17, 2026, Taylor Farms de Mexico announced a voluntary recall of iceberg lettuce sourced from central Mexico, covering 236,192 cases of iceberg lettuce and salad mixes. While the recall was first identified in connection with certain Taco Bell locations, Taco Bell accounted for only a fraction of the recalled product; nearly half was distributed to Walmart for its Marketside salad brand. Taco Bell completed removal of the affected lettuce from its restaurants, and the recall covered both restaurant and retail grocery channels. A complete list of affected products, lot codes, and use-by dates is available on FDA's recall notice.

As for laboratory confirmation: throughout this investigation, there were no confirmed positive sample results for product testing for Cyclospora. This is worth explaining directly, since it can be a confusing point. The recall and this outbreak's findings were based on epidemiological evidence (patient interviews) and traceback (tracing product distribution back to a common supplier), not on a positive laboratory test. Produce testing for Cyclospora has real, documented limitations, including low sensitivity at low contamination levels, and implicated products are often gone by the time testing becomes possible. The absence of a positive sample did not mean the epidemiological and traceback findings were wrong.

One specific episode is worth noting for the record: on July 18, 2026, FDA reported one positive sample, collected through routine random sampling, something FDA does commonly throughout the year, unrelated to the product that was voluntarily recalled. That result was reclassified the next day as a false positive after expert review determined it did not reflect true amplification.

A recall is the removal of a food product from the marketplace when there is reason to believe it may pose a health risk to consumers. In many cases, recalls are initiated voluntarily by a company in coordination with FDA, as was the case here. If you had any of the recalled product at home during the outbreak, FDA's guidance was to discard it rather than eat it, per the recall notice. Fresh produce sold in grocery stores and served at other restaurants was not affected by this recall, unless otherwise identified in the recall notice itself.

Were these case numbers unusual? Yes. Michigan's Department of Health and Human Services reported more than 11,500 confirmed cases, across more than 70 of the state's counties. This made this outbreak of cyclosporiasis the largest in Michigan's history, and far above the state's typical annual total. Ohio also reported approximately 4,013 confirmed cases, well above its usual seasonal range. These state-reported totals included both confirmed and probable cases, which is part of why they ran higher than the federal confirmed-case count for the specific subcluster described below.

The confirmed subcluster tied to Taylor Farms de Mexico lettuce reached a final total of 12,883 illnesses across 21 states, with 570 hospitalizations and 2 deaths, before CDC declared the outbreak over on September 11, 2026.

It's worth understanding that public health agencies routinely monitor cyclosporiasis cases in groups, or clusters, across the country each season as a normal part of surveillance, and this year was no different in that respect. CDC and state partners investigated additional clusters beyond the confirmed subcluster throughout the outbreak. This was a standard part of how outbreaks are investigated, comparing cases across different areas to see whether any share a common thread, not a sign that the situation was broader or more severe than what's described here.

Where can I see where cases occurred? CDC published a map showing the reported locations of domestic cyclosporiasis cases throughout this outbreak, available on CDC's Surveillance of Cyclosporiasis page and on the CDC outbreak page. As the outbreak concluded, CDC reduced the frequency of updates to this data. For the final, authoritative case map and figures, refer directly to those CDC pages.

Why does Cyclospora tend to show up in certain places or times of year? Cyclospora is closely tied to environmental conditions. The parasite needs warmth and moisture to become infectious, so cases tend to rise in the summer, and clusters can follow periods of heavy rainfall or water system disruptions, which can affect water used in irrigation or food handling as well as recreational water areas (however, this correlation does not hold in locations outside of continental North America).

There was documented, significant rainfall and combined sewer overflow activity in parts of the affected region in mid-June. IFPA believes this timing is worth continued attention as investigators work through the separate, still-unconfirmed clusters described above. For the confirmed subcluster specifically, FDA's traceback points to an imported product from central Mexico, a different pathway than the domestic water exposure IFPA has raised as a question for some of the remaining clusters.

How it spreads

How does someone get Cyclospora? People get infected by ingesting contaminated food and/or water. Unlike many foodborne pathogens, Cyclospora is most commonly associated with environmental contamination involving water, and historically, outbreaks have been attributed to a variety of fresh produce commodities as well as contaminated irrigation or processing water, reinforcing why investigators need to evaluate all plausible contamination pathways rather than assuming food alone is the source.

Importantly, the parasite requires time outside the human host before becoming infectious, meaning a person who is sick with cyclosporiasis cannot pass it directly to someone else the way a cold or flu spreads. This delay also means contamination events often happen well before the resulting illnesses are even recognized as part of an outbreak, which is a significant part of why finding the exact source takes time.

Is Cyclospora contagious? Not in the way many people assume. Humans are the only known host of Cyclospora, so there's no evidence pets or livestock can carry or spread it. And because the parasite needs 7-15 days to mature in the environment before it can infect someone, it doesn't spread directly from person to person the way a cold or the flu does.

That means a couple of things people often wonder about: a sick employee or a member of a household isn't shedding a form of the parasite that could immediately contaminate food they touch that day (though sick employees are still kept away from food handling as a standard precaution). And within a household, if more than one person gets sick around the same time, it's far more likely they all ate or drank the same contaminated thing, not that one person spread it to another.

In rural areas that use septic tanks and well water, there is a possibility of introducing infectious forms of the parasite into well water, although this outcome would likely be impacted by failure of the septic system or excessive rainfall and/or flooding.

How does Cyclospora end up in a production environment? Because Cyclospora cayetanensis only infects humans, it can only enter a farm environment if human waste is not properly managed, for example wastewater reaching agricultural water or soil in a way that shouldn't happen. Oocysts shed by an infected person are not immediately infective though. They need 7-15 days in a warm, moist environment to mature before they can cause illness, which means the contamination pathway almost always runs through the environment rather than directly from person to produce.

What does water have to do with Cyclospora on a farm? While infected individuals are the only source of Cyclospora, water is believed to be a way that Cyclospora travels into and through a production environment. Surface water sources including rivers, canals, ponds, and reservoirs can carry oocysts if exposed to sewage or inadequate sanitation upstream. If irrigation or processing water comes into contact with a compromised sewage line, a poorly maintained septic system, or runoff from a nearby facility with inadequate sanitation controls, it can carry the parasite to crops before or after harvest. Soil can also harbor oocysts for weeks to months, and flooding or runoff can move them into production areas.

How does Cyclospora actually get onto fresh produce? Once the parasite is present in water or soil, there are a few main ways it can end up on a crop. However, it’s worth noting that all water used for crop irrigation must meet cleanliness standards set by the FDA.

Overhead watering is the most direct route for leafy greens and herbs, since water sprayed onto the plant lands right on the leaves people eventually eat. Drip irrigation, which waters the roots instead of the leaves, carries meaningfully lower risk for this reason, though it doesn't remove every source of contamination, since splashing soil can still reach low-growing plants. Heavy rain or flooding can do the same thing, splashing contaminated soil or water directly onto crops.

Contamination can also happen after harvest, not just in the field. Water used for washing, cooling, or packing produce, or contact with dirty surfaces or equipment at a packing facility, can introduce contamination even after the crop leaves the ground. This is part of why both farm water and post-harvest processing water are separately regulated, which we cover further below.

Can farms, municipal water systems, or recreational water facilities like pools add chlorine to water to eliminate Cyclospora? No, and this is an important distinction from most other waterborne pathogens. Chlorine and other standard antimicrobial chemical treatments are not considered effective against Cyclospora, regardless of whether they are applied at the farm level in an irrigation system, at a municipal water treatment facility, or in a recreational water setting such as a swimming pool or splash pad. This includes the chlorination levels typically used in all of those settings.

Alternative treatment approaches such as UV light, ozone, or microfiltration can reduce the parasite in water and may be appropriate depending on the source and the level of risk identified.

This is one of the reasons prevention at the source matters so much for Cyclospora specifically. For farms, that means the annual water assessment and source protection are the primary line of defense rather than chemical treatment after the fact. For municipalities, standard disinfection protocols that reliably handle bacteria and viruses do not provide the same assurance for this parasite.

For pools and other recreational water facilities, the chlorine levels maintained for routine sanitation are not sufficient to kill Cyclospora, which is why people who swallow water in a pool or other recreational water body are not protected the way they might be from other waterborne illnesses. People traveling to regions where Cyclospora is more common should also be aware that locally treated tap water and recreational water may not eliminate the risk, even when it meets local treatment standards. CDC's July 14 health alert reinforces this directly, stating that 'no EPA-registered disinfectant products have been demonstrated to be effective against Cyclospora.'

What can consumers do to reduce their risk and shop safely? Standard food-safety practices apply: wash your hands before and after preparing food, rinse fresh produce under running water, and thoroughly clean surfaces that come in contact with foods (kitchen counters, sinks, microwave tables, etc.) with household chemicals labeled for that use. Use separate cutting boards for fresh produce and meats/poultry, and thoroughly wash them with hot water and dish detergents after each use. Separate fresh produce from meats/poultry and household chemicals in the fridge and pantry.

When peeling fruits and vegetables, wash them first under running warm water with a scrubber. Prepared foods, including peeled or cut fruits and vegetables, should be refrigerated promptly and should not be left outside the fridge for longer than 2 hours. These are good practices at any time, not just during an active outbreak.

During recreational activities (swimming, water sports, visiting aquatic parks), it is imperative to follow the advice of public health officials based on water quality. If you experience gastrointestinal distress, follow your doctor's advice on treatment and do not attend swimming pools, water parks, or gatherings where food is prepared or served, while Cyclospora is not transmitted directly person-to-person, these are best food safety practices.

These practices also apply to routine grocery shopping and should be followed consistently, not just during an active outbreak. Separate fresh produce, meats/poultry, and household chemicals both in the shopping cart and shopping bags. If using cloth shopping bags, wash them often in hot water with detergents, dry them thoroughly after washing, and keep them in a dry, clean place between trips to the grocery store.

Do not bring reused containers (e.g., food storage-like containers) with you to grocery stores for loose, unpackaged items, even if you think you cleaned the containers thoroughly. When selecting unpackaged fruits or vegetables, select the ones closest to you, touching or squeezing produce just bruises it. Keep your hands clean when shopping. During warm months, bring your groceries home quickly, they should not sit in the trunk of a hot car.

Can chlorine or washing remove Cyclospora from produce? Not completely, and this is important to understand about this specific parasite.

Chlorine and other common disinfectants don't work well against it. Health officials have found that Cyclospora may resist routine chemical disinfection, including chlorine, and no approved disinfectant has been shown to fully get rid of it. This is different from many other germs, where chlorine-based cleaning does the job.

It is important to note that outbreaks of foodborne illness are rare, and the vast majority of consumers are not exposed to Cyclospora any given day. Using soaps, detergents or other home-made solutions for washing fruits and vegetables represents a more significant and well documented risk of poisoning.

Why are there so few options for dealing with Cyclospora at home? To test the effectiveness of any approach (e.g. chemical spray/wash or physical, like aggressive scrubbing/washing), researchers need to have access to live Cyclospora cells to test what kills them. However, Cyclospora cannot be grown in the lab, it does not grow in any laboratory animal or human cell/tissue culture. The only source of Cyclospora cells for research are those obtained from patients and this limits what’s available for studies on effectiveness of these treatments.

Should consumers have stopped eating fresh produce during this outbreak? No. Throughout this outbreak, federal and state public health officials conducted their investigations, and IFPA closely monitored developments as new information became available. As a trade association representing the entire supply chain, IFPA provided resources to members and supported the work of public health agencies. Once the specific product involved was identified, Taylor Farms de Mexico and affected retailers quickly issued a recall to remove the product from commerce. Outside of that identified product, FDA and CDC guidance never changed: fruits and vegetables remained safe to eat and continued to be an essential part of a healthy diet throughout the outbreak.

Testing and Traceback

How does a doctor test for Cyclospora if someone is sick? Testing for Cyclospora requires a stool sample, but it will not show up on the standard parasite test that most labs run as a matter of routine. A doctor must specifically ask the lab to look for it, and the lab must use the right technique to find it. This is one of the reasons Cyclospora infections are frequently missed or diagnosed late.

There are two main ways labs look for it. The first is examining the sample under a microscope using special staining techniques that make the parasite visible. The most reliable approach uses ultraviolet light, under which Cyclospora naturally glows blue or green, but not all labs have that equipment. The second approach uses a DNA-based test called PCR, which looks for the parasite's genetic characteristics rather than trying to spot it visually. Some broader panels that test for many GI illnesses at once do include Cyclospora, but not all of them do, so a negative result on a general stomach illness panel does not automatically rule it out.

Can someone test negative even if they actually have Cyclospora? Yes. The parasite is shed in stool inconsistently and in small amounts, so a single negative sample does not rule it out. Doctors are advised to test at least three separate stool samples on different days before concluding a result is truly negative. If you have persistent, unexplained watery diarrhea and a first test came back negative, it's reasonable to ask your doctor about additional testing.

How do investigators test fresh produce for Cyclospora, and is that the same as the clinical test? It is a similar concept but a different process, and the two are not interchangeable.

When investigators test produce, they wash the surface of the food and then test the wash liquid for signs of the parasite's DNA. They are not testing the food itself in the way you might imagine. The FDA has an official method for this which was updated relatively recently. The method can detect very small amounts of contamination, as few as five oocysts (the microscopic form of the parasite) on a sample.

Do all labs use the same method to test produce for Cyclospora? No. The FDA has an official validated method (BAM Chapter 19b) that its regulatory labs use, but there is currently no international standard requiring all labs to follow the same approach. The International Organization for Standardization is in the process of developing one, but until it exists, labs in different countries, and potentially different labs within the U.S., may be using approaches with different levels of sensitivity and precision. This makes it harder to compare results across investigations and complicates coordination during international outbreaks.

What does a negative test result on produce actually mean? Testing is one important tool in outbreak investigations, but it works best when samples are collected early and in sufficient quantity. The FDA's validated method for detecting Cyclospora on produce (BAM Chapter 19b) should be specific and scientifically rigorous. When samples are available and tested promptly, results are meaningful.

The challenge in many investigations is not the method itself but the combination of two compounding factors. First, investigators frequently do not yet know which product, if any, to test. Identifying the vehicle requires patient interviews, purchase records, and traceback work that takes time, and until that picture comes together, there is no clear target. Second, by the time a likely vehicle is identified, the implicated product (if food) has often already been consumed or has deteriorated past the point where reliable testing is possible.

When testing is part of a well-coordinated, timely response with a clearly identified vehicle, it is a valuable piece of that larger picture.

Why is it so hard to trace Cyclospora back through the supply chain? Fresh produce supply chains are complex by nature, and that complexity works against fast traceback even when investigators have a strong lead, and it's substantially harder still when they don't. A salad kit can contain items from multiple sources, sometimes subject to different regulatory oversight and packed together at a single facility. Once commingled, there's no way to separate out which grower's product is in any given bag. Restaurant supply chains add another layer: a single menu item can draw ingredients from multiple distributors, and a chain's locations in one region may not all source from the same supplier.

This complexity is compounded by Cyclospora's biology, which limits nearly every tool investigators would normally rely on. Unlike bacteria such as Salmonella or E. coli, Cyclospora can't be cultured in a lab, which limits how well standard whole-genome DNA fingerprinting techniques work for linking individual cases to a common source. CDC has developed a genotyping tool that can help link cases during an investigation, and it has been used in past outbreaks, but it is still being refined and does not yet provide the same speed or resolution as whole-genome sequencing.

Produce testing has its own limitations too, since perishable products are often gone by the time a lead emerges, and even when samples are available, detection sensitivity drops off at low contamination levels. That leaves patient interviews and purchase records as an important piece of the puzzle, but not a substitute for the physical and laboratory evidence that's harder to come by with this parasite. This combination, limited lab tools, limited testing windows, and a genuinely complex supply chain, is why outbreak investigations involving Cyclospora consistently take longer, and are harder to resolve, than those involving bacteria. For all of these reasons, findings in a Cyclospora investigation are strongest when they're supported by multiple, complementary lines of evidence, epidemiologic, environmental, traceback, and laboratory, together, rather than resting on any single source of evidence in isolation.

Is anything being done to address these supply chain traceability challenges? Yes. FDA's FSMA 204 Food Traceability Rule is designed to address the commingling and complex supply-chain challenges described above. It should also be noted that while federal compliance with FSMA 204 is delayed, a majority of grower/shippers have already implemented traceability in their operations. IFPA has been actively educating industry members on traceability, advocating for end-to-end traceability, and proposing technological solutions that will leverage modern tools to minimize human error that could be unavoidable during manual tracebacks. IFPA advocacy focuses on bringing the entire supply chain into compliance using a Warehouse Management System.

Learn more on our FSMA 204 Traceability Resources page, which contains webinar recording and useful tools designed to support traceability adoption across the industry. While built primarily for industry members, the content there may also be useful for consumers wanting a deeper understanding of how traceability works.

Did the delay in FSMA 204 implementation affect how quickly the source of this outbreak could be traced? It's reasonable to ask, and the honest answer is that we can't quantify a precise effect, but the underlying gap is real. FSMA 204's full compliance deadline has been delayed, meaning the standardized, end-to-end recordkeeping it requires isn't yet universally in place across the supply chain. In this outbreak, traceback still succeeded in identifying a supplier, but through a more traditional combination of patient interviews, purchase records, and manual traceback work, the same limitations described throughout this page. Whether full FSMA 204 compliance would have meaningfully shortened that timeline isn't something we can state with certainty, but faster, more standardized traceability data is precisely the outcome full implementation is intended to produce, which is why IFPA continues to advocate for it.

Can genomic sequencing help trace Cyclospora outbreaks? Genomic sequencing is possible but far more limited than what's used for bacterial pathogens, for a specific and persistent reason: Cyclospora cannot be grown or cultured in a lab. Every genetic sample has to come directly from purified stool specimens, a slow, technically difficult process that typically yields only tiny amounts of usable DNA. Because of that, full whole-genome sequencing, the gold-standard tool used routinely for Salmonella and E. coli investigations, isn't practical for Cyclospora as a routine outbreak tool. As of recent published research, only a few dozen Cyclospora genomes have ever been fully sequenced worldwide.

Instead, CDC has used a more targeted approach since 2018: a method that reads eight specific genetic markers (rather than the organism's entire genome) to generate a partial genetic profile for each case, which can then be compared across patients to see whether cases might share a common source. This has genuinely helped investigators in past outbreaks, but researchers who developed and use this method have themselves noted it has limited resolving power compared to full genome sequencing, meaning it can suggest cases are related without offering the same level of certainty bacterial genome matching provides.

Newer research has developed methods aimed at reading far more genetic markers, and even at applying this directly to contaminated produce samples rather than just patient stool, which could eventually help link illnesses to a specific product more precisely. These newer approaches show promise in published studies, but aren't yet established as a routine, everyday tool the way genomic sequencing is for bacterial outbreaks.

Bottom line: genomic tools for Cyclospora exist and are improving, but they remain meaningfully behind what's available for bacterial pathogens, which is a real, documented reason investigations involving this parasite take longer and rely more heavily on epidemiological interviews.

Regulatory and Industry

What are the FSMA requirements for Cyclospora prevention? The federal Produce Safety Rule (21 CFR Part 112) doesn't call out Cyclospora specifically, but several of its rules directly help prevent it, mainly because humans are the parasite's only known source. Broadly, the rule focuses on two things: keeping sick workers away from produce, and keeping water sources clean.

On the worker side, farms are required to keep any employee who is sick, or appears to be sick, away from tasks involving produce or anything that touches produce (§112.31). Farms must also train workers on proper hygiene, and toilet and handwashing facilities have to be placed and maintained so they can't contaminate crops, food-contact surfaces, or water sources (§112.32).

On the water side, farms are required to review their water supply every year, looking at where it comes from, how it's used on crops, and whether anything nearby could affect its quality. If that review turns up a concern, farms have to take action to fix it, and they're required to move especially quickly if the concern involves nearby sanitation issues. Water used after harvest, for washing or cooling produce, is held to an even stricter, testable standard.

For more detail on the water-specific requirements, see the questions below.

Are farms required to do anything about their water to prevent this? Yes. Under the FDA's Food Safety Modernization Act (FSMA) Produce Safety Rule, farms that grow fruits and vegetables covered by the rule must meet standards for agricultural water, which is any water used during growing, harvesting, packing, or holding that is likely to contact the produce or surfaces that touch the produce. The core requirement is that all agricultural water must be safe and of adequate sanitary quality for its intended use.

What specifically are farms required to do to check their water? As of a 2024 update to the rule, pre-harvest agricultural water is not required to be tested using specific numerical criteria the way it used to be. Instead, farms are required to take a systems-based approach: a careful, documented assessment of their water supply every year, before and during the growing season. This goes beyond simply running a water test against a numeric standard. It is a whole-picture review: where the water comes from, how it moves through the farm, how it is applied to crops through irrigation systems, and whether anything nearby could affect its quality.

That includes evaluating surrounding land uses such as wastewater treatment facilities, septic systems, and portable or fixed restroom facilities, whether those are located on the farm itself or on neighboring properties. Importantly, if a neighboring property is upstream of a farm's water supply and the farm cannot get information about what that neighbor is doing, the rule expects the farm to account for that uncertainty by treating it as a potential risk rather than assuming everything is fine. Based on what they find, farms determine whether any changes or safeguards are needed, with the goal of catching potential issues before produce ever reaches a store shelf.

What happens if the assessment finds a problem with the water? Finding a potential issue does not mean a farm is in trouble. It means the system is working as intended. When an assessment identifies a concern, farms are required to take steps to address it, and the rule gives them several practical options for doing so. They might repair or upgrade part of the water system, change how water is delivered to crops (for example, switching from overhead sprinklers that spray water onto leaves to drip irrigation that delivers water directly to the roots instead), or treat the water using a method verified to be effective. For concerns tied to sanitation issues on nearby land, the rule asks farms to act on a faster timeline than they would for other types of issues, reflecting how seriously that particular risk is taken.

Are water safety requirements under the rule limited to the growing season, or do they extend to harvest and packing as well? They extend well beyond harvest. Water used for washing, cooling, transporting, or packing produce after it leaves the field is also regulated under the rule, and it is actually held to a stricter standard than pre-harvest water. It must meet a specific measurable microbial quality criterion with no detectable generic E. coli per 100 milliliters of water, and it is subject to testing requirements rather than the assessment-based approach used for pre-harvest water. Water used to make ice that contacts produce and water used for handwashing during harvest activities are also included in these requirements.

Some third-party audit programs go further still on water quality, requiring that water used in post-harvest operations meet potable (drinking-quality) standards rather than simply the regulatory criterion of no detectable E. coli. For a parasite like Cyclospora, where E. coli testing does not directly indicate the parasite's presence or absence, that higher standard provides a meaningful additional layer of protection.

What can growers do to reduce the risk of Cyclospora contamination on their farm? It's important to be direct about something here: there is currently no FDA guidance or validated, Cyclospora-specific protocol that tells growers exactly how to prevent contamination. This is a real gap, not an oversight, it reflects how difficult this particular parasite is to study and detect, something we've noted throughout this page.

What does exist is general Good Agricultural Practices (GAPs), which are believed to reduce risk broadly across many pathogens, though they were not developed or validated specifically against Cyclospora. Beyond that, researchers at the University of Florida have published practical recommendations specifically discussing Cyclospora, offering thoughtful, expert-informed suggestions rather than an established or validated protocol: Prevention of Cyclospora Contamination and Transmission on the Farm (UF/IFAS Extension) and Preventing Foodborne Illness: Cyclospora cayetanensis (USDA/NIFA).

Their key recommendations include the following, though growers with specific questions are encouraged to consult their local university extension service, regulatory contacts, or other qualified technical resources for guidance tailored to their specific situation.

Know your water sources. Map all water sources on and adjacent to your farm, including nearby sewage systems, septic tanks, and drain fields. After crops are established, avoid using surface water for any activity that contacts the harvestable portion of the crop. Where water quality is uncertain, use potable (drinking-quality) water for washing produce and for any post-harvest activities that contact food surfaces.
Have a plan for weather events. Flooding and heavy rainfall can move contamination from sanitation infrastructure into growing areas and water systems. UF researchers specifically recommend developing a written corrective action plan for significant weather events before they occur, not after.
Maintain sanitation infrastructure. Provide sufficient, accessible, and properly functioning toilet facilities for all workers. Use reputable companies for cleaning and maintaining portable toilets and site those facilities away from growing areas and all water sources. Have written corrective action procedures in place for any spills or leaks.
Train workers thoroughly and in their language. Training materials should be appropriate for workers' native language and background, and should cover proper handwashing, recognizing illness symptoms, not working while sick, and correct use of toilet facilities.
Avoid untreated manure. Do not use untreated manure as fertilizer on crops eaten raw. If composted amendments are used, follow applicable USDA guidelines on timing and application.

IFPA's Response

What did IFPA do throughout this outbreak? IFPA monitored this situation from early July onward and remained in ongoing, active contact with CDC, FDA, and state health officials as the investigation expanded to a multistate response. IFPA shared verified updates with members as they became available and worked to help ensure members, media partners, and others had up-to-date information to understand the actual state of the evidence.

The fresh produce industry took this outbreak seriously throughout. Growers, packers, processors, shippers, retailers, foodservice operators, and regulators shared the common goal of identifying the true source of contamination as quickly and accurately as possible so that effective corrective actions could be implemented. Getting to the root cause mattered not just for resolving this outbreak, but for minimizing the risk and magnitude of future events.

What is IFPA doing on traceability? IFPA advocacy is focused on bringing the entire supply chain into compliance through the Warehouse Management System, a comprehensive approach to end-to-end traceability that recognizes the realities and limitations of the entire supply chain and incorporates technological approaches for filling compliance gaps. Learn more on our FSMA 204 Traceability Resources page, which contains webinar recordings and useful tools designed to support traceability adoption across the industry and could be informative to consumers as well.

Has IFPA submitted formal recommendations to federal agencies? Yes. IFPA submitted formal comments to CDC on its Cyclosporiasis National Hypothesis Generating Questionnaire, the tool used to interview patients during outbreak investigations. Our comments recommended adding structured questions on drinking water source, recreational water exposure, and related environmental exposures; reviewing past unresolved cyclosporiasis investigations for exposure patterns that may not have been systematically captured; and considering routine wastewater surveillance to better understand the parasite's presence across the U.S. We believe these changes would help investigators reach faster, more precise conclusions, exactly the kind of specificity that reduces unnecessary confusion for consumers and unwarranted disruption for unaffected parts of the industry.

What questions did IFPA continue to raise during the investigation? Throughout this outbreak, IFPA raised concerns about recent municipal sewage overflows in the greater Detroit/Toledo region and the likelihood of these events impacting the quality of drinking water (especially water wells) and recreational water in Lake Erie and surrounding bodies of water. Cyclospora is fundamentally a waterborne parasite, and IFPA believed a comprehensive investigation should consider all scientifically plausible sources of contamination, including agricultural water, post-harvest water systems, and other environmental reservoirs, alongside food.

This position was informed by timing: there was documented, significant rainfall and combined sewer overflow activity in parts of the affected region in mid-June. IFPA raised this as worth continued attention as investigators worked through the separate, still-unconfirmed clusters. These concerns were raised specifically in connection with those broader, unconfirmed clusters, not as an alternative explanation for the confirmed Taylor Farms de Mexico lettuce finding, which FDA's traceback tied to an imported product from central Mexico. For IFPA's specific recommendations to strengthen how future investigations account for water exposure, see 'Has IFPA submitted formal recommendations to federal agencies?' above.

What did IFPA advocate for during and after this investigation? IFPA supported FDA's traceback, environmental assessment, and product testing efforts throughout the investigation, and encouraged a comprehensive approach that considered all scientifically plausible sources of contamination, including agricultural water, post-harvest water systems, environmental reservoirs, and other potential exposure pathways associated with this waterborne parasite. IFPA also encouraged continued collaboration among industry, FDA, CDC, state partners, and the research community to strengthen the scientific tools available for future investigations, since improvements in environmental detection methods, validated molecular typing technologies, and robust epidemiologic methodologies help increase confidence in source attribution while minimizing unnecessary disruption to producers and consumers alike.

Beyond this specific investigation, IFPA proposed a coordinated, FDA-led public-private task force, bringing together government, industry, and academic partners, to conduct a thorough root cause analysis once the investigation concluded and translate what was learned into durable, actionable prevention measures. FDA has indicated it plans to conduct a root cause analysis of its own; IFPA continues to advocate for that effort to include input from industry and academia alongside government expertise, believing that kind of collaborative approach tends to produce prevention measures that are easier to put into practice, since it draws on the full range of expertise and on-the-ground knowledge each group brings.

Where can I learn more or follow what happens next? This page serves as IFPA's record of the 2026 Cyclospora outbreak, reflecting what was known and confirmed as the investigation concluded. While the outbreak itself is over, related work continues. FDA has launched a dedicated page tracking that ongoing work: Post-Outbreak Response Activities: Multistate Outbreaks of Cyclospora Illnesses. For deeper technical background on the parasite and its relationship to the fresh produce industry, visit IFPA's Cyclospora resource page. For members with specific questions, IFPA's food safety experts remain available.

Media Contact: Media@freshproduce.com
Food Safety Contact: FoodSafety@freshproduce.com

What Is Cyclospora? FAQs from IFPA