Cyclospora

Cyclospora is a parasite, not a bacterium, and it behaves like one—causing a prolonged, relapsing illness that can drag on for weeks. It is usually traced to fresh imported produce, and because it is hardy, ordinary washing does not reliably remove it. Marler Clark, The Food Safety Law Firm, is the nation’s leading firm representing victims of Cyclospora outbreaks. Our Cyclospora attorneys have represented victims in the only U.S. law practice devoted exclusively to foodborne illness, which has recovered more than $850 million for victims and families nationwide. We have litigated Cyclospora cases traced to basil, bagged salad, snap peas, and other fresh produce, including the large 2018 outbreaks linked to McDonald’s salads and Del Monte vegetable trays.

If you or a family member became ill with a Cyclospora infection after eating contaminated food, contact the Marler Clark Cyclospora attorneys for a free case evaluation.

FAQ

What is Cyclospora?

Cyclospora is a microscopic parasite that causes cyclosporiasis, a prolonged, relapsing intestinal illness that can last for weeks. It usually spreads through fresh imported produce, and because it is hardy, ordinary washing does not reliably remove it.

What foods cause Cyclospora outbreaks?

Fresh produce is the usual source—basil, cilantro, bagged salad, snap peas, and pre-packaged vegetable trays have all been implicated, often when imported.

What are the symptoms of cyclosporiasis?

Watery diarrhea that comes and goes, fatigue, loss of appetite, cramping, and weight loss. Untreated, symptoms can persist or relapse for weeks.

How is it treated?

Cyclosporiasis usually requires a specific antibiotic—not the standard treatment for other diarrheal illnesses—so an accurate diagnosis matters. Ask your doctor about testing for parasites.

Can I sue for a Cyclospora infection?

If your illness is tied to a contaminated produce item or a recognized outbreak, you may have a product-liability claim against the grower, importer, or seller.

Additional Resources:

• About Cyclospora — a complete online resource on Cyclospora infection

Working with Marler Clark

Marler Clark, The Food Safety Law Firm, represents victims of foodborne illness nationwide. Here are answers to the questions people ask us most often.

FAQ

How much does it cost to hire a food poisoning lawyer?

Marler Clark handles food poisoning cases on a contingency-fee basis. There is no charge for the initial consultation, and no attorney’s fees unless we obtain a recovery for you through a settlement or verdict. When your case concludes, you receive a full written accounting of all fees and expenses for your approval before any money is disbursed.

Do I have a food poisoning case?

The strongest cases share three things: a laboratory-confirmed infection, usually from a stool sample; a documented link between your illness and a specific food, restaurant, or product, often through a public health investigation or a genetic match to an outbreak strain; and real damages such as hospitalization, lasting injury, or lost income. A free case evaluation is the fastest way to learn where you stand.

How much is a food poisoning lawsuit worth?

Every case is different. Value depends on the severity and permanence of the injury, medical expenses, lost wages, and how strongly the illness can be tied to a contaminated food. Cases range from short, self-resolving illnesses to catastrophic injuries such as kidney failure or paralysis. We can offer a realistic assessment after reviewing your medical records and the outbreak evidence.

How long do I have to file a claim?

Statutes of limitation set the deadline for filing a lawsuit, and they vary by state and by the type of injury—sometimes as little as one year. Because evidence like receipts, leftover product, and medical samples can disappear quickly, it is best to speak with a lawyer as soon as possible.

Does Marler Clark handle cases nationwide?

Yes. We represent clients across the country and have litigated food poisoning cases in more than 35 states. Claims are often referred to us by attorneys elsewhere, and we work with local counsel where needed, so you do not have to live in Washington to work with us.

Cyclospora is a parasite composed of one cell, too small to be seen without a microscope. The organism was previously thought to be a blue-green alga or a large form of Cryptosporidium. Cyclospora cayetanensis was long regarded as the only species of this organism found in humans; however, genomic analyses reported by CDC scientists in 2023 indicate that what had been identified as C. cayetanensis actually comprises at least three genetically distinct, reproductively isolated species that infect people—C. cayetanensis, C. ashfordi, and C. henanensis.^[1]

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis, which is transmissible by ingestion of fecally contaminated food or water.^[2] Cyclosporiasis is most common in tropical and subtropical regions of the world. In the United States, foodborne outbreaks of cyclosporiasis have been linked to various types of imported fresh produce (e.g., basil, raspberries, and snow peas). For years, the lack of validated molecular typing tools hampered efforts to link cases and trace outbreaks. Since about 2018, however, CDC has developed and begun using a C. cayetanensisgenotyping system—based on targeted deep sequencing of mitochondrial and nuclear DNA markers—to complement outbreak investigations and connect geographically scattered cases, and work continues to refine it into a nationwide typing network.^[3]

Outbreaks of cyclosporiasis in humans have been reported mostly from North America, from the infection sources of contaminated fresh food products, such as soft fruits (raspberries), leafy vegetables (coriander, basil, and mixed salad), and herbs. Soil is another possible infection source, particularly in areas with poor environmental sanitation.^[4]

The Centers for Disease Control and Prevention (CDC) has been conducting national surveillance for cyclosporiasis since it became a nationally notifiable disease in January 1999. As of 2026, cyclosporiasis is reportable in 47 states, the District of Columbia, and New York City (NYC).^[5] Health departments voluntarily notify CDC of cases of cyclosporiasis through the National Notifiable Diseases Surveillance System and submit additional case information using the CDC cyclosporiasis case report form or the Cyclosporiasis National Hypothesis Generating Questionnaire (CNHGQ).^[6]

While cyclosporiasis cases are reported year-round in the United States, cyclosporiasis acquired in the United States (i.e., “domestically acquired,” or cases of cyclosporiasis that are not associated with travel to a country that is considered endemic for Cyclospora) is most common during the spring and summer months. The exact timing and duration of U.S. cyclosporiasis seasons can vary, but reports tend to increase starting in May. In 2020, multiple outbreaks of cyclosporiasis were identified and found to be linked to different produce items. As of September 23, 2020, the CDC documented 1,241 laboratory-confirmed cases of cyclosporiasis in people who had no history of international travel during the 14-day period before illness onset.^[7] Reported cases have climbed markedly over the past decade—from 537 in 2016 to 3,519 in 2018 and 4,703 in 2019—an increase that reflects both a genuine rise in illness and the growing use of rapid multiplex molecular stool panels (such as the FDA-cleared BioFire FilmArray gastrointestinal panel) that now detect Cyclospora as a matter of routine.^[8] The seasonal pattern has continued in the years since; early in the 2026 season, for example, CDC reported 145 domestically acquired cases across 17 states between May 1 and June 16.^[9]

What are the typical symptoms of Cyclospora infection?

Cyclospora infects the small intestine (bowel) and usually causes watery diarrhea, bloating, increased gas, stomach cramps, and loss of appetite, nausea, low-grade fever, and fatigue. In some cases, vomiting, explosive diarrhea, muscle aches, and substantial weight loss can occur. Some people who are infected with Cyclospora do not have any symptoms. The time between becoming infected and becoming ill is usually about one week. If not treated, the illness may last from a few days up to six weeks. Symptoms also may recur one or more times (relapse). In addition, people who have previously been infected with Cyclospora can become infected again.^[10]

Where does Cyclospora come from?

The modes of transmission of C. cayetanensis are still not completely documented, although fecal–oral transmission is the major route. Direct person-to-person transmission is unlikely. Indirect transmission can occur if an infected person contaminates the environment, the oocysts sporulate under the right conditions, and then contaminated food and water are ingested. The role of soil in transmission has also been proposed. The relative importance of these various modes of transmission and sources of infection is not known.^[11]

The dissemination of infective Cyclospora oocysts via water, soil, and unprocessed foods (e.g., fruits and vegetables, including ready-to-eat salads) is enabled by their small size (8–10 μm), low specific gravity, and high infectivity. Such oocysts can survive for weeks to months in water and food, depending on the environmental temperature, and are resistant to the routine sanitization or chemical disinfection procedures used in irrigation systems, recreational waters, or drinking water treatment plants.^[12]

How is Cyclospora diagnosed?

Cyclosporiasis is usually diagnosed symptomatically in clinical settings, including the presence of watery diarrhea, abdominal cramping, and bloating. In untreated, immunocompetent people, the diarrhea can last from days to weeks to a month or more, and can wax and wane, with variable oocyst shedding. Oocysts can continue to be shed (intermittently or continuously) by non-symptomatic people, and symptoms can also persist in the absence of oocysts in feces. In a clinical context, conventional diagnosis usually involves microscopic examination of intestinal tissue biopsy sections, stool samples for the presence of developmental stages of Cyclospora, or advanced molecular testing for DNA. Improved specificity and sensitivity have been possible largely through the use of PCR, which enables the specific amplification of genetic loci from tiny amounts of genomic DNA of Cyclospora. Because of the intermittent nature of oocyst shedding and the low numbers of this stage in feces, it is recommended that multiple stool samples be collected at 2–3-day intervals over a period of more than a week, to increase the likelihood of identifying the disease microscopically.^[13]

What are the serious and long-term risks of Cyclospora infection?

Cyclospora has been associated with a variety of chronic complications such as malabsorption, reactive arthritis, and cholecystitis (inflammation of the gallbladder). Since Cyclospora infections tend to respond to the appropriate treatment, complications are more likely to occur in individuals who are not treated or not treated promptly. Extraintestinal infection also appears to occur more commonly in individuals with a compromised immune system.^[14]

Although human cyclosporiasis is usually not fatal in developed countries such as the United States, protracted diarrhea often leads to dehydration, particularly in infants who are at greatest risk of severe dehydration and death, especially if cyclosporiasis is complicated by infections with other pathogens (viral, bacterial, or parasitic—e.g., Cryptosporidium and Giardia), malnutrition, or malabsorption, particularly in underprivileged communities.^[15]

According to the CDC^[16], the recommended treatment is a combination of two antibiotics, trimethoprim-sulfamethoxazole, also known as Bactrim, Septra, or Cotrim. It is advisable for people who have diarrhea to also rest and drink plenty of fluids.

How can Cyclospora infection be prevented?

There is no vaccine for cyclosporiasis, and no medication is available to prevent infection before exposure. Because the parasite is spread through food or water that has been contaminated with feces, the best available protection, according to the CDC, is to avoid consuming food or water that may be contaminated.^[17]

Standard food-safety and hygiene practices reduce the likelihood of infection. Public health authorities recommend washing hands with soap and water before and after handling or preparing raw produce; washing all fruits and vegetables thoroughly under running water before eating, cutting, or cooking (items labeled “prewashed” need not be washed again); scrubbing firm produce such as melons and cucumbers with a clean produce brush; cutting away any damaged or bruised areas; and refrigerating cut, peeled, or cooked produce within two hours.^[18]

These measures decrease but do not eliminate the risk of transmission. Rinsing or washing produce is not likely to remove Cyclospora oocysts, which adhere tightly to surfaces, and the parasite is resistant to routine chemical disinfection methods such as those using chlorine.^[19] The theoretical infective dose may be as low as a single sporulated oocyst, and there is no way to render contaminated produce reliably safe short of avoiding it altogether.^[20]

Travelers to tropical or subtropical regions where cyclosporiasis is endemic face a heightened risk and should follow the food and water precautions set out in the CDC’s Yellow Book, consuming only water known to be safe—such as sealed bottled water, boiled tap water, or carbonated beverages. In such settings, routine chemical disinfection or sanitization of food or water is unlikely to inactivate the parasite.^[21]

For retailers, restaurants, and other food-service operators, the FDA recommends washing and sanitizing utensils, cutting boards, surfaces, display cases, and refrigerators before and after handling potentially contaminated products, sourcing produce from reputable suppliers, and maintaining purchase records so that traceback investigations can identify a contaminated source when an outbreak occurs.^[22]

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^[1]           CDC. (2024, May 17). Three of a Kind: CDC Researchers Find Cyclospora Is Not Just a Single Species. Advanced Molecular Detection, Centers for Disease Control and Prevention. https://www.cdc.gov/advanced-molecular-detection/php/success-stories/cyclospora.html

^[2]           Casillas, S. M., Hall, R. L., & Herwaldt, B. L. (2019). Cyclosporiasis Surveillance – United States, 2011-2015. Morbidity and mortality weekly report. Surveillance summaries (Washington, D.C.: 2002), 68(3), 1–16. https://doi.org/10.15585/mmwr.ss6803a1

^[3]           Nascimento, F. S., et al. (2019). Mitochondrial Junction Region as Genotyping Marker for Cyclospora cayetanensis. Emerging Infectious Diseases, 25(7). https://doi.org/10.3201/eid2507.181447

^[4]           Giangaspero, A., & Gasser, R. B. (2019). Human cyclosporiasis. The Lancet Infectious Diseases, 19(7), e226–e236. https://doi.org/10.1016/S1473-3099(18)30789-8

^[5]           CDC. (2026). Surveillance of Cyclosporiasis. Centers for Disease Control and Prevention. Retrieved July 2026, from https://www.cdc.gov/cyclosporiasis/php/surveillance/index.html

^[6]           Casillas, Ibid, Note 2 at Page 1.

^[7]           CDC. (2020, September 24). Cyclosporiasis Outbreak Investigations – United States, 2020. Centers for Disease Control and Prevention. https://www.cdc.gov/parasites/cyclosporiasis/outbreaks/2020/seasonal/index.html  

^[8]           CDC. (2023). Notes from the Field: Doubling of Cyclosporiasis Cases Partially Attributable to a Salad Kit — Florida, 2021–2022. MMWR Morbidity and Mortality Weekly Report, 72(27), 748–749.

^[9]           CDC, Ibid, Note 5.

^[10]         Cyclosporiasis – Disease. (2018, May 11). https://www.cdc.gov/parasites/cyclosporiasis/disease.html

^[11]         Almeria S, Cinar HN, Dubey JP. Cyclospora cayetanensis and Cyclosporiasis: An Update. Microorganisms. 2019; 7(9):317.

^[12]         Giangaspero, Ibid, Note 4 at Page 1.

^[13]         Giangaspero, Ibid, Note 4 at Page 3-4.

^[14]         CDC. (2020, October 21). CDC – Cyclosporiasis – Resources for Health Professionals. Centers for Disease Control and Prevention. https://www.cdc.gov/parasites/cyclosporiasis/health_professionals/index.html

^[15]         Giangaspero, Ibid, Note 4 at Page 2.

^[16]         CDC. (2020, September 17). CDC – Cycloporiasis – General Information – Cyclosporiasis FAQs. https://www.cdc.gov/parasites/cyclosporiasis/gen_info/faqs.html

^[17]         CDC. (2024, August 8). Preventing Cyclosporiasis. Centers for Disease Control and Prevention. https://www.cdc.gov/cyclosporiasis/prevention/index.html

^[18]         New York State Department of Health. (2025). Cyclospora Infection (Cyclosporiasis) Fact Sheet. https://www.health.ny.gov/diseases/communicable/cyclosporiasis/fact_sheet.htm

^[19]         U.S. Food and Drug Administration. Cyclospora. https://www.fda.gov/food/foodborne-pathogens/cyclospora

^[20]         Goodrich Schneider, R., Schneider, K. R., et al. Preventing Foodborne Illness: Cyclosporiasis (FSHN0519/FS130). University of Florida IFAS Extension. https://ask.ifas.ufl.edu/publication/FS130

^[21]         CDC, Ibid, Note 17.

^[22]         U.S. Food and Drug Administration, Ibid, Note 19.

As of October 24, 2023, 41 jurisdictions, including 40 states and New York City, have reported a total of 2,272 laboratory-confirmed cases of cyclosporiasis. 

These individuals had not traveled outside of the United States during the 14 days before they got sick. This is an increase of 315 cases since the last update on August 31, 2023.

Sick people ranged in age from 2 to 96 years, with a median age of 51, and 57% were female. The median illness onset date was June 24, 2023 (range: April 1 to August 31). Of 2,242 people with information available, 186 have been hospitalized. Zero deaths have been reported.

Food Safety News reports:

The International Fresh Produce Association (IFPA), formerly the United Fresh and Produce Marketing Association, has distributed a report on Cyclospora cayetanensis in produce.

This report is released and published by the National Advisory Committee on Microbiological Criteria for Foods (NACMCF).  The USDA empowers this committee, and it is not otherwise associated with IFPA otherwise.

The committee worked for two years to prepare the report, which is based on expert interviews and data collected from expert sources,  published literature, reports, and other sources. The report has been published and can be read in full on the USDA website.  

Cyclospora is a microscopic parasite that causes Cyclosoriosis, an intestinal illness. People can become infected with Cyclosporine by consuming food or water, including fresh produce, contaminated with the parasite. Living or traveling in areas where cyclosporiasis is endemic increases the risk of infection.

The IFPA report answers 18 questions the U.S. Food and Drug Administration put forth. The FDA had sought  “information on the factors that can contribute to C. cayetanensis contamination of domestically grown and imported produce and recommendations for developing an effective prevention and management strategy.”

In response to the FDA’s questions, the IFPA report makes these four recommendations:

1. To facilitate future research, e.g., validation of surrogates, studies on environmental persistence and attachment, and identification and validation of control strategies, the committee urges the development of a practical method to propagate C. cayetanensis oocysts in laboratory settings.

2. Because of the limited availability of C. cayetanensis oocysts, research with surrogates — and specifically with the close relative Eimeria — can be informative for identifying control strategies and learning about persistence in the production environment.

3. Method development for detecting C. cayetanensis in food and environmental samples should include the evaluation of multiple genetic targets representing different genome regions. Modifications to current molecular methods for detecting C. cayetanensis should be thoroughly validated for impacts on specificity before using modified methods on food or environmental samples. Conversely, detection methods should be robust, reproducible, and tolerant of minor modifications in the methodologies, e.g., brand of equipment or reagents, minor deviations in PCR conditions, etc., without sacrificing specificity or sensitivity.

4. Given that the hypothesized likeliest source of the parasite in the food production environment (individuals with a history of recent travel to areas where infections with C.cayetanensis are common or other exposures to the parasite), preventative measures should center around clear sanitation guidelines, ensuring on-site capacity for implementing sanitation protocols (i.e., readily accessible hand washing stations with soap, etc.) and periodic training of the employees.

“Cyclospora spp. are protozoan parasites in the phylum Apicomplexan that can parasitize different species of mammals with remarkable host-specificity. Cyclospora has a complex life cycle and can only multiply within the infected hosts. Among the Cyclospora species, only Cyclospora cayetanensis is known to infect humans; all other species are associated with infections in other animals,” according to the IFPA report.  

In releasing the report, IFPA said there were “four major takeaways” for the produce industry, including:

• Based on the research from the committee, the current testing procedures in place do not adequately differentiate between the species of Cyclospora that causes illness in humans and others, referencing reports indicating 90 percent false-positive rates of methodologies underlying some standard tests. To manage this parasite and the risks associated with it, there must be a reliable and replicable testing procedure to identify Cyclospora in environmental samples and foods.  
• The pathogen C. cayetanesis appears to be resistant to common chemical interventions, and it is recommended that antimicrobials or chemicals should be evaluated.  This is an area of potential innovation for the industry.  
• The report also highlights the need for a risk-based (rather than hazard-based) approach to managing this parasite. 
• Cyclospora is only carried by humans, and individuals with a recent history of travel to areas where Cyclospora is highly prevalent are likely the primary source of contamination with the parasite along the entire production-processing-food service/retail continuum.  Therefore, it is essential to ensure that workers are well-trained in inappropriate hygienic practices and that necessary equipment and infrastructure are on-site to manage any contamination of farm water sources. This includes well-managed toilet facilities, gloves, aprons, etc, are all available.  Public health aspects of managing Cyclospora cannot be overlooked. 

“Humans are the only known reservoir for Cyclospora cayetanensis and an essential host for the lifecycle of this protozoan parasite, but there is so much that we still do not understand about the organism,” said Natalie Dyenson, IFPA chief food safety officer. 

“The produce industry, through organizations like the Center for Produce Safety, has been funding research over the past six years, but to fill these knowledge gaps, public health agencies must engage and provide federal funding to support these efforts. Treating this organism as a public health concern by early identification and treatment of human cases in communities where the parasite is endemic to disrupt the life cycle of the parasite is already being used effectively in countries outside of the U.S. where Cyclospora is endemic.”  

IFPA’s  Dr. Max Teplitski said much is unknown about Cyclospora because we don’t have reliable means to identify it in our food system. 

“The produce industry is committed to being the best partner with our regulatory bodies to use the science available to us to improve our ability to keep our consumers safe,” Teplitski added. “As an industry, we’re committed to following the best available science to guide decisions and strategies to ensure that produce is as safe as possible.”