Medically Reviewed by Dr. Abhinaya K, MBBS, MD (Biochemistry)
More than 7,000 confirmed or suspected cases of cyclosporiasis have been reported across the United States in 2026, prompting the U.S. Centers for Disease Control and Prevention (CDC) to issue a nationwide Health Alert Network (HAN) advisory to clinicians.
Of these, 1,645 are laboratory-confirmed domestically acquired infections, while more than 5,100 additional reported cases are awaiting confirmation or classification. A total of 141 hospitalizations have been reported, with no deaths linked to the outbreak so far.
Health officials warn that the actual number of infections is likely much higher because many people with mild illness do not seek medical care, and routine stool tests do not detect the parasite unless Cyclospora-specific testing is requested.
While cases have been reported across 34 states, Michigan has emerged as the most affected state.
Michigan has reported the highest number of cases, accounting for 3,309 confirmed or probable infections recorded by the Michigan Department of Health and Human Services (MDHHS) as of early July 2026.¹
According to the Michigan Department of Health and Human Services (MDHHS), the state has recorded 3,309 confirmed or probable cases of cyclosporiasis and 44 hospitalizations as of early July 2026. Other states, including Ohio, Kentucky, West Virginia, North Carolina, Illinois, New York, Connecticut, Florida, and New Jersey, have also reported increased numbers of infections.
Public health officials continue to investigate whether the illnesses stem from one contaminated food source or multiple unrelated sources.
Cyclospora infections typically increase during late spring and summer. Previous U.S. outbreaks have often been linked to fresh imported produce, including leafy greens, herbs, berries, and vegetables. Investigators continue tracing possible sources in the current outbreak.¹
The CDC's Health Alert Network advisory, issued on July 14, asks healthcare providers to consider Cyclospora cayetanensis infection in patients presenting with prolonged or recurrent watery diarrhea, especially during the summer months when infections typically peak.
The agency recommends that clinicians:
Specifically request laboratory testing for Cyclospora, as standard stool cultures do not detect the parasite.
Collect detailed food exposure histories from patients.
Report confirmed cases promptly to state or local health departments.
Begin appropriate treatment without unnecessary delay when clinically indicated.
The CDC also notes that diagnosing Cyclospora can be challenging because patients may need specialized molecular testing or repeated stool examinations before the parasite is identified.
Cyclosporiasis is caused by the microscopic parasite Cyclospora cayetanensis, which infects the small intestine.
Unlike many foodborne illnesses, Cyclospora parasites require time outside the human body before becoming infectious. Because of this life cycle, the disease is unlikely to spread directly from one person to another. Instead, infections usually occur after consuming contaminated food or water, resulting in a parasite infection.
The parasite has historically been associated with imported fresh produce such as leafy greens, herbs, berries, and vegetables. Traceback investigations into the 2026 outbreak remain ongoing.¹
Symptoms usually develop about one week after exposure, although the incubation period ranges from 2 to 14 days. Once symptoms begin, they may come and go for several weeks if left untreated.⁴
Common symptoms include:
Profuse watery diarrhea
Frequent bowel movements
Abdominal cramps
Loss of appetite
Nausea
Fatigue
Bloating
Excessive gas
Low-grade fever
Weight loss
Without treatment, symptoms can last for weeks or even months and often follow a relapsing pattern, with patients temporarily improving before symptoms return.
Because these symptoms resemble many other gastrointestinal illnesses, clinicians may not immediately suspect Cyclospora unless specific laboratory testing is ordered.
Taco Bell has voluntarily and temporarily removed select fresh ingredients from some restaurants while federal and state health officials investigate a possible connection between the chain and the ongoing multistate cyclosporiasis outbreak. Some locations, particularly in the Midwest, have stopped serving items containing lettuce, cilantro, onions, pico de gallo, and guacamole as a precaution.
The company emphasized that public health officials have not confirmed a link between Taco Bell and the outbreak, nor have they identified any specific ingredient, supplier, restaurant, or retailer as the source. Taco Bell said it will continue to follow guidance from health authorities while the investigation remains underway.
According to the CDC and Cleveland Clinic, people with weakened immune systems may experience more prolonged illness from Cyclospora infection. Persistent diarrhea can also increase the risk of dehydration, particularly in older adults and other vulnerable individuals. Most otherwise healthy people recover with appropriate treatment, although symptoms may persist for weeks if left untreated.² ⁴
Federal and state investigators continue working to determine the source of the outbreak.
The CDC states that epidemiologic investigations have identified clusters of related cases in several states, but no single contaminated food product, distributor, grower, or supplier has been confirmed as the nationwide source.
Health officials have interviewed affected patients about foods they consumed before becoming ill and are conducting traceback investigations to identify any common exposures. Until those investigations are complete, the CDC has not issued a nationwide food recall related to the outbreak.
According to the CDC, washing fresh produce under running water remains an important food safety practice, although it may not completely remove Cyclospora if contamination is present. Because the parasite can adhere to fresh produce, foods that are eaten raw may continue to pose a risk if contaminated. Thorough cooking destroys the parasite, but many produce items linked to previous outbreaks are commonly consumed without cooking.⁴
Although no method completely eliminates the risk of Cyclospora infection from contaminated produce, the CDC recommends several food safety practices that may help reduce exposure:⁴
Wash hands with soap and water before preparing or eating food and after handling fresh produce.
Rinse fresh fruits and vegetables under running water before eating, peeling, or cutting them, even though washing may not completely remove Cyclospora.
Peel fruits and vegetables when appropriate after washing them under running water.
Cook foods thoroughly whenever possible, as heat destroys the parasite.
Drink safe, treated water when traveling to areas where cyclosporiasis is more common.
Because Cyclospora is primarily spread through contaminated food or water rather than direct person-to-person contact, practicing good food hygiene remains an important preventive measure.⁴
The CDC recommends trimethoprim-sulfamethoxazole (TMP-SMX), an oral antibiotic, as the standard treatment for cyclosporiasis. Most otherwise healthy people recover with appropriate treatment, although symptoms may persist for weeks if left untreated.⁴
People who are allergic to sulfonamide antibiotics should consult their healthcare provider about alternative management options, as no highly effective alternative treatment has been identified by the CDC.⁴
Maintaining adequate fluid intake is important to help prevent dehydration, particularly in children, older adults, and people with prolonged diarrhea.⁴
People experiencing persistent diarrhea, dehydration, severe abdominal pain, or symptoms lasting more than a few days should seek medical evaluation.
As laboratories continue confirming suspected infections and investigators trace possible food sources, health officials expect additional cases to be reported. The CDC advises clinicians to consider Cyclospora testing in patients with persistent watery diarrhea and encourages the public to follow recommended food safety practices while the investigation remains ongoing.¹ ⁴
Reference:
1. Centers for Disease Control and Prevention. “Health Alert Network (HAN) No. 00531: Increase in Reported Cases of Cyclospora cayetanensis Infection in Multiple States, United States, Summer 2026.” CDC, July 14, 2026. https://www.cdc.gov/han/php/notices/han00531.html?
2. Cleveland Clinic. “Cyclosporiasis: Transmission, Symptoms & Treatment.” Cleveland Clinic, last updated April 14, 2026. https://my.clevelandclinic.org/health/diseases/17957-cyclosporiasis
3. Mackay, Michael. “CDC HAN: Domestically Acquired Cyclosporiasis Cases Continue to Rise.” A Flu Diary, July 15, 2026. https://afludiary.blogspot.com/2026/07/cdc-han-domestically-acquired.html?
4. Centers for Disease Control and Prevention. "About Cyclosporiasis." CDC. Accessed July 2026. https://www.cdc.gov/cyclosporiasis/about/index.html
(Rh/ARC/MSM)