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Tracking Cyclosporiasis: Understanding the Current Outbreak, Case Investigations, and Prevention Efforts

July 20, 2026 | Heather Tomlinson, Courtney Anderson

Decorative.

This post has been updated to reflect the latest developments. It was originally published on July 16, 2026.

The summer of gastrointestinal distress? A recent foodborne illness outbreak has captured national attention as thousands of people across the country have been diagnosed with cyclosporiasis.

Several unique variables affect case reporting, disease investigation, and source identification for this particular illness, including the delay of symptom onset and routine testing measures that may miss the parasite. However, federal, state, and local health partners have been working closely and diligently on the investigation of the current outbreak — which is vital to protecting our communities.

What Is Cyclosporiasis?

Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis, also known as Cyclospora. People can become infected by consuming food or water contaminated by human waste, with symptom onset typically one to two weeks after exposure. Therefore, direct person-to-person transmission is unlikely. In previous outbreaks, contaminated sources included fresh produce (e.g., ready-to-eat fresh fruits and vegetables, herbs like parsley and cilantro, salad mixes, and raspberries).

Symptoms and Treatment

Cyclospora infects the small intestine and usually causes watery diarrhea with frequent and sometimes explosive bowel movements, occasionally resulting in dehydration. However, individuals infected may or may not experience symptoms. When treated with antibiotics, illness subsides in a few days. Without antibiotics, illness may last from a few days to over a month, and symptoms may go away and then relapse. The time between infection and becoming sick is usually about one week but can range from two days to two weeks. This delay can make disease investigations more complex when trying to determine the source, especially during traceback investigations when patients are asked to recall the food they consumed.

Cyclosporiasis is a nationally notifiable disease in 47 states, where state health departments report confirmed cases to CDC. However, many people infected may try to wait out their symptoms or may not have access to a health care provider, resulting in a lag or underreporting of cases. Additionally, Cyclospora sheds intermittently in stools and many need multiple tests to identify cases.

2026 Cyclosporiasis Outbreak

Case Counts

As of July 14, CDC has received reports of 1,645 confirmed domestic cases of cyclosporiasis and is aware of more than 5,100 cases that require further analysis to confirm the illness as domestically acquired cyclosporiasis. Cyclosporiasis is often underdiagnosed and underreported, indicating the true number of illnesses is likely higher than current estimates.

CDC includes only lab-confirmed cases in their case counts, but state reporting often includes probable and confirmed cases, leading to higher case count numbers. Michigan has reported the highest cases in this outbreak with over 3,700 cases of cyclosporiasis and 44 hospitalizations from June 22 through July 15. Typically, Michigan records only 40 to 50 cases of cyclosporiasis annually. There are presumed to be several outbreaks occurring in up to 34 states; however, one large multi-state (Michigan, New York, Ohio, and Kentucky) has been confirmed. We may see other states linked to this outbreak or additional single/multi-state outbreaks identified as the investigation continues.

Identifying the Source

Tracing the source of cyclospora infections compared to other foodborne pathogens is extremely difficult as whole genome sequencing is unavailable. Parasitic genomes, such as cyclospora, are more complex than bacterial pathogens, preventing labs from tracking case connections. The investigation of the current outbreak remains ongoing. Here is a timeline of the latest developments:

  • On July 16, shredded lettuce from Taylor Farms served at Taco Bell stores in five states is investigated as a potential source of  the outbreak.
  • On July 17, Taylor Farms initiates voluntary recall of all iceberg lettuce sourced from central Mexico.
  • As of July 20, epidemiologic evidence continues to link the outbreak to lettuce from Taylor Farms. 

The FDA advisory page will be updated promptly as new information becomes available.

Coordinated Public Health Response and Prevention

CDC, FDA, and state and local health departments have been working together to investigate the 2026 multistate outbreaks of Cyclospora infections.

Federal

CDC monitors the national surveillance system and confirms case counts while FDA helps conduct traceback investigations, tracing back food products from consumption to production.

State and Local

State and local health departments work to input cases into the national surveillance network and conduct case investigations within their jurisdictions, which involves conducting in-depth interviews of individuals testing positive for cyclosporiasis. They are also partnering and coordinating with federal agencies, CDC and FDA, on the traceback investigations. State and local health agency staff review restaurant and grocery receipts, conduct menu reviews, and review supply chain records. These investigations can be extremely time-consuming, especially for an outbreak of this size, to go through a full food history of each case. Following the investigations, investigators review the data to look for commonalities. FDA and state partners are actively investigating the source and scope of the contamination. Despite identifying shredded iceberg lettuce as a link between cases, this remains an active investigation to identify any additional sources.

Case interviews and traceback investigations are often time intensive, creating a burden on state and local public health infrastructure. A coordinated, flexible, and robust public health workforce is vital to investigating foodborne disease outbreaks, like cyclosporiasis, in a timely and efficient manner.

“Outbreaks like this underscore the importance of a strong public health system. Having a workforce that can quickly detect and respond to emerging health threats can help prevent illness and protect communities.”
– Susan Kansagra, MD, MBA, Chief Medical Officer at ASTHO

Public Guidance

FDA is advising the public to not eat food items with recalled iceberg lettuce from Taylor Farms. In addition:

  • If you experience cyclosporiasis symptoms, reach out to your health care provider to notify them and seek care (especially if you consumed the source).
  • If you obtained food items with recalled lettuce from Taylor Farms, carefully clean/sanitize any surfaces it touched.
  • To reduce the risk of cross-contamination, follow cleaning advice and safe handling guidelines from FDA.

State health agencies advise the public to continue to follow routine food safety practices, such as washing hands, cleaning fresh produce, preventing cross-contamination, and (when possible) cooking foods above 158°F to kill Cyclospora. The Michigan Department of Health and Human Services created additional guidance for local food establishments to help reduce risks of exposure. In addition, state health agencies have been sending out Health Alert Network messages to deliver urgent public health information and updates to clinicians and local agencies.

As this is an ongoing investigation, ASTHO will continue to monitor this active outbreak and provide any necessary updates.

Additional Resources

Reviewed by Susan Kansagra, MD, MBA, Chief Medical Officer; Meredith Allen, DrPH, MS, Vice President, Health Security; Abe Kulungara, MPH, Senior Director, Environmental Health; and Jessica Baggett, DrPH, MPH, Senior Advisor, Public Health Strategy & Response.