A fast-moving parasitic illness is sweeping through at least 31 states this summer, and federal investigators still cannot tell the public what food to avoid.
As of July 9, 2026, the CDC confirmed 843 domestically acquired cases of cyclosporiasis across 31 states — people who became ill after eating food in the United States and did not report any travel in the 14 days before getting sick. Simultaneously, the agency is tracking more than 1,500 additional cases that require further analysis to confirm as domestically acquired cyclosporiasis.
State health departments are reporting far higher numbers on their own. Michigan's statewide total reached 1,562 cases as of July 10, in a state that typically logs 40 to 50 Cyclospora cases in an entire year. The gap between what the CDC confirms and what states report is not an error — it reflects different standards for case classification and confirmation timelines.
The illness is not mild. Of the 843 CDC-confirmed cases, 86 people have been hospitalized. No deaths have been reported.
Why This Matters
Cyclospora is not spread person to person — you cannot catch it from a sick coworker or family member. But that also means there is no way to avoid exposure without knowing which food is contaminated.
Fresh produce has historically been behind outbreaks. Cyclospora parasites cling to fruit, vegetables, and herbs, making them difficult to rinse away. Previous outbreaks have involved raspberries, bagged salads, cilantro, and basil — staples of summer eating in the United States.
The investigation is further complicated by a diagnostic challenge most Americans do not know exists. Routine stool cultures and many standard diarrhea panels miss Cyclospora. Clinicians must request modified acid-fast staining or PCR testing explicitly, particularly for persistent watery diarrhea without a clear cause. Patients who see a doctor for diarrhea may be tested for more common pathogens and told their results are negative — while the real cause goes undetected.
The longer the food source remains unidentified, the longer contaminated products may remain in distribution and on dinner tables.
What We Know So Far
The CDC's cyclosporiasis season runs from May 1 through August 31, meaning the outbreak is at its midpoint with the highest-risk weeks still ahead. Illness onset dates in the current case series range from May 1 through July 5, 2026.
The CDC and the FDA's outbreak investigations team are investigating several multistate clusters, but as of July 9 they had not tied the outbreak to a specific food. No product recalls have been issued.
Sick people in the CDC-confirmed case series ranged in age from 5 to 88 years, with a median age of 44, and 59 percent were female. The median illness onset date was June 18.
The case numbers are almost certainly undercounts. The CDC has acknowledged that some people recover without medical care and are never tested for Cyclospora, meaning the true number of people sick is likely higher than what is reported.
There is also a structural reason the numbers may be underrepresented at the federal level. The Foodborne Diseases Active Surveillance Network previously required 10 participating states to monitor Cyclospora, but the CDC scaled the program down after major budget cuts. Only Salmonella and E. coli monitoring continue — a change that experts say makes it harder to track and identify foodborne illness outbreaks.
Where the Risk Is Highest
State-level data show the outbreak is not distributed evenly.
Michigan, New York, Ohio, Illinois, and North Carolina are among the states hit hardest by the parasitic illness, according to NBC News and Today.com reporting based on state health department data.
New York State has recorded approximately 394 cyclosporiasis cases since May 1. The Ohio Department of Health has reported at least 364 cases in 2026, with at least 171 occurring since late June. Illinois has seen 141 cases this year, described by the state health department as a "higher than average" number. North Carolina has reported 205 infections since May.
The Midwest cluster — particularly Michigan and neighboring Ohio — has drawn particular attention from public health researchers. Some have suggested the surge in those two states may be part of an epidemic cluster pointing to a shared source.
What Doctors and Experts Say
Dr. Natasha Bagdasarian, chief medical executive of Michigan, described the rapid rise as "highly unusual" and said laboratories in the state are working to sequence the genome of the parasite to track its origin. Genetic sequencing can reveal whether isolates are closely related — suggesting a common source — and potentially help investigators trace contamination back to a specific food or supplier.
Dianna Blau, acting chief of the CDC's Parasitic Disease Branch, explained that investigations are challenging because it can take a week or more for symptoms to appear after exposure. In an average year, only a small proportion of cases are successfully traced back to a specific food item. Whatever is making people sick now was likely consumed more than a week ago — potentially food that has already been fully distributed and consumed.
An important clinical note highlighted by Pharmacy Times: because cyclosporiasis is not spread person to person, there is no need to isolate from family members. However, anyone preparing food for others while symptomatic should be especially diligent about handwashing.
What the Evidence Shows and What It Does Not
This is an active, confirmed outbreak. The cases are real, the hospitalizations are documented, and the CDC and FDA are actively conducting traceback. What investigators have not yet determined is a specific food or supplier linked to the multistate spread.
MedicalDaily Consumer Alert Check
- Pathogen: Cyclospora cayetanensis (microscopic intestinal parasite)
- Confirmed cases (CDC): 843 domestically acquired across 31 states as of July 9, 2026
- Cases under analysis: More than 1,500 additional
- Hospitalizations: 86 confirmed; no deaths reported
- Food source identified: No
- Recalls issued: None
- What consumers should know: No specific food to avoid has been named. Practice standard food safety, wash all produce thoroughly, and seek medical care for persistent diarrhea — requesting Cyclospora-specific testing by name.
Who Faces the Greatest Risk?
Cyclospora can sicken anyone who consumes contaminated food or water, but certain groups face more severe illness if the infection is not treated promptly.
- People with weakened immune systems, including those undergoing cancer treatment or taking immunosuppressive medications
- People living with HIV/AIDS
- Children under 5 and adults over 65, who face higher rates of dehydration from prolonged diarrhea
- People without access to primary care, who may not receive the specific diagnostic test required
- Residents of states with the highest current case counts: Michigan, New York, Ohio, Illinois, and North Carolina
People without symptoms who live in heavily affected areas are not required to take action beyond standard food safety practices. Cyclosporiasis cannot be caught from another person.
Symptoms and Warning Signs to Watch For
The illness typically begins with severe fatigue and body aches that can resemble flu, followed by the hallmark symptom: explosive, watery diarrhea that is sometimes uncontrollable. Additional symptoms include unusually bad gas, stomach cramps, nausea, and loss of appetite. Low-grade fevers are possible but not typical. Without treatment, symptoms can linger for weeks, and relapse is possible even after apparent recovery.
Mild symptoms may be managed in consultation with a health-care provider. Seek prompt medical evaluation for:
- Diarrhea lasting more than three days
- Signs of dehydration: dry mouth, dizziness, decreased urination, or dark urine
- Blood in stool (not typical of Cyclospora, but warrants evaluation)
- Severe abdominal cramping or inability to keep fluids down
Tell your doctor you are concerned about Cyclospora and ask specifically for modified acid-fast staining or PCR testing.
What You Can Do Now
- Wash all fresh produce — including herbs like cilantro and basil — thoroughly under running water before eating, cutting, or cooking.
- Cook produce when possible. Heating food to 158 degrees Fahrenheit or higher kills Cyclospora , according to public health officials.
- If you develop persistent watery diarrhea, contact a health-care provider and ask specifically for Cyclospora testing — standard stool panels will not detect it.
- Do not prepare food for others while experiencing symptoms.
- Monitor the CDC's Cyclospora surveillance page and the FDA's outbreak investigations table for updates, recalls, or new food linkages.
- Seek urgent care for severe dehydration or rapidly worsening symptoms.
Cost and Access: What Patients Should Know
Cyclosporiasis is treated with the antibiotic trimethoprim-sulfamethoxazole, commonly known as Bactrim or Septra. With treatment, most patients improve within days. Alternative regimens for patients allergic to sulfa drugs are less validated, so clinicians managing those cases should consult infectious disease specialists.
For people without insurance, most county and state health departments can provide referrals to low-cost or free clinics. Federally Qualified Health Centers across the United States offer sliding-scale fees for uninsured or underinsured patients — find one at findahealthcenter.hrsa.gov. Generic trimethoprim-sulfamethoxazole is widely available and typically costs under $20 for a standard course with a prescription.
What Happens Next
Federal investigators at the CDC and FDA are conducting active traceback across multiple clusters. Michigan's state laboratory is sequencing Cyclospora isolates to determine whether cases share a common source. The FDA's outbreak investigations page is updated as traceback yields results. If a food vehicle is identified, a consumer advisory or recall is expected to follow quickly.
The cyclosporiasis surveillance season runs through August 31, and case counts are expected to continue rising through mid-summer. MedicalDaily will update this report as new data are published.
The Bottom Line
A confirmed Cyclospora outbreak is spreading across more than half of U.S. states, with the largest concentration in Michigan, New York, Ohio, Illinois, and North Carolina. The source has not been identified, and no food has been recalled. The season is not yet over. The most important steps readers can take are washing all produce thoroughly, watching for the hallmark symptom of prolonged watery diarrhea, requesting Cyclospora-specific testing if they become ill, and monitoring official health department pages for food source updates.
