Michigan's Cyclospora cayetanensis outbreak climbed to 1,562 confirmed cases as of Friday morning's update from the Michigan Department of Health and Human Services — a jump of more than 300 from the 1,251 reported Thursday morning — as the parasitic illness continues to spread across the state and investigators remain unable to identify a food source after more than two weeks of active investigation.
Forty-four people have been hospitalized. Cases have now been confirmed in 43 of Michigan's 83 counties, including counties in the northern Lower Peninsula and even the Upper Peninsula — a geographic spread that underscores how rapidly an outbreak whose source remains unknown can expand when no targeted recall or advisory is possible.
The national picture is also worsening: NBC News now tallies nearly 3,000 cyclosporiasis cases across 31 states, including Michigan, Ohio, Colorado, Illinois, New York, North Carolina, Texas, Wisconsin, and more — making this one of the largest Cyclospora surges ever recorded in the United States.
Why This Matters
Cyclospora cayetanensis is a microscopic intestinal parasite that spreads through food or water contaminated with fecal matter. It does not spread from person to person. That biology shapes every aspect of how this outbreak unfolds: its continued explosive growth in Michigan almost certainly reflects a shared food source — something multiple people are still eating — that has not yet been identified.
Without a confirmed food source, there is no product to recall and no specific item to avoid. The absence of a food advisory puts the full burden of protection on consumer behavior: produce selection, preparation, cooking temperatures, and handwashing. Every new wave of cases represents people who have been exposed through whatever produce item is driving the outbreak, while investigators continue conducting patient interviews, analyzing grocery receipts, and sequencing parasite genomes to find the common thread.
"We can see if isolates are closely related, meaning that there was likely a common source, and then we can potentially go back and look for the source of that contamination," Dr. Natasha Bagdasarian, Michigan's chief medical executive, told NBC News.
What We Know So Far
The MDHHS outbreak dashboard updates daily by 11:00 a.m. Eastern Time on weekdays. As of the July 10, 2026 morning update:
- Total Michigan confirmed cases : 1,562 (up from 1,251 on July 9)
- Hospitalizations : 44
- Counties affected : 43 of 83 Michigan counties
- Outbreak start date : June 22, 2026
- Food source : Not identified as of July 10, 2026
- Michigan's typical annual Cyclospora case count : 40 to 50
The outbreak is the largest in Michigan's recorded history and represents more than 30 times the state's annual average in under three weeks.
Detroit News reporting on the July 10 update noted that the most cases — 285, or just over 20% of all confirmed cases — have been detected in adults aged 30 to 39. Young children and adults over 80 have been the least affected. The case distribution skews toward working-age adults, which is consistent with higher fresh produce consumption in this demographic and more frequent dining out.
At the national level, the outbreak's scope has now been documented across 31 states. Donald Schaffner, a food microbiology professor at Rutgers University, told NBC News that the CDC made Cyclospora tracking optional last year as part of broader agency resource reductions, raising questions about whether the outbreak's national scope was identified as quickly as it might have been under prior surveillance protocols.
Where the Risk Is Highest
Within Michigan, the highest case concentration remains in southeastern counties. Monroe County continues to lead with 215 cases, followed by Wayne County (160), Washtenaw County (159), and Lenawee, Shiawassee, Jackson, Oakland, and Livingston counties, which also carry significant case burdens. Detroit and Ann Arbor, as the two most populous cities in Wayne and Washtenaw counties, respectively, are at the center of the outbreak's geographic footprint.
The emergence of cases in the northern Lower Peninsula and the Upper Peninsula marks a notable geographic expansion. It suggests either that contaminated produce is reaching a wider distribution area, or that outbreak awareness is driving increased testing beyond the initial hotspot — or both.
Across the Ohio border, Lucas County (Toledo area) has reported more than 300 cases. Northwest Ohio overall has logged more than 500 cases, establishing a contiguous outbreak zone that spans the Michigan-Ohio boundary and likely reflects shared regional food supply chains.
Other states with documented case clusters — Colorado, Illinois, New York, North Carolina, Texas, Wisconsin — represent the national distribution footprint, though whether all clusters share a single food source remains unconfirmed by the CDC or FDA.
What Health Officials Say
Dr. Bagdasarian described the rapid rise as "highly unusual," noting that the state normally sees just 40 to 50 Cyclospora cases in a full year. Her team is conducting whole-genome sequencing on parasite isolates from different patients to determine whether they are closely related — a test that would confirm whether cases share a common food source. Results from that sequencing have not yet been released publicly.
"Since the outbreak started, MDHHS is continually interviewing new cases to conduct thorough food exposure histories," the department said in a statement to ABC News. Laboratory teams in Michigan are analyzing the resulting dietary data for overlapping food purchases and brand patterns.
Dr. Bagdasarian's leading hypothesis remains contaminated produce, consistent with all prior major Cyclospora outbreaks in the U.S. and Canada, which have been linked to bagged salad mixes and kits, raspberries, cilantro, basil, green onions, and snow peas.
The CDC's Blau told NBC News there has been no operational change in how Cyclospora cases are handled at the federal level despite the agency's 2025 decision to make Cyclospora tracking optional in its Foodborne Diseases Active Surveillance Network.
What the Evidence Shows — and What It Does Not
The 1,562 confirmed cases in Michigan represent laboratory-confirmed diagnoses. Cyclospora is chronically underdiagnosed because the standard stool test does not detect it unless the laboratory specifically tests for it. The CDC estimates that many people who develop symptoms — particularly those with mild illness who recover without medical care — are never counted. The true number of Michiganders exposed through whatever contaminated food item is driving this outbreak is almost certainly much higher than 1,562.
No food source has been confirmed. No product recall has been issued. Whole-genome sequencing is in progress. The investigation is active and ongoing.
MedicalDaily Outbreak Tracker
- Michigan confirmed cases: 1,562 (July 10, 2026 MDHHS update)
- Michigan hospitalizations: 44
- Michigan counties affected: 43 of 83
- U.S. total (NBC News tally): ~3,000 across 31 states
- Food source: Not identified
- Investigation status: Active; whole-genome sequencing underway
- Most affected age group in Michigan: Adults 30–39 (285 cases, ~20% of total)
- Michigan's annual average Cyclospora cases: 40–50
Who Faces the Greatest Risk?
Michigan data shows that young and middle-aged adults represent the bulk of confirmed cases, with adults aged 30 to 39 accounting for the single largest group. This demographic distribution may reflect higher rates of raw produce consumption, more frequent dining at restaurants and food service establishments, and higher rates of seeking medical care for gastrointestinal illness compared to both younger children and older adults.
People at highest risk for severe illness — as opposed to infection itself — include:
- Immunocompromised individuals (chemotherapy patients, transplant recipients, people with HIV)
- Adults over 65
- Infants and young children
- Pregnant individuals
MDHHS has specifically called out these groups as priorities for early treatment, given higher dehydration risk and potential for more severe or prolonged illness.
Symptoms and Warning Signs to Watch For
According to the CDC, Cyclospora infection typically causes:
- Watery diarrhea — often frequent and explosive
- Loss of appetite and significant fatigue
- Bloating and stomach cramping
- Nausea, sometimes vomiting
- Low-grade fever (less common)
Symptoms begin approximately one week after exposure, though onset can range from two days to more than two weeks. Without treatment, illness can persist for weeks to months and may relapse.
See a clinician if:
- Diarrhea has lasted more than a few days
- Signs of dehydration develop (very little urination, dry mouth, dizziness)
- You are immunocompromised, elderly, pregnant, or caring for a young child with symptoms
Tell your clinician specifically that you want to be tested for Cyclospora. Standard stool parasite tests do not always detect the organism.
What You Can Do Now
With no specific food product to avoid, consumer-level produce safety measures remain the best available protection:
- Buy whole-head lettuce rather than pre-washed, bagged salad mixes. Remove the outer two to three leaves and wash remaining leaves under running water.
- Wash cilantro and basil leaf-by-leaf under running water. Cook them when possible.
- Trim and peel green onions before washing thoroughly. Cook when possible.
- Cook all suspect produce to 158°F (70°C) when possible. This temperature kills Cyclospora.
- Wash hands thoroughly before and after produce preparation.
- Sanitize cutting boards and surfaces after contact with raw produce.
- If diarrhea lasts more than a few days, see a clinician and specifically request Cyclospora testing.
Cost and Access: What Patients Should Know
Cyclospora is treated with the antibiotic trimethoprim-sulfamethoxazole (TMP-SMX, also known as Bactrim), which is available in generic form for as little as $4 to $10 at major pharmacies. Most health insurance plans cover it. For uninsured patients, local health department clinics in Michigan can provide evaluation and testing during an active outbreak at no or reduced cost. Find your local Michigan health department at Michigan.gov/MDHHS.
What Happens Next
The MDHHS dashboard updates daily on weekdays by 11:00 a.m. Eastern Time. Whole-genome sequencing of parasite isolates is expected to provide investigators with more clarity on whether cases share a single outbreak source — a finding that could accelerate traceback and ultimately lead to a specific food recall.
If a food source is confirmed, the FDA and MDHHS will issue an advisory and, if warranted, a recall notice. Until then, the produce safety guidance above represents the most actionable protection available. MedicalDaily will update this story with each meaningful case count or investigation development.
The Bottom Line
Michigan's Cyclospora outbreak reached 1,562 confirmed cases as of Friday morning — more than 30 times the state's annual average — with 44 hospitalizations and spread across 43 counties. The national total is approaching 3,000 cases in 31 states. No food source has been identified. Young and middle-aged adults are the most heavily affected demographic. Until investigators identify and remove the source, the best protection is avoiding pre-washed bagged produce, washing and cooking all suspect vegetables thoroughly, and seeking medical care for any diarrheal illness lasting more than a few days.
