Every summer, emergency rooms and urgent care centers see a steady stream of stomach bugs. Most are short-lived viral illnesses. Some are food poisoning. A smaller number turn out to be something more specific.
Right now, one of those specific causes is getting more attention: Cyclospora.
Several state health departments are investigating a growing outbreak of cyclosporiasis, the illness caused by the microscopic parasite Cyclospora cayetanensis. Michigan has seen the largest jump so far, with local reports showing cases rising from 177 in late June to 572 by July 4, then to 1,251 by July 9. That is far above what the state would usually expect this time of year. Ohio, Illinois, and New York have also reported increases, though not at Michigan’s level.
The CDC had previously reported 145 domestically acquired cases and 20 hospitalizations across 17 states through June 16, 2026, but state-level updates suggest the picture is moving quickly.
That does not mean everyone with diarrhea has Cyclospora. It does mean clinicians and patients should keep it on the radar, especially when symptoms last longer than the typical stomach bug.
What is Cyclospora?
Cyclospora is a parasite that can contaminate food, especially fresh produce. Past outbreaks have been linked to items like leafy greens, herbs, berries, and other fruits and vegetables.
One important point: Cyclospora does not usually spread directly from person to person. People generally become sick after eating or drinking something contaminated with the parasite.
As of now, federal and state agencies are still investigating the source of the current outbreak. No single grower, supplier, restaurant chain, or produce item has been publicly identified as the source.
What symptoms does Cyclospora cause?
The most common symptom is watery diarrhea, often lasting longer than patients expect.
Symptoms usually begin about one week after exposure, though timing can vary. Patients may also have:
- Loss of appetite
- Abdominal cramping
- Bloating
- Increased gas
- Nausea
- Fatigue
- Weight loss from poor intake or ongoing diarrhea
- Symptoms that improve, then come back again
That relapsing pattern is one reason Cyclospora can be frustrating. A patient may think they are turning the corner, then several days later the diarrhea returns.
Most healthy people recover, but symptoms can last for weeks if untreated. Dehydration is the main short-term concern, especially in children, older adults, and people with medical problems.
When should you seek medical care?
You should consider being evaluated if you have:
- Diarrhea lasting more than a few days
- Signs of dehydration, such as dizziness, very dark urine, dry mouth, or inability to keep fluids down
- Severe abdominal pain
- Blood in the stool
- High fever
- Recent travel to a tropical or subtropical area
- A weakened immune system
- Persistent symptoms after eating fresh produce during a known outbreak period
From an ER standpoint, the big question is not just “what caused the diarrhea?” It is also “is this patient dehydrated, unstable, or at risk for complications?”
If you are lightheaded, unable to hydrate, or getting worse instead of better, it is worth being seen.
How is Cyclospora diagnosed?
Cyclospora is diagnosed through stool testing, but there is a catch: not every standard gastrointestinal PCR panel includes Cyclospora.
That matters. If symptoms fit and the first test is negative or incomplete, the clinician may need to specifically request testing for Cyclospora. In some cases, more than one stool specimen collected on different days may be needed.
At iCare ER & Urgent Care, we have on-site gastrointestinal testing that includes Cyclospora, with results typically available within about one hour. That can make a meaningful difference for patients who have had several days of unexplained diarrhea and want answers quickly.
So if you have prolonged watery diarrhea and you are being evaluated, it is reasonable to ask: “Does this stool test include Cyclospora?”
That one question can save time.
How is it treated?
The treatment of choice is trimethoprim-sulfamethoxazole, often known as TMP-SMX or Bactrim.
Not everyone needs antibiotics, and many healthy people recover without treatment within about a month. But when symptoms are prolonged, severe, or affecting hydration and daily function, treatment can shorten the course.
Patients with sulfa allergies or complex medical histories should talk with their clinician about options, because alternative treatments are less straightforward.
Can you prevent Cyclospora?
You can reduce risk, but you cannot completely eliminate it.
Practical steps include:
- Wash fresh fruits and vegetables under running water
- Refrigerate produce properly
- Separate produce from raw meat, poultry, and seafood
- Wash cutting boards, knives, and countertops
- Wash hands before food prep and before eating
- Be cautious with raw produce during active outbreak investigations if public health agencies identify a specific product
One frustrating detail: Cyclospora can be harder to remove than some routine bacteria, and washing does not guarantee zero risk. Still, careful food handling helps.
The bottom line
Most diarrhea illnesses are not Cyclospora. But during a summer outbreak, especially when symptoms are watery, prolonged, and associated with bloating, cramping, gas, appetite loss, and fatigue, Cyclospora belongs on the differential.
For patients: do not panic, but do not ignore symptoms that drag on.
For clinicians: remember that Cyclospora may not be included on every GI panel. If the story fits, request the test specifically.
And for everyone: stay hydrated, pay attention to public health updates, and get evaluated if symptoms are severe, persistent, or concerning.
Sources reviewed: CDC clinical and surveillance information; Michigan Department of Health and Human Services outbreak updates; recent national and local media reports on the July 2026 cyclosporiasis outbreak.