More than 300 cases in Michigan: alone as of July 2, compared to ~50 cases typically seen annually in the state.
At least 145 cases across 17 other US states (as of June 16), including Alaska, Colorado, Connecticut, Florida, Georgia, Illinois, Louisiana, Massachusetts, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Texas, Virginia, and Wisconsin.
The parasite Cyclospora cayetanensis spreads through the fecal-oral route, typically via contaminated fresh produce such as raspberries, basil, lettuce, snow peas, and cilantro.
Symptoms appear 2 days to 2 weeks after exposure, with the most common being watery, frequent, and explosive diarrhea.
Why this matters: This outbreak coincides with the July 4th holiday weekend, a peak time for picnics and consumption of fresh produce, increasing the risk of exposure.
Historical context: Past US outbreaks have been linked to imported produce from tropical regions, but health experts note a growing trend of **domestically acquired cases** in recent years.
Cyclosporiasis is an intestinal infection caused by the single-celled parasite Cyclospora cayetanensis. It is classified as a foodborne illness and is most commonly contracted by consuming food or water contaminated with fecal matter containing the parasite.
According to the CDC and Cleveland Clinic, the hallmark symptom is watery, frequent, and sometimes explosive diarrhea. Additional symptoms include:
Loss of appetite
Bloating, burping, gas, and stomach cramps
Extreme fatigue
Low-grade fever
Nausea and vomiting
Most healthy individuals can recover without treatment, but the illness can last for weeks or even months if left untreated, and symptoms may recur.
While anyone can contract cyclosporiasis, children, older adults, and immunocompromised individuals (such as those undergoing cancer treatment or organ transplant recipients) are at higher risk for severe illness and complications.
Michigan's outbreak is particularly concerning. The state's health department (MDHHS) confirmed the first case on June 22, and within just 10 days, the case count surged past 300. Lynn Sutfin, public information officer for MDHHS, stated, *"We are working closely with our state and local partners to identify the source of this outbreak that is making so many people ill as quickly as possible."*
Dr. Peter Chin-Hong, an infectious diseases specialist at UCSF, noted that while cyclosporiasis cases typically rise in May, *"the number of cases in Michigan is particularly high."* He also highlighted a worrying trend: the US is seeing more domestically acquired cases, rather than infections originating solely from imported produce.
Cyclosporiasis is treatable with the oral antibiotic trimethoprim-sulfamethoxazole (TMP-SMX) , sold under brand names like Bactrim, Septra, and Cotrim, taken for 10 days. Dr. Zoe Weiss, director of clinical microbiology at Tufts Medical Center, emphasized, *"If you're in an area that's been affected and you have sudden ongoing watery diarrhea, you should definitely seek a physician and get treatment."*
The CDC, Cleveland Clinic, and Michigan Health Department recommend the following preventive measures:
Wash hands: thoroughly with soap and water after using the bathroom and before handling food.
Wash all produce: thoroughly under running water before eating, cutting, or cooking.
Scrub firm-skinned produce: (melons, cucumbers) with a clean brush.
Cut away bruised or damaged areas: on fruits and vegetables.
Refrigerate prepared produce: within two hours.
Avoid untreated water: for drinking or cooking.
Clean all food prep surfaces: including utensils, cutting boards, and countertops.
Monitor your symptoms — If you develop watery diarrhea that persists for more than a few days, contact your healthcare provider.
Request testing — A stool sample can confirm Cyclospora infection.
Stay hydrated — Diarrhea can lead to dehydration; drink plenty of clear fluids.
Practice extra caution with produce — Thoroughly wash all fruits and vegetables, even pre-washed bagged items.
What is cyclosporiasis?
It's an intestinal infection caused by the parasite Cyclospora cayetanensis, transmitted through contaminated food or water.
What are the main symptoms?
Watery, frequent, and sometimes explosive diarrhea is the most common symptom. Others include loss of appetite, bloating, stomach cramps, fatigue, fever, nausea, and vomiting.
How long after exposure do symptoms appear?
Symptoms typically appear about one week after exposure, but can range from 2 days to 2 weeks.
Is cyclosporiasis contagious from person to person?
Direct person-to-person transmission is very unlikely because the parasite requires days to weeks of sporulation in the environment before becoming infectious.
How is it treated?
The infection is treated with a 10-day course of the antibiotic trimethoprim-sulfamethoxazole (TMP-SMX), also known as Bactrim or Septra.
Which states are affected?
As of June 16, the CDC reports cases in Alaska, Colorado, Connecticut, Florida, Georgia, Illinois, Louisiana, Massachusetts, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Texas, Virginia, and Wisconsin. Michigan has a separate cluster of over 300 cases.
If you live in or are traveling to an affected state: , be extra cautious with fresh produce this summer, especially during the July 4th holiday weekend.
Wash all fruits and vegetables thoroughly: before consumption, even those labeled as pre-washed.
Seek medical attention promptly: if you develop persistent watery diarrhea, particularly if you are immunocompromised, elderly, or caring for young children.
The Cyclospora season runs from May through August: , so vigilance should continue throughout the summer.
This outbreak is still under investigation: — check the CDC's cyclosporiasis surveillance dashboard for monthly updates.
Are you taking extra precautions with your food this summer because of the Cyclospora outbreak? Have you or someone you know been affected? Share your thoughts and experiences in the comments below — your story could help others stay informed.
Do you think the rise in domestically acquired cases signals a need for stricter food safety regulations? Let us know!
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*Compiled by Yanuki using the latest trends and data.*
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