Parasite outbreak sickens 400+ people across 18 US states
A parasite outbreak linked to Cyclospora has sickened more than 400 people across 18 U.S. states, with at least 20 hospitalizations and no reported deaths. The intestinal infection spreads through raw produce or water contaminated with feces, causing prolonged watery diarrhea. Health officials are investigating multiple regional clusters rather than a single national source.
As Americans load picnic tables with berries and leafy greens this summer, federal and state agencies are racing to trace a sharp rise in cyclosporiasis—the illness caused by the microscopic parasite Cyclospora cayetanensis. Reporting from CNN and The New York Times has put the outbreak on the radar just as case counts climb past federal mid-June totals.
Key Takeaways
- More than 400 cyclosporiasis cases are reported across 18 states, far above the CDC's count of 145 domestically acquired cases in 17 states from May 1 through June 16.
- Michigan alone confirmed more than 300 cases in weeks—a dramatic jump from the roughly 50 it typically sees in a full year.
- Officials have found no evidence linking all illnesses to one multistate food source; several clusters remain under FDA traceback review.
- Symptoms can take two to 14 days to appear and may last weeks without antibiotic treatment.
- Whole-genome sequencing is critical to linking clusters, a capability under scrutiny as CDC staffing has fallen sharply.
What Is Cyclospora and How Does It Spread?
Cyclosporiasis is an intestinal infection you get by eating food or drinking water tainted with Cyclospora. The parasite does not spread person to person; it must mature in the environment first. Past U.S. outbreaks have been tied to fresh herbs and produce such as basil, cilantro, spinach, and berries.
Symptoms include watery diarrhea—sometimes described as explosive—along with cramps, nausea, vomiting, fatigue, loss of appetite, and low-grade fever. Healthy adults may recover on their own, but vulnerable people can become dehydrated and need hospital care. The illness is treatable with antibiotics when diagnosed.
How Many People Are Sick and Where?
The CDC reported 145 confirmed U.S.-acquired cases across 17 states through June 16, with 20 hospitalizations. Since then, state-level surges have pushed the nationwide total above 400 across 18 states, according to health officials cited by major outlets.
Michigan has emerged as a hotspot, with more than 300 cases clustered in counties including Monroe, Lenawee, Washtenaw, and Wayne. New York State outside New York City logged 107 cases since May 1. Texas, Illinois, and other states from Alaska to Florida have also reported illnesses. None of the federally tracked patients reported international travel in the two weeks before symptoms began.
Why Hasn't a Single Food Source Been Identified?
The CDC and FDA are investigating multiple potential clusters with distinct traceback paths. Federal officials emphasize there is currently no evidence of one multistate outbreak linking every case. The true toll is likely higher because some people recover without testing, and not every state mandates reporting.
That uncertainty is exactly where modern outbreak science matters. Labs use whole-genome sequencing to match pathogen fingerprints across patients and suppliers—tools highlighted in coverage of how agencies hunt foodborne threats. For more on how data and surveillance tech reshape crisis response, see our Future Tech & AI Wonders coverage.
What Should You Do If You Ate Raw Produce?
Health officials urge caution with raw berries, salads, and other uncooked produce while investigations continue. Wash fruits and vegetables under running water before eating. If you develop persistent diarrhea, cramps, nausea, or fatigue, contact a clinician and mention possible Cyclospora exposure.
Summer is peak cyclosporiasis season, and this year's numbers are unusually high with no named recall yet. Investigators continue tracing supply chains while the CDC operates with a workforce reduced by roughly 3,000 positions since early 2025, raising questions about how quickly the next cluster can be mapped.