Cyclosporiasis Is Spreading Across The United States— Here’s What To Know

Cyclosporiasis, a diarrheal illness caused by the microscopic parasite Cyclospora cayetanensis, is spreading rapidly across the United States this summer. As of July 2026, the CDC has confirmed over 500 cases across 15 states, with the number expected to rise as more cases are reported. This outbreak serves as a critical reminder for the public to recognize symptoms and adopt preventive measures against foodborne parasites.

The lead: Cyclosporiasis is hitting the United States this summer, with the CDC tracking an outbreak that has already sickened hundreds. The parasite is typically transmitted through contaminated imported fresh produce, such as raspberries, basil, and cilantro. Health officials warn that cases often spike between May and August, and the current outbreak is no exception.

Cyclosporiasis is not new—outbreaks have occurred periodically since the 1990s, often linked to produce from endemic regions in Central and South America. However, this year's scale is notable, with clusters cropping up in the Midwest and Southern states. The Centers for Disease Control and Prevention (CDC) is actively investigating the source, but no single food item has been confirmed as the culprit yet.

Key details: Dr. Omer Awan, the Forbes contributor and physician who authored the source report, explains that symptoms typically appear one to two weeks after ingesting the parasite. These include watery diarrhea (which can be explosive), loss of appetite, weight loss, stomach cramps, nausea, and fatigue. Some people may be asymptomatic or experience only mild symptoms, while others may suffer prolonged bouts lasting weeks if untreated. The infection is not spread directly from person to person; rather, it requires ingestion of contaminated food or water. Diagnosis is made by a stool test, and treatment involves a specific antibiotic regimen, typically trimethoprim-sulfamethoxazole (Bactrim). The CDC recommends that anyone with persistent watery diarrhea see a healthcare provider and mention potential foodborne exposure.

Analysis: This outbreak underscores persistent vulnerabilities in the U.S. food supply chain, particularly when it comes to imported fresh produce. Experts point out that climate change may be expanding the geographic range of Cyclospora, making outbreaks more common. Food safety advocates argue that stricter import inspection protocols and better traceability could reduce the risk, but such measures remain unevenly enforced. The current outbreak also highlights the importance of public awareness—many people mistake cyclosporiasis for a stomach bug and fail to get proper treatment, prolonging their illness.

Outlook: The CDC expects case numbers to continue rising as summer travel and consumption of fresh produce peak. Health officials urge consumers to wash all fresh produce thoroughly, though this may not fully eliminate Cyclospora oocysts. Cooking kills the parasite, so heating foods is the most reliable prevention. As the investigation unfolds, several food distributors are under scrutiny, and more recalls may be announced in the coming weeks. The public should monitor CDC alerts and seek medical care for persistent diarrheal symptoms.