The Parasite Hiding in Your Salad Bowl Is Now a National Health Emergency

A gastrointestinal illness caused by the parasite Cyclospora has swept across the United States in one of the worst outbreaks in recent years. According to the CDC, since May 1, 2026, at least 1,645 confirmed cases of cyclosporiasis have been reported across 34 states, with over 5,100 additional cases awaiting confirmation. That is dramatically higher than the 249 cases reported nationally during the same period last year.

What Is Cyclospora and Why Is It So Hard to Detect?

Cyclospora cayetanensis is a microscopic, foodborne parasite that causes cyclosporiasis, a gastrointestinal illness affecting the digestive system. Standard lab tests often miss it entirely. Clinicians must specifically request Cyclospora diagnostic testing through PCR-based methods or modified acid-fast staining, as routine stool examinations do not reliably detect it.

How Does the Cyclospora Parasite Spread?

Cyclospora does not spread person to person. People contract it through contaminated food or water. The parasite's oocysts are not immediately infectious after leaving the body and require time to mature (sporulate) before contaminating the environment, making source tracing significantly harder.

What Symptoms Should People Watch For?

The hallmark symptom is frequent, watery diarrhea. According to UC Davis Health, other symptoms include nausea, bloating, and excessive gas. Unlike norovirus, significant vomiting and high fever are uncommon, making cyclosporiasis clinically distinctive.

Which States Are Bearing the Worst of This Outbreak?

Michigan is the hardest hit, with reportedly 3,309 cases and 44 hospitalisations. Ohio's Toledo-Lucas County has reported 1,119 cases with 46 hospitalisations, according to CIDRAP. Together, the two states account for over 4,000 illnesses.

Which Foods Are Most Commonly Linked to Cyclosporiasis?

Past outbreaks have been associated with bagged salad greens, basil, cilantro, parsley, raspberries, and snow peas. The current outbreak's food source has not yet been confirmed.

Can Cyclosporiasis Be Treated?

According to the CDC, confirmed cases are treated with a 7 to 10-day course of trimethoprim-sulfamethoxazole. Without treatment, symptoms can persist for weeks in a relapsing pattern.

Is the Public Health Response Moving Fast Enough?

Experts are concerned it is not. As per CIDRAP, Michael Osterholm of the University of Minnesota noted the CDC only issued its Health Alert Network advisory on July 14, despite receiving case reports as early as May 1. Last year, the CDC also made Cyclospora surveillance optional under its FoodNet programme, a decision researchers say may have worsened the response to this cyclosporiasis outbreak.

Until a source is identified, health authorities advise washing all produce thoroughly and seeking medical care for persistent diarrhoea, specifically requesting Cyclospora testing.

(With inputs from yMedia)