Explosive Diarrhea Parasite Sickens 145 in 17 States as Investigators Hunt Foodborne Source
Cyclosporiasis, an intestinal illness caused by a microscopic parasite, has sickened at least 145 people in 17 U.S. states so far this season.
The Centers for Disease Control and Prevention (CDC) said all patients reported no international travel in the two weeks before symptoms began, suggesting the source is likely domestic, foodborne rather than infections acquired abroad.
Patients range in age from 5 to 86 years. At least 20 people have required hospitalization, though no deaths have been reported.
Local, state, and federal agencies, including the Food and Drug Administration (FDA), are investigating several clusters of cases in multiple states, using patient interviews and product traceback to identify common foods that might have carried the parasite. So far, there is no evidence of a single multistate source linking all illnesses.
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis, which infects the small intestine and is spread when people ingest food or water contaminated with stool. In the United States, past foodborne outbreaks have most often been linked to fresh produce, often imported, such as leafy greens, herbs, and berries, which are eaten raw and may be difficult to thoroughly sanitize.
A 2025 ProPublica investigation found that U.S. Food and Drug Administration inspections of foreign food facilities fell to their lowest level in more than a decade (excluding pandemic years), after staffing and budget cuts under the Trump administration. Food‑safety advocates quoted in the report warned that these “decimated” oversight functions create an “enhanced risk of more outbreaks,” because in‑person inspections are often the only way to uncover problems like insect infestations, unsanitary equipment, and falsified testing records at plants that ship food into the U.S. market.
Symptoms usually begin about one week after exposure, though the incubation period can range from two days to two weeks or more. Many patients experience prolonged, watery diarrhea that can be “explosive,” along with stomach cramps, nausea, fatigue, loss of appetite, body aches, and low‑grade fever. Without treatment, illness can last from a few days to over a month, and symptoms may appear to resolve and then return multiple times.
Unlike some other intestinal infections, Cyclospora does not typically spread directly from person to person because the parasite needs time in the environment to become infectious after being shed in stool. That environmental maturation step makes contaminated food or water the primary vehicle for transmission.
The most effective prevention steps focus on basic food safety: washing hands, thoroughly rinsing fresh fruits and vegetables under running water, and refrigerating cut or peeled produce promptly.
CDC has documented that significant multistate outbreaks have occurred before, including a 2013 episode in which 631 cyclosporiasis cases were reported from 25 states and New York City, some of which were traced to imported salad mix and cilantro.
