Americans are experiencing a challenging cyclospora season with thousands of reported illnesses nationwide. Health officials are actively working to identify contaminated foods behind several outbreaks. The Centers for Disease Control and Prevention (CDC) reported 4,173 laboratory-confirmed cases since May 1, and expects 2026 to be the largest cyclospora season recorded.

The Cyclospora Parasite

Cyclospora is a microscopic parasite that causes cyclosporiasis, an intestinal illness. Symptoms include prolonged watery diarrhea, stomach cramps, fatigue, and loss of appetite. Although cases typically rise in spring and summer, this year’s outbreak is unprecedented.

Federal investigators have linked one significant outbreak to iceberg lettuce from central Mexico. On July 17, Taylor Farms recalled certain lettuce products as part of the investigation. Of the confirmed cases, 308 people have been hospitalized, approximately 7.38%. No deaths have been reported.

Comparative Regional Impact

Cyclospora case numbers vary across states. Michigan has reported 7,664 cases with 160 hospitalizations, or 2.08%. Oklahoma has 172 cases with 12 hospitalizations, or 6.97%. Ohio reports 1,300 cases with 96 hospitalizations, or 7.38%. Health officials note the hospitalization rate may exaggerate the risk for most infections.

Origin of Cyclospora

Cyclospora cayetanensis originates from human fecal contamination. People contract it by consuming contaminated food or water, especially fresh produce consumed raw. Past outbreaks linked to cilantro, basil, berries, and leafy greens.

The FDA continues investigating multiple clusters. In North Carolina, suspect foods include lettuce, parsley, and cilantro.

Symptoms and Treatment

Symptoms start around a week after exposure and include watery diarrhea, stomach cramps, bloating, nausea, weight loss, fatigue, and loss of appetite. Without treatment, symptoms can persist and recur. The standard treatment is the antibiotic trimethoprim-sulfamethoxazole, known as Bactrim. Hydration is crucial due to fluid loss.

Seeking Medical Attention

Some infections resolve without treatment, but medical attention is important if diarrhea continues or dehydration signs appear. Cyclospora doesn’t usually show up on standard tests, so specific testing may be necessary.

Dr. Tyler Evans notes dehydration, rather than the parasite, typically leads to hospital visits. Prolonged diarrhea can damage kidneys and disrupt electrolytes. Seek medical help for persistent symptoms, signs of dehydration, or if immunocompromised.

Fatality Risk

Deaths from cyclospora are rare. Despite thousands of cases, no deaths in the current outbreak have been reported. For immunocompromised patients, risks of more severe illness exist, but the disease is generally treatable.

Doctors recommend staying hydrated, seeking care if symptoms persist, and considering cyclospora testing for unexplained severe diarrhea. Early diagnosis and treatment prevent complications.