Health officials have confirmed 1,645 domestically acquired cases of cyclosporiasis across 34 U.S. states since May 1, 2026, marking a significant increase over last year’s figures. While investigators work to identify a common source, experts suggest the parasite’s complex biology and testing challenges are complicating the public health response.
Surveillance Data and Regional Impact
The Centers for Disease Control and Prevention reported 1,645 laboratory-confirmed cases of cyclosporiasis between May 1 and July 16, 2026. This figure represents a sharp rise compared to the 249 cases recorded during the same period in 2025. Of those affected, 141 individuals have required hospitalization, though no deaths have been linked to the current outbreak.
Discrepancies in case counts have emerged between federal and state reporting. Public health analysts attribute these gaps to reporting delays and the time required to confirm whether cases are domestically acquired or linked to international travel.
Diagnostic Challenges in Laboratory Settings
Identifying Cyclospora is inherently difficult, contributing to potential underreporting. Unlike common bacteria or viruses that can be cultured in a laboratory, this protozoan parasite requires specialized detection methods.
For more on this story, see Cyclosporiasis Outbreak Sickens Over 4,300 in Michigan and Thousands Nationwide.
Rodney E. Not all gastrointestinal panels include cyclospora, and not every laboratory routinely performs testing for intestinal parasites,
Rohde explained. Consequently, clinicians must specifically request diagnostic testing, such as PCR-based molecular exams, to ensure accurate results.
Symptoms and Clinical Management
The infection typically presents with watery diarrhea, which can persist or relapse over several weeks if left untreated. Patients may also experience fatigue, bloating, and loss of appetite. Symptoms generally appear within two to 14 days following exposure to contaminated food or water.
For confirmed cases, the CDC recommends a 7-to-10-day course of trimethoprim-sulfamethoxazole (TMP-SMX) for eligible patients. Clinicians are advised to maintain a high index of suspicion for the parasite during the peak season of May through August, particularly when patients present with prolonged gastrointestinal distress and no recent history of international travel.
Community Perspectives on Food Safety
Consult your healthcare provider if you experience persistent symptoms or suspect a foodborne illness.