The Centers for Disease Control and Prevention (CDC) is investigating an outbreak of cyclosporiasis causing severe diarrhea across the U.S. [1].

This surge in intestinal infections is significant because the exact source of contamination remains unknown, posing a continued risk to the public through the food and water supply [1, 2].

Reports of the outbreak began on May 1, 2026 [3]. The infection is caused by the parasite *Cyclospora cayetanensis*, which leads to intense diarrhea and gastrointestinal distress [1, 2]. Health officials said there are significant clusters of cases in Florida, though the spread is national [5].

Data regarding the scale of the outbreak varies across reports. One report indicates 1,645 cases have been documented since May 1 [1]. Another source cites 7,000 cases of intense diarrhea associated with the outbreak [2]. Earlier data from mid-June recorded 145 confirmed cases across 17 states [4].

While the CDC continues its investigation, some reports suggest the infection has been detected in as many as 34 states [2]. This volume of illness is notable when compared to the typical annual range of 1,000 to 2,000 cases in the U.S. [6].

Medical experts, including Dr. Fabián Sandoval, president of the Emerson Clinic, said the parasite is typically transmitted through the consumption of contaminated water or fresh produce [1, 2, 3]. Because the source has not been identified, officials are urging caution with food consumption.

Experts also said the outbreak could potentially extend beyond U.S. borders if contaminated food products are exported to neighboring countries like Mexico [2].

“The infection is caused by the parasite Cyclospora cayetanensis, which leads to intense diarrhea”

The discrepancy in case numbers, ranging from hundreds to thousands, suggests a rapidly evolving public health situation or a difference between confirmed laboratory cases and reported symptomatic cases. Because cyclosporiasis is often linked to imported produce, the inability to pinpoint a specific food source indicates a potential systemic failure in the supply chain that could lead to international spread.