Cyclosporiasis Outbreak Update: CDC and FDA Investigation

Public health officials are currently investigating an unusually high number of cyclosporiasis cases across the United States. As of July 2026, the Centers for Disease Control and Prevention (CDC) has confirmed at least 1,645 laboratory-confirmed cases of the intestinal illness since May 1, with reports spanning 34 states.

Understanding Cyclosporiasis and Symptoms

Cyclosporiasis is an intestinal infection caused by the microscopic parasite Cyclospora. According to the CDC, the parasite is typically transmitted through the consumption of food or water contaminated with the parasite. It does not spread directly from person to person. Symptoms generally appear one to two weeks after exposure and include:

• Watery, sometimes frequent, diarrhea
• Abdominal cramping and nausea
• Loss of appetite and fatigue
• Low-grade fever

The CDC has issued a Health Alert Network (HAN) advisory. This notice encourages clinicians to specifically order Cyclospora testing, as the parasite is not included in routine stool testing panels.

Investigation Challenges and Surveillance Methods

Identifying the source of Cyclospora outbreaks is difficult for federal agencies. Dr. Donald Prater, the FDA’s Acting Deputy Commissioner for Food, noted that while traceback investigations are underway for multiple produce items, the nature of the parasite complicates the process. Unlike many bacterial pathogens, there is no standardized whole-genome sequencing (WGS) available to definitively link a contaminated product to specific patient samples. Instead, the CDC and FDA rely on targeted genotyping, which is less precise and more time-consuming than the methods used for traditional bacterial pathogens.

The investigation is further hampered by the time lag between exposure and diagnosis. Because patients often wait weeks before seeking medical care, identifying the specific supply chain or contaminated lot of produce becomes a complex epidemiological puzzle. The CDC is currently working alongside state and local health departments to triangulate data from patient interviews, laboratory genotyping, and food supply chain traceback.

Food Safety Recommendations

While the investigation continues, the CDC and FDA have not issued a recall for specific food products. However, they emphasize that standard food safety practices remain the best defense against infection. The following steps are recommended to lower the risk of illness:

• Wash Produce: Thoroughly wash all fresh fruits and vegetables under running water before eating, cutting, or cooking.
• Cook Thoroughly: Heating food to a temperature of at least 158°F (70°C) is effective at killing the parasite.
• Seek Medical Care: If you experience prolonged watery diarrhea, contact a healthcare provider and specifically request testing for Cyclospora.
• Hydration: Patients should stay well-hydrated while managing symptoms.

Future Updates and Surveillance

In response to the elevated case counts, the CDC has committed to increasing the frequency of its surveillance updates. Information regarding the multistate outbreak and national case counts will now be updated on the CDC’s official investigation webpage at least weekly, rather than the historical monthly cadence. The FDA will similarly provide weekly updates on its core investigations table every Wednesday. Public health officials anticipate that cases may continue to rise through the end of August, marking the conclusion of the typical cyclosporiasis season.