Health officials have confirmed 1,645 cases of cyclosporiasis across 34 states since May 1, 2026, marking a significant increase over last year’s figures. While investigators continue to trace the source of the parasite, which causes prolonged watery diarrhea, experts emphasize that fresh produce remains a safe, healthy dietary choice with proper hygiene.
A Sharp Rise in Domestic Cyclosporiasis Cases
The current outbreak of cyclosporiasis—a gastrointestinal illness triggered by the microscopic parasite Cyclospora—has reached a scale far beyond previous years. According to the Centers for Disease Control and Prevention (CDC), the 1,645 confirmed domestic cases reported since May 1, 2026, represent a substantial jump from the 249 cases recorded by the same time in 2025. While the illness is generally not life-threatening, it has resulted in 141 hospitalizations, a nine percent rate among those with available medical information.
Public health authorities are currently analyzing over 5,100 additional potential cases to determine if they meet the criteria for domestically acquired cyclosporiasis. The illness, which typically peaks between May and August, is often underdiagnosed because standard stool exams may fail to detect the parasite.
Detective Work: The Challenge of Tracing Contaminated Produce
Tracing the origin of a Cyclospora outbreak presents unique epidemiological hurdles. Unlike bacterial pathogens such as Salmonella or E. coli, the parasite cannot be cultured in a laboratory, making it difficult to generate the genetic identifiers needed to link specific cases to a single grower or field. Lee Harrison, an infectious disease expert at the University of Pittsburgh, notes that the long incubation period—ranging from two to 14 days—further complicates investigations.
“Anybody can remember what they did in the last few hours. But with this, you do these detailed interviews and it’s like, what did I eat in the previous two weeks? And then, sometimes the produce is just an ingredient. People may not know if they ate parsley or cilantro.”
Lee Harrison, Director of Pitt’s Center for Genomic Epidemiology
While Michigan officials have pointed toward lettuce and salad greens as potential vehicles for transmission, no definitive supplier or farm has been identified as the source.
Restaurant Responses and Local Sourcing Strategies
As the outbreak spreads, restaurant owners are balancing consumer concern with standard safety protocols. In Portland, Maine, where two cases have been reported but remain unlinked to the national surge, many establishments are doubling down on their reliance on local supply chains.
Lanai Monahan, owner of The Garden Bar, noted that her business exclusively uses greenhouse-grown greens from Little Leaf Farms in Massachusetts. They’re all greenhouse grown, so it doesn’t really apply to us,
Monahan said, emphasizing the peace of mind that comes from knowing the origin of the produce. Other local operators, such as Melissa Coriarty of Verbena, have taken additional steps by shifting some fresh produce to hot applications
as a precautionary measure, though she remains confident in her local distributors.
For restaurants that rely on broader distribution networks, the approach remains focused on rigorous sanitation. Josh Sobel, owner of Ramona’s in Portland, stated that the team is staying hyperaware of the developing news while maintaining standard high-level hygiene practices, such as frequent handwashing and proper glove use, which are recognized by the CDC as effective measures to prevent the spread of the parasite.
Clinical Guidance and Ongoing Uncertainty
For patients, the primary defense remains early recognition and treatment. Symptoms typically include watery diarrhea, abdominal cramping, nausea, and fatigue. If left untreated, the illness can follow a relapsing course lasting up to a month.
Despite the rise in cases, public health experts maintain that produce remains an essential part of a healthy diet. Harrison, who has spent years tracking such outbreaks, remains undeterred in his own habits. I can almost guarantee you that I will be having a salad with my dinner tonight,
he said, adding the necessary caveat: With proper precautions.
As the investigation into the common source continues, the primary challenge remains the lack of a clear genetic link between the clusters, leaving the exact origin of this year’s widespread contamination an open question for health officials.
