Over 1,600 confirmed cases of cyclosporiasis have been reported across 34 US states as of July 15, 2025, with 141 hospitalizations and more than 5,100 additional cases awaiting analysis, according to the CDC. The outbreak is the largest in years and has been linked to a downgrade in active surveillance for the parasite, which became optional at FoodNet sites on July 1, 2025, as part of budget cuts.
Cyclospora cayetanensis, a parasite that causes prolonged watery diarrhea, is often missed in routine stool tests. Clinicians must specifically request testing, and the downgrade means that FoodNet—the CDC's active surveillance network in partnership with the FDA, USDA, and 10 state health departments—no longer mandates tracking of Cyclospora, along with listeria, campylobacter, shigella, vibrio, and yersinia. Only Salmonella and E. coli remain mandatory.
Impact of the Surveillance Downgrade
The change, implemented without public announcement, has hampered outbreak detection. Michigan, which typically sees 40-50 cases annually, has reported over 3,700 cases this year. The CDC's national tally initially stood at 145 cases in early July, but by July 13, confirmed cases had surged to 1,645, with a single state reporting more illness than the entire country had officially registered. This delay in accurate counts means contaminated food may be consumed before the outbreak is identified, preventing timely intervention.
Dr. Robert B Shpiner, a clinical professor of medicine at UCLA, wrote in an opinion piece that the downgrade reflects a broader trend of reduced public health capacity. 'More than 3,000 public health workers have left the CDC through firings, forced retirements and attrition, roughly a quarter of its workforce by the end of last year, according to an analysis by KFF Health News,' he noted. This loss of personnel has weakened the agency's ability to conduct food tracebacks and interviews at state and local levels.
Official Rationale and Consequences
The CDC has stated that funding has not kept pace with maintaining surveillance for all eight pathogens, and that other, slower passive systems can still track them. However, the current outbreak demonstrates the limitations of passive surveillance: it cannot stop a fast-moving outbreak in time. Shpiner emphasizes that 'surveillance is the treatment' for Cyclospora, as identifying the source is critical to removing contaminated food from the supply chain.
The Trump administration has described the CDC as a bloated bureaucracy and pledged to eliminate waste. But critics argue that the cuts have eliminated the capacity to notice emerging threats. Shpiner warns that while Cyclospora rarely kills, the next pathogen may be less forgiving. He calls for restoring mandatory active surveillance for Cyclospora at FoodNet sites, publishing weekly national counts during summer, and rebuilding state and local teams.
Broader Implications for Public Health
Shpiner, who has practiced intensive care since 1981, draws a parallel to the early days of AIDS, noting that 'what a health system does not measure can spread in plain sight.' The cost of restoring surveillance is modest compared to the illness and hospitalizations it prevents. 'Surveillance is not clerical overhead,' he writes. 'It is the promise a country makes to its citizens that it will notice when they begin to get sick.'
The outbreak is expected to continue through August, according to the CDC. As of now, investigators have not identified the source of contamination. The situation underscores the importance of robust public health surveillance systems in protecting the food supply and preventing widespread illness.
