Cyclospora surveillance downgraded by CDC amid large US outbreak
8 reported2 unconfirmed
A large outbreak of cyclosporiasis, a parasitic infection causing severe diarrhea, is spreading through the US food supply this summer, with the CDC reporting 1,645 confirmed domestically acquired cases across 34 states as of July 15, 2026, and over 5,100 additional cases awaiting analysis. Michigan has reported more than 3,700 cases, far exceeding its normal annual count of 40 to 50. The outbreak comes after the CDC downgraded active surveillance for Cyclospora cayetanensis on July 1, 2025, making tracking optional at its FoodNet sites, along with five other pathogens, due to budget cuts. The change was not publicly announced and was reported nearly two months later after a journalist inquired. The author, a UCLA critical care professor, argues that the downgrade has hindered timely detection, noting that the national tally held at 145 cases through early July before jumping to 1,645 by July 13. The CDC has stated that funding has not kept pace with resources needed for full surveillance and that other systems can track the pathogens, but the author contends these are slower and less effective during fast-moving outbreaks.
What’s reported
As of July 15, 2026, the CDC confirmed 1,645 domestically acquired Cyclospora cases across 34 states, with 141 hospitalizations, and over 5,100 further cases awaiting analysis.
Michigan reported more than 3,700 cases, compared to a normal annual count of 40 to 50.
On July 1, 2025, the CDC downgraded FoodNet surveillance for Cyclospora, listeria, campylobacter, shigella, vibrio, and yersinia to optional; only Salmonella and E coli remained mandatory.
The downgrade was made with budget cuts and no public announcement, reported almost two months later after a journalist asked.
The CDC stated funding has not kept pace with resources needed for all eight pathogens, that remaining pathogens are trackable through other systems, and that a narrower mandate lets staff focus on core work.
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 KFF Health News.
Cyclospora is not transmitted person-to-person; oocysts must mature in the environment for days before infecting others.
Effective treatment exists for individual patients but does not stop the outbreak without identifying the contaminated food source.
Open questions
The source or sources of the contamination have not been identified.
Whether the CDC will restore Cyclospora to mandatory active surveillance.
Key figures
Robert B Shpiner, clinical professor of medicine in pulmonary and critical care at the David Geffen School of Medicine at UCLA
CDC (Centers for Disease Control and Prevention)
FDA (Food and Drug Administration)
USDA (United States Department of Agriculture)
KFF Health News (source of workforce analysis)
Trump administration (mentioned in context of CDC workforce reductions)
Sources: The Guardian
