CDC downgrades cyclospora surveillance as case counts surge past 1,600

More than 3,000 public health workers have left the agency

• The CDC downgraded FoodNet active surveillance for Cyclospora and five other pathogens to optional on July 1, 2025, without public announcement.
• As of July 15, the CDC had confirmed 1,645 domestically acquired cases of cyclosporiasis across 34 states, with 141 hospitalizations, and was tracking more than 5,100 additional suspected cases.
• Michigan, which typically records 40 to 50 cyclosporiasis cases annually, has reported more than 3,700 cases this summer.
• More than 3,000 public health workers have left the CDC through firings, forced retirements, and attrition, roughly a quarter of its workforce, according to a KFF Health News analysis.

FoodNet downgrade left outbreak detection capacity reduced

The U.S. Centers for Disease Control and Prevention downgraded a key active surveillance system for Cyclospora cayetanensis to optional in July 2025, a decision that left health authorities unable to detect the scale of a fast-moving parasitic outbreak until weeks after contaminated food had likely already reached consumers, according to Dr. Robert B. Shpiner, a clinical professor of medicine in pulmonary and critical care at the David Geffen School of Medicine at UCLA.

Shpiner wrote in a commentary published Thursday in The Guardian that the downgrade of FoodNet, the active surveillance network the CDC has operated with the FDA, the USDA, and 10 state health departments since 1995, made tracking of Cyclospora optional at its sites, along with listeria, campylobacter, shigella, vibrio, and yersinia. Only salmonella and E. coli remained mandatory. The change arrived with budget cuts and was not publicly announced at the time; it was reported nearly two months later after a journalist inquired, Shpiner wrote.

The consequence of that change has played out in real time this summer. As of July 15, the CDC had confirmed 1,645 domestically acquired cases of cyclosporiasis across 34 states, with 141 hospitalizations, and said it was aware of more than 5,100 further cases awaiting analysis. Michigan, which in a typical year records 40 to 50 cases, had reported more than 3,700. Investigators have not yet identified the source or sources of the contamination.

MSI previously reported that the outbreak had surpassed 2,800 total reported cases across 31 states as of July 13, with Michigan accounting for the largest share. By mid-July, that single state was reporting more illness than the entire country had officially registered in early July, Shpiner noted.

“The surveillance change did not contaminate anyone’s lettuce,” Shpiner wrote. “Cyclospora would have entered the food supply this summer, whoever was counting.” But he said FoodNet’s purpose was to serve as “the instrument sensitive enough to tell the nation that something unusual is happening, and to say so against a consistent baseline.”

“That is the capacity the CDC downgraded,” Shpiner wrote. “A count that lands after the food has been eaten can document an outbreak. It cannot stop one.”

Shpiner said the FoodNet downgrade was not an isolated administrative move. More than 3,000 public health workers have left the CDC through firings, forced retirements, and attrition — roughly a quarter of its workforce, according to an analysis by KFF Health News. “Much of what the CDC does is push money and expertise down to the state and local departments that conduct the interviews and the food tracebacks, and those are the people who will find whatever is doing this,” Shpiner wrote.

Cyclospora presents unique challenges for investigators. The parasite is not transmitted directly from person to person; the oocysts it sheds must mature in the environment for days before they can infect anyone, meaning every case traces back to contaminated food or water. The incubation period runs about a week, so by the time a patient is ill enough to be tested, the meal in question is often a hazy memory and the produce that carried the parasite has been eaten or shipped onward. Many routine stool tests do not include Cyclospora, so clinicians must specifically suspect the parasite before a laboratory will test for it.

“Surveillance is not the paperwork that accompanies the treatment,” Shpiner wrote. “Surveillance is the treatment.”

Shpiner, who began practicing intensive care medicine in Los Angeles in 1981 during the early months of the AIDS epidemic, said the institutional lesson from that era applies: “What a health system does not measure can spread in plain sight, and by the time the measurement catches up, the argument is no longer about prevention.”