Last year, the federal government downgraded active surveillance for Cyclospora cayetanensis, a parasite that causes cyclosporiasis.
This summer, thousands of Americans are sick, and the outbreak is spreading through the food supply on a scale not seen in years.
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As of July 15, the CDC confirmed 1,645 domestically acquired cases across 34 states, with 141 hospitalizations.
The agency is aware of more than 5,100 additional cases awaiting analysis.
Michigan alone reported over 3,700 cases, compared to a typical 40-50 cases in a normal year.
On July 1, 2025, the CDC downgraded FoodNet, its active surveillance network, making tracking of Cyclospora optional at its sites.
The change also affected listeria, campylobacter, shigella, vibrio, and yersinia. Only Salmonella and E.
coli remained mandatory. The downgrade came with budget cuts and no public announcement.
Cyclospora is difficult to detect. Routine stool tests often miss it, requiring clinicians to specifically request testing.
The parasite's biology complicates outbreak response: oocysts must mature in the environment before causing infection, and the incubation period is about a week.
By the time patients are tested, the contaminated food is often gone.
Effective treatment exists, but identifying the source is critical to stopping outbreaks. Surveillance is essential for that work.
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The CDC's downgrade reduced the capacity to detect unusual patterns early. Through early July, the national tally held at 145 cases.
