Cyclosporiasis case count may exceed 11,000, CDC tracking shows

Michigan reports 7,000-plus cases as state-federal data diverge

The Food and Drug Administration is investigating six cyclosporiasis outbreaks, including one large cluster spanning nine states. The only source identified to date is iceberg lettuce supplied by Taylor Farms de Mexico, which initiated a voluntary recall of lettuce sold to restaurants in 27 states and grocery stores in 15 states. Taco Bell, whose locations were linked to cases in nine states, is no longer using the lettuce, according to the FDA.

Barbara Kowalcyk, an associate professor at George Washington University and director of the school’s Institute for Food Safety and Nutrition Security, said the outbreak’s scale reveals vulnerabilities in the food safety system.

“What’s surprising to me is the magnitude of it, and how it highlights all these system vulnerabilities,” Kowalcyk said.

Cyclosporiasis is a gastrointestinal infection caused by cyclospora, a microscopic parasitic protozoa. The illness is characterized by weeks of watery, explosive, relapsing diarrhea, according to the Guardian. The protozoa is spread in food and water contaminated with human feces, its only known host. Cyclospora outbreaks occur annually, and public health workers sometimes refer to the period as “cyclospora season.”

Michigan has been the hardest-hit state, with state officials reporting more than 7,000 cases. The divergence between state and federal case counts reflects the way the US tracks foodborne illness, experts said. States hold authority over the health and welfare of their residents, making public health outbreaks a state responsibility. They coordinate with federal officials, who in turn coordinate with multiple investigating agencies depending on the type of product suspected.

The reporting process begins when a sick person sees a doctor and the doctor orders a test for cyclosporiasis — a test not included in a typical stool sample panel. Public health authorities said this means any confirmed case count is an undercount. If the test is positive, the physician reports the case to the state health department, which initiates an investigation that typically includes an interview to determine whether the person likely became ill in the US or internationally. State health officials communicate the case report to the CDC through the National Notifiable Diseases Surveillance System (NNDSS).

Only 47 states require cyclosporiasis to be reported to the NNDSS. In other states, such as Pennsylvania, reporting is voluntary. The CDC assumes a six-week reporting lag between illness onset and receiving a report.

The CDC’s website dedicated to the nine-state outbreak counts cases as confirmed only if both an interview and lab confirmation have been received. Michigan health authorities said they send all lab-confirmed cases to the CDC, though some cases may lack interviews.

The outbreak has unfolded amid significant strain on state and federal health departments. The Trump administration initiated major cuts to public health in 2025. Pandemic-era grants to state and local health departments were cut by $11.4bn, according to the Guardian. The CDC lost between 25% and 30% of its staff. Within the CDC, a specialized parasitic disease team was downsized from 11 people to three, in part because the group was partially funded by USAID, which also faced cuts.

“Ideally, we would identify and solve these outbreaks when they’re small, you don’t want an outbreak of 11,000 people,” Kowalcyk said. “It’s just symptomatic of the fact we have cut public health funding over the last two years to an area we haven’t fully funded to begin with.”