A nationwide cyclosporiasis outbreak in the United States has surpassed 18,000 suspected and confirmed cases by late July, with Midwestern states hit hardest.
The outbreak has been linked to contaminated Mexican iceberg lettuce from Taylor Farms.
Health officials in at least nine states have connected regional illness clusters to Taylor Farms' operations in Mexico.
The product was distributed across 27 states.
The Centers for Disease Control and Prevention (CDC) has confirmed 6,707 US-acquired cases and is verifying an additional 11,500 reports through patient interviews.
In Michigan's Washtenaw County alone, over 900 cases have been reported since mid-June, out of more than 10,000 statewide.
Local contact tracers face significant delays because the parasite's incubation period can last up to two weeks, forcing nurses to review grocery app histories and restaurant receipts.
Testing Data and Public Awareness
Testing data from bioMerieux shows parasite positivity rates peaked at 15.6% in mid-July, up from 2.9% during the same week in 2025.
However, company officials noted that increased testing could influence overall percentages.
John Osiecki, Vice President of Medical Affairs at bioMerieux, said, "I'm feeling confident we're heading in that direction, but we need to continue to monitor this as we go forward."
Osiecki added that consumer awareness might be slowing transmission as people alter dining habits.
"I've been in a lot of social settings, and I've heard people request not to have lettuce just because they're aware of cyclospora," he said.
Impact of Funding Cuts
The surge coincides with disruptions to state and local disease surveillance infrastructure.
Federal grant eliminations briefly cut funding for 123 full-time public health positions across 44 Michigan county health departments, along with reductions in laboratory maintenance and equipment budgets.
A temporary restraining order restored some funds, but local departments still face staffing freezes and eliminated health equity programs.
Linda Kim, Public Health Nurse at the Washtenaw County Health Department, described the transition from managing a local measles outbreak in May to investigating hundreds of severe gastrointestinal cases this summer.
Rebuilding contact tracing networks during active outbreaks has been difficult following federal workforce cuts, including temporary termination of CDC personnel stationed at county offices.
Kim noted public resistance: "People were like, 'Oh, you're just trying to restrict my life,' or 'You're just trying to get information out of me and get me in trouble.'"
Nurses continue conducting hour-long dietary interviews to map purchase logs against distribution chains.
Local health officials expressed frustration over delayed federal guidance.
"If nationally they don't know what's going on, how are we locally expected to know what's going on?"
Kim said.
Staff shortages have forced remaining employees to absorb higher caseloads.
"And also just frustrating to be like, 'Wow, I don't think even our government knows how important public health is,'" Kim added.
Christina Zilke, Nursing Supervisor at the Washtenaw County Health Department, said, "It took them forever to say that this was lettuce, and fast food restaurants were taking it off the shelves before the CDC ever said what it was."
Department leaders emphasized the need for basic provisions to prevent burnout. "It's more like, 'Here's some food for survival.
Here's a break so you don't quit,'" Zilke said.
Federal health agencies cited prolonged exposure-to-symptom lag times and supply chain complexities as reasons for extended investigations.
The FDA's broader investigation into additional unlinked gastrointestinal outbreaks is ongoing.
