Cyclospora Symptoms Recur for Weeks in Record U.S. Outbreak

Q: What common summer salad ingredient is secretly fueling the largest parasitic outbreak in US history?

The ingredient at the center of the largest confirmed cluster is **shredded iceberg lettuce**, especially product traced to **Taylor Farms de Mexico**. Federal investigators from the CDC and FDA say epidemiologic and traceback evidence links the multistate cyclospora outbreak to contaminated iceberg lettuce served at some Taco Bell locations and also sold through retail and food-service channels, including recalled Marketside products. Taylor Farms de Mexico recalled all implicated iceberg lettuce sourced from central Mexico on July 17. That does not mean every cyclospora case nationwide came from one salad ingredient. Health officials are investigating multiple outbreaks and say other produce may also be involved in the broader 2026 surge. But in the biggest identified outbreak cluster, the common ingredient is shredded or iceberg lettuce. Cyclospora is a parasite spread through food or water contaminated with human feces, and raw produce is a common vehicle because it is often eaten uncooked. Symptoms can include watery or “explosive” diarrhea, cramping, nausea, fatigue and dehydration, and they may improve and then return, as described in the news story. Anyone who still has recalled iceberg lettuce should throw it away or return it, and clean any surfaces it touched. People with persistent or recurring diarrhea should seek medical care and ask specifically to be tested for **Cyclospora**, since routine stool tests may miss it.

Q: Why are standard hospital tests completely missing this explosive, relapsing illness currently sweeping across 15 states?

Standard hospital tests are missing many Cyclospora cases because the parasite is not reliably detected by routine stool workups. A standard ova-and-parasite exam often does not pick it up, and many common gastrointestinal PCR panels do not include a Cyclospora target unless a clinician specifically asks for it. That mismatch is especially important in this outbreak because Cyclospora causes a relapsing illness. Patients can feel better, then suddenly worsen again, as seen in the Brooklyn and Pittsburgh cases. Doctors say the parasite is also shed intermittently and sometimes in very low numbers, so even symptomatic patients may test negative on a single stool sample. One negative result does not rule it out. Accurate diagnosis usually requires special testing methods that many hospitals do not run automatically: PCR assays that explicitly include Cyclospora, or specialized microscopy such as modified acid-fast or safranin staining, often on concentrated stool samples. Public health guidance also recommends collecting multiple stool specimens on different days because shedding can come and go. The result is a blind spot at exactly the wrong moment. During the largest known U.S. outbreak, now tied in a major cluster to recalled iceberg lettuce from Taylor Farms de Mexico and spanning 15 states, many patients with prolonged or recurring watery diarrhea may be missed, delayed, or misclassified unless clinicians think of Cyclospora early and order the right test.

3 articles · Updated · The New York Times · Aug 7

Weeks after seeming to recover, some U.S. cyclospora patients are seeing severe diarrhea return, with one Brooklyn patient hospitalized for IV fluids after a second test still found the parasite.
Health experts say the food- or waterborne parasite can cause symptoms to wax and wane repeatedly over weeks, a pattern that leaves patients thinking they are better before the illness flares again.
Two patient accounts illustrate that cycle: a 25-year-old in Brooklyn relapsed after Bactrim, while a 31-year-old Pittsburgh nurse suffered two waves of illness before antibiotics finally stopped the diarrhea.
The recurrence is drawing attention because the U.S. is in its largest cyclospora outbreak on record, yet doctors say research on how a typical infection behaves remains limited.