U.S. Officials Declare Record Cyclospora Outbreak Over, Origin Still Unknown

The largest outbreak of cyclosporiasis — a diarrheal illness caused by the microscopic parasite cyclospora — in U.S. history is over, U.S. health officials said Friday. The Food and Drug Administration said it is confident that all recalled iceberg lettuce tied to the outbreak is off the market. Nearly 13,000 reported cases were linked to the multistate outbreak, federal officials said — the bulk of an unprecedented surge in the illness this year.

Even with the outbreak declared over, its origin remains unknown. Cyclospora spreads through human feces, and officials still do not know how sewage could have contaminated enough food to sicken so many people. "This contamination can happen if produce is grown in soil or comes into contact with water that has been contaminated," said Ellen Shumaker, director of outreach for Safe Plates, a food safety program at North Carolina State University.

Since May 1, the government has received reports of nearly 20,000 lab-confirmed cyclospora cases, more than 16 times the number reported over the same period last year, plus more than 6,100 suspected cases. The worst previous year on record was 2019, with about 4,700 illnesses reported nationally. This year's surge was dominated by an outbreak across 21 states linked to iceberg lettuce, though thousands of other cases were not connected to it. Michigan was the hardest-hit state, with the most reported cases and both of the outbreak's confirmed U.S. deaths.

Investigators initially focused on lettuce served at Taco Bell before identifying Taylor Farms as the source; the company recalled iceberg lettuce grown in central Mexico that was shipped in packaged salad products to major restaurant chains, including Yum Brands, which owns Taco Bell, Pizza Hut and KFC. The FDA said Friday it has ended its on-site inspections and sample collection at the growers and processing facility in Mexico, with results from those samples still pending.