Cyclospora outbreak ends after sickening 12,833 across 21 states

The largest cyclosporiasis outbreak in U.S. history has officially ended, the Centres for Disease Control and Prevention announced Friday, September 11, though questions about its origin remain unanswered.

CDC reported that the foodborne illness sickened 12,833 people across 21 states, with the largest cluster associated with shredded iceberg lettuce supplied by Taylor Farms in Mexico.

Overall, the outbreak fuelled the worst cyclosporiasis season on record, with 19,595 total cases caused by the Cyclospora parasite.

Two deaths were reported in Michigan, the epicentre of the outbreak. The FDA said it is confident that all recalled iceberg lettuce tied to the outbreak is off the market. Taylor Farms recalled the lettuce in July, and Taco Bell, which served the shredded iceberg lettuce, pulled it from restaurants that same month.

The outbreak caused increased examination of U.S. food safety practices, corporate consolidation of the food supply chain, and FDA resources and staffing. It also resulted in decreased sales of restaurants serving fresh lettuce, especially Taco Bell, as well as decreased sales of fresh lettuce in grocery stores. Fresh lettuce prices fell 16.4% between June and July and 6.2% between July and August.

Cyclospora was difficult to trace because of its long incubation period, which can last several weeks. The parasite is transmitted via faecal matter, but it is not known how sewage infected enough produce to make so many sick.

The FDA has stopped on-site inspection of iceberg lettuce growers and processors in Mexico, and samples are still being analysed. This outbreak has also highlighted an increasing concern: fewer international inspections by U.S. regulatory agencies of contaminated products.