CDC Declares End to Cyclospora Outbreak Linked to Iceberg Lettuce

CDC Ends Cyclospora Outbreak

The Centers for Disease Control and Prevention (CDC) has declared the end of a significant Cyclospora outbreak connected to iceberg lettuce. This outbreak affected 12,883 individuals across 21 states, resulting in 570 hospitalizations and two deaths. The outbreak was traced back to processed iceberg lettuce provided by Taylor Farms de Mexico.

On July 17, the company recalled all iceberg lettuce sourced from central Mexico. The CDC confirmed that these products are no longer in stores or restaurants. According to the CDC’s final update on September 11, there is now no risk of infection from this source.

Increasing Cyclospora Infections

The outbreak was part of a broader rise in Cyclospora infections, caused by the parasite Cyclospora cayetanensis. Since May 1, the CDC has documented 19,595 laboratory-confirmed, domestically acquired cases in 49 states and Washington, D.C., including 1,043 hospitalizations and two deaths.

The CDC’s latest map indicates where affected people lived. However, it does not specify where they encountered the parasite. Investigations are ongoing regarding isolated clusters of cyclosporiasis and other foodborne pathogens such as Salmonella, E. coli, and Listeria.

Investigation into Iceberg Lettuce Contamination

The source of the outbreak was connected to iceberg lettuce through patient interviews and supply-chain tracing. Michigan officials conducted initial investigations linked to Taco Bell restaurants where many people reported consuming iceberg lettuce.

FDA investigators traced the lettuce to a single company. A sample that initially tested positive was later deemed a false positive as it did not show true amplification of the parasite. As of July 19, no confirmed positive sample results emerged from FDA testing.

The precise mechanism of contamination remains unknown; it could have occurred at growing operations, through contaminated water, or during processing. The parasite spreads when food or water is contaminated with human feces, requiring one to two weeks outside the body to become infectious. Direct person-to-person transmission is unlikely.

The FDA, along with Mexican authorities, conducted inspections and sampling at growing operations and processing facilities in Mexico. Investigations into the source of contamination by the FDA are ongoing.

Other Foodborne Outbreaks Under Investigation

The FDA is investigating eight active foodborne outbreaks involving different pathogens as of September 12. These include:

• Salmonella Bovismorbificans linked to broccoli sprouts: Infected 22 people in four states; two hospitalizations. Evergreen Fresh Sprouts issued a recall after finding the outbreak strain in broccoli sprout samples.
• Salmonella Newport, source unknown: 109 cases reported. Traceback efforts are ongoing.
• Shiga toxin-producing E. coli and Salmonella Agona linked to sprouts: Sickened 55 people in 15 states, hospitalized four. Alfalfa sprouts from Everything Sprouts implicated; multiple sprout products recalled.
• Salmonella I 4,[5],12:i:-, source unknown: 43 cases recorded. FDA performing traceback, inspections and sampling.
• Salmonella Javiana linked to jalapeño peppers: 431 people affected in 32 states, 57 hospitalized. Linked to peppers from Sinaloa, Mexico; Coast Citrus Distributors recalled implicated jalapeños.
• Listeria monocytogenes, source unknown: Nine cases reported. FDA conducted traceback, inspections, and sampling.
• Salmonella Oranienburg, source unknown: 99 cases linked. Inspections, traceback, and sampling are in progress.
• E. coli O145:H28 linked to frozen blueberries: Infected 17 people in Florida and Georgia, six hospitalized. Recalls include GreenWise frozen berries and Great Value Organic Triple Berry Blend sold at Walmart.

Consumers should check for recalled products with 2028 best-by dates, especially if they have these frozen berries in their freezers.

Contact Newsweek editor on this story: Edward Pearcey.