Cyclospora is causing explosive diarrhea in the U.S. One vegetable may be to blame.

Key Points:

• Lettuce and leafy greens have a history of being linked to foodborne illness outbreaks, including E. coli and Cyclospora, with the current 2024 Cyclospora outbreak being widespread and unresolved in its source.
• Cyclospora is a parasitic protozoa primarily associated with raw produce like berries, herbs, and leafy greens, with contamination likely occurring during the growing phase, especially in widely distributed products such as bagged salads.
• The parasite’s origins remain unknown, complicating prevention efforts; hypotheses include human-only contamination, animal vectors, or contaminated irrigation water, with most outbreaks linked to imported produce from Central or South America.
• Cyclospora is difficult to study because it cannot be cultured in the lab, has complex life stages, and requires specialized testing for diagnosis, while reduced public health resources and surveillance have hindered outbreak detection and response.
• Traceability challenges, including mixed produce products and long incubation periods, make it hard to pinpoint contamination sources, delaying outbreak investigations and complicating public health interventions.