A map of the historical spread of Cyclospora cayetanensis with a focus on the United States of America (USA)

Cyclospora cayetanensis is a parasite causing significant seasonal foodborne illnesses. The United States is experiencing the largest recorded outbreak of this infection in history during summer 2026. Researchers used phylogenetic network analysis and mitochondrial sequence data from 1997 to 2022 to reconstruct the historical spread of this parasite in the USA. The analysis identified Texas as a primary sink for C. cayetanensis introduction, which aligns with historical epidemiologic investigations including the 2013 multistate outbreak. The study revealed critical surveillance gaps, including the lack of molecular data for the 2026 outbreak. Researchers emphasize the need for integration of real-time molecular surveillance with network analysis and improved data sharing among food, clinical, and agricultural sectors to prevent transmission cycles.