What to know about cyclospora parasite and how to avoid it

Key Points:

• Cyclosporiasis, a parasitic infection causing prolonged diarrhea, cramps, and bloating, is seeing unusual outbreaks in several U.S. states, including Michigan, Ohio, and New York, with case numbers far exceeding typical annual counts.
• The parasite Cyclospora cayetanensis reproduces sexually in the human gut, making genetic tracing difficult; thus, outbreak investigations rely heavily on detailed patient interviews and epidemiological detective work.
• Infection occurs through ingestion of contaminated food or water, often from raw produce like berries and herbs, or recreational water sources, with symptoms lasting weeks and requiring specific diagnostic tests not included in standard stool panels.
• Treatment involves a 7-10 day course of antibiotics (trimethoprim-sulfa), which interfere with the parasite’s ability to metabolize folate; untreated infections can persist and contribute to environmental spread.
• Washing produce reduces but does not completely eliminate Cyclospora eggs, with methods like vinegar rinses and salad spinners performing better than plain water, especially on smooth fruits like blueberries compared to raspberries.