What to Know About Cyclospora: Symptoms, Risks, and Prevention

As the summer season shifts into high gear, health officials across the United States are reminding the public about a persistent gastrointestinal threat: Cyclospora. This microscopic parasite, which causes an intestinal infection known as cyclosporiasis, has been linked to several clusters of illness across multiple states in recent weeks, prompting renewed focus on food safety.

Cyclospora cayetanensis is a single-celled parasite that typically spreads when a person consumes food or water contaminated with microscopic amounts of infected human feces. Unlike some other foodborne pathogens that might thrive in undercooked meats, Cyclospora is most commonly associated with fresh produce, particularly leafy greens, fresh herbs like cilantro and basil, and imported berries.

One of the reasons Cyclospora is particularly challenging for public health officials to track is its incubation period. Unlike food poisoning caused by bacteria like salmonella, which might cause symptoms within a few hours, Cyclospora is more deliberate. It usually takes about a week—sometimes as long as two weeks—after exposure for an individual to start feeling ill. This delay makes it extremely difficult for people to remember exactly what they ate that might have caused their infection, complicating the work of contact tracers.

The hallmark symptom of cyclosporiasis is watery, explosive diarrhea. Other common symptoms include a significant loss of appetite, weight loss, severe stomach cramps, bloating, increased gas, nausea, and fatigue. Some people also experience low-grade fevers and body aches. Because these symptoms mirror many other stomach bugs, cases often go undiagnosed or are misidentified as typical traveler’s diarrhea or stomach flu.

For most healthy individuals, the infection is unpleasant but not life-threatening. However, if left untreated, the symptoms can persist for weeks or even months, often coming and going in waves. Doctors typically treat the infection with a combination of antibiotics, specifically trimethoprim-sulfamethoxazole (TMP-SMZ). Because the parasite is not a bacteria, standard over-the-counter anti-diarrheal medications are generally ineffective and are often discouraged by medical experts.

Preventing a Cyclospora infection primarily involves rigorous food hygiene. While washing produce is a standard recommendation, it is important to understand the limitations. Cyclospora is notoriously difficult to wash off fruits and vegetables because it can attach itself to the microscopic grooves and surfaces of leaves and skins. Thorough washing, scrubbing, and drying produce can help reduce the risk, but it does not eliminate it entirely. Health authorities suggest buying produce from reputable sources and, whenever possible, opting for produce that is cooked, as heat is highly effective at killing the parasite.

Another key prevention strategy involves avoiding cross-contamination in the kitchen. Using separate cutting boards for raw produce and raw meats, washing hands thoroughly with soap and water before preparing food, and keeping kitchen surfaces clean are essential practices. For those traveling to regions where the parasite is more common, it is recommended to drink only bottled or boiled water and avoid raw foods that may have been washed in local tap water.

If you believe you have contracted an illness after consuming fresh produce, it is vital to contact your local health department, as this assists officials in identifying potential outbreaks. While the risk of a severe outcome is low for most, vulnerable populations—including the elderly, young children, and those with weakened immune systems—should be particularly cautious and monitor their hydration levels closely if symptoms arise.

Consult a healthcare professional.