What is Cyclospora? The parasite causing nearly 2,000 cases in the US and leading to severe diarrhea

At least nearly 2,000 people in the United States have been infected by the Cyclospora parasite, which causes "explosive" diarrhea and is typically found in agricultural products, although authorities have yet to identify the source of the outbreak that has resulted in cases in nearly 30 states.

The state most affected is Michigan, with 1,251 documented cases, compared to an average of 50 per year, while neighboring Ohio confirmed 177, but some counties are investigating up to 500 potential infections, reported the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota.

New York has also confirmed 394 cases statewide, while Illinois has registered 141, North Carolina reports 110, and Florida nearly 50, according to counts by national media, which report that at least 29 states are investigating cases.

The parasite causes Cyclosporiasis, an infection that can last for days or weeks, with symptoms such as "explosive diarrhea," anorexia, weight loss, cramping, flatulence, nausea, fever, and generalized muscle pain, explained the American Medical Association (AMA) in a report published amid the outbreak.

CIDRAP warned that, although Michigan appears to be the epicenter of the outbreak, the true number of cases is actually unknown because as of July 2025, the Centers for Disease Control and Prevention (CDC) made tracking of Cyclospora optional.

In fact, the latest CDC report, dated July 1, shows only 145 cases nationwide, including 20 hospitalizations, which contrasts with the figure reported by the states.

The cause of the current outbreak has not been identified, although the Michigan Department of Health and Human Services (MDHHS) is asking restaurants, kitchens, and consumers in general to increase precautions in the handling of raw foods.

"Cyclosporiasis is generally not life-threatening, but dehydration caused by frequent episodes of diarrhea can lead to serious illness, particularly among the very young or elderly and those with weakened immune systems," the MDHHS stated in a release.

The AMA recommends washing hands, especially after using the bathroom, changing diapers, or caring for someone who is sick, in addition to washing food "thoroughly," cutting and discarding all damaged or bruised areas on fruits and vegetables, and refrigerating them within two hours of cutting.