A microscopic parasite known as Cyclospora cayetanensis is sweeping across the United States, leaving thousands of Americans grappling with severe gastrointestinal symptoms and fueling frustration over gaps in public health communication. The pathogen spreads through human fecal contamination and has turned up in produce supplies nationwide, prompting urgent questions about food safety infrastructure.
Since May 1st, the Centers for Disease Control and Prevention has confirmed 1,645 cases of cyclosporiasis and is aware of at least 5,100 additional cases requiring further analysis. The total number of infections is believed to be substantially higher, as many cases go unreported. So far, the government has recorded 141 hospitalizations and no deaths.
Symptoms and the Search for Answers
Symptoms of cyclosporiasis include nausea, loss of appetite, cramping, bloating, and watery, explosive diarrhea. They can begin anywhere from two days to two weeks after exposure and tend to wax and wane. The diarrhea may subside for a day or two before returning in full force. In extreme cases, severe dehydration can lead to hospitalization.
Bryan, a food broker from Michigan who asked that his last name be withheld, described needing to use the bathroom every 15 to 30 minutes by the Saturday after he first felt unwell. At urgent care, he received a full battery of tests — except for the one that detects Cyclospora, which standard diarrhea tests cannot identify. A nurse practitioner told him labs in Michigan were so backed up they could not keep up with demand. Bryan was prescribed Bactrim, an antibiotic used to treat the infection, without a confirmed diagnosis.
In the absence of concrete federal guidance, thousands of people have turned to online forums like Reddit to crowdsource information — and, inevitably, misinformation. Some have speculated that the government is protecting farmers or food distributors. Health officials say the reality is more mundane: federal agencies are cautious about issuing recommendations until they have sufficient data, and Cyclospora infections are notoriously difficult to trace.
Michigan at the Epicenter
Michigan has reported more confirmed cyclosporiasis cases than any other state, with 2,640 as of Monday, according to state health officials. They identified lettuce and other salad greens as a potential source, though other food items have not been ruled out. State officials have not traced the outbreak to a specific type of produce, grower, or supplier.
According to The Washington Post, federal and state officials are investigating Taco Bell after the fast food chain voluntarily recalled lettuce, cilantro, onion, pico de gallo, and guacamole at some of its locations. The CDC has identified an epidemiologic link between four states — Michigan, Ohio, West Virginia, and Kentucky — though cases have been reported in 34 states total. It remains unclear how many of those are connected.
Why Cyclospora Is So Hard to Track
Rodney E. Rohde, program chair of the Medical Laboratory Science Program at Texas State University, told The Verge that Cyclospora outbreaks are among the most challenging foodborne outbreaks to investigate. The parasite's long incubation period — usually about a week — combined with the short shelf life of most fresh produce makes it difficult to determine what foods made someone sick.
Even when a culprit is identified, testing foods for Cyclospora is notoriously difficult. Pathogens are often present in very low numbers and may be unevenly distributed throughout a food lot, meaning a lab can analyze a 25-gram sample from thousands of pounds of product without obtaining a conclusive result. Tracing remains complicated because fresh produce typically passes through multiple growers, packers, distributors, and retailers before reaching consumers, and contaminated lots may no longer be available by the time illnesses are recognized.