Parasite tied to fresh produce has sickened 840 in 31 states, and officials still seek the source

Summer produce is filling shopping carts again, but health officials are warning that a parasite linked to fresh fruits and vegetables has already sickened hundreds of people across the United States.

More than 840 confirmed cases have been reported in 31 states since May, and investigators have not yet identified the food item responsible for the outbreak.

What's happening?

KTLA reported that the U.S. Centers for Disease Control and Prevention is investigating a multistate cyclosporiasis outbreak, an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

California has recorded a small number of cases this year, but state officials said those infections are not tied to the larger outbreak.

Cyclosporiasis can develop after someone consumes contaminated food or water, and unlike many other gastrointestinal illnesses, it typically does not pass from person to person.

Symptoms usually begin about five to seven days after infection, Dr. Ariel Malamud, a gastroenterologist, said: "The most common symptoms are diarrhea, which can be watery and explosive, nausea, vomiting, low-grade fever and abdominal pain."

Officials have not yet linked this year's cases to a particular fruit or vegetable. In past outbreaks, though, Cyclospora has been associated with produce such as cilantro, basil, raspberries, and leafy greens.

Why does it matter?

Public health investigations often take time. Officials must compare interviews, shopping histories, and supply-chain information across multiple states before they can confidently identify a source and issue targeted warnings. 

Until then, guidance tends to remain broad rather than focused on a single product.

In KTLA's reporting, a Southern California woman who recovered from the illness described how severe it was, saying days of intense gastrointestinal symptoms left her down nearly 10 pounds in roughly a week.

What can I do?

Handle produce carefully.

That includes washing hands before preparing food, rinsing produce under running water, and cleaning kitchen surfaces and utensils that come into contact with raw fruits and vegetables.

For households, food safety expert Candice Christian offered one simple recommendation: "The best defense you can take is to scrub any firm produce."

Pay attention to symptoms if you become sick after eating fresh produce, especially if diarrhea is severe or prolonged. Seeking medical care can help with recovery and may also support health officials' efforts to trace the outbreak.

The Southern California woman told KTLA, "It was the sickest I've ever been."

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