What to Know
Just as summer plans are ramping up for millions of families in the United States, a parasitic infection is also on the rise. The Centers for Disease Control and Prevention issued a warning to Americans about the illness that causes severe diarrhea and can last for weeks.
The Cyclospora cayetanensis parasite has caused thousands of cases of cyclosporiasis in at least 31 states. The illness isn’t life-threatening, but it can be transmitted from person to person, and symptoms can last for weeks. Doctors warn that the sharp increase in cases is concerning.
The symptoms of cyclosporiasis are miserable.
Cyclosporiasis causes watery and sometimes explosive diarrhea and other stomach issues, according to the Cleveland Clinic. Those affected may also experience a loss of appetite, bloating, fatigue, fever, stomach cramps, nausea, and vomiting.
The parasite lives in contaminated water and food. Basil, bagged salads, cilantro, mesclun lettuce, parsley, raspberries, snow peas, and sweet peas are often linked to outbreaks in the United States, per the Cleveland Clinic.
Cyclosporiasis cases are soaring.
As of July 9, the CDC confirmed 843 cases of cyclosporiasis in 31 states since May 1. NBC News, using data from state health departments, reported 4,000 cases as of July 13. Dianna Blau, acting chief of the CDC’s Parasitic Disease Branch, told NBC News that only 2,700 cases were reported in 2025. Michigan, Ohio, Illinois, New York, North Carolina, Colorado, Indiana, and Texas have reported the most cases of cyclosporiasis, according to NBC News.
Due to the massive uptick in cases, investigators are looking into common food sources and urging people to take extra precautions when preparing food.
Cyclosporiasis can be tricky.
Dr. Partha Nandi explained cyclosporiasis to WXYZ in greater detail. He said the parasite’s symptoms don’t always show up quickly, and they can linger for quite a while.
“The parasite is shed in human stool, but it doesn’t become infectious right away. It actually needs about one to two weeks in the environment to mature before it can infect someone else,” he explained.
“So, when it comes to recreational water, it’s possible that Cyclospora may be able to survive for quite some time. And get this, it’s resistant to chlorine. So swallowing contaminated water from lakes, untreated water sources, or potentially even pools or splash pads could pose a risk if conditions allow the parasite to mature and remain infectious,” according to Nandi.
The only way to prevent cyclosporiasis is to kill the parasite.
The parasite is often transferred from person to person through food and water contaminated with feces. NBC News reported that to stop the spread of cyclosporiasis, food must be cooked to 158 degrees Fahrenheit.
Freezing may kill the parasite, but it is not a guarantee.
Experts offer the following tips to help mitigate the spread
- Always wash hands with warm soapy water before handling any raw produce
- Wash all produce under running water and use a produce brush to clean fruits and vegetables
- Remove the outer layer of produce items like lettuce and green onions if possible
- Separate fresh herbs and run them under water before eating
- Cut away damaged produce pieces before eating
- Refrigerate fruits and vegetables no longer than two hours after preparing
The CDC recommends washing all produce under running water and cooking food to 158 degrees Fahrenheit to kill the parasite. Symptoms can last weeks and may relapse.
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