On May 13, 2026, the first case of illness from the parasite cyclospora was reported to the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Food & Drug Administration (FDA).
As of July 21, the CDC announced it has received reports of 4,173 laboratory-confirmed cases of cyclosporiasis in the U.S., with more than 7,400 suspected cases still needing analysis. According to the CDC, cases have been reported in 41 states, with Michigan and Ohio among the hardest-hit.
On July 17, the FDA announced it had traced one possible cause of the cyclospora outbreak to iceberg lettuce sold by Taylor Farms de Mexico to Taco Bell restaurants and Walmart stores, prompting a voluntary recall by the company.
However, on July 19, the FDA announced, after reviewing sample results from Taylor Farms de Mexico lettuce, that it should be considered a false positive. The FDA says there is currently no confirmed product sample that tests positive for cyclospora.
With uncertainty as to where the cyclospora outbreak is coming from, how can you protect yourself from becoming sick?
Medical News Today spoke with seven experts to learn what exactly cyclospora is, how it spreads, what to do if you think you’re infected, and how to protect yourself.
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According to Alexis Perera, MD, medical director of Baptist Health Urgent Care, part of Baptist Health South Florida, Cyclospora cayetanensis, or cyclospora, is a tiny parasite too small to see with the naked eye that infects the small intestine.
“When you swallow the parasite through contaminated food or water, it invades the cells lining your intestine and begins to multiply,” Perera explained to MNT. “This damages the intestinal wall, flattening the tiny finger-like projections called villi that help your body absorb water, nutrients, and electrolytes. The illness it causes is called cyclosporiasis.”
Cyclosporiasis is endemic to tropical and subtropical regions, Heather Swanson, MD, regional medical director for CareMore Health, told MNT.
“Unlike many pathogens which affect the GI tract, cyclospora oocysts are not immediately infectious when shed in stool,” Swanson explained. “They require one to two weeks of environmental sporulation under favorable conditions (72–90°F/22–32°C) to become transmissible, making direct person-to-person transmission unlikely. Transmission is often secondary to irrigation of produce with fecally contaminated water.”
Symptoms of cyclosporiasis typically appear about a week after ingesting the parasite, said Swapnil Patel, MD, MHCM, FACP, vice chair of the Department of Medicine at Hackensack Meridian Jersey Shore University Medical Center, and assistant professor at the Hackensack Meridian School of Medicine in New Jersey.
“The most common sign is watery diarrhea, which can be frequent and sometimes ‘explosive’,” Patel told MNT.
Other symptoms include:
Monica Gandhi, MD, MPH, professor of medicine in the Division of HIV, Infectious Diseases, and Global Medicine at the University of California, San Francisco (UCSF), said the most concerning symptom of cyclosporiasis is the frequency of diarrhea.
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“The diarrhea can occur almost every hour and be of a large volume and watery, which leads to dehydration,” Gandhi explained to MNT. “The diarrhea can be so explosive that it comes out involuntarily, before the person can make it to the bathroom. The diarrhea does not have blood or mucus, but is just watery and high volume.”
Particular caution is warranted for young children, older adults, and individuals with underlying health conditions or weakened immune systems, said David Michalik, a pediatric infectious disease specialist at Miller Children’s and Women’s Hospital in Long Beach, CA.
“Warning signs that require prompt evaluation include dehydration, electrolyte imbalances, prolonged diarrhea (especially if bloody), severe abdominal pain, dizziness, decreased urination, dry mouth, or fever,” he detailed.
Gandhi said that cyclosporiasis is treated with an antibiotic called trimethoprim-sulfamethoxazole, which has several brand names, including Septra or Bactrim.
“The antibiotic is usually given for seven to 10 days and is very effective against cyclospora,” Gandhi told MNT. “The infection may require hospitalization for supportive care. … The infection is not usually fatal, though, and no patients have died in the current outbreak.”
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Patel urged readers to seek medical care if experiencing cyclosporiasis-like symptoms, such as diarrhea that doesn’t resolve on its own.
“The illness is treatable with antibiotics, but if left untreated, it can last for a month or longer, with symptoms that may seem to disappear and then return,” he continued. “While some mild cases may resolve on their own, treatment with antibiotics can shorten the duration of the illness and prevent relapses.”
If you suspect you or a family member has been infected by cyclospora, Carl J. Fichtenbaum, MD, Gregory W. Rouan, MD, Endowed Professor of Internal Medicine and vice chair of internal medicine and infectious diseases researcher in the College of Medicine at the University of Cincinnati, said you should contact your doctor.
“Testing requires specific tests to look for cyclospora in a fecal sample. Some people with immune-compromised conditions can have more severe cases resulting in the need for hospitalization, largely due to dehydration and low blood pressure.”
— Carl J. Fichtenbaum, MD
“Early in the infection, (cyclospora) testing can be challenging because the parasite may not yet be easily detectable in stool samples, meaning repeat testing is sometimes needed to confirm the diagnosis,” added David Cutler, MD, a board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA.
And diagnosing cyclosporiasis itself can be challenging, Michalik said.
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“Many pathogens such as norovirus, rotavirus, Salmonella, and Escherichia coli (E. coli) can cause similar diarrheal symptoms, and not all clinics or urgent care centers have the specialized testing needed to detect this parasite,” Michalik explained to MNT. “In many cases, testing must be sent to external laboratories, which can delay results.
Cyclospora prevention largely comes down to food and water safety, Cutler said.
“Cyclospora is resistant to many standard disinfecting methods, so simply rinsing produce may not fully eliminate the parasite,” he explained. ”However, thoroughly washing fresh fruits and vegetables and avoiding potentially contaminated food or water, especially when traveling to areas where the parasite is more common, can help reduce risk.”
Perera said that cyclosporiasis outbreaks occur every year in the United States during the spring and summer months, and that cases have been increasing nationwide.
“South Florida is historically one of the hardest hit areas, with fresh produce like berries, salad mixes, and fresh herbs being the most common source of infection. Be cautious with fresh herbs, leafy greens, and berries during the spring and summer months, when outbreaks are most common.”
— Alexis Perera, MD
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Patel advised readers to prioritize produce that can be easily washed, such as smooth-skinned items like apples and tomatoes.
“If I were to avoid anything, it would be pre-washed lettuce, berries, and foods that have a lot of crevices for the parasite to hide,” he continued. “It is important to remember that cooking these items will lower the risk of infection. People can also eat canned or frozen produce that was likely processed before this outbreak.”
“After handling these vegetables and fruit, wash your hands with soap and water (while) singing the Happy Birthday song twice (30 seconds).”
— Carl J. Fichtenbaum, MD
While this year’s cyclospora outbreak has been larger than most, Swanson reminded readers that fruits and vegetables remain an important part of a balanced diet and need not be eliminated from your diet.
“Thorough washing, good hand hygiene, and careful cooking techniques ensure you continue to safely enjoy nutritious meals,” she added.
