A tiny parasite is making headlines all over the United States, and this time, your salad may be the culprit. As summer unfolds, reports of cyclosporiasis are rising across several states, reminding us that the biggest outbreaks begin with the smallest organisms. The question is: how well informed are you about cyclosporiasis and its implications? Keystone Infectious Disease’s Medical Director, Dr. Raghavendra Tirupathi, along with his students, Dr. Sanjana Medarametla and Dr. Sirish Reddy, explain in today’s Take Care article.
What is cyclosporiasis?
Cyclosporiasis is a gastrointestinal illness caused by the microscopic parasite Cyclospora cayetanensis, mainly infecting the small intestine. It causes prolonged diarrhea and is transmitted through the ingestion of food or water contaminated with Cyclospora oocysts. More people get sick in the summer because warm weather helps the parasite grow, and people often eat more fresh produce.
While cyclosporiasis outbreaks are not uncommon during the summer, this year’s outbreak has been particularly concerning. More than 1,947 people have fallen ill with 98 hospitalizations, and investigators are still working to identify the exact source of this massive outbreak.
How does cyclosporiasis spread?
Cyclospora is shed in human feces (poop) as tiny eggs called oocysts. These oocysts become infectious in soil or water approximately 1-2 weeks after they are shed, depending on environmental conditions, preferably in warm, humid surroundings, before they contaminate fresh produce such as fruits and vegetables or drinking water.
Food can become contaminated when an infected person with poor hand hygiene handles it. People get sick when they eat food (usually raw), or drink water contaminated with the parasite.
Unlike other foodborne illnesses, cyclosporiasis doesn’t spread from person-to-person.
Does past cyclosporiasis infection make a person immune?
No. A previous infection of Cyclospora does not provide lasting immunity. People can get reinfected if they are exposed to the parasite through contaminated food or water. No vaccine is currently available for cyclosporiasis.
What are the symptoms?
Cyclosporiasis infects the small bowel of our gut. The symptoms may start 2-14 days or more after ingesting the contaminated food or water. Cyclosporiasis is not usually life-threatening, but it can make some people very sick.
Most commonly, people experience watery diarrhea, loss of appetite, nausea, abdominal cramps, fatigue, bloating and weight loss. Cyclosporiasis is distinctive in causing explosive watery diarrhea, which makes you persistently feel the need to use the restroom right away. This illness can last from a few days to a month or longer, and the symptoms may relapse one or more times.
The severity of the disease can range from infection without any symptoms to severe symptomatic disease. Immunocompromised people like children and the elderly have a risk of developing severe and prolonged illness.
Cyclosporiasis outbreaks
Cyclosporiasis outbreaks have been reported since the mid-1990s in the USA, Canada, Europe and Australia, where they are usually linked to consumption of fresh produce, such as raspberries, basil, mesclun, lettuce, snow peas, cilantro and green onions. Outbreaks of cyclosporiasis can occur when large amounts of produce are contaminated either during harvesting or processing.
The CDC, FDA and public health officials in several states are investigating this year’s multistate outbreak of Cyclospora infections linked to iceberg lettuce. On July 17, 2026, Taylor Farms initiated a recall of all iceberg lettuce sourced from central Mexico.
The CDC warned the public not to eat the recalled lettuce, and to discard or return it if already purchased. Additionally, the CDC is investigating other outbreaks and illnesses of cyclosporiasis nationally that are unrelated to this outbreak.
What should you do if you think you have cyclosporiasis?
You should contact your healthcare provider if you have symptoms of cyclosporiasis, like watery diarrhea, loss of appetite, nausea, abdominal cramps, fatigue, body aches, low-grade fever and weight loss. If symptoms are severe, seek care at a hospital.
There are many causes of diarrhea, and since cyclosporiasis is a treatable infection, getting diagnosed is important. You may need to request testing for Cyclospora as routine stool tests don’t always screen for this parasite.
Stay well-hydrated while you await the test results, as profuse diarrhea can cause dehydration and weakness. If you have confirmed cyclosporiasis, public health officials may contact you about the food you ate before you got sick.
How is cyclosporiasis diagnosed?
Cyclosporiasis is routinely diagnosed by stool examination. Your physician might ask for two or more stool samples on different days, as the parasite sheds intermittently. Although not readily available at various clinics and health centers, advanced tests such as molecular testing to detect parasite DNA in a single stool sample and laboratory testing with special dyes may yield results faster.
How is it treated?
Cyclosporiasis is treated with antibiotics for 7-10 days (or longer for patients who have a weakened immune system). Your physician may also recommend anti-diarrheal medication and adequate hydration. Although some infections can resolve on their own, treatment is recommended for patients with confirmed cyclosporiasis.
How can cyclosporiasis be prevented?
The best way to prevent cyclosporiasis is to avoid consuming contaminated food or drinks. Stay up to date with food safety alerts and avoid recalled food. Wash your hands thoroughly before and after handling fresh produce to help avoid contamination.
It is important to wash all fruits, vegetables and other raw produce properly under running water before eating or cooking, even if the label says pre-washed. Eating cooked food is preferred to raw food as heating inactivates the Cyclospora oocysts. Washing alone may not remove all parasites.
Firmly scrub fruits and vegetables such as melons and cucumbers with a clean produce brush and cut away any damaged or bruised areas before preparing and eating. Removing the outer layer of produce (such as a head of lettuce) decreases risk of cyclosporiasis because oocysts are usually found on the outer parts of produce. Refrigerate cut, peeled or cooked fruits and vegetables as soon as possible (within two hours).
If you are travelling to tropical or subtropical areas where cyclosporiasis is more common, it’s important to know that routine chemical disinfection or sanitization of food or water is unlikely to kill Cyclospora.
Stay informed, stay vigilant, stay safe
As the investigation into the Cyclosporiasis 2026 outbreak continues, the situation extends beyond a single parasite or a contaminated food source. It underscores the complex connection between our food systems, public health surveillance and clinical vigilance, reminding us that timely recognition, diagnosis and coordinated response remain central to controlling outbreaks such as these.
This article contains general information only and should not be used as a substitute for professional diagnosis, treatment or care by a qualified health care provider.
