Avoid an Explosive Summer With the Latest on Cyclospora

Recently, Dr. Daniel Griffin, President and Co-Founder of Parasites Without Borders, spoke with Bloomberg about the headline-grabbing multi-state U.S. parasitic outbreak of the summer – Cyclospora. Here’s what we know and how you can avoid becoming ill:

The United States regularly monitors reports of Cyclospora outbreaks, with the peak occurring from May 1 to August 31. Currently, the U.S. is experiencing multiple significant outbreaks of cyclosporiasis. From May 1 to July 27, 2026, the Centers for Disease Control (CDC) has received reports of 6,707 laboratory-confirmed cases of cyclosporiasis in 45 states, with 423 hospitalizations and 0 deaths. A multi-state outbreak tied to iceberg lettuce sold in various package types by Taylor Farms de Mexico has recently made headlines. According to the most recent figures from the CDC, as of July 24, 2026, 1,947 laboratory-confirmed cases have been reported in 9 states from the Taylor Farms outbreak. There have been 98 hospitalizations, with 0 deaths reported. Although a recall has been issued, the lettuce was distributed and sold to consumers, restaurants, and retailers in at least 27 states.

Cyclosporiasis is a gastrointestinal disease caused by the microscopic parasite Cyclospora cayetanensis. It spreads when people eat food or drink water contaminated with feces. “The parasite is typically passed between humans through fairly indirect transmission,” Dr. Griffin said. “For example, someone who was infected with Cyclospora or who recently had diarrhea caused by it could contaminate food and transmit the pathogen when it is consumed.”

Usually, people become sick about one week after infection, but the onset can range from two days to two weeks or more. Cyclospora infects the small intestine or bowel, causing cyclosporiasis. Symptoms include:

• Watery diarrhea
• Loss of appetite
• Weight loss
• Cramping
• Bloating
• Increased gas
• Nausea
• Fatigue

“It could really be this explosive, significant diarrhea that doesn’t get better,” Dr. Griffin said, noting it can take hold even in healthy people. “People should seek medical care if gastrointestinal issues persist for longer than a few days and continue to hydrate if they are experiencing symptoms,” he continued. “Young children and older adults are the most susceptible to needing hospitalization.” If left untreated, cyclosporiasis may last from a few days to over a month, and many patients will experience symptom relapse one or more times.

Cyclosporiasis is diagnosed through laboratory testing of a stool or fecal sample. It is treated with trimethoprim-sulfamethoxazole, a sulfa drug commonly sold as Bactrim, Septra, or Cotrim. Most people with a healthy immune system will eventually recover without treatment. Those who are in poor health or have weakened immune systems may be at higher risk for more severe or prolonged illness. All patients must rest and prioritize hydration, especially for those experiencing severe or prolonged bouts of diarrhea.

You can help reduce the risk of cyclosporiasis by following food safety handling recommendations:

• Wash your hands with soap and water before and after handling raw fruits and vegetables.
• Wash all fruits and vegetables thoroughly under running water before eating, cutting, or cooking - even if it's labeled as pre-washed. Scrub firm fruits and vegetables, like melons and cucumbers, with a clean produce brush. Cut away any damaged or bruised areas on fruits and vegetables before preparing and eating.
• Refrigerate cut, peeled, or cooked fruits and vegetables as soon as possible, within two hours.

Dr. Griffin has been discussing the Cyclospora outbreak during his Clinical Update with Dr. Daniel Griffin as part of the This Week in Virology podcast, on episode 1338 and episode 1340. For more resources about parasitic infections, visit www.ParasitesWithoutBorders.com.