Cyclospora cases top 1,400 as outbreak source stays a mystery

To protect yourself during this vegetable parasite outbreak, wash all fresh produce under running water, cook food to at least 158°F whenever possible, and avoid untreated water and public swimming areas if cases are rising locally. Cyclospora spreads through contaminated produce and water—not from person to person—and more than 1,400 Americans have already fallen ill while investigators still hunt a single shared source.

Key Takeaways

• At least 1,400 people across multiple states have been sickened, with Michigan reporting more than 1,200 cases.
• Federal and state officials have not identified one common food source, and trace-back is unusually slow for this parasite.
• Cyclospora does not spread person to person; infection comes from eating or drinking something contaminated weeks earlier.
• Thorough washing and cooking to 158°F reduce risk, but rinsing alone cannot guarantee safety.
• See a doctor if diarrhea lasts more than 48 hours; prescription antibiotics can shorten an illness that may otherwise drag on for weeks.

Why Is This Vegetable Parasite Outbreak Hard to Solve?

A summer surge of cyclosporiasis—the intestinal illness caused by the Cyclospora parasite—has left health officials searching for answers as case counts climb past 1,000 nationwide. Michigan is the epicenter, with more than 1,200 people ill. Ohio has seen nearly 200 cases, and New York, Illinois, Indiana, North Carolina, and Texas have also reported jumps.

More than 40 people have been hospitalized. While the illness is rarely fatal, watery diarrhea, cramping, and bloating can leave victims dehydrated and miserable for weeks or even months with a relapsing pattern.

Investigators say they have not yet determined the source or sources behind this year's cases. Unlike E. coli or listeria outbreaks, cyclospora is not routinely tracked with whole-genome sequencing. The parasite is hard to culture, often appears in tiny quantities in stool samples, and roughly 20% of submitted specimens fail genotyping, according to a CDC study cited by USA Today.

The long incubation period—averaging one week but stretching up to two weeks or more—also makes it harder for sick people to recall what they ate. For investigators, that turns every interview into a cold case. As coverage in our True Crime & Unsolved Mysteries section often explores, some outbreaks stay unsolved when the evidence trail goes cold.

What Foods and Habits Put You at the Highest Risk?

You get cyclosporiasis by eating or drinking something contaminated, usually fresh produce. The parasite is resistant to bleach, so it can survive in chlorinated swimming pools, splash pads, lakes, and rivers. During a local surge, experts suggest avoiding public swimming areas.

Past outbreaks have been linked to raspberries, basil, salad mixes, cilantro, berry and fruit mixes, lettuce, and snow peas—foods with crevices that are often eaten raw. Bagged salad kits, vegetable trays, and coleslaw have also been implicated before.

How Can You Protect Yourself Until the Source Is Found?

Cooking is the safest option. Heating food to an internal temperature of 158°F or higher kills cyclospora, according to Michigan health guidance cited by CNN. Use a food thermometer to confirm.

For raw produce, wash thoroughly for at least one minute by immersing items in water and swishing gently. A one-part vinegar to three-parts water rinse can remove most spores, though researchers have found cyclospora stickier than other parasites—rinsing helps but is not fully reliable.

Other steps include discarding outer lettuce leaves, scrubbing firm produce with a soft brush, washing hands before and after food prep, sanitizing surfaces and utensils, refrigerating cut produce within two hours, and avoiding untreated water. Immunocompromised people may want to skip high-risk raw items entirely until the investigation concludes.

When Should You See a Doctor?

If diarrhea lasts more than 48 hours during a known surge, infectious disease experts recommend seeking a diagnosis. Standard stomach-bug tests often omit cyclospora, so your doctor may need to order a specific test—and repeat it 24 hours apart because the parasite sheds intermittently.

Treatment is typically seven to 10 days of the antibiotic combination sulfamethoxazole-trimethoprim (Bactrim or Septra). The CDC notes that cyclosporiasis season runs May 1 through August 31, and local, state, and federal agencies are still investigating several multistate clusters. Until a source is named, careful food handling remains your best defense.