New Cyclospora Taking over the United States; Everything to Equip, Prepare and Protect

The parasite itself isn’t new, but the 2026 U.S. outbreak is unusually large, and investigators are still working to identify the contaminated food source.

No, this isn’t about us coronavirus, but-there’’s a lot of attention on Cyclospora right now.

Cyclospora (Cyclospora cayetanensis) is a microscopic parasite that infects the small intestine and causes an illness called cyclosporiasis. It is a protozoan—not a bacterium or a virus.

Unlike many foodborne illnesses, it has a long incubation period and can cause symptoms that come and go for weeks if left untreated.

How do people catch it?

Most people become infected by eating or drinking something contaminated with the parasite.

Commonly implicated foods include:

  • Leafy greens

  • Lettuce

  • Cilantro

  • Basil

  • Raspberries

  • Other fresh produce

The parasite usually reaches food through contamination with human feces somewhere during growing, harvesting, or processing—not because the food itself is inherently unsafe.

Can you catch it from another person?

One unusual feature of Cyclospora is that direct person-to-person spread is extremely unlikely.

The parasite passed in stool is not immediately infectious. It needs days to weeks in the environment before it can infect someone else. That means:

  • Hugging someone won’t spread it.

  • Sharing a bathroom generally isn’t enough by itself.

  • The main concern remains contaminated food or water.

Symptoms

Symptoms usually begin about 1–2 weeks after exposure and can include:

  • Frequent watery diarrhea

  • Severe abdominal cramping

  • Bloating

  • Gas

  • Nausea

  • Loss of appetite

  • Fatigue

  • Weight loss

  • Occasionally vomiting

  • Low-grade fever in some people

Many people describe the illness as improving for a few days and then returning. Without treatment, symptoms can last weeks or even months.

Why is this outbreak getting so much attention?

Health officials are investigating one of the largest U.S. outbreaks in years.

Current findings include:

  • Cases have been reported across 30+ states.

  • Michigan has experienced an especially large surge.

  • Investigators suspect fresh produce—particularly lettuce or salad greens in some regions—but no single food source has been definitively confirmed yet.

How is it diagnosed?

Routine stool testing doesn’t always detect Cyclospora.

Healthcare providers often need to order:

  • A stool PCR gastrointestinal pathogen panel that includes Cyclospora, or

  • A stool test specifically looking for Cyclospora.

If someone has prolonged diarrhea, it’s worth mentioning the possibility of Cyclospora to their healthcare provider, especially during an outbreak.

How is it treated?

The standard treatment is the antibiotic:

  • Trimethoprim-sulfamethoxazole (TMP-SMX, commonly known as Bactrim or Septra).

Most people improve after starting treatment.

For people with sulfa allergies, treatment options are more limited and should be discussed with a healthcare professional. Supportive care—especially staying hydrated—is also important.

Can washing produce prevent it?

Washing fruits and vegetables is still recommended, but it does not guarantee removal of Cyclospora.

The parasite can adhere tightly to produce, making it difficult to wash away completely. Cooking is much more effective at eliminating the parasite than rinsing alone.

Who is most at risk for severe illness?

Anyone can become infected, but complications are more likely in:

  • Older adults

  • Young children (mainly due to dehydration)

  • People with weakened immune systems

  • Anyone who becomes severely dehydrated from prolonged diarrhea.

If you’re interested, we can also dive into:

  • How Cyclospora differs from norovirus, Salmonella, and E. coli

  • Why investigators are having such a hard time finding the source of this outbreak

  • The parasite’s life cycle (it’s surprisingly fascinating)

  • What foods are considered lowest risk while the investigation continues

 
 
 

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