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Overview

What Is Cyclosporiasis?

Cyclosporiasis (sy-klo-spuh-RY-uh-sis) is an infection caused by a parasite called Cyclospora cayetanensis. Kids can get cyclosporiasis by eating food or drinking water contaminated with the parasite.

The infection usually causes diarrhea and other intestinal problems. Without treatment, symptoms may come and go and can last for weeks or longer.

Most kids recover completely from this illness. But severe diarrhea can lead to dehydration, especially in young kids and those with weak immune systems.

Signs & Symptoms

What Are the Signs & Symptoms of Cyclosporiasis?

The most common symptom of cyclosporiasis is watery diarrhea. This usually starts about 1 week after a person eats or drinks something contaminated with the parasite, but it can begin as soon as 2 days or as long as 2 weeks after being exposed.

Other symptoms can include:

  • stomach cramps
  • bloating and gas
  • nausea or vomiting
  • loss of appetite
  • fatigue (feeling very tired)
  • headache or body aches
  • low-grade fever

Kids who are dehydrated may:

  • pee less than usual
  • have a dry mouth
  • cry with few or no tears
  • feel dizzy
  • be extra sleepy or tired

When Should I Call the Doctor?

Call your doctor if your child has diarrhea that is severe, lasts more than a few days, or keeps coming back. And call right away if your child shows any signs of dehydration. Also let the doctor know if there's blood in your child’s poop.

Causes & Prevention

How Does Cyclosporiasis Happen?

Kids get cyclosporiasis by eating food contaminated with the parasite. Fresh fruits and vegetables that are eaten raw have been linked to some outbreaks. An outbreak is when a disease happens in greater numbers than expected in a particular area.

Foods linked to outbreaks include:

  • raspberries and blackberries
  • lettuce and other leafy greens
  • basil
  • cilantro
  • snow peas

Is Cyclosporiasis Contagious?

No, cyclosporiasis does not spread from person to person. People become infected by swallowing food or water contaminated with the parasite.

Sometimes cyclosporiasis outbreaks happen when many people eat the same contaminated food.

Can Cyclosporiasis Be Prevented?

Avoiding food that’s believed to be contaminated with Cyclospora is the best way to prevent cyclosporiasis. But safe food preparation can go a long way toward protecting your family from infections. Follow these tips:

  • Cut away damaged or bruised parts of produce before washing or eating.
  • Wash all fruits and vegetables with plain running water (even if you plan to peel them) to remove any pesticide residue, dirt, or bacteria. Scrub firm produce, such as carrots, cucumbers, or melons, with a clean produce brush.
  • Wash melons, such as cantaloupes and watermelons, before cutting to avoid carrying bacteria from the rind to the knife to the inside of the fruit.
  • Dry washed produce with a clean towel or paper towel.
  • Make sure drinking water is clean and has been treated to remove harmful contaminants.

Teach your kids to wash their hands well and often, especially after going to the bathroom, touching animals, or playing outside, and before eating or preparing food. They should avoid swallowing water while swimming.

Diagnosis

How Is Cyclosporiasis Diagnosed?

Doctors usually do a stool test to look for Cyclospora parasites. It sometimes takes more than one sample to find the parasite. They also might order blood tests to check for dehydration or other problems.

Treatment & Care

How Is Cyclosporiasis Treated?

Cyclosporiasis usually goes away on its own, but it can take a long time for kids to feel better without treatment. Doctors treat cyclosporiasis with antibiotics to help kids feel better sooner. The most common treatment is trimethoprim-sulfamethoxazole (TMP-SMX).

Kids with cyclosporiasis should rest as much as possible and drink plenty of fluids to prevent dehydration. Some kids who are dehydrated may need to stay in the hospital to get better with IV (intravenous) fluids.

When Can Kids Return to School & Activities?

As kids recover from an infection, they usually can return to:

  • normal activities after 24 hours with no symptoms
  • swimming after 2 weeks have passed with no symptoms

These recommendations may vary in different areas, so it’s a good idea to ask your doctor or check with your health department.

Date reviewed: July 2026