Cyclospora Infection: What to Know

Medically Reviewed by Sabrina Felson, MD on July 16, 2023
4 min read

A parasite that’s too tiny to see without a microscope can make you ill if you eat or drink the food or water it fouls. The illness is called a cyclospora infection (or cyclosporiasis), and it can bring on problems like watery diarrhea and stomach pain.

About 16,000 people in the U.S. catch it each year, and outbreaks of the infection have been linked to different kinds of imported fresh produce.

Here’s what you need to know to stay safe and lower your chances of catching this bug.

The culprit is a one-celled, microscopic parasite called Cyclospora cayetanensis. It spreads through food or water that’s been contaminated by an infected person’s feces.

You’re not likely to catch it from direct contact with someone else. That’s because the parasite takes about 1 to 2 weeks to become infectious after it’s passed through a bowel movement.

In the U.S., past outbreaks have been linked to foods like:

  • Raspberries
  • Basil
  • Cilantro
  • Snow peas
  • Mesclun lettuce

Your chances of catching cyclospora could also go up if you travel to or live in places where it’s common, like tropical or subtropical parts of the world.

It usually takes about a week for symptoms to show up after you get infected. Some common signs are:

  • Watery or explosive diarrhea
  • Little to no appetite
  • Weight loss
  • Stomach pain or cramps
  • Bloating
  • More gas
  • Nausea
  • Tiredness

It’s also possible to have flu-like symptoms such as vomiting, fever, headaches, or body aches.

Call your doctor if you have diarrhea that doesn’t go away after a few days. Or if you’re having trouble keeping fluids down, because that can lead to dangerous dehydration.

Without treatment, the illness can last anywhere from a few days to a month or more. Your symptoms may disappear and then come back. You’ll probably feel more tired than usual.

That said, some people with a cyclospora infection don’t have any symptoms.

The doctor may start by asking you what you’ve eaten in the last 7 to 10 days to get a sense of whether food might be playing a role in your symptoms. They might also ask if you’ve recently traveled abroad.

Diarrhea and other digestive problems can have lots of possible causes. To confirm a cyclospora infection, the doctor will need to have samples of your stools (possibly from different days) tested by a lab to find out if the parasite is in it. Blood tests can’t diagnose the illness.

If you’re healthy, you may get better on your own.

If you need treatment, the doctor can prescribe antibiotics to knock out the infection. They might have you take a drug that combines two antibiotic meds called sulfamethoxazole and trimethoprim (Bactrim, Cotrim, Septra).

It’s important to rest and drink lots of water while you recover. Drinking fluids is key because severe diarrhea can make you dangerously dehydrated. That can lead to serious health problems, especially for:

  • Elderly people
  • Babies
  • People with serious illness or weakened immune systems

If your child or baby has cyclospora, you can also give them an oral rehydration solution. Skip carbonated drinks and sports drinks. They don’t have the right balance of nutrition for kids.

Yes. Follow these simple steps to lower your chances of getting a cyclospora infection:

Wash up. Scrub your hands with warm water and soap for at least 20 seconds before and after you handle produce.

Prepping raw meat, poultry, or seafood first? Clean any kitchen utensils or surfaces they touch with hot water and soap before you prepare any uncooked fruit or veggies.

Clean fresh produce. Rinsing or washing fruits and veggies tainted with cyclospora probably won’t remove it. In general, though, it’s a good idea to thoroughly rinse off fresh produce under running water before you eat, chop, or cook it.

Scrub firm produce like cucumbers and melons with a clean fruit or vegetable brush. Also, slice off any bruised or damaged parts on produce before you prepare and eat it.

If you bought fruits or veggies that came in a package labeled “prewashed,” you don’t need to wash them again.

Store safely. Place cut, peeled, or cooked produce in the refrigerator ASAP or within 2 hours. Keep fruit and veggies away from raw meat, poultry, and seafood in the fridge to avoid cross contamination. If something leaks or spills, clean it up right away.

Keep the kitchen clean. Take these steps to clean the inside of your refrigerator, cutting boards, and countertops:

  • Wash them with soap and water.
  • Sanitize them with a mix of 1 tablespoon of chlorine bleach to 1 gallon of hot water.
  • Dry them with a clean paper or cloth towel you haven’t used before.

Anytime something spills inside your fridge, wipe it up right away.