Cyclosporiasis: Causes, Symptoms, and Treatment

Few things disrupt summer picnics and warm weather plans like a case of food poisoning. Cyclosporiasis is a type of food poisoning — one that tends to spike in the spring and summer months. So to help you prevent it from ruining your summer plans, let’s take a closer look at its symptoms and treatment. And the best ways to keep you and your family safe. 

What is cyclosporiasis?

Cyclosporiasis is an infection that comes from the cyclospora parasite. The main symptom is frequent, watery diarrhea. You get it by eating food or drinking water contaminated with the parasite.

The parasite survives better in hot and humid environments, so cyclosporiasis is more common in tropical parts of the world. You’re more likely to get it if you live or travel in certain places. But outbreaks happen in the U.S., too. Especially during the summer. 

When many people have the same infection, public health workers try to find the source of it. But this is not always easy. In the meantime, there are steps you can take to lower your risk of cyclosporiasis.

What causes cyclosporiasis?

Cyclospora is a parasite that spreads through the feces (poop) of animals — including humans. If it gets into a water supply, you can get sick from drinking that water. Cyclospora can also end up on food items through contact with sewage and soil. 

Washing your foods can help get rid of the parasite. But it can be tough to completely eliminate it, even with thorough washing. And rinsing isn’t a helpful option if the water is contaminated (though this isn’t usually a problem in the U.S.).  

Heat kills the spores that cause cyclospora infections. So uncooked foods are more likely to cause cyclosporiasis.

What are the symptoms of cyclosporiasis?

Symptoms of cyclosporiasis don’t start for a few days or even a week after exposure. When you get food poisoning, you might wonder if something you ate earlier that day caused it. But with cyclosporiasis, the culprit is likely something you ate several days earlier. 

The most telling symptom of cyclosporiasis is watery diarrhea. People sometimes describe it as “explosive diarrhea” because of the frequency and force of it. Symptoms may last a few days to a few weeks.

Along with the diarrhea, you may just feel generally off or unwell. Cyclosporiasis symptoms may include:

• Bloating and gassiness

• Nausea and upset stomach

• Stomach cramps

• Fatigue (feeling tired)

• Mild fever

You may have only mild symptoms. Or you may have no symptoms at all, especially if you’ve lived in a place where cyclosporiasis is common. 

How do you treat cyclosporiasis?

A mild case of cyclosporiasis might clear up on its own. But for more serious symptoms, or diarrhea that lasts more than a few days, antibiotics help to clear the infection faster.

The most effective antibiotic for cyclosporiasis is sulfamethoxazole / trimethoprim, often called TMP-SMX or Bactrim. It’s a tablet you take twice a day, usually for 7 days. Some people — like those with a weakened immune system — may need to take antibiotics for longer to cure the infection.

If you’re allergic to sulfa drugs, other antibiotics that work to treat cyclosporiasis include ciprofloxacin or nitazoxanide. 

Supportive treatments also help alleviate symptoms and lower the risk for dehydration. These include:

• Plenty of fluids: Try different kinds of liquids. Take frequent sips if it’s hard to keep food or fluids down.

• Anti-diarrhea medication: Loperamide is a common option. But it’s important to talk to a healthcare professional before you start taking this. Sometimes these medications can make it harder for your body to clear the infection.  

• Pain and fever medication: If needed, over-the-counter acetaminophen (Tylenol) can help.

How do you prevent cyclosporiasis?

With any kind of food poisoning, prevention is the best form of treatment. Some ways you can lower your risk of getting cyclosporiasis include:

• Thoroughly wash fresh fruits and vegetables. Some produce claims that it’s pre-washed, but it’s best to always wash your fruits and vegetables yourself — especially when there’s an outbreak.

• Opt for heads of lettuce rather than pre-packaged types. Remove the outer leaves of the head of lettuce before washing.

• Consider peeling firmer fruits and vegetables. Wash produce before you peel or slice it. Keep sliced fruits and vegetables in the refrigerator.

• Cook produce to kill the spores that cause infection. Raw fruits and vegetables have some great health benefits. But heat kills cyclospora. So cooking your veggies is a safer option, especially during an outbreak. 

• Eat locally grown produce. This may have a lower risk than food grown and shipped from a distance.

• Wash your hands before and after preparing food. Use soap and warm water. 

• Drink from trusted water sources. When traveling, opt for bottled water and avoid uncooked fruits and vegetables.

Frequently asked questions

Why trust our experts?

Written by:

Anne Jacobson, MD, MPH

Anne Jacobson, MD, MPH has been a board-certified physician since 1999. She was a full-scope family physician (inpatient, outpatient, obstetrics, and office procedures) in the Cook County Ambulatory Health Network for 15 years.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

Our editorial standards

Meet our experts