Cyclospora is a parasite that can infect the intestines and cause an illness called cyclosporiasis. This infection mainly causes watery diarrhea and can last for several days or weeks if it is not treated.
Cyclospora is usually spread when a person eats food or drinks water contaminated with stool that contains the parasite. In the United States, outbreaks have often been linked to fresh produce, such as berries, herbs and leafy greens.
Treatment usually involves an antibiotic prescribed by a doctor, as well as fluids to prevent dehydration. Medical care is especially important when diarrhea is severe, lasts for more than a few days, or occurs in people with a weakened immune system.
Main symptoms
The main symptoms of cyclospora infection affect the digestive system and may come and go if the infection is not treated.
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Watery diarrhea
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Sudden or frequent diarrhea
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Stomach cramps
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Bloating
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Gas
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Nausea
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Loss of appetite
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Fatigue
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Weight loss
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Low-grade fever
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Body aches
Symptoms usually start after an incubation period following exposure to contaminated food or water. In some cases, diarrhea can improve and then return, which may make the illness last longer.
How it is transmitted
Cyclospora is transmitted through the fecal-oral route, which means the parasite leaves the body in stool and can later contaminate food, water or the environment. A person becomes infected after swallowing the parasite, usually through contaminated fresh produce or unsafe water.
Cyclospora does not usually spread directly from one person to another right after exposure. This is because the parasite needs time outside the body to mature before it can infect someone else.
Foodborne outbreaks have been linked to imported and fresh produce, including raspberries, fresh herbs and leafy greens. Water contamination can also play a role, especially in areas where sanitation or food handling systems are limited.
Confirming a diagnosis
Cyclospora is diagnosed with stool testing. A doctor may request one or more stool samples to look for Cyclospora oocysts, which are the parasite’s egg-like form.
Special lab methods may be needed because Cyclospora can be hard to see on a routine stool exam. Tests may include acid-fast staining, autofluorescence microscopy or molecular tests, such as PCR.
Doctors may suspect cyclospora when watery diarrhea lasts for several days, comes and goes, or happens after eating fresh produce, drinking unsafe water, or traveling to areas where the infection is more common.
Treatment options
Treatment for cyclospora will typically include:
1. Antibiotics
The main treatment for cyclospora is an antibiotic called trimethoprim-sulfamethoxazole, also known as TMP-SMX. This medicine helps clear the parasite and usually improves diarrhea and other symptoms.
The dose and length of treatment should be prescribed by a doctor. People who are allergic to sulfa medicines or who cannot take TMP-SMX should be evaluated so the safest option can be chosen.
2. Fluids and symptom care
Fluids are important because diarrhea can lead to dehydration. Water, oral rehydration solutions, broths and other clear fluids may help replace lost fluids.
Food should be gentle while symptoms are active. Smaller meals may be easier to tolerate until diarrhea, nausea and stomach cramps improve.
3. Care for higher-risk groups
Cyclospora can be more serious in people with weakened immune systems. This includes people using immune-suppressing medicines or living with conditions that reduce the body’s ability to fight infections.
These cases should be monitored by a doctor. Treatment may need closer follow-up, especially if diarrhea is severe or symptoms do not improve.
When to see a doctor
Medical care is recommended when diarrhea is severe, lasts more than a few days, returns after improving, or occurs with signs of dehydration. Signs of dehydration can include dizziness, very dark urine, dry mouth or weakness.
A doctor should also be consulted if symptoms appear after travel, after eating foods linked to an outbreak, or in people who are pregnant, older adults, young children, or people with weakened immune systems.
Prevention measures
Cyclospora prevention focuses on lowering the risk of swallowing contaminated food or water.
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Wash hands well before preparing or eating food
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Wash fresh fruits, vegetables and herbs before eating them
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Use safe drinking water, especially during travel
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Avoid food or water that may have been exposed to stool contamination
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Be careful with raw fresh produce in areas where Cyclospora is more common
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Follow public health guidance during foodborne outbreaks
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Store and prepare food safely to reduce contamination risk
Washing produce can lower the risk of infection, but it may not remove all contamination. For this reason, food safety systems, clean water and safe handling practices are also important for preventing cyclospora outbreaks.