Cyclosporiasis
Commonly treated with Sulfamethoxazole/Trimethoprim (Bactrim DS)
Cyclosporiasis is an intestinal infection caused by the microscopic parasite Cyclospora cayetanensis, most often spread through contaminated fresh produce or water. It typically causes watery diarrhea, cramping, and fatigue that can last for weeks without treatment. After a licensed provider reviews your health history, prescription treatment can be prescribed online and shipped from our U.S. pharmacy.
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How It Works
- Select your medication
- Licensed providers review & prescribe
- Our licensed U.S. pharmacists fill your prescription
- Delivered to you as soon as the next day
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HSA/FSA Eligible*Doctor visit fee & delivery cost not included in price. Refills at provider discretion.
Order Cyclosporiasis Treatment Online
Medically reviewed by David Paul Mackarey, RPh, Pharmacist-in-Charge — Last updated July 14, 2026
Choosing and Using Your Treatment
| Treatment | Choose this if… | How to Take |
|---|---|---|
| Sulfa/TMP 800mg/160mg (Bactrim DS) | First-line treatment for adults with confirmed or suspected cyclosporiasis who are not allergic to sulfa drugs. | Take 1 tablet by mouth twice daily for 7 days. |
About Cyclosporiasis (Cyclospora infection)
Cyclosporiasis is a diarrheal illness caused by the parasite Cyclospora cayetanensis. People become infected by eating food or drinking water contaminated with the parasite — in the United States, outbreaks have been linked to imported fresh produce such as basil, cilantro, raspberries, and bagged salad mixes. Symptoms usually begin about a week after exposure and often include frequent watery diarrhea, loss of appetite, bloating, cramping, and tiredness. If untreated, symptoms can last a month or longer and may seem to improve and then return. Unlike many stomach bugs, cyclosporiasis does not spread easily from person to person, because the parasite needs time outside the body to become infectious. The infection is confirmed with a stool test and responds well to a specific prescription antibiotic.
Signs & symptoms
- Frequent, watery diarrhea
- Loss of appetite and weight loss
- Stomach cramping, bloating, and increased gas
- Nausea and fatigue
- Low-grade fever in some people
- Symptoms that improve and then relapse
- Illness lasting weeks to a month or longer if untreated
Causes & risk factors
- Infection with the parasite Cyclospora cayetanensis
- Eating fresh produce contaminated with the parasite (basil, cilantro, raspberries, lettuce)
- Drinking contaminated water
- Travel to tropical or subtropical regions where the parasite is common
- Consuming imported produce linked to outbreaks
- Poor sanitation in areas where food is grown or handled
Prevention
- Wash your hands before handling or eating food
- Wash fresh fruits and vegetables thoroughly before eating
- Avoid untreated water when traveling to high-risk regions
- Follow food recall alerts during produce-linked outbreaks
- Choose cooked foods when traveling in tropical areas
- Keep fresh produce separate from raw meats during preparation
When to see a doctor
Online treatment can be a good fit if you have been diagnosed with cyclosporiasis by a stool test, or if you have typical symptoms after a known exposure or outbreak and a provider determines treatment is appropriate. Seek in-person or emergency care if you have signs of severe dehydration (dizziness, very little urination, confusion), a high fever, bloody stools, severe abdominal pain, or if you are pregnant, immunocompromised, or caring for a young child or older adult who is becoming weak or unable to keep fluids down. Diarrhea lasting more than a few days without a clear diagnosis should be evaluated with stool testing before treatment.
Sources & References
Frequently Asked Questions
What causes cyclosporiasis?
Cyclosporiasis is caused by the microscopic parasite Cyclospora cayetanensis. People are infected by consuming food or water contaminated with the parasite, most often imported fresh produce such as herbs, berries, and salad greens.
Is cyclosporiasis contagious from person to person?
It is very unlikely. The parasite must spend days to weeks outside the body before it becomes infectious, so direct person-to-person spread is not considered a significant risk.
How is cyclosporiasis diagnosed?
Diagnosis requires a stool test that specifically looks for Cyclospora, since routine stool tests may miss it. Your provider may ask for one or more stool samples if the first test is negative and symptoms continue.
How long does cyclosporiasis last?
Without treatment, symptoms can last a month or longer, and they may seem to improve and then come back. With the appropriate prescription antibiotic, most people feel better within a few days of starting treatment.
What is the treatment for cyclosporiasis?
The standard treatment in the U.S. is the antibiotic combination trimethoprim-sulfamethoxazole (commonly known as Bactrim DS). People who are allergic to sulfa drugs should discuss alternatives with their provider, as options are limited.
Can cyclosporiasis go away on its own?
In otherwise healthy people, symptoms may eventually resolve without treatment, but this can take weeks and relapses are common. Treatment shortens the illness and reduces the chance of symptoms returning.
How can I prevent cyclosporiasis?
Wash fresh produce thoroughly, follow food recall notices during outbreaks, and avoid untreated water when traveling to tropical or subtropical regions. Note that washing may not remove all parasites from heavily contaminated produce, so staying informed about outbreaks is important.
Treatments for Cyclosporiasis
Find out more information about each treatment.