Overview
Cyclosporiasis is an intestinal infection caused by a tiny parasite called Cyclospora cayetanensis. This parasite is too small to see with the naked eye and lives in the gut (intestines). People usually get infected by eating or drinking something contaminated with the parasite's eggs, called oocysts. Common sources include fresh produce like raspberries, basil, snow peas, and lettuce, as well as contaminated water. The infection is not spread directly from person to person. Once inside the body, the parasite infects the lining of the small intestine and causes inflammation. This leads to the main symptoms: watery diarrhea that can come and go, stomach cramps, bloating, nausea, fatigue, and weight loss. Symptoms usually start about one week after exposure and can last for weeks or even months if not treated. Some people, especially those with weakened immune systems, can become very ill. The good news is that cyclosporiasis is treatable. The standard treatment is a combination antibiotic called trimethoprim-sulfamethoxazole (TMP-SMX), sold under brand names like Bactrim or Septra. Most people recover fully with treatment. Without treatment, symptoms can drag on for a long time and keep coming back. Early diagnosis and treatment lead to the best outcomes.
Key symptoms:
Watery diarrhea that may come and goStomach cramps and painBloating and gasNausea and sometimes vomitingLoss of appetiteUnexplained weight lossFatigue and feeling very tiredLow-grade feverMuscle achesFeeling generally unwell
Sporadic
Usually appears on its own, not inherited from a parent
Variable
Can begin at different ages, from infancy through adulthood
Treatments
No FDA-approved treatments are currently listed for Cyclosporiasis.
View clinical trials →Clinical Trials
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Specialists
View all specialists →No specialists are currently listed for Cyclosporiasis.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Cyclosporiasis.
Community
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.How do I take TMP-SMX correctly, and what should I do if I miss a dose?,What should I do if I am allergic to sulfa drugs — are there other treatment options for me?,How will I know if the treatment is working, and when should I expect to feel better?,Do I need to have my stool tested again after treatment to confirm the infection is gone?,Is there any risk of passing this infection to family members living in my home?,Are there any foods or activities I should avoid while I am recovering?,If my symptoms come back after treatment, what should I do and could I need a longer course of antibiotics?
Common questions about Cyclosporiasis
What is Cyclosporiasis?
Cyclosporiasis is an intestinal infection caused by a tiny parasite called Cyclospora cayetanensis. This parasite is too small to see with the naked eye and lives in the gut (intestines). People usually get infected by eating or drinking something contaminated with the parasite's eggs, called oocysts. Common sources include fresh produce like raspberries, basil, snow peas, and lettuce, as well as contaminated water. The infection is not spread directly from person to person. Once inside the body, the parasite infects the lining of the small intestine and causes inflammation. This leads to the
How is Cyclosporiasis inherited?
Cyclosporiasis follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.