Cyclospora may not be a household name, but a growing multistate outbreak in the U.S. has brought renewed attention to this foodborne parasite and the illness it causes, known as cyclosporiasis.
A multistate Cyclospora outbreak is currently under investigation across the United States. As of mid-June, at least 145 people in 17 states have been diagnosed, with 20 hospitalizations reported, according to the U.S. Centers for Disease Control and Prevention (CDC). New York, Illinois and Texas are among the states reporting cases.
The outbreak continues to grow, with Michigan recently reporting an unusually large surge of more than 170 cases across several counties. Public health agencies are working to identify the contaminated food source, which remains unknown.
While cyclosporiasis is relatively rare, it is more common during the warmer months when fresh produce consumption increases. In fact, case counts typically rise in the spring and summer, and the cyclosporiasis season is generally considered May 1 through August 31, according to the CDC.
Knowing how Cyclospora spreads, recognizing symptoms and seeking care when needed can help reduce your risk and ensure timely treatment. While outbreaks can be concerning, most people recover fully with appropriate care.
Cyclospora at a Glance
- Cause: Cyclospora cayetanensis parasite
- How it spreads: Contaminated food or water
- Most common symptom: Watery diarrhea
- Other symptoms: Stomach cramps, nausea, bloating, fatigue, weight loss
- When symptoms start: Usually about one week after exposure
- Treatment: Prescription antibiotics
- Can it go away on its own? Yes, but symptoms may last for weeks and can return after temporarily improving
What Is Cyclosporiasis?
Cyclosporiasis is an intestinal illness caused by a microscopic parasite called Cyclospora cayetanensis, commonly referred to as Cyclospora. The parasite infects the small intestine and can cause prolonged digestive symptoms if left untreated.
One important thing to know: you cannot see, smell or taste Cyclospora on contaminated food. The parasite is so small it can only be detected under a microscope, which is part of what makes it difficult to identify and avoid.
How Does Cyclospora Spread?
Cyclospora spreads when people eat food or drink water contaminated with feces containing the parasite. According to the U.S. Food and Drug Administration, past U.S. outbreaks have been linked to raspberries, basil, cilantro, snow peas and mesclun lettuce, though the source of the current outbreak remains under investigation.
Fresh produce is commonly involved in outbreaks because the parasite can be introduced through contaminated irrigation water or while handling during growing and harvesting. Cyclospora is resistant to some routine disinfection methods, and rinsing or washing produce alone is unlikely to completely remove it.
Cyclospora is not usually spread from person to person. After it leaves the body, the parasite needs time in the environment before it can infect someone else.
What Are the Symptoms of Cyclosporiasis?
Symptoms usually appear about one week after exposure, although they can develop anywhere from two days to two weeks or more. Some infected people may not experience symptoms at all.
Common Symptoms
- Watery diarrhea
- Frequent bowel movements
- Stomach cramps
- Bloating
- Increased gas
- Nausea
- Loss of appetite
- Weight loss
- Fatigue
Less Common Symptoms
- Vomiting
- Headache
- Body aches
- Low-grade fever
Many people describe Cyclospora-related diarrhea as sudden, frequent and difficult to control. In some cases, symptoms may be severe enough to be described as “explosive diarrhea.” Fatigue may also linger even after digestive symptoms begin to improve.
Dehydration Risks
In addition, severe or prolonged diarrhea can lead to dehydration. Signs of dehydration include:
- Extreme thirst
- Dry mouth
- Dizziness or lightheadedness
- Dark-colored urine
- Urinating less often than usual
Without treatment, symptoms can last from a few days to more than a month. It is also common for symptoms to improve and then return, a pattern known as relapse.
How Is Cyclosporiasis Different From Typical Food Poisoning?
Many people assume Cyclospora is a typical case of food poisoning. However, unlike many foodborne illnesses that improve within a few days, cyclosporiasis can cause persistent diarrhea that lasts for weeks.
If your diarrhea has lasted longer than expected or keeps returning, it may be more than a typical stomach bug.
Who Is at Higher Risk for Cyclospora Infection?
Anyone can become infected after consuming contaminated food or water. However, some groups may be at higher risk of infection or more severe illness:
- Older adults
- Young children
- People with weakened immune systems
- People receiving cancer treatment
- Individuals taking immunosuppressive medications
- People in underlying health conditions
- Travelers to tropical or subtropical regions where Cyclospora is more common
How Is Cyclosporiasis Diagnosed and Treated?
Diagnosis
Diagnosis requires a stool sample. Because Cyclospora can be difficult to detect, healthcare providers may request multiple stool samples collected on different days.
It is important that your provider specifically requests testing for Cyclospora, since it is not included in routine stool tests.
Treatment
The recommended treatment for cyclosporiasis is a prescription antibiotic called trimethoprim-sulfamethoxazole. It is sold under brand names such as Bactrim, Septra and Cotrim. If you are allergic to sulfa medications, talk with your healthcare provider about alternative treatment options.
Staying hydrated is also an important part of recovery, especially if diarrhea is frequent or severe. Drinking fluids helps prevent dehydration and supports the healing process.
Most healthy people recover from cyclosporiasis, even without antibiotics. However, symptoms can last for weeks if untreated and may improve and then return.
How to Prevent Cyclospora Infection
Simple food safety and hygiene steps can help reduce the risk of Cyclospora infection, especially during active outbreaks.
- Wash your hands with soap and water before preparing food.
- Rinse fresh fruits and vegetables under running water.
- Follow food recall and outbreak alerts issued by public health authorities.
- Practice safe food handling and storage.
- Avoid untreated water, especially when traveling to regions where Cyclospora is more common.
When Should You See a Doctor?
Contact a healthcare provider if you experience:
- Diarrhea lasting more than three days
- Severe or explosive diarrhea
- Signs of dehydration
- Significant weight loss
- Fever along with digestive symptoms
- Symptoms that improve and then return
- Symptoms after consuming a recalled food product
- A weakened immune system or underlying health condition
Frequently Asked Questions
What is cyclosporiasis?
Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis. It infects the small intestine and commonly causes watery diarrhea, stomach cramps, nausea and fatigue.
How does Cyclospora spread?
Cyclospora spreads through contaminated food or water. It is not typically spread directly from one person to another because the parasite must spend time in the environment before it becomes infectious.
How long do Cyclospora symptoms last?
Without treatment, symptoms can last from several days to more than a month. Symptoms may also improve and then return.
Can Cyclospora cause explosive diarrhea?
Yes. Many people experience sudden, frequent watery diarrhea. In some cases, symptoms can be severe enough to be described as explosive diarrhea.
What foods are commonly linked to Cyclospora outbreaks?
Past U.S. outbreaks have been linked to raspberries, basil, cilantro, snow peas and mesclun lettuce. The source of the current outbreak is still under investigation.
What is the treatment for cyclosporiasis?
The recommended treatment is prescription antibiotics. Staying hydrated is also important during recovery.
Should You Be Concerned About the Current Cyclospora Outbreak?
Public health agencies continue to investigate the source of the outbreak and will issue additional guidance if a contaminated food product is identified. In the meantime, staying informed, practicing good food safety habits and seeking medical care if symptoms develop are the most effective steps you can take to avoid this illness.
