Health officials are investigating a multistate increase in cyclosporiasis, an intestinal illness caused by the parasite Cyclospora cayetanensis. Recent cases have been reported in multiple states, and investigators are working to identify the food source responsible for the outbreak. Because the parasite is often linked to fresh produce, outbreaks can affect people across several regions before the source is identified.
Although cyclosporiasis is not as well known as illnesses caused by bacteria like Salmonella or E. coli, it can cause severe diarrhea and other digestive symptoms that may last for weeks if left untreated. Understanding how the parasite spreads and how to reduce your risk is especially important during the summer months, when cases are most common.
What Is Cyclosporiasis?
Cyclosporiasis is an infection caused by the microscopic parasite Cyclospora cayetanensis. People become infected by swallowing food or water contaminated with the parasite.
Unlike many other foodborne illnesses, cyclosporiasis is not spread directly from person to person. The parasite must first mature in the environment before it becomes infectious, which means someone who is sick cannot immediately pass the infection to another person.
Most outbreaks in the United States have been linked to contaminated fresh produce, including leafy greens, herbs, berries, and other fruits and vegetables that are eaten raw.
What Are the Symptoms?
Symptoms usually begin about one week after a person becomes infected.
The most common symptom is frequent watery diarrhea, but people may also experience:
- Loss of appetite
- Weight loss
- Stomach cramps
- Bloating
- Nausea
- Fatigue
- Increased gas
Some people also have vomiting, low-grade fever, or muscle aches.
Without treatment, symptoms can last for several weeks or even longer. Some patients experience symptoms that improve and then return before finally resolving.
People with weakened immune systems may develop more severe or longer-lasting illness.
Why Cases Increase During the Summer
In the United States, cyclosporiasis cases are reported every year, but infections are most common during the spring and summer.
Many outbreaks occur because fresh produce can become contaminated before it reaches grocery stores or restaurants. Since the parasite requires time in the environment to become infectious, contamination usually happens before food is harvested or processed rather than during food preparation at home.
Public health officials use surveillance systems to identify clusters of illness across multiple states. When several people become sick after eating the same contaminated food, investigators work to trace the source and remove it from the food supply.
Current investigations are ongoing, and officials have not yet identified the specific source responsible for the recent increase in cases.
How Can You Reduce Your Risk?
Because Cyclospora is most often spread through contaminated produce, practicing good food safety is important.
The CDC recommends:
- Washing fruits and vegetables before eating them.
- Refrigerating fresh produce when appropriate.
- Practicing good hand hygiene before preparing food.
- Following food recalls and public health alerts if contaminated products are identified.
It’s important to know that washing produce may reduce some contamination but may not completely remove the parasite, especially if it is firmly attached to the surface of fruits or vegetables.
If you develop prolonged watery diarrhea, particularly during an outbreak, contact your healthcare provider. Cyclosporiasis can usually be treated successfully with prescription antibiotics.
Why Public Health Surveillance Matters
Tracking cyclosporiasis helps health officials identify outbreaks more quickly and protect the public from additional illness.
When healthcare providers diagnose a case, they report it to public health authorities, who compare cases across different states. If investigators find that multiple patients became sick after eating the same food, they can work with the CDC, FDA, state health departments, and food producers to identify the contaminated product.
These investigations have helped identify sources during previous outbreaks and continue to play an important role in improving food safety.
The Bottom Line
The recent increase in cyclosporiasis cases serves as a reminder that foodborne parasites remain an important public health concern. While the illness is usually treatable, it can cause weeks of uncomfortable symptoms and may require medical care.
Knowing the symptoms, practicing good food safety, and staying informed about outbreak investigations can help reduce your risk. As health officials continue investigating the current multistate outbreak, additional information about the source may become available in the coming weeks.
Source
Centers for Disease Control and Prevention. About Cyclosporiasis. Updated 2025. Accessed by: https://www.cdc.gov/cyclosporiasis/about/index.html
Centers for Disease Control and Prevention. Preventing Cyclosporiasis. Updated 2025. Accessed by: https://www.cdc.gov/cyclosporiasis/prevention/index.html
Centers for Disease Control and Prevention. Cyclosporiasis Surveillance. Updated 2025. Accessed by: https://www.cdc.gov/cyclosporiasis/php/surveillance/index.html
