Cyclosporiasis Outbreak 2026: What You Need To Know About The Parasite Spreading Across 31 US States

CDC Reports Rapid Spread of Cyclospora Parasite Across the United States

The Centers for Disease Control and Prevention (CDC) is currently tracking a significant outbreak of cyclosporiasis, an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis. As of July 2026, the outbreak has spread across 31 states, with more than 1,500 suspected cases under investigation.

Health officials are urging the public to be aware of the symptoms and take preventive measures as cases continue to rise. This article provides a comprehensive overview of the outbreak, the parasite behind it, and practical steps you can take to stay safe.

What Is Cyclosporiasis?

Cyclosporiasis is an intestinal infection caused by the Cyclospora cayetanensis parasite. When ingested through contaminated food or water, the parasite infects the small intestine and causes a range of gastrointestinal symptoms.

According to the CDC, the illness is not typically life-threatening, but it can cause significant discomfort and dehydration. It is less common than other foodborne illnesses such as salmonella or E. coli, but this current outbreak is proving to be one of the largest in recent years.

Key Facts About Cyclospora

• Causative agent: Cyclospora cayetanensis — a single-celled microscopic parasite
• Transmission: Fecal-oral route via ingestion of contaminated food or water
• Not person-to-person: The parasite requires time outside the body to become infectious, so direct human-to-human transmission does not occur
• Incubation period: Symptoms typically appear about one week after infection
• Duration: If untreated, symptoms can last from a few days to more than a month

Current Outbreak Statistics

The CDC has released the following data as of July 9, 2026:

• 843 confirmed cases between May 1 and July 9
• More than 1,500 suspected cases requiring further laboratory confirmation
• 86 hospitalizations reported, with no deaths to date
• 31 states affected across the United States

Most Affected States

Michigan has been hit hardest, with state officials reporting more than 1,000 diagnoses in a single two-week period. New York follows closely with nearly 300 cases reported as of July 8. Ohio has confirmed 177 cases, while Illinois reported 141 cases, which health officials described as higher-than-average for this time of year.

The actual number of infections is likely significantly higher than reported figures, as many people recover without seeking medical care and are never tested for the parasite. The CDC anticipates case counts will continue to rise as more data comes in.

Symptoms of Cyclosporiasis

Not everyone infected with Cyclospora will develop symptoms. However, when symptoms do occur, they can be severe:

• Watery diarrhea — often frequent and explosive in nature
• Loss of appetite and weight loss
• Abdominal cramping and bloating
• Nausea and vomiting
• Fatigue and low-grade fever
• Muscle aches

Symptoms may appear and then subside, only to return days or weeks later, making diagnosis challenging without specific laboratory testing.

How Is It Spreading?

The CDC has confirmed that infected individuals became sick after eating food within the United States. Notably, those affected did not report any international travel during the 14 days before becoming ill, confirming that the contamination is occurring domestically.

No specific produce item, grower, or supplier has yet been identified as the source. Dr. Caitlin Rivers of the Johns Hopkins Center for Health Security explains that contamination typically occurs at the farm or irrigation level, making traceback investigations particularly challenging.

Previous cyclosporiasis outbreaks in the United States and Canada have been linked to:

• Bagged salad mixes and kits
• Fresh cilantro
• Fresh basil
• Raspberries
• Snow peas
• Green onions

Treatment and Diagnosis

Cyclosporiasis is diagnosed through a specialized stool test that looks for the presence of Cyclospora parasites. Because the symptoms resemble many other gastrointestinal infections, healthcare providers must specifically request testing for Cyclospora.

The infection is treatable with a specific antibiotic — typically trimethoprim-sulfamethoxazole (also known as Bactrim or Septra). For those with sulfa allergies, alternative treatments are available under medical supervision. Early diagnosis and treatment can significantly shorten the duration of illness.

Prevention Tips

Given the large and increasing number of cases, Michigan health department has issued specific recommendations for restaurants and home kitchens:

• Thoroughly wash all fresh produce under running water before consumption
• Cook raspberries and leafy greens when possible, as heat kills the parasite
• Remove outer layers of lettuce, cabbage, and green onions before use
• Practice good hand hygiene — wash hands thoroughly with soap and water before and after handling food
• Avoid cross-contamination between raw produce and other foods in the kitchen

While the U.S. Food and Drug Administration (FDA) notes that rinsing produce alone may not fully eliminate Cyclospora, the CDC still recommends washing as a basic food safety practice.

Frequently Asked Questions

Is cyclosporiasis contagious from person to person?

No. Cyclospora cayetanensis requires time outside the body (sporulation) to become infectious, so direct person-to-person transmission does not occur. Infection only happens through consuming contaminated food or water.

How long does the illness last?

Without treatment, symptoms can last from a few days to more than a month. Symptoms may also appear to resolve and then return. With appropriate antibiotic treatment, most people recover more quickly.

Should I be worried if I live outside the United States?

Cyclosporiasis occurs worldwide, particularly in tropical and subtropical regions. However, this specific outbreak is concentrated in the United States. If you develop symptoms, consult your healthcare provider and mention the possibility of Cyclospora infection.

Can I catch it from swimming pools or shared water sources?

While Cyclospora is spread through contaminated water, properly chlorinated swimming pools and municipal water treatment systems are generally effective at killing the parasite. The primary concern is food that has been irrigated or washed with contaminated water.

When should I see a doctor?

If you experience persistent watery diarrhea lasting more than a few days, especially if accompanied by abdominal cramping, loss of appetite, or fatigue, contact your healthcare provider. Mention the current Cyclospora outbreak so they can order the appropriate stool test.

Summary

The ongoing Cyclosporiasis outbreak across the United States serves as an important reminder of the vulnerability of our global food supply chain. While the illness is rarely life-threatening, it can cause significant discomfort and disruption.

The CDC continues to investigate the source of the outbreak and has deployed additional resources to affected states. Public health officials recommend remaining vigilant about food safety practices, particularly when handling raw produce, and seeking medical attention if symptoms develop.

Health authorities expect case numbers to rise further as investigations continue and more tests are completed. In the meantime, consumers can protect themselves by thoroughly washing produce, practicing good kitchen hygiene, and staying informed through official CDC and state health department updates.