Six questions answered about the current cyclospora outbreak by a TXST microbiology and virology specialist

Each summer, public health officials closely monitor foodborne illnesses that increase with warmer temperatures. This year, one of those illnesses—cyclosporiasis, caused by the microscopic parasite Cyclospora cayetanensis—has once again made headlines as health officials investigate a growing number of illnesses across multiple states. As of early July 2026, an expanding cyclosporiasis outbreak is impacting at least 18 states with more than 1,000 confirmed cases. The states reporting the highest number of cyclospora cases in the 2026 outbreak are Michigan, followed by Illinois, New York, and Texas.

The true number of people sick with this parasite is likely much higher than the numbers reported because many infected will recover without testing or seeking medical care. Federal and state public health agencies are working to determine whether contaminated fresh produce is responsible, although no single food source has yet been identified.

As both a microbiologist and virologist who studies infectious diseases and diagnostic readiness, I often receive questions whenever outbreaks like this occur. Here are six of the most common associated with this outbreak. 

1. What is cyclospora and why is it making people sick?

Cyclospora is a microscopic, single-celled parasite too small to be seen without a microscope and one that infects the small intestine after a person consumes contaminated food or water. Cyclospora gets into food when raw produce encounters feces-contaminated water or soil. Unlike many bacterial foodborne illnesses, cyclospora infections often produce symptoms that can last for weeks if left untreated.

The most common symptom is profuse watery diarrhea, often accompanied by abdominal cramping, nausea, fatigue, bloating, loss of appetite and weight loss. Some patients experience symptoms that improve, only to return days later. Fortunately, most healthy people recover completely with appropriate treatment, but dehydration and prolonged illness can be especially concerning for older adults, young children and individuals with weakened immune systems. 

2. Why are outbreaks often linked to fresh produce?

Cyclospora is unusual because people do not typically become infected directly by another person.

The parasite requires time outside the human body to mature into its infectious form. That means contamination usually occurs before food reaches your kitchen—often somewhere along the agricultural supply chain through contaminated irrigation water, produce washing, or environmental contamination.

Fresh produce such as cilantro, basil, leafy greens, raspberries, and salad mixes have all been linked to previous outbreaks because these foods are commonly eaten raw and receive little or no cooking that would destroy the parasite.

Carefully washing produce at home helps reduce risk but it cannot guarantee complete removal of the parasite, as cyclospora organisms can adhere tightly to the surface of fruits and vegetables. 

3. How is this outbreak different from the large cyclospora outbreaks around 2013?

Many public health professionals remember the cyclospora outbreaks of 2013, when more than 600 illnesses were reported across multiple states including Texas. Investigators eventually linked several clusters to imported fresh cilantro and salad mix ingredients.

Those outbreaks highlighted important weaknesses in produce traceability and the complexity of modern food distribution networks.

Today's outbreak differs in several important ways.

First, investigators have not yet identified a single contaminated food item responsible for all reported illnesses. Instead, public health officials are investigating several separate clusters that may or may not share a common source.

Second, today's investigators have access to far more sophisticated epidemiologic tools than existed a decade ago. Enhanced laboratory surveillance, improved molecular typing methods, advanced food traceback investigations and stronger collaboration among the CDC, FDA and state health departments allow investigators to identify potential connections more rapidly than what was possible in 2013. However, in today’s world we continue to grapple with the issue of misinformation regarding public health, healthcare, and research.  

Finally, improvements in food safety regulations and produce traceability implemented over the past decade have strengthened outbreak investigations, although identifying the exact source of fresh produce contamination remains one of the most difficult challenges in food safety. 

4. What lessons have we learned since the 2013 outbreaks?

The biggest lesson is that food safety extends far beyond the grocery store. As the public continues to learn, human health is interwoven tightly with animal health and environmental health. This concept is known as One Health.

Preventing cyclospora infections requires attention throughout the entire food production system—from irrigation water quality and agricultural practices to harvesting, processing, transportation and retail distribution.

We've also learned that rapid communication between medical and clinical laboratories, physicians, epidemiologists and public health agencies is essential. Early diagnosis helps identify outbreaks sooner, allowing investigators to interview patients before important food exposure information is forgotten.

Perhaps most importantly, outbreaks have reinforced the value of continued investment in public health infrastructure, laboratory capacity and food surveillance systems. Diagnostic readiness is not simply about responding after people become ill. It's about building systems that detect emerging threats quickly enough to limit their impact. 

5. Should Texans be worried?

There is no reason to panic, but there is good reason to remain informed.

Cyclospora infections occur every year in the United States, particularly during the spring and summer months. While several states have reported an increased number of cases this season, investigators are still determining whether they represent one outbreak or multiple unrelated events.

For most people, the risk remains relatively low. However, anyone who develops persistent watery diarrhea lasting more than a few days, especially after eating fresh produce, should seek medical evaluation.

Unlike many viral stomach illnesses, cyclospora can be diagnosed through specialized stool testing and is treatable with prescription antibiotics when appropriate.

6. What can people do to reduce their risk?

While no prevention strategy is perfect, several practical steps can reduce risk:

• Wash hands thoroughly before preparing or eating food.
• Rinse fresh fruits and vegetables under running water before consumption.
• Refrigerate perishable produce promptly.
• Stay informed about food recalls and public health advisories.
• Seek medical care if prolonged diarrhea develops, particularly if accompanied by dehydration or significant fatigue.

One important reminder is that people should avoid assuming every case of diarrhea is "just a stomach bug." Modern medical and clinical laboratories play an essential role in distinguishing viruses, bacteria and parasites so patients receive the appropriate treatment.  

The bottom line

Cyclospora outbreaks remind us that food safety is a shared responsibility involving agriculture, food producers, public health agencies, medical and clinical laboratories, healthcare providers and consumers.

While today's outbreak is understandably receiving attention, it also demonstrates how much stronger our public health surveillance systems have become since similar outbreaks more than a decade ago. Continued investment in diagnostic laboratories, epidemiologic investigations and food traceability remains one of our best defenses against future foodborne diseases.

As we enjoy fresh fruits and vegetables this summer and beyond, awareness and education—not alarm—is our most valuable public health tool. 

Rodney E. Rohde, Ph.D., is a Regents’ Professor and Chair of the Medical Laboratory (MLS) Science Program, College of Health Professions at Texas State University with more than three decades of experience in clinical microbiology, virology, molecular biology and public health. Prior to his academic career, he spent a decade as a public health microbiologist and molecular epidemiologist with the Texas Department of State Health Services and served as a CDC Visiting Scientist.

Rohde’s expertise includes emerging infectious diseases, outbreak preparedness, zoonotic diseases, and laboratory diagnostics, with extensive work related to rabies, hantavirus, MRSA, COVID-19, monkeypox and Ebola virus disease.

Rohde is a subject matter expert alongside other medical laboratory and public health professionals with Diagnostic Equity and MyPathologyReport. Each of these sites showcase experts who have shared their years of professional experience by answering your diagnostic questions, writing and editing articles in the knowledge base, and linking their publications.

The MLS Program at TXST prepares graduates for rewarding careers at the forefront of healthcare by developing the knowledge, technical expertise, and critical thinking skills needed to perform and interpret complex laboratory testing. Graduates are equipped to work in hospitals, public health laboratories, reference laboratories, research institutions, biotechnology, and industry, where they play a vital role in disease detection, diagnosis, treatment monitoring, outbreak response, and the advancement of precision medicine making a direct impact on patient care and public health. Rohde teaches a course in Medical Parasitology for MLS majors and minors that is directly related to the detection of Cyclospora and other dangerous and deadly parasites.