Cyclosporiasis Outbreak in the U.S.
Health officials are investigating a growing outbreak of cyclosporiasis, a parasitic illness that can cause severe diarrhea and other gastrointestinal symptoms, after cases were reported across multiple states. While the exact source of the outbreak remains unknown, federal officials say contaminated fresh produce is the leading suspect, and an investigation is underway to determine what is making people sick.
The outbreak has drawn attention because of the illness’s hallmark symptom: prolonged, sometimes explosive diarrhea that can last for days or even weeks if left untreated.
What Is Cyclosporiasis?
Cyclosporiasis is an intestinal illness caused by the parasite Cyclospora cayetanensis. People become infected by consuming food or water contaminated with the microscopic parasite. Unlike many foodborne illnesses, the parasite must mature in the environment before it becomes infectious, meaning it is not typically spread directly from person to person.
Fresh produce has historically been linked to outbreaks, including cilantro, basil, raspberries, lettuce, snow peas, and bagged salad mixes. Because many fruits and vegetables are eaten raw, they can carry the parasite if contaminated during growing, harvesting, or processing.
Cases Reported Across Multiple States
According to health officials, the largest concentration of reported illnesses is in southeastern Michigan. Additional cases have also been identified in:
• Ohio
• North Carolina
• Illinois
• New Jersey
The U.S. Food and Drug Administration is working alongside state and local health departments to identify a common source of exposure. As of now, investigators have not identified a single food item responsible for the outbreak.
Officials note that outbreaks often increase during the summer months when fresh produce consumption is at its highest.
Symptoms Can Last for Weeks
Symptoms usually begin about one week after a person consumes contaminated food or water. The illness can become debilitating, especially for older adults, young children, and people with weakened immune systems.
Common symptoms include:
• Frequent watery or explosive diarrhea
• Loss of appetite
• Weight loss
• Stomach cramps and bloating
• Nausea and vomiting
• Fatigue
• Low-grade fever
Without treatment, symptoms can disappear and then return repeatedly over several weeks or even months.
How Is It Diagnosed and Treated?
Doctors diagnose cyclosporiasis through specialized laboratory testing of stool samples. Because routine stool tests may not always detect Cyclospora, physicians often need to specifically request testing for the parasite.
The infection is treated with the prescription antibiotic trimethoprim-sulfamethoxazole (TMP-SMX), which is generally effective at eliminating the parasite. People who cannot take sulfa-based antibiotics should discuss alternative management options with their healthcare provider.
Most healthy individuals recover completely with appropriate treatment.
Can Washing Produce Prevent It?
Health experts say washing fruits and vegetables is always recommended, but it may not completely eliminate Cyclospora because the parasite can strongly adhere to produce surfaces.
Consumers can reduce their risk by:
• Washing fresh fruits and vegetables thoroughly under running water.
• Refrigerating perishable produce promptly.
• Following any FDA food recalls or public health advisories.
• Avoiding foods identified as part of an outbreak if officials announce a source.
Because investigators have not yet identified the contaminated food responsible for the current outbreak, there are no specific products consumers have been advised to avoid.
FDA Investigation Continues
The FDA says it is continuing to trace potential food sources and analyze epidemiological data from affected patients. Additional cases may be reported as health departments continue testing and interviewing infected individuals.
Officials encourage anyone experiencing persistent diarrhea lasting more than a few days, especially after eating fresh produce or traveling, to seek medical attention. Early diagnosis can shorten the duration of illness and help public health investigators identify the source more quickly.
While cyclosporiasis is relatively uncommon compared with other foodborne illnesses, outbreaks have occurred repeatedly in the United States over the past decade, particularly during the summer growing season. Health officials say identifying the contaminated food source remains the top priority to prevent additional illnesses.
