CDC Investigates Cyclosporiasis Outbreak Across 17 States with 145 Cases

The Centers for Disease Control and Prevention (CDC) is currently investigating an outbreak of cyclosporiasis, a parasitic infection, which has resulted in 145 confirmed cases and 20 hospitalizations across 17 states between May 1 and June 16. Officials are working to identify the source of the infection, which is known for causing intense, watery, and often “explosive” diarrhea.

Understanding the Infection

Cyclosporiasis is caused by a microscopic parasite called Cyclospora cayetanensis. According to the CDC, the parasite is transmitted when individuals consume food or beverages contaminated with feces. Once ingested, symptoms typically begin within seven days. While the illness is characterized by frequent watery diarrhea, it may also include cramping and bloating.

Health officials emphasize that the parasite is unlikely to spread directly from person to person. Because the parasite requires one to two weeks outside of the body to become infectious after being passed in a bowel movement, transmission is almost exclusively linked to contaminated food or water.

Scope of the Outbreak

As of mid-June, the 17 states reporting cases include Alaska, Colorado, Connecticut, Florida, Georgia, Illinois, Louisiana, Massachusetts, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Texas, Virginia, and Wisconsin. New York reported the highest number of cases during this period, though the CDC noted that actual case counts may be higher than those officially reported.

The demographic data for those affected ranges from 5 to 86 years old, with an average age of 42. Approximately 61% of the cases have been identified in females. Notably, none of the individuals affected by this specific outbreak reported international travel in the 14 days prior to the onset of their symptoms, indicating they were exposed while eating food within the United States. Furthermore, while the investigation is ongoing, no deaths have been reported in connection with this outbreak.

In addition to the 17-state investigation, a large, separate cluster of cases has emerged in Michigan. The Michigan Department of Health and Human Services (MDHHS) is currently coordinating with local health departments to identify a common exposure for this specific surge.

Treatment and Clinical Guidance

The CDC recommends that individuals who believe they are infected should see a healthcare provider for testing and treatment. The primary treatment of choice for cyclosporiasis is a combination of trimethoprim-sulfamethoxazole, commonly sold under the brand names Bactrim, Septra, or Cotrim.

These medications are antibiotics and require a prescription; they are not available over-the-counter. For patients who are allergic to sulfa drugs, the CDC advises consulting with a healthcare provider to discuss alternative options, noting that there are currently no highly effective alternatives identified for those who cannot tolerate the primary treatment. In addition to medical treatment, patients are advised to rest and maintain hydration by drinking plenty of fluids.

While individuals with healthy immune systems may recover without medical intervention, the illness can last from a few days to over a month if left untreated. Those with compromised immune systems may face a higher risk of severe or prolonged illness.

Prevention and Risk Mitigation

In the United States, cyclosporiasis outbreaks are most frequently linked to the consumption of contaminated fresh produce. Common items historically associated with the parasite include:

• Romaine lettuce
• Basil
• Cilantro
• Snow peas
• Raspberries

To reduce the risk of infection, health officials recommend thorough hygiene and food preparation practices. Consumers should wash their hands with soap and water before and after handling raw produce. All fruits and vegetables should be washed under running water before being cut, cooked, or consumed.

Additional safety measures include:

• Scrubbing firm produce, such as melons and cucumbers, with a clean brush.
• Cutting away any bruised or damaged areas of produce before preparation.
• Refrigerating cut, peeled, or cooked fruits and vegetables within two hours.

As of the latest reports, investigators have not yet linked the current multi-state cases to a single common food source. The CDC continues to collaborate with the FDA and state partners to monitor the situation and provide updates as the investigation progresses.

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