An investigation by the Daily Mail has revealed that the Centers for Disease Control and Prevention (CDC) may be significantly undercounting cases of cyclosporiasis, a parasitic infection that causes severe diarrhea. The investigation uncovered nearly 5,400 cases across the U.S., a figure more than three times the 1,645 infections officially reported by the CDC. This discrepancy has led to questions about the agency's surveillance effectiveness.
Cases of cyclosporiasis began to rise in May, with infections reported across multiple states throughout June. The CDC's initial report on the domestic outbreak documented 145 cases in 17 states, including 20 hospitalizations. However, at the same time, the Michigan Department of Health alone reported 150 cases. In response to these disparities, the Daily Mail requested data from all 50 state health departments. Forty-eight responded, with 41 confirming cases, revealing a substantially larger outbreak.
Sources within the health community suggested to the Daily Mail that recent budget cuts and staff burnout at the CDC could be contributing to the undercount and hindering outbreak surveillance. Cyclosporiasis is typically contracted by consuming food or water contaminated with the Cyclospora parasite, often through fresh produce like leafy greens, herbs, and berries.
While most U.S. cases are usually linked to international travel or imported produce, the emergence of domestically acquired infections in the spring raised concerns about contamination within the U.S. supply chain. Despite extensive efforts, public health officials have not yet identified a single food item definitively linked to the current outbreak. The state-reported figures are not always directly comparable to CDC totals due to varying reporting methods, such as distinguishing between travel-related and domestically acquired infections.
Dr. Amy Edwards, an assistant professor of pediatrics at Case Western Reserve University, stated that the CDC numbers are likely an undercount. She noted that some individuals may recover without seeking medical attention, thus not appearing in official records. Cases have been confirmed by most states that responded, with only Hawaii, Minnesota, Mississippi, Utah, and Vermont reporting no cases. New Hampshire and Nebraska did not respond to the request for comment, and Georgia provided a figure without specifying an exact number. Idaho confirmed that cyclosporiasis is not a reportable disease in the state, meaning no official records are kept.
Several states reported significantly more cases than reflected in CDC data. California confirmed 41 cases compared to the CDC's 10 or fewer. Florida recorded 40 cases versus 11 to 30 in federal data, and Indiana logged 206 cases compared to 31 to 80. Iowa and Maryland each reported 28 cases, while Louisiana had 23 under investigation. Ohio confirmed 177 cases. The most substantial difference was in Michigan, which reported 3,762 cases to the Daily Mail, far exceeding the CDC's range of 501 to 900.
In a July 14 update, the CDC acknowledged that states might report higher case counts and stated they are working with states to update numbers. The agency reported 1,645 confirmed domestic cases since May 1, 2026, and noted over 5,100 additional cases requiring further analysis. The CDC expressed concern about the increase in cases since early May, noting that multiple states have reported higher numbers this year compared to 2025.
Experts agree that while some reporting lag is expected during an outbreak, the current gap is unusually large. Dr. Darin Detwiler, a food safety expert at Michigan State University, explained that the CDC verifies each case before adding it to national totals, which inherently causes a delay. The difficulty in tracing the outbreak's source is compounded by Cyclospora's incubation period of one to three weeks, making it challenging for patients to recall specific food consumption from weeks prior. The supply chain for fresh produce can also span multiple entities across different regions or countries.
While no specific source has been identified, Michigan health officials are investigating lettuce or salad greens as potential culprits. Federal and state health officials are reportedly examining Taco Bell as a possible source, according to anonymous sources familiar with the investigation. Previous outbreaks have been linked to bagged salad kits, cilantro, basil, and other leafy greens.
Fresh produce can become contaminated if washed or irrigated with water containing human feces. According to Dr. Donald W. Schaffner, chair of the Department of Food Science at Rutgers University, rinsing produce is not highly effective at removing microbial contamination. While washing may remove about 90 percent of microorganisms, enough can remain to cause illness. Cooking produce, however, reliably kills the parasite.
Cyclosporiasis symptoms typically include explosive diarrhea, abdominal cramping, nausea, vomiting, and fatigue. Unlike common stomach bugs, symptoms can be intermittent, with periods of recovery followed by recurrence. Without treatment, the illness can last for weeks or return multiple times. Dr. Swapnil Patel, vice chair of medicine at Hackensack Meridian Jersey Shore University Medical Center, advises anyone with diarrhea lasting more than a few days to seek medical care and specifically request a Cyclospora test, as it is not routinely ordered. Treatment usually involves the antibiotic trimethoprim-sulfamethoxazole. Patients are also advised to stay hydrated and consume bland foods. Over-the-counter anti-diarrheal medications should be avoided without consulting a doctor, as they may hinder the body's ability to clear the parasite.
Brelynn Daniels, an Ohio woman, described experiencing violent diarrhea, severe abdominal cramping, nausea, and vomiting after eating a salad. Her symptoms initially eased but returned intensely. After ten days, she sought emergency care, where tests confirmed Cyclospora. She is still experiencing occasional symptoms and remains on medication weeks later. Daniels recounted the experience as deeply unpleasant, with abdominal pain so severe she felt like her liver was ripping.