Federal health officials are investigating a multistate outbreak of cyclosporiasis that may involve more than 7,000 cases, which would be the largest recorded outbreak of the parasitic infection in U.S. history. The Centers for Disease Control and Prevention (CDC) has confirmed over 1,600 cases, while an additional 5,000 cases across more than 30 states remain under investigation. The outbreak is believed to be linked to shredded iceberg lettuce.
The Food and Drug Administration (FDA) reported on Monday that a lettuce sample from Taylor Farms, which was previously reported as positive for the parasite, was a false positive. Despite this, the FDA stated that the weight of epidemiological evidence and shipping invoices still links the company's facility in Mexico to the outbreak. Some of the affected lettuce was distributed to Taco Bell restaurants and other food service providers.
Health experts noted that identifying the specific source of cyclosporiasis is difficult because symptoms can take up to 12 days to appear, making it challenging for patients to recall what they ate. Dr. Katelyn Jetelina of the Yale School of Public Health stated that the parasite's long incubation period and complex distribution networks contribute to the difficulty of the investigation. Officials have advised consumers in 27 affected states to avoid iceberg lettuce as the investigation continues.