Cyclospora Parasite Caused the Largest Outbreak in U.S. History
More than 20,000 cases, 740 hospitalizations, and two deaths linked to contaminated lettuce from Mexico, while mass salmonella outbreaks are also ongoing.
More than 20,000 cases, 740 hospitalizations, and two deaths linked to contaminated lettuce from Mexico, while mass salmonella outbreaks are also ongoing.
New data from U.S. health authorities reveal the scale of the largest cyclosporiasis outbreak in U.S. history. The Cyclospora parasite, most commonly transmitted through contaminated lettuce and fresh vegetables, has been linked to over 20,000 cases so far, according to a report by Tagesschau on August 13, 2026.
The U.S. Centers for Disease Control and Prevention (CDC) has confirmed nearly 14,000 cases, with over 10,000 more suspected cases under investigation. According to available data, about 740 patients required hospitalization, and two deaths have been reported.
Health authorities are focusing their investigation on contaminated iceberg lettuce, with at least some cases linked to products from Taylor Farms in Mexico. This connection has raised concerns among consumers, although the issue does not affect all suppliers.
"Many people ask us about this. The issue is with Taylor Farms, from which we are not supplied. But people are still worried," said Tom, a market vendor in Washington, to Tagesschau.
The disease causes prolonged diarrhea, fatigue, and weight loss, and a particular challenge is the incubation period, which can last up to two weeks. Dr. Omer Awan, a physician at the University of Maryland, warns that patients often cannot recall what they ate before symptoms appeared, making it significantly harder to determine the source of infection.
"Between infection and the first symptoms, up to two weeks can pass. By then, many patients no longer remember what they ate," Awan explained. As a result, the search for the source often takes weeks.
In addition to the outbreak itself, criticism has emerged regarding U.S. health institutions. Dr. Awan points out that many of the CDC staff who were laid off were precisely those responsible for monitoring such outbreaks, and an additional problem is that since July 2025, the CDC no longer requires mandatory reporting of cyclosporiasis.
The CDC, in turn, responds that the disease remains reportable in most states, but the number of cases remains unusually high. Meanwhile, the U.S. Food and Drug Administration (FDA) has recommended stricter hygiene controls and supply chain oversight for fresh fruits and vegetables, although these recommendations are not mandatory.
While authorities investigate new cases, mass salmonella outbreaks are also occurring, further straining the system. Many consumers are therefore changing their habits. "I'm careful about where I shop, and I almost always buy frozen vegetables," said Marissa, one consumer.
Some go even further. "Now I grow my own lettuce. Without this outbreak, I probably never would have tried it," said Ivan, another consumer.
