After months of widespread transmission that impacted dozens of U.S. states and left thousands of people ill, the largest recorded cyclospora outbreak in modern U.S. history has officially come to an end, U.S. Centers for Disease Control and Prevention (CDC) officials announced Friday.
The parasitic intestinal infection, which causes severe, explosive diarrhea, has been linked to two deaths in Michigan and hospitalized 570 people since the outbreak began earlier this year. Both of the deceased individuals had serious pre-existing underlying health conditions that left them more vulnerable to complications from the infection and related dehydration, Michigan health authorities confirmed. While cyclospora infections are rarely fatal for otherwise healthy people, the outbreak’s scale and impact have drawn widespread public attention and public health intervention.
Investigators have traced the majority of confirmed cases to contaminated lettuce imported from central Mexico by produce supplier Taylor Farms, which distributes fresh leafy greens to countless food retailers and restaurant chains across the United States. Following the link being established, Taylor Farms issued a voluntary nationwide recall of all lettuce sourced from its central Mexican growing operations, and major fast-food chain Taco Bell moved quickly to remove the supplier’s lettuce from all menu items to limit further exposure.
CDC data shows that as of early September, nearly 20,000 confirmed cyclospora cases have been reported across all 49 U.S. states and the District of Columbia since May 1, with total hospitalizations topping 1,000. Of that total, more than 12,000 cases were tied to the multi-state outbreak linked to the Mexican lettuce. Public health experts emphasize that the true number of infections is almost certainly far higher than the confirmed count, as many mild cases go unreported by patients who do not seek medical care. It is also important to note that while the majority of cases were connected to the contaminated lettuce, thousands of reported illnesses have not yet been linked to that source.
In its official advisory declaring the outbreak over, the CDC stated that new case counts have dropped significantly after the recall and menu changes. However, agency officials added that investigations into the full origin and spread of the parasite will continue to help prevent similar large-scale outbreaks in the future.
This outbreak marks a stark increase in cyclospora cases compared to previous years. Prior to 2025, the worst year for cyclospora infections in the U.S. was 2019, when just 4,700 cases were recorded nationwide. Beyond U.S. borders, public health officials in the United Kingdom have also issued warnings to travelers after multiple returning UK residents contracted the parasite during trips to the U.S. this year.
Cyclospora is a microscopic parasite that spreads exclusively through contaminated food or water. Infection, called cyclosporiasis, most commonly causes severe intestinal distress including the explosive diarrhea that has become synonymous with this outbreak, and can lead to dehydration if left untreated.