Public health authorities at the federal and state levels are continuing an active investigation into a large outbreak of cyclosporiasis, an intestinal infection caused by the Cyclospora parasite. The probe involves the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC) and dozens of state health departments as they attempt to map the scope of the outbreak and identify all contaminated food items.
Scope and human toll
Michigan has emerged as the state reporting the most cases, noting two deaths and in excess of 11,000 illnesses as it seeks additional links beyond the initial product tied to Taco Bell. The CDC, reporting national laboratory-confirmed cases, has recorded 6,707 infections across 45 states; among those patients, 423 had required hospitalization. The agency also cautions that the number of reported cases is likely to grow because it can take up to six weeks to determine whether a given ill person is connected to the outbreak.
What cyclosporiasis is
Cyclospora is an intestinal parasitic infection most often acquired through consumption of food or water contaminated with feces carrying the Cyclospora organism. Fresh produce that is eaten raw is a common vehicle. Symptoms vary from mild to severe, and certain populations - children, older adults and people with weakened immune systems - are at greater risk of serious illness. While the infection itself is not typically fatal in the United States, untreated cases can last for weeks and lead to dehydration that requires hospitalization. Michigan health officials said the two deaths they reported involved individuals with significant underlying health conditions who may have been affected by cyclosporiasis and dehydration.
The CDC identifies May 1 to August 31 as the annual cyclosporiasis season and has previously documented multistate outbreaks linked to fresh produce.
Traceback, testing and product actions
FDA traceback work has connected thousands of illnesses to shredded iceberg lettuce served at Taco Bell restaurants in nine states: Indiana, Kentucky, Michigan, Ohio, West Virginia, Illinois, Kansas, Oklahoma and Pennsylvania. In mid-July, the FDA reported that a sample of shredded iceberg lettuce supplied by Taylor Farms tested positive for Cyclospora, but that particular laboratory result was withdrawn the following day after a review determined it was a false positive.
Despite the withdrawn test result, investigations continue to point to Taylor Farms as a central focus. Taylor Farms initiated a voluntary recall of iceberg lettuce sourced from central Mexico and closed its processing plant there. The recall extended beyond restaurant distribution to include Marketside-branded product sold by Walmart and multiple items supplied through Sysco and other distribution channels, according to the FDA. Taylor Farms stated that the recall was voluntary, asserted that it maintains strong cyclospora prevention protocols, and said it has suspended sourcing iceberg lettuce from the implicated region.
Consumer precautions and treatment
The FDA advises that the most reliable method to inactivate Cyclospora on produce is cooking to at least 158 degrees Fahrenheit (70 degrees Celsius), because the parasite resists routine chemical disinfection. The agency also recommends discarding outer leaves of leafy vegetables and thoroughly rinsing fruits and vegetables before peeling or eating them. Cyclospora typically spreads via contaminated food or water rather than direct person-to-person transmission.
For individuals diagnosed with cyclosporiasis, the CDC recommends treatment with trimethoprim-sulfamethoxazole - commonly known by the brand name Bactrim - taken twice daily for seven to 10 days. People living with HIV may need a longer course of therapy, the agency says.
Surveillance, reporting and program limits
Cyclospora is a nationally notifiable pathogen, and most states maintain robust reporting to the CDC. Healthcare providers are legally obligated to report cyclosporiasis cases to public health departments in 47 states. Gwen Biggerstaff, deputy director of the CDC's Division of Foodborne, Waterborne and Environmental Diseases, explained that states regularly share cases with the CDC through national disease surveillance systems.
The Foodborne Diseases Active Surveillance Network, known as FoodNet, is a collaboration among the CDC, the U.S. Department of Agriculture, the FDA and 10 state health departments designed to monitor trends over time. Last July, FoodNet stopped tracking six of eight pathogens, including Cyclospora, due to funding reductions. Biggerstaff emphasized that FoodNet's role is to evaluate trends and that it does not replace national surveillance systems; participating states continue to report cyclospora cases on a national basis, and the current outbreak data are comparable to prior outbreaks in how they are collected and shared.
Ongoing investigation
Federal and state authorities continue laboratory testing, traceback activities and coordination with food distributors and restaurant chains as they work to identify all contaminated items connected to the outbreak. Public health officials have emphasized consumer guidance on handling and cooking produce and outlined treatment recommendations for clinicians and patients as part of the response.
Note: This report compiles information released by federal and state health agencies on the ongoing cyclosporiasis outbreak and summarizes current guidance and investigative steps.