During a June 16 briefing hosted by George Washington University's Institute for Food Safety and Nutrition Security (IFSNS), experts representing academia and consumer advocacy discussed the current challenges of investigating the growing number of Cyclospora cayetenensis infections and warned that continued failure to invest in public health could hamper future responses to foodborne illness outbreaks. (Update, July 20: A recording of the briefing is now available here).

Resource Constraints Are Slowing Outbreak Response, Sowing Confusion

Sarah Sorscher, J.D., M.P.H., Director of Regulatory Affairs at the Center for Science in the Public Interest (CSPI), said delays in reporting between state health departments and the U.S. Centers for Disease Control and Prevention (CDC) contributed to public confusion during the early stages of the outbreak.

Michigan, which has reported more than 4,000 cyclosporiasis cases as of July 16, began issuing public health notices about the situation nearly two weeks before CDC published its own outbreak alert. During that period, reporters often looked to CDC's national Cyclospora surveillance data, which included unrelated cases from across the country, and did not align with more recent figures from Michigan or other affected states.

"The biggest issue is that neither CDC nor its state partners have identified the food or water source that caused this large outbreak," Ms. Sorscher said. "There is no way then for consumers to eliminate that pathogen on the fresh produce that we have other than by cooking it."

She stressed that the current situation should not be interpreted as a failure of CDC investigators.

"This confusion that we're seeing is not due to any lack of skill or dedication by the CDC staff," Ms. Sorscher said, adding that investigators have continued working under increasingly difficult conditions while facing staffing reductions and growing workloads. "These programs are completely overwhelmed by the scale and scope of the work."

Barbara Kowalcyk, Ph.D., M.A., Associate Professor at the George Washington University Milken Institute School of Public Health, described the outbreak as "a symptom of potential system vulnerabilities."

Panelists pointed to significant workforce losses under the Trump Administration, stagnant public health funding, and reductions in allocations to state and local health departments as factors increasingly straining foodborne illness surveillance and outbreak response.

Ms. Sorscher noted that CDC's food safety budget has failed to keep pace with inflation and said the agency reportedly fulfilled only about 40 percent of requests for support from state and local partners during the previous year.

Surveillance Is the Foundation of Prevention

Throughout the discussion, speakers emphasized that surveillance systems remain one of the most effective public health tools for preventing foodborne illness. Surveillance is the starting point for identifying outbreaks, determining root causes, improving food safety systems, and ultimately, preventing future illnesses.

Don Schaffner, Ph.D., Distinguished Professor and Extension Specialist in Food Science at Rutgers University, warned that weakening surveillance systems could have long-term consequences. "I think cuts at the federal level will weaken our ability to manage risks from [C. cayetenensis]," he said.

The experts cited estimates suggesting that every $1 invested in CDC’s PulseNet—a national laboratory network that connects foodborne, waterborne, and related illnesses to detect outbreaks—saves Americans an estimated $70 in foodborne illness-related costs and that the network prevents thousands of illnesses annually through earlier outbreak detection and response.

Notably, in 2025, C. cayetenensis was dropped from the list of pathogens included in CDC's Foodborne Diseases Active Surveillance Network (FoodNet), which is a collaborative program between federal and state agencies that conducts active surveillance for specific foodborne pathogens. Dr. Kowalcyk emphasized that FoodNet was not designed to detect outbreaks but rather to monitor long-term trends in foodborne illness. She noted that the elimination of Cyclospora from FoodNet surveillance resulted in the loss of valuable data that can help public health officials understand how the current outbreak compares with historical trends.

Calls to Restore U.S. Food Safety Surveillance Programs

In November 2025, a coalition of more than 20 organizations, including George Washington University’s IFSNS and CSPI, sent a letter to U.S. Health Secretary Robert F. Kennedy Jr. urging adequate funding for FoodNet, as well as a 50 percent ($36 million) increase in funding for the CDC Food Safety Program.

The letter states, “The Food Safety Program at CDC has been chronically under-funded, particularly in the last few years; it received only $72 million in Fiscal Year 2024. This amount is wholly inadequate to maintain FoodNet, including the continued reporting of the full scope of pathogens historically tracked by FoodNet partners, along with all other food safety work at CDC, which also passes through grants to state departments of health to fund epidemiology and laboratory work needed to solve outbreaks.”

Additionally, in a July 14 letter, U.S. Senator Amy Klobuchar (Democrat-Minnesota) urged CDC to restore FoodNet and other food safety programs in light of the current cyclosporiasis situation. “Cuts to these programs are impacting our nation's ability to prevent, detect, and contain foodborne illnesses and protect public health," she wrote.

Why Cyclospora Outbreaks Are Difficult to Solve

Craig Hedberg, Ph.D., Professor in the Division of Environmental Health Sciences at the University of Minnesota, explained that Cyclospora outbreaks are particularly difficult to investigate because of the parasite's biology.

Unlike many bacterial foodborne illnesses, C. cayetenensis has a relatively long incubation period. Investigators often must reconstruct foods consumed over a two-week period, identify common restaurants or grocery stores among cases, and determine whether multiple clusters are linked to the same contaminated product.

"Although Cyclospora is a nationally notifiable disease, reporting is an individual state requirement," Dr. Hedberg said, noting that outbreak investigations require extensive coordination among local, state, and federal public health agencies.

Investigations often begin at the local or state health department level. Epidemiologists interview patients to identify common food exposures and potential clusters, while laboratories analyze clinical samples and public health agencies share data across jurisdictions. Once a likely source is identified, the U.S. Food and Drug Administration (FDA) and state departments of agriculture can conduct traceback investigations to determine where contamination occurred.

The Potential Role of Improved Testing in Rising Cyclosporiasis Rates

Dr. Hedberg also suggested that the year-over-year increase in reported Cyclospora infections in the U.S. could, in part, be a result of improved diagnostic testing. The growing use of culture-independent diagnostic tests (CIDTs), including multiplex polymerase chain reaction (PCR) panels capable of detecting numerous pathogens simultaneously, has made cyclosporiasis cases more likely to be identified than they were a decade ago.

Domestic cases of Cyclospora infections more than doubled from 537 in 2016 to 1,194 in 2017, and then nearly tripled to 3,519 cases in 2018. By 2023, there were nearly 3,000 cases of cyclosporiasis reported in the U.S.

However, scientists continue to face major knowledge gaps about C. cayetenensis, said Dr. Schaffner. Questions about Cyclospora for which researchers do not yet have the answers include: why infections peak seasonally, how produce most commonly becomes contaminated, and what environmental factors influence oocyst development. Scientists are also still working to better understand waterborne transmission, dose-response relationships, and rapid detection methods.

What Should Consumers Do? Uncertainty Creates Public Communication Challenges

Beyond the scientific investigation, panelists said the outbreak highlights the challenge of communicating uncertainty to consumers and described how information delays inherent to complex outbreak investigations can erode consumer confidence in food safety. Without identifying a contaminated food source for consumers to avoid, public health agencies have limited evidence-based recommendations they can provide, beyond general food safety advice.

The discussion also underscored the limitations of consumer interventions once fresh produce becomes contaminated with C. cayetenensis. Dr. Schaffner said handwashing and washing fresh produce are "not terribly effective" against the parasite—despite some messaging that has been circulating stating otherwise (for example, U.S. Agriculture Secretary Brooke Rollins told The Hill on Wednesday that “washing your fruit and vegetables, being diligent in where you are” is the best way for consumers to stay safe). Cooking is the only way to reliably eliminate the parasite on contaminated food.  

Panelists said these realities illustrate why timely surveillance and source identification are critical. When investigators cannot identify the contaminated product, consumers have few practical actions available to reduce their risk beyond following routine food safety practices and staying informed as new information becomes available.

Some consumers may be dissuaded from eating fresh produce while investigators continue searching for the outbreak source. The experts agreed that this may be a negative public health consequence of murky details and incomplete media reporting as the outbreak remains unsolved.

Update, July 17, 2026: FDA announced an outbreak cluster including 1,644 people across Indiana, Kentucky, Michigan, Ohio, and West Virginia. Shredded iceberg lettuce served at Taco Bell locations and sourced from a single Mexican supplier has been identified as the vehicle of infection. Read more.

Update, July 20, 2026: Taylor Farms of Mexico has been officially named as the supplier of implicated iceberg lettuce products to firms like Taco Bell and Walmart. Michigan is now reporting more than 5,000 cyclosporiasis infections in the state since June. Read more.

Update, July 21, 2026: As of July 20, Michigan reports 6,571 cyclosporiasis infections and Northwest Ohio has seen 2,029 cases. Read more.

Update, July 23, 2026: CDC has reported 4,173 laboratory-confirmed, domestic cases of cyclosporiasis connected to the five-state outbreak, with an additional 7,400 cases under investigation. Michigan is now reporting 7,171 cases.

FDA has added a new Cyclospora outbreak of 72 cases to its CORE Investigation table.

Several senators have written letters to U.S. Health Secretary Kennedy urging Cyclospora surveillance to be restored to the FoodNet program. Experts say that FoodNet cuts, although problematic, did not cause the current outbreak. Read more.

Update, July 24, 2026: The outbreak linked to Taylor Farms iceberg lettuce has been expanded to nine states. More than 1,900 people infected with Cyclospora have reported exposure to Taco Bell, and there have been at least 98 hospitalizations. Michigan and Northwestern Ohio report 7,664 and 2,380 cases, respectively.FDA is currently investigating three other cyclosporiasis outbreaks aside from the nine-state cluster, comprising eight, ten, 18, and 72 cases. A food vehicle of infection has not yet been identified in any of these outbreaks. Read more.

Update, August 5, 2026: CDC has updated its total laboratory-confirmed case count of cyclosporiasis in the U.S. to 10,468 illnesses and 517 hospitalizations, as of August 3. CDC has also updated the number of states reporting cases to 47. The agency noted on August 4 that an additional 12,255 cases require further analysis and have not yet been laboratory confirmed or determined to be part of the U.S. domestic outbreak.

Additionally, CDC has expanded its list of states specifically associated with the Taylor Farms iceberg lettuce outbreak to 15, up from nine, and is reporting 6,358 illnesses, 278 hospitalizations, and two deaths associated with this outbreak. Affected states now include Arkansas, Iowa, Nebraska, New Hampshire, North Carolina, Missouri, Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, Oklahoma, Pennsylvania, and West Virginia.

Update, August 12, 2026:  CDC has updated its total laboratory-confirmed case count of cyclosporiasis in the U.S. to 13,895 illnesses, 740 hospitalizations, and two deaths in 47 states. CDC is aware of at least 10,455 additional cases of cyclosporiasis that are not laboratory-confirmed or require further investigation to determine whether they were somestically acquired. Many of the additional cases continue to be reported by Michigan, which, as of August 6, reports 12,485 cases and 279 hospitalizations.

Update, August 13, 2026: According to FDA, the number of cyclosporiasis cases linked to Taylor Farms lettuce is 9,481 in 17 states. Since the last update, two additional states have been added: Maine and Massachusetts. 

Update, August 20, 2026: Since May 1, 2026, CDC has received reports of 15,716 laboratory-confirmed cases of cyclosporiasis acquired in the United States. For comparison, 1,180 cases were reported in the United States between May 1 and August 31, 2025. At least 11,841 additional cases of cyclosporiasis may require further investigation and analysis. The Taylor Farms lettuce outbreak has contributed significantly to the increase of Cyclospora cases in 2026, but CDC has not updated its official outbreak-specific case count since August 13.

Update, August 21, 2026: The total case count associated with the multistate lettuce outbreak is now 10,930 illnesses reported from 17 states.