Cyclospora cases top 17,000 as feds cut parasite research

Confirmed infections linked to the foodborne parasite Cyclospora have climbed past 17,000 since May 1, according to the latest data from the U.S. Centers for Disease Control and Prevention (CDC), even as federal support for research into the pathogen is reportedly being scaled back.

Public health experts caution that the reported figures represent only a fraction of the outbreak's true scope, as many infections go undiagnosed or unreported due to the specialized testing required to detect the microscopic parasite.

The surge coincides with the discontinuation of several U.S. Department of Agriculture (USDA) research projects following funding cuts, raising concerns among scientists about the future of tracking and mitigating foodborne illnesses.

Cyclospora research projects cut amid record outbreak

The Trump administration is scaling back much of the federal government's cyclospora research effort at the same time the country is experiencing its largest known outbreak of the parasite in years. According to a report from Politico, two of the three USDA research projects focused on cyclospora were defunded by Congress earlier this year, while a third project is being relocated from Maryland to Iowa in the coming months as part of a broader USDA reorganization. Politico reported that none of the scientists working on that project plan to relocate, raising concerns among researchers that key expertise could be lost.

Researchers told Politico the cuts could slow efforts to better understand how cyclospora contaminates food and help investigators respond more quickly to future outbreaks. However, a USDA spokesperson told the outlet that no research would be disrupted with the changes.

“Congress did not appropriate funding for the two BARC [Beltsville Agricultural Research Center] research projects referenced in the FY2026 Agriculture Appropriations Act,” the USDA spokesperson told Politico in a statement, adding that the USDA's Agricultural Research Service “is working with research leaders to ensure an orderly transition of programs.”

According to two USDA employees familiar with the issue who spoke with Politico, the scientists tasked with researching parasites, like cyclospora, are retiring.

Newsweek reached out to the USDA and the White House by email for comment.

Lettuce recall drives multistate spread

A substantial share of this season's illnesses has been linked to a multistate outbreak associated with shredded iceberg lettuce from Taylor Farms de Mexico, which health officials connected to cases across at least 20 states.

At least 11,458 cases have been tied to the recalled lettuce, which was served through food-service channels and sold at retail stores. The outbreak has resulted in at least 495 hospitalizations, according to the CDC.

While federal health officials linked the outbreak to the company's produce through epidemiological and traceback evidence, Taylor Farms has stated that no product or environmental sample tested during the investigation yielded a confirmed positive result for the parasite.

The Food and Drug Administration (FDA) has stated that the affected products' best-by dates have passed and expressed confidence that the recalled items are out of supply chains, though investigators continue working to determine the origin of the contamination.

What is cyclospora and its symptoms

Cyclospora is a microscopic parasite that causes the intestinal illness cyclosporiasis and is typically spread through food or water contaminated with human fecal matter. In the United States, outbreaks are most often linked to fresh produce such as leafy greens, herbs and berries, because the parasite can survive on foods that are eaten raw.

Infection commonly causes prolonged watery or explosive diarrhea, stomach cramps, nausea, fatigue, bloating and weight loss, and symptoms can last for weeks or even recur if left untreated. Public health officials say cyclospora can be difficult to detect because it requires specialized laboratory testing and symptoms may not appear until days or weeks after exposure.

Cyclospora map shows infection hotspots

Cyclospora cases have been confirmed in 48 states and the District of Columbia, as of the most recent CDC data updated on August 25. Only Delaware and Hawaii have no confirmed cases, according to the CDC, but state health officials from both states told Newsweek that cyclospora has been detected.

“Delaware is not exempt from cyclospora activity this season,” Delaware Department of Health and Social Services Chief of Public Affairs Sean Dooley told Newsweek. “The state has identified 13 probable Cyclospora cases. CDC's national map shows zero confirmed cases for Delaware because confirmation requires whole‑genome sequencing (WGS), which is not routinely performed here. Specimens from our three most recent cases have been sent to CDC for sequencing, and those results are still pending.”

Hawaii has confirmed five cyclosporiasis cases, a press release from the state's Department of Health said.

Michigan remains the hardest hit state, with the CDC data saying its confirmed cyclospora case count falls between 4,000 and 6,999. Two people from Michigan died after contracting the parasite. Ohio has also been disproportionately impacted by the parasite, with 1,000 to 3,999 cases detected there.

Last year, the CDC detected 1,180 cases of cyclospora nationwide.

What happens next

Despite the FDA expressing confidence that the recalled lettuce is out of supply chains, the number of reported illnesses may continue to rise in the coming weeks because cyclospora cases can take time to be diagnosed, confirmed and reported to public health agencies.

Cyclospora infections typically peak during the spring and summer months, with the CDC defining the domestic cyclosporiasis season as running from May 1 through August 31.

Contact Newsweek editors for this story: Jason Lemon and Anthony Murray.