Cyclospora Infections Surge in the U.S.

The number of confirmed cyclospora infections nationwide has almost doubled recently, jumping to 1,645 as of Tuesday from 843 reported on Friday, according to data from the Centers for Disease Control and Prevention (C.D.C.).

The C.D.C. noted that numerous states are seeing higher-than-normal case counts of this parasitic illness, with 141 individuals hospitalized. Additionally, there are about 5,100 suspected cases currently being examined.

In Michigan, health officials suggested on Monday that lettuce or salad greens might be linked to the state’s cyclospora infections, which are the highest in the country at this time. However, both Michigan and C.D.C. officials emphasize that the investigations are still ongoing, leaving the possibility that other food sources could be implicated as well.

Experts indicate that the delay in identifying the source or sources of the rising infections is typical in cyclospora outbreaks. This parasite presents unique challenges for investigation, primarily due to its biological characteristics, as explained by Craig Hedberg, a professor at the University of Minnesota School of Public Health.

John Guzewich, a former Food and Drug Administration employee, pointed out that insufficient funding for health departments and recent cuts to federal surveillance programs have exacerbated the situation. Tracking cyclospora back to specific food items is a complex and labor-intensive process, and Dr. Hedberg mentioned that staffing shortages hinder these efforts.

Investigations typically require health officials to conduct extensive interviews with thousands of infected individuals about everything they consumed over several weeks. This effort is compounded by the fact that the C.D.C. recently scaled back its most comprehensive tracking system for foodborne illnesses, known as FoodNet, which removed the obligation for 10 states to report cyclospora infections to the agency.

While the reporting from states continues through other means, this reduction has still created significant gaps in surveillance. “We’re probably missing an awful lot of cases,” stated Dr. Glenn Morris, a professor at the University of Florida’s Emerging Pathogens Institute. He emphasized the lack of a robust surveillance system makes it difficult to ascertain the full extent of these infections.

Barbara Kowalcyk, director at George Washington University’s Institute for Food Safety and Nutrition Security, noted that state and local health departments heavily rely on federal grants for their operations. Unfortunately, she reported that in 2026, they only received 40 percent of the requested funding for monitoring and addressing foodborne illnesses.

During the pandemic, many health departments received emergency funding, which helped them enhance their capacity for future outbreak responses, including foodborne illnesses. However, that funding has since ceased, leading to a precarious situation for ongoing projects and staffing levels.

Dr. Natasha Bagdasarian, Michigan’s chief medical executive, highlighted that recent funding cuts have diminished critical programs and staffing in the state’s health department, stating, “The work is only growing, and the resources we have are only declining.”

Angie Onofre, a 25-year-old from Brooklyn, shared her experience with cyclospora on TikTok, receiving a flood of comments asking what she had eaten before falling ill.

Ms. Onofre feels the whole situation resembles a “Scooby-Doo episode,” suspecting a store-bought bagged salad might be the culprit behind her monthlong struggle with diarrhea. Yet, like many others across the U.S., she’s uncertain about how or when she contracted the parasite.

Cyclospora behaves differently from many foodborne pathogens; symptoms may take weeks to appear, according to Matthew Moore, a food safety microbiologist at the University of Massachusetts Amherst. The parasite’s eggs must first be ingested, leading to intestinal infection after several days or weeks, which then results in symptoms like cramping and diarrhea.

When public health officials investigate the causes of illness, most individuals struggle to remember everything they’ve consumed over weeks. Professor Felicia Wu from Michigan State University pointed out that items associated with cyclospora—like basil, cilantro, lettuce, berries, and scallions—are often part of mixed dishes, complicating recall.

When patients with symptoms like diarrhea visit a doctor, they may simply be sent home to rest without thorough testing, meaning their infections often go unrecorded. If symptoms are severe or last unusually long, stool samples may be taken for routine testing; however, not all labs include cyclospora in these tests without a specific request from the doctor. Additionally, identifying the strain causing the infection poses challenges, as cyclospora cannot be cultured like bacteria.