Cyclospora Cases Continue to Rise in Over Half of US States: What Infection Prevention Professionals Need to Know

As summer reaches its peak, infection preventionists (IPs) and other infection prevention and control (IPC) professionals are once again being reminded that not all outbreaks begin within health care facilities. A growing multistate increase in cyclosporiasis, caused by the intestinal parasite Cyclospora cayetanensis, has sickened hundreds of people across the US, with many additional suspected cases under investigation. Health officials continue to search for a common food source, but as of mid-July, no specific produce item or supplier has been identified.

The CDC has confirmed more than 800 domestically acquired cases across 31 states since May 1, with more than 1,500 additional suspected cases under review. Eighty-six hospitalizations have been reported, although no deaths have been linked to the outbreak. Several states, including Michigan, Ohio, and New York, have reported particularly high case counts, underscoring the widespread nature of the outbreak.

Michigan alone reported 1,562 cyclosporiasis cases as of Friday, July 10, 2026.

Several states have reported an increase in cases in the past 2 weeks compared to the same period in 2025. Investigations into multiple outbreaks continue, with efforts to identify sources ongoing.

“Fortunately, there have been no deaths in Ohio, as is consistent with our past experiences with this illness,” Ohio Department of Health Director Bruce Vanderhoff, MD, MBA, said. “Nevertheless, this is a serious illness that can cause dehydration and require people to seek emergency medical care, and it should be taken seriously.”

Although Cyclospora infections are primarily associated with foodborne transmission rather than health care-associated spread, IPC professionals play an important role in recognizing cases, implementing appropriate precautions, and collaborating with public health authorities.

A Challenging Parasite to Trace

Unlike many bacterial foodborne pathogens, Cyclospora cayetanensis presents unique epidemiologic challenges. The parasite is transmitted by consuming food or water contaminated with human feces, most commonly fresh produce such as leafy greens, herbs, berries, or other fruits and vegetables. Direct person-to-person transmission is considered unlikely because the parasite requires days to weeks in the environment before becoming infectious.

That characteristic complicates outbreak investigations. Patients often become ill approximately 1 week after exposure and may have difficulty recalling what they ate. Fresh produce also moves rapidly through complex supply chains, making traceback investigations particularly difficult.

Clinical Presentation

Patients typically present with prolonged watery diarrhea that may be accompanied by abdominal cramping, bloating, nausea, fatigue, loss of appetite, and weight loss. Symptoms can persist for weeks or even months if left untreated and may relapse after temporarily improving. Immunocompromised individuals are at increased risk for prolonged illness and complications.

Because symptoms overlap with those of many other gastrointestinal illnesses, clinicians should consider Cyclospora in patients with persistent diarrhea, particularly during the spring and summer months or when multiple similar cases are identified.

Surveillance Changes May Complicate Outbreak Detection

The current Cyclospora outbreak is also unfolding amid changes to federal foodborne disease surveillance. Beginning in July 2025, the CDC made reporting to its long-standing Foodborne Diseases Active Surveillance Network (FoodNet) optional for several pathogens, including Cyclospora, while continuing routine surveillance for Salmonella and Shiga toxin-producing Escherichia coli (STEC). FoodNet has historically provided active surveillance data that help federal and state partners monitor trends, detect outbreaks, and identify potential food sources.

Public health experts have expressed concern that scaling back active federal surveillance for pathogens such as Cyclospora could delay outbreak detection or make it more difficult to identify nationwide patterns, placing greater responsibility on state and local health departments to recognize and investigate clusters. However, Cyclospora remains a nationally notifiable disease, and the CDC continues to work with state health departments and the FDA to investigate outbreaks and coordinate traceback efforts.

The CDC states, “Cyclosporiasis is a nationally notifiable disease and is reportable in 47 states, the District of Columbia, and New York City. Even if it is not reportable in a state, it is important for health care providers and the public to inform local health departments about potential cases and clusters of the disease so that they can take appropriate action to prevent additional cases.”

For IPs and other IPC professionals, these changes underscore the importance of timely case recognition, appropriate diagnostic testing, and prompt reporting to local public health authorities. As surveillance systems continue to evolve, frontline health care professionals remain critical to the nation's ability to identify emerging foodborne outbreaks.

"The Cyclospora outbreak highlights the dangerous downstream impact of public health funding cuts,” Brenna Doran, PhD, MA, ACC, CIC, AL-CIP, consultant/coach for Innovative Partners Institute, LLC (IP-i), told Infection Control Today^®. “When surveillance rigor is compromised, we lose the ability to rapidly detect and contain pathogens."

Implications for Infection Prevention

Early communication with microbiology laboratories is essential because Cyclospora is not routinely detected on standard stool cultures. Providers must specifically request appropriate stool testing, often using molecular gastrointestinal pathogen panels or ova-and-parasite examinations that include Cyclospora detection.

IPs should also remain alert for unusual clusters of gastrointestinal illness among patients or health care workers. Prompt reporting to local and state public health agencies supports broader surveillance efforts and may help investigators identify common food exposures.

Within health care settings, standard precautions remain appropriate for most patients. Emphasis should continue to be placed on hand hygiene, environmental cleaning, and safe food handling practices. While washing produce may reduce contamination, experts note that rinsing alone may not completely eliminate Cyclospora because the parasite adheres tightly to fresh produce.

Looking Ahead

Cyclospora outbreaks have become a recurring summer challenge in the US, often peaking between May and August. Public health officials continue to investigate this year's outbreak while FDA traceback efforts attempt to identify the contaminated food source.

For IPC professionals, the current outbreak serves as another reminder that surveillance extends beyond hospital walls. Foodborne illnesses can rapidly affect health care operations through patient admissions, employee illness, and increased diagnostic demands. Maintaining close collaboration with clinicians, laboratories, dietary services, and public health partners remains essential to recognizing cases early and supporting timely outbreak response.