Parasite outbreak sickens 145 people across 18 U.S. states

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Publicly available surveillance data show a growing outbreak of cyclosporiasis, a parasitic intestinal illness that can cause severe stomach cramps and prolonged diarrhea, with at least 145 people reported sick across multiple U.S. states since early May.

Cases climb as summer foodborne illness season begins

Reports compiled from federal and state health updates indicate that, between May 1 and June 16, 145 people in the United States were confirmed to have cyclosporiasis acquired domestically. These cases span at least 17 states, with broader tallies from subsequent reports suggesting that overall infections have now surpassed 400 when additional weeks and separate state-level outbreaks are included.

The illness is linked to Cyclospora cayetanensis, a microscopic parasite that infects the small intestine. Infections are most often associated with contaminated fresh produce, particularly during the warmer months when consumption of raw fruits and vegetables and outdoor dining tends to increase.

While the initial federal surveillance summary referenced 17 affected states, later coverage citing public health data notes that illnesses have now been reported in 18 states. Some states, notably Michigan, are tracking sizable in-state surges that appear to be managed as separate from the national domestic case count, underscoring how quickly local clusters can expand once transmission-linked food items are in circulation.

Despite the rising numbers, publicly available information indicates that investigators have not yet identified a single food source tying all reported cases together. Instead, the pattern so far resembles multiple overlapping clusters occurring during the usual seasonal uptick in Cyclospora infections.

What is cyclosporiasis and how does it spread?

Cyclosporiasis is an intestinal illness caused by ingesting food or water contaminated with Cyclospora parasites. After the parasite is shed in human feces, it must undergo a maturation process in the environment before it becomes infectious, which means it does not spread directly from one person to another in the way that many viral stomach bugs do.

Historical outbreak investigations published by federal agencies point to a recurring link between cyclosporiasis and certain types of fresh produce. Past foodborne clusters in the United States have involved imported raspberries, basil, salad mixes, cilantro, and other leafy greens and herbs served raw. Because Cyclospora is not killed by standard chlorine levels used in many water systems, contamination can occur in fields, during irrigation, or along complex supply chains.

Once ingested, the parasite infects the small intestine and can trigger a range of gastrointestinal symptoms. The incubation period typically ranges from several days up to about two weeks, meaning individuals may not immediately recognize that their illness is connected to something they ate days earlier.

Cyclosporiasis is considered a nationally notifiable condition, so confirmed cases are reported through surveillance networks. Those systems, together with targeted interviews of patients about foods eaten before they became ill, are central to identifying potential common exposures during an outbreak investigation.

Symptoms: from severe diarrhea to weeks of fatigue

Current medical references describe the hallmark symptom of cyclosporiasis as watery, sometimes explosive, diarrhea that can be frequent and debilitating. Many patients also experience intense stomach cramps, bloating, nausea, loss of appetite, weight loss, and low-grade fever. Some report muscle aches and a general sense of exhaustion as the illness progresses.

Without appropriate treatment, symptoms can follow a relapsing course and persist for several weeks or even longer, with periods of temporary improvement followed by a return of diarrhea and cramping. This prolonged trajectory distinguishes cyclosporiasis from many brief, self-limited foodborne infections.

Most otherwise healthy people eventually recover, but the illness can be particularly burdensome for older adults, people with compromised immune systems, and those who become dehydrated from repeated diarrhea. Recent summaries of the current U.S. situation indicate that at least 20 people have required hospital care, though no deaths have been attributed to the parasite in the latest reports.

Treatment typically involves a specific antibiotic regimen, which means laboratory confirmation can be important for ensuring patients receive targeted therapy rather than only symptomatic care. Clinicians are being reminded in several state advisories to consider Cyclospora in patients with persistent watery diarrhea, especially during the summer.

Where infections are being reported

Publicly available summaries based on Centers for Disease Control and Prevention surveillance list at least 17 states reporting domestically acquired cases between May 1 and mid-June. Those reports identify affected states including Alaska, Colorado, Connecticut, Florida, Georgia, Illinois, Louisiana, Massachusetts, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Texas, Virginia and Wisconsin.

Additional coverage highlights Michigan as a significant hotspot, where the health department has documented a sharp jump in cases in late June and early July. That rise is being tracked separately from the 145-case national count, reflecting both the scale of the state’s outbreak and the timing of case onset dates relative to the federal reporting window.

Regional news outlets and health briefs describe elevated case numbers in states such as Florida, Texas and Ohio, consistent with the pattern that cyclosporiasis tends to emerge in clusters tied to specific food distribution networks. Because produce is commonly shipped across state lines, an exposure in one processing facility or farm can lead to scattered cases in geographically distant communities.

Federal updates characterize the current situation as a seasonal increase under close observation rather than a single, clearly defined multistate outbreak. Investigators are examining whether some clusters share a common food item or supply chain, but as of the latest reporting no public recall or product-specific warning has been issued.

How travelers and consumers can reduce their risk

Although Cyclospora contamination is not visible and cannot be detected by taste or smell, food safety guidance emphasizes several practical steps that may lower the risk of infection, especially during peak season. Washing fresh fruits and vegetables under running water before eating, cutting or cooking them is widely recommended, even for produce labeled as prewashed.

Rubbing firm produce such as cucumbers or melons under running water and removing outer leaves of items like lettuce or cabbage can help dislodge dirt and potential contaminants. Drying produce with a clean cloth or paper towel after washing may further reduce the presence of microorganisms on the surface.

Travelers and diners are also encouraged to be cautious with raw produce in settings where the water quality or handling practices are uncertain. Choosing cooked options when possible, particularly in regions known for previous Cyclospora outbreaks, can provide an extra margin of safety.

Because cyclosporiasis does not spread easily from person to person, standard hygiene steps such as thorough handwashing after using the bathroom and before preparing food are aimed more at overall gastrointestinal illness prevention than at stopping direct person-to-person transmission of this specific parasite. However, these habits remain important parts of broader food safety and infection control.

What to watch for as the investigation continues

As summer progresses, disease trackers expect additional cyclosporiasis cases to be reported, in keeping with patterns seen in previous years. The key unknown is whether ongoing investigations will pinpoint one or more specific food vehicles responsible for the current clusters, which could trigger targeted advisories or recalls.

Analysts following public updates note that case counts often lag behind real-time transmission because of the incubation period, delays in seeking care, and the time required for specialized laboratory testing. For that reason, the 145 domestically acquired cases reported through mid-June likely represent only part of the overall impact.

Members of the public who develop prolonged watery diarrhea, especially if accompanied by stomach cramps and fatigue lasting more than a few days, are being urged through public health messaging to seek medical evaluation and mention any recent consumption of fresh herbs, leafy greens, berries or other raw produce. Early diagnosis can help shorten illness and contributes to more complete surveillance data.

For now, experts cited in recent reporting describe the situation as a reminder of the challenges in tracking foodborne parasites across complex supply chains. As agencies continue their seasonal surveillance and traceback work, travelers and at-home cooks alike are being encouraged to apply careful produce-handling practices while paying close attention to any new public health advisories tied to this evolving outbreak.