Concerns About Recent Cyclospora Outbreaks
Lately, discussions about an “explosive diarrhea” parasite have become quite prevalent, stirring up significant worry among the public. Cyclosporiasis, which typically spreads through contaminated food, is affecting thousands across the United States.
This intestinal infection caused by the cyclospora parasite is not a new phenomenon—it often sees higher incidences during the summer months. However, this year seems to be different, particularly in Michigan, where a significant proportion of U.S. cases have been recorded, far exceeding typical numbers for this time of year, according to recent reports.
“The rapid increase and sheer volume of cases is, I’d say, unusual,” noted Kali Kniel, a professor specializing in microbial food safety at the University of Delaware.
People usually contract the parasite through food or water that has been contaminated, with previous outbreaks often linked to raw produce. So, what’s fueling this latest spike? And should we be hesitant to enjoy fresh fruits and veggies this summer?
Health officials are still on the hunt for possible sources. In a statement released recently, the Michigan Department of Health and Human Services indicated that initial findings suggest lettuce or salad greens might be involved in the state’s surge, though they emphasize that other foods could still be implicated.
As for whether these outbreaks across different states are connected, that remains unclear. The U.S. Centers for Disease Control and Prevention has expressed uncertainty about potential links between cases in various states.
Understanding Cyclosporiasis
Cyclosporiasis stems from Cyclospora cayetanensis, a microscopic organism found in human feces. Infection occurs when contaminated food or water is consumed, as noted by Kniel.
Upon ingestion, the cyclospora parasite infects the small intestine, leading to significant gastrointestinal distress. The most frequently reported symptom is sudden, watery, and severe diarrhea, which may last for weeks, according to the CDC.
“It’s akin to what you experience with a stomach flu or food poisoning, but many report it being even more severe,” remarked NBC medical contributor Dr. John Torres.
While cyclosporiasis is rarely life-threatening and healthy individuals often recover without medical intervention, treatment with specific antibiotics is very effective, Kniel noted. After being expelled in feces, the parasite takes one to two weeks to become infectious, making person-to-person transmission highly unlikely.
The parasite can infiltrate produce grown in contaminated soil or washed with tainted water, and it seems fresh fruits and vegetables are often to blame.
Surge in Cyclosporiasis Cases
As of mid-July, approximately 5,000 cases have been recorded in over 30 states, according to confirmations from state health departments. The CDC has also verified 843 cases and 86 hospital admissions since the beginning of what is recognized as cyclosporiasis season in the U.S.
Michigan is experiencing the brunt of the outbreak, with over 3,300 cases reported in the state and multiple hospitalizations. Neighboring states such as Ohio, New York, North Carolina, and Illinois are also witnessing a worrying rise in cases.
There’s no proof of a single, widespread outbreak across states, and it’s uncertain if the clusters are interrelated, the CDC has said.
“It’s entirely possible there are multiple unrelated outbreaks happening concurrently,” commented Donald Schaffner, a food microbiology professor at Rutgers University.
In reality, the actual count of cyclospora infections is likely much higher, as many individuals experiencing diarrhea don’t seek medical attention or testing.
Drivers of Rising Cyclospora Cases
The sources behind the recent outbreaks remain elusive. The CDC is collaborating with the U.S. Food and Drug Administration to look into potential origins.
Michigan health officials recently pointed to “lettuce or salad greens” as potential sources for their outbreak, while cautioning that other food items cannot be completely dismissed. No specific type of produce or supplier has been definitively linked to the incidents.
This preliminary finding is currently specific to Michigan. The state health department has introduced special safety measures for residents in affected areas. However, connections between Michigan’s outbreak and the recent case increase in other states are still unclear.
“It seems more plausible that multiple avenues could lead to infection,” suggested Dr. Trevor Suslow, a food safety expert at UC Davis.
Historically, past outbreaks in the U.S. have tied to contaminated salad greens, cilantro, basil, and even raspberries. Yet the professionals warn that water could equally play a role, as feces-contaminated water can be used to irrigate crops.
With surges in counties along Lake Erie in both Michigan and Ohio, some experts theorize that these cases may lean more toward being waterborne rather than strictly foodborne, though conclusions are premature.
In any case, Michigan officials have emphasized that “there’s no current evidence linking recreational water activities to this outbreak” and are primarily focusing on contaminated produce as a probable source.
Tracking Cyclosporiasis Outbreaks
Experts indicate that tracking cyclospora can be quite challenging. It exhibits a longer incubation period than many other types of foodborne illnesses.
Symptoms may take up to 10 days to manifest, with testing and epidemiological insights potentially taking months. By the time diagnoses are confirmed, individuals might not recall what they consumed that led to illness.
Consequently, only a small fraction of cases each year can be traced to a specific food item.
Additionally, since July 2025, the CDC’s foodborne surveillance program scaled back testing for cyclospora, an adjustment that might be affecting the overall response.
Should You Avoid Certain Foods?
The key to preventing cyclosporiasis is to steer clear of food and water that could be contaminated with feces. Since no specific source has been isolated, it’s tough to pin down precisely which items should be avoided—experts stress not to overreact.
“Most fresh fruits and vegetables available currently are not linked to this outbreak and don’t pose an elevated risk of illness,” reassured Schaffner. Thus, there’s no reason to eliminate raw produce from your diet, particularly given that summer offers so many tasty options.
“Fresh produce is essential for a balanced diet—I definitely wouldn’t want to discourage that,” he added, noting his plans to keep enjoying fruits and veggies this season.
For residents in impacted counties in Michigan, the health department suggests the following precautions:
- Choose whole heads of lettuce instead of pre-washed salad greens.
- Discard the outer two or three layers of leaves.
- Wash inner leaves thoroughly with clean, running water.
- If cooking greens, ensure they reach at least 158 degrees Fahrenheit, as washing won’t guarantee elimination of the parasite.
Preventing Cyclosporiasis
“There are proactive steps you can take,” noted Kniel.
Cooking food to a minimum of 158 degrees Fahrenheit is one solid method for protection. Freezing may help eliminate cyclospora, but it’s not foolproof.
Thoroughly washing produce can minimize the risk of foodborne illness, but it won’t completely remove cyclospora. State health departments recommend several additional tips:
- Wash hands thoroughly with soap and hot water before and after handling raw produce.
- Scrub fresh fruits and vegetables with a clean produce brush under running water—don’t use soap.
- If possible, peel off the outer layer of leaves or skin.
- Cut away any damaged areas before consuming.
Those with weakened immune systems should consult a healthcare professional for tailored advice on avoiding foodborne illnesses, Kniel mentioned.
“We’re observing some hospitalizations, so staying hydrated is crucial if you do become ill, and seeking medical care is important as this can be treated,” she added.
If any symptoms of cyclosporiasis arise, it’s wise to reach out to a healthcare provider.
