Cyclospora Outbreak in 41 States, Hospitals Pull Greens: What Nurses Need to Know

Image source: CDC

A fast-growing cyclosporiasis outbreak has spread to 41 states, and some hospitals have pulled lettuce and other leafy greens from their own cafeterias as the investigation continues. The CDC has issued a Health Alert Network advisory urging clinicians to watch for the parasitic infection, which is running at more than 16 times last year’s pace.

Here is what nurses need to know about recognizing, reporting, and counseling patients on cyclosporiasis this summer.

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• 4,173 confirmed domestic cases reported to the CDC since May 1, per the CDC advisory
• 7,400+ additional cases under review to confirm domestic acquisition
• 308 hospitalizations (7% of confirmed cases); no deaths reported
• 41 states affected, per the CDC advisory
• For comparison: 249 cases had been reported nationally by this point last year
• Source: under investigation; a 5-state cluster is linked to recalled iceberg lettuce. 

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The CDC has received reports of 4,173 confirmed domestic cyclosporiasis cases since May 1, with more than 7,400 additional cases still being analyzed, according to the agency’s advisory. That is substantially higher than the 249 cases reported nationally by the same time last year, and because cyclosporiasis is often underdiagnosed and underreported, the true count is likely higher.

The outbreak’s largest identified cluster spans five states — Indiana, Kentucky, Michigan, Ohio, and West Virginia — and is tied to shredded iceberg lettuce served at Taco Bell, with Michigan and Ohio hardest hit. State case counts run well above the CDC’s national figure, and the agency explains why: its surveillance updates count only laboratory-confirmed cases, while state data may include probable cases as well. The Michigan DHHS has issued repeated public advisories throughout July and updates its count regularly.

On July 17, Taylor Farms voluntarily recalled all iceberg lettuce sourced from central Mexico — a product distributed June 29 through July 16 in 27 states, and sold in both food service and retail, including Marketside-brand product at Walmart.

The lab picture is more tangled than the epidemiology. On July 18, the FDA reported that a Taylor Farms lettuce sample had tested positive for Cyclospora, then reversed a day later, concluding the result was a false positive; as of July 19 it had no confirmed positive product samples. But the agency stressed this does not change its investigation: epidemiologic and traceback data still link the five-state Taco Bell outbreak to Taylor Farms iceberg lettuce, and the recall remains in effect. In short, no product sample has independently confirmed contamination, but the case data still point to the same source.

This current outbreak is epidemiologically linked to shredded iceberg lettuce; however, the CDC continues to investigate all cases. Previous cyclosporiasis outbreaks have been linked to fresh produce, including bagged salads, leafy greens, fresh basil, cilantro, and raspberries, according to the CDC.

Out of caution, some health systems are changing what they serve. Kalamazoo, Michigan-based Bronson Healthcare announced July 15 that it has temporarily removed certain salad bar items, leafy greens, and other higher-risk fresh produce from both patient and public food service areas, citing alignment with current public health guidance while the source is investigated.

South Bend, Indiana-based Beacon Health System removed all raw lettuce and leafy greens from its hospital cafeterias across Indiana and southwest Michigan and closed its Kalamazoo salad bar, with its infection-prevention director telling local media the step was a response to the statewide outbreak.

That makes the outbreak a workplace issue as much as a clinical one, since hospital food service feeds staff and admitted patients, not just visitors.

Cyclosporiasis is a gastrointestinal illness caused by the microscopic parasite Cyclospora cayetanensis. People become infected by consuming contaminated food or water; the illness is not usually spread person to person, per the CDC. Case counts typically rise in spring and summer, and the CDC considers May 1 through August 31 the annual cyclosporiasis season. Compared to other common GI bugs – norovirus, salmonella, E. coli – cyclosporiasis is much rarer in the U.S. Cyclosporiasis is most common in tropical areas such as Central America, South America, Asia, and Africa. 

Symptoms typically begin about one week after exposure, with an onset window of 2 to 14 days, per the CDC. The most common presentation is frequent, watery diarrhea along with:

• Loss of appetite and weight loss
• Bloating and increased gas
• Nausea and fatigue
• Less commonly, low-grade fever and vomiting

Two features matter most for triage and bedside assessment. First, untreated cyclosporiasis can follow a remitting-relapsing course lasting from days to a month or longer, so the patient whose “stomach bug” keeps coming back deserves a second look this summer. Second, diagnosis requires stool testing that specifically identifies Cyclospora oocysts; the parasite can be missed if the lab isn’t asked to look for it, so documentation of recent produce consumption and outbreak exposure helps direct testing.

Cyclosporiasis is a reportable disease, so confirmed cases must be reported to local health departments. Prompt reporting is what allows investigators to trace the source.

One difference nurses should be aware of when caring for a patient with a possible cyclosporiasis infection is that it does not cause significant inflammation, meaning that typically most patients do not experience as much pain or bloody diarrhea as other GI bugs. 

For example, patients with norovirus will complain of crippling stomach pain or the worst abdominal pain of their lives.

The CDC-recommended treatment is trimethoprim-sulfamethoxazole (Bactrim), along with rest and fluids to maintain hydration, per Michigan DHHS. Bactrim disrupts the microbe’s ability to produce the folic acid it needs to replicate. Patients with sulfa allergies should discuss alternatives with their provider. Immunocompromised patients face higher risk of prolonged illness and should be encouraged to seek testing and treatment early, according to Johns Hopkins.

• Watch the waiting room. Persistent or relapsing watery diarrhea with fatigue and appetite loss, especially with recent fresh produce consumption, should raise suspicion, and stool testing must specifically request Cyclospora.
• Counsel on prevention honestly. Washing produce reduces risk but may not fully remove Cyclospora oocysts, so patients at higher risk may reasonably avoid implicated categories of fresh produce until a source is identified. Note that alcohol-based hand sanitizer does not kill Cyclospora, per Bronson Healthcare, so counsel soap-and-water handwashing after handling produce.
• Know your reporting pathway. Confirmed cases are reportable; infection preventionists and nurses play a direct role in outbreak surveillance.

🤔 Nurses, are you seeing GI complaints that fit this picture in your ED or clinic? Has your facility changed its cafeteria offerings? Share what you’re seeing in the comments.